I can honestly say I didn't learn a damn thing from this video, BECAUSE... I'm very familiar with most engines. I have studied and built two strokes for years and have always been amazed at the looks I get when trying to explain how they operate to those who are unfamiliar. Every time I thought there was going to be something you left out, you covered it 3 seconds later. Hours of my life arguing over this same subject in the past. I agree with everything you said and you explained it so well that I could have gone to some other video after 5 min but watched the whole thing anyway. Very well explained, keep up the good work.
th-cam.com/video/_gYCaLDKxNY/w-d-xo.html I've got you beat. I am the greatest in the world, and the only man in the world that can convert four stroke engines to two-strokes retaining the stock piston/rods/crankshaft. My family made them in 1910, the 'Roberts aluminum boat/aircraft two stroke.' You are wrong. Cylclic dispersion takes over. Small port two strokes run exactly like four strokes when run rich. There's a four stroke combustion schedule in fast two-strokes. Try again..
To sum this up, the greater the difference between input pressure and ambient exhaust tip pressure becomes, the lower the efficiency of a 2 stroke will be. At no time is a 2 stroke sealed, to maintain any kind of reasonable efficiency it completely relies on equalibrium. Definitely the best explanation I've seen online completely correct with common sense included!
Thank you for putting that too bed for all of the naysayers. In the western US we have been running turbos on our 2 stroke snowmobiles for years and the performance gains are incredible, especially when you are talking about elevations from 6-14 thousand feet. They do work and they do work very very well. I have a skidoo summit 850 that is 165hp stock and at just 8psi boost it is about 225-240hp depending on elevation and fuel used and absolutely incredible. The funnest thing you can experience in my opinion.
Think it would work on my 1999 KTM EXC300? I’m 19 building a supermoto build with the ktm and my dad has a turbo laying around from when he did it to normal bikes. But do you think I could actually well put it together and turbo the ktm 300?
done for years on snowmobiles, boondocker are making complete plug and play turbokits to ALL 2 stroke sleds, the upside with the new sleds are that they have EFI and have a lot more tuning capabilities. I've personally built turbo 2 stroke sleds, 2004 ski doo rev 800cc was my second turbo 2 stroke, my first was a 97 rotax 580, both carburetor engines. my biggest problem was jetting. and maintain a good air fuel mixture. I used adjustable powerjets so I could rejet on the run, when there was a temperature change or altitude change. otherwise a completely stock engines, pipes and so on. on the 800cc I had to change reed blades to handle the extra flexing caused by the boost. let's take the rotax 800cc etec for example, 150 stock hp, 2 cylinder, with 5 psi boost by a turbo, and it gets around 200hp on crank, a bit less on the track(wheel). some Swedish students turbocharged a AM6 50cc to 30 hp and they also turbocharged a yamaha tzr 125 with stock engine, and doubled the power. my experience with turbocharging 2 stroke engines that uses carburetors are a pain in the ass to jet, and to make it work 100% all the time. if anyone wants to turbo a 2 stroke, go foor a EFI fueling setup, ecotrons.com have EFI kits for most engines up to 800cc, and you'll save a lot of time on the tuning part, because that's where the problems start ;)
I turboed my switchback assault, the boondocker 2860 turbo is actually to small for 800cc in my opinion. I went for a 2873 kpa turbo, it was so much better for temps over all, cooler engine, more fun on higher boost etc. Had that sled for years with no issues, engine took it well, was never under 10-11 psi. With the big turbo i went for 18.3 psi, that was a kicker, still no issues lol. 2 stroke turbo`s is so much fun, not hard to get right either with a little bit of knowledge or help. Today, kits and pull and go.
@@abccba2344 how many miles did you get out of that engine. Did u ever get to tear it downn to see what kind of wear and tear the turbo did to the engine
@@joshlaquerre3197 rebuilding an 800 costs me around 1k in parts. i have a 2013 m800, i converted to the alpha 1 suspension (video on yt), i put a speed works turbo kit on and im sitting around 230hp on the crank. i rebuild it every other year, like any good two stroke owner should do, and have no issues.
FYI - check out the McCulloch BP-399-T engine from the 70's, that was going to be for snowmobiles .. production was canceled, only a few were made .. it had a small piston opposing the main combustion piston/cylinder ... that small piston was used to pump / supercharge the fuel/air mixture and to also balance the motor. IMO, its almost as complicated and costly as a 4 cylinder 2 stroke, so why not just do that? 2 strokes are simple, adding parts and complexity is almost always a step backward.
There where more companies who where experimenting with this design. I have a moped which also uses this double piston design. The air pump piston has a very large diameter with a very small stroke. The piston is also ludicrously heavy to balance the system. Check out the Motobecane 99z engine. You can find photo's on internet of this engine. This engine was mass produced somewhere between 1976 en 1982 I think (I don't know the exact dates).
everyone's using the Detroit diesel 2 strokes as an argument for turboing 2 strokes, but those engines and gasoline 2 strokes are completely different. on the Detroit, the fuel doesn't go through the crank case, it goes straight into the cylinder through ports in the sleeve. you must supercharge them, or else the exhaust wouldn't be forced out and the new air/fuel wouldn't be forced in.
metallicakid83 correct and they are oil lubricated like a four stroke.dont always need a blower they made one way clutched turbos that would spool at idle until the exhaust would build up past idle and spool the turbos
metallicakid83 they only need a few psi of boost to idle till the turbos take off on exhaust.look up emd motors im pretty sure some detroits were only turbo charged to with no blower
You're quickly becoming my favorite mechanical style channel. The simple fact that you give the TL;DR at the beginning for 5 seconds. Watch the rest if you want. You're informative, easy to understand, and funny at spots too. I love it. Cheers brother
This guy's brain is super charged. It must weigh 52 pounds. Hat's off to his mastery of the topic and his superb ability to communicate it in a manner we mere mortals understand. Genius.
I can understand where you're coming from for 2 stroke engines I'm general, but for snowmobiles you'd be suprised how big of a market after market turbos are. On most modern 2 stroke snowmobile engines, 1 psi from a turbo is 7-8 hp and most engines will handle up to 11 psi on pump gas. So for most engines you will go from 150-160hp on a 800cc twin to 220-240 hp. You may think that's not worth it but it most cases where people use turbos it absolutely is worth it lol.
Great explanation, I have been a 2 stroke mechanic since the late 60's, my father was a McCulloch dealer, raced go cart's and even set a track record in the single engine class at 127.5 MPH, the engine was only 5 cu.in. or 80cc. Turbo charging isn't worth the trouble, you are better of "stuffing" the crankcase (filling all empty space in the crankcase that you can, Now McCulloch had a prototype snowmobile engine BP-399 and a chainsaw BP-1 that used a balance piston to not only balance the engine but to draw more fuel/air mix in and compress it just that much more these engines put out insanely high power and RPM for their size. my BP-1 would turn 15K rpm and practically vibration-less. here is a video I found on the BP-399 that scares the daylights out of me because where on earth are they going to find a clutch that will stay together at 16,600 RPM? enjoy th-cam.com/video/c7eTGDn8mmk/w-d-xo.html
Back in the late 80s I had a tuned Honda VT250 (4 stroke) and that reved to over 12,000. There was a racing series in Japan, so you could get parts if you had money, it did blow up a lot though. I think I red lined at 13500 but that is from memory and with a lot of tuning parts and work.
Yet another person that doesn't get how a two stroke turbo works. I.ve seen over thirty five lbs of crankcase pressure with a turbo, never seen ten by stuffing.
we have been turbo-ing our 2 stroke Arctic cat (suzuki) snowmobile engines since 2006 with fuel injection and we get from 300 to 400 h.p. on our 1000-1200 and 1300 c.c. cat engines with excellent engine life. change pistons every 2000 miles and run them from 11-16 lbs. boost all day long. we do some mild cylinder/head mods to enhance turbo performance. one other note is that a 2-stroke will use a much larger turbo than a 4-stroke cc to cc we use garrett gtx3076r turbos on our big bores and they work. 2-strokes forever!!!
LOL sorry but "change pistons every 2000 miles" isn't excellent engine life. You do know that the piston is part of the engine??? "one other note is that a 2-stroke will use a much larger turbo than a 4-stroke cc to cc" - of course you do - you burn double the fuel............
2000 miles is excellent piston life for a turbo engine running race gas boost and we change them at that interval for maintenance NOT because they are wore out, you obviously know nothing about a 2-stroke engine but thanks for your uneducated reply
2000 miles for an engine is shit andthe whole point of the reason why 2 strokes are shit. The phrase "engines with excellent engine life." then followed by "change pistons every 2000 miles" is shit. Excellent = 2000 miles? I get what you mean but that's just madness. That was the point I was making - but you got all 2 stroke butt hurt about it.............
I would like to see you run a yzf450, crf450, kxf450...ANY race 4-stroke run 2000 miles without changing the piston. You would fail and destroy the engine... so 4-strokes have their downfalls also.
The reason why any off-road dirt bike dies is because you revving the nuts off the engine and not really going anywhere. Take that same bike onto the road and race around and you'll be fine. Heat saturation is what kills these engines.
the part you are overlooking in this video is the expeller of the turbo acts as a constantly fluctuating valve. it's rotatiomal movement, or lack there of creates the pressure in the exhaust pipe to cause the reverb of pressure back into the cylinder as the exhaust gas pushes on it's vanes... and the open, 2-stroke system is actually the better option for spooling a turbocharger, you can put a bigger turbo on a 2 stroke than a 4 stroke because it moves twice the air at a given rpm...
One of the big reasons to turbo a sled is altitude. Air gets thin at high altitude, so even with perfect jetting, the 150 hp your engine makes at sea level is knocked back considerably. With a turbo you can gather more of that thin air and keep your power.
An excellent explanation of the basic pros and cons of 2-stroke turbocharging. A lot of the problems can be solved by having an exhaust valve instead of an exhaust port -- but that's more complexity, and the whole point of 2-stroke engines is to make as much power as possible with the least complexity possible.
Chears matt. Great channel l understand how you feel. I worked for a company full of delboys with a delboy line manager. After paying to go to Australia for some experience (couldn't find any one willing in Scotland) and paying to go to college for two years to achieve two asme 9 qualifications and finish top of my class. I found myself in Fife welding copper boilers for a company(fantastic work) Unfortunately I only lasted 2 years before having a mini breakdown. This was due to the relentless bullshit, lies and fukin morons that I worked beside. To give you an idea, the company had a cad system, used the cad system on a daily basis, but my "technical" drawings came from Microsoft word with no measurements and not to scale. I've been working delivering pizzas on minimum wage since I left, and that was 3 years ago. I love fabricating and welding, but can't shake the massive dent in my confidence in the industry ( I worked a couple other places for a couple of weeks and they were the same sort of thing) If you have any advice I'll take it. (or a job) If not, I hope this helps explain why people like dell are a bad influence and shows the effects they can have on people as well as there chosen profession. FAKIN CANTS
did you cover the pressure rise in the exhaust from the turbo. if your turbo provides boost it will provide back pressure. say a 1.5:1 ratio. if you have 10psi of boost youll have about 15psi of back pressure on the hot side of the turbo. youll get exhaust reversion with a turbo you wont piss away the intake pressure when the intake and exhaust ports are open together, you have the chance to fill you intake with exhaust instead. this is a good example oh a supercharged instance not a turbo.
I guess it depends On intake the piston scavenging may be enough to offset the backpressure of the exhaust On exhaust the chamber has just fired and it will be at even higher psi than the backpressure because it is so hot, blowing the backpressure and exhaust out through the turbine together
It seems from your explanation that the biggest issue is the exhaust geometry? I think it’s a good rule of thumb to thoroughly research the tolerances of any engine before modifying it. I appreciate you taking time to explain to the average person what to expect when turbocharging a two stroke!
Back in the 80's we used to "turbo the crank" of our 2 stroke motors. This consisted of machining deep groves on the outer edge of the crank flywheel to pick up more fuel mixture from the case like a fan blowing straight into the intake port. To this day I have no idea if it actually had any benefit, we thought it was pretty trick.
@@danielg6967 We didn't have access to a dyno back then, so any "difference" was measured only subjectively. Was it a significant night & day difference, no. That said, having a psychological advantage of my magic secret weapon did improve my competitive confidence.
I was just looking at some of the comments you get. OMG. You have the patients of a saint. Thanks for showing my bike. The 750turbo. I am a member of Lorcan's site.
Another thing is that a turbocharged goes on the exhaust first then exhaust fumes spin the turbine and then the air made with that goes in to intake, thous getting higher pressure in engine, which Would require to tune to run more fuel as well to even out the a/f ratio
Thing is a 2-Stroke is relatively simple, powerful and light, so adding a turbo to it seems like you don’t get a lot of pay-back? Now it is more complicated, more powerful and heavier. And as said they were being fased out because of emissions. To be honest the last time I rode a Turbo was the 90s, and it wasn’t fun on a motorcycle.
its to bad that the two stroke engine is slowly dying out. love the sound of them. you learn us so much. wished there where more channels like yours. cheers
Main problem is they kinda stop developing them . Imagine if they put the same amouth of money in 2 stroke that company put in 4 stroke .... Direct injection could help a lot 2 stroke performance .
This is why power valves became the choice for manufacturers to increase horsepower reliably. The part about increased heat and pressure forces the manufacturer to use better quality parts which increases cost.
the way I see it, four-stroke engines have completely isolated intake and exhaust cycles, so you are free to add pressure to the intake (to an extent). In two-stroke engines, intake and exhaust cycles overlap, so if you add pressure to the intake, a lot of fresh air/gasoline mixture will rush out of the exhaust port (something that already happens to some extent in regular two-stroke engines)
I think you mean the Detroit Deltic (greatest engine ever) which had opposing cylinders and ports at the bottom of each stroke, detroit engines with one crank and a head would use valves 2 or 4 for exhaust and ports for intake
@The Workshop It is supercharged. It has a volumetric effeciency of greater then 1. meaning it is able to process more then it's static displacement per revolution.
A similar thing happens with normal 2 strokes, although this is compounded when using a turbo system. This is called reed valve flutter and I'll go into more detail in the next video on this subject - good comment - matt
I agree with everything your saying, on a stock engine, charging (super or turbo) a 2 stroke can work and work really well, but only with porting arrangements that suite it, ie way less overlap in the intake and exhaust porting, I've done a little RnD work with a local two stroke dirtbike engine builder, and he has built one two stroke that worked well with a turbo, the problem he finds with most is that the porting arrangement needed to work can't be archived with the stock cylinder castings, there isn't enough material in the right places, and he kept having to cut port's to close to water jackets and in every case completely lost the ability to run the power valve, making them unridable except for drag racing (who drag races a dirtbike?), adding turbo lag to no powervalve makes a KX60 seem like a chevy big block in terms of power curve. The one engine he's made work well was a maico (or ATK if your in north america) 700cc he built for an attempt at the dirtbike top speed record, eventually making 140hp, but again, it was completely useless for anything else and unreliable as well.
Everything I have turboed had untouched porting and worked perfectly. My very first project was a 4 cyl outboard motor that made 40 hp. The very first dyno pull showed 85 hp with more to go.
The Container Vessel I am working on has a 2-Stroke Main Engine wich is turbocharged, so the answer should be yes. I see your point, but I can not fully agree.
I'm seeing alot of 'Detroit Diesels are supercharged'. No, they are not. The blower is used as a scavenge pump to pull exhaust/ push air through the engine
Quite true, that was coming up in the next video to this subject, but you've beat me to it lol Technically is known as artificial aspiration. - great comment - matt
I clicked this video intending to make my second rude youtube comment in ages. This one is a lot better than your E-Tec video, though. You might want to clarify that this applies to gasoline engines designed for natural aspiration. I fiddled around with a Wichman 3DC just the other day; it has factory turbocharging and works quite nicely.
I'm 3 min in to this and I am very interested.. lol, thank you. I've subscribed. never learned motor works but like to pretend I can understand what all these # are.
the first thing you said: can you turbo 2-strokes, yes. can it be down well, no. on that fact is a turboed snowmobile putting out around 160hp stock naturally aspirated. turboed they put out over 300hp. doubling your horsepower isn't good enough to be considered well? it's only the thousandth time I've heard some youtuber spurge bullshit on a topic which they didn't research well enough
The Workshop no need to even build it from there. because power is such a high priority for snowmobiles running at the high elevation the precision fit of the parts are much more spot on than a normal car. that's why 800cc produces 160hp
I don't understand the dislikes, this was a pretty clear and informative video. Explained your points well and didn't leave me with questions. I thought it was a great video.
Great video, you didn't really explain the reflected pressure wave from the back of the expansion too well for anyone who doesn't understand it, but other than that good vid. I've lay in bed at night and wondered how it would go on a dirt bike but other that, too much fucking around to make it work well, like you say, and the best thing about a two stroker is simplicity and reliability....and they scream their tits off anyway! Leave it alone, mix up some fuel, tip it in the tank and try not to kill yourselves, how fast do you really want to go anyway! Peace bro ✌️
There is a 2 stroke v10 japanese diesel tank engine that is twin charged and they had a lot of problems while developing that engine. Its called mitsubushi 10 zf mod 21 which was in their early to mid cold war tank which i currently dont remember its name
Sticking the turbo before the expansion chamber is silly because the airflow is both back into the cylinder and forward into the expansion chamber. The stored rotational energy in the turbine would over come the suck back into the engine as a result it would be sucking the unburnt charge into the exhaust thus wasting it. The expansion chamber on the other hand acts a receiver to provide a constant flow (or what passes for one in 2 strokes) thus providing the turbo with what it needs to compress the inlet air.
Yes you can i have done it before. But they get hot so godamn quick. A/F is hard to understand on a 2 stroke. But if running on NOS you should add a little more oil to your gas.
Would it work on a PWC? My standard ratio of oil to fuel is 30:1 .... what would be the right amount now?...... would I want to have 10.7 - 11.7 afrs under load on pump fuel?.... I am thinking maybe even pump E85 which 9.7 (stoich) and 7.7 AFR under load with NOS.... any thoughts? Engine Longevity? Its just more brainstorming right now.... also now that you said the engine heats up it is concerning but detonation/knock would be more concern..... the engine is cooled from water flowing through exhaust and engine cylinders so I think water temp and ambient temp would play a factor there. E85 is supposedly better at preventing knock/detonation.... I just have to plan to best way like bigger fuel pump(s) bigger injectors ... fuel pressure regulator, NOS and special NOS controller w/AFR gauge.... and of course finding the right oil to fuel mixture..... 30:1 won't cut it lol
2 stroke engines are very temperature sensitive adding NOS always increases the combustion temperature due to the free oxygen. As for engine longevity - its only going down. Alot of the heat is transfered into the piston rings, even more so with NOS included, this is usually what gives up the ghost first. I have seen a couple of drag racers use thicker rings when running NOS to reduce things going tits up. As for premix etc I wouldn't know to be honest, although it don't think it would be too much of a problem. By the time the oil makes it into the cylinder its done most of its job with the bearings etc. Changing the premix ratio will have an effect on how stable the combustion is, and I don't know what chemical reactions take place with NOS and the oil itself. As for coolant and knock, the knock occurs during compression, the coolant has little effect with a system that is fixed. Coolant removes waste heat after the fact, and obviously from the power stroke previous. In other words you have to test the heat saturation of the cylinder/head before making any judgements out changing the coolant system. If the cylinder/head is too cool then this could cause condensation, which when running NOS would lean out the mixture. This would cause combustions temperatures to climb and then knock would occur. So you then cool it some more making it worse. - matt
What is the base fuel pressure for this 3 cylinder EFI 2-stroke.... is it the same as 4 stroke 43.5psi? Do you think a standard eBay type of fuel pressure regulator would suffice for measuring that set base pressure someone on the forums locally is having issues with hesitation and the like and I suggested 5 tips: 1)upgrade and Hardwire Fuel pump to relay (hardwire cause of voltage drop issues in electric pumps), 2) clean, replace or totally remove fuel pump's filter (fuel pump wasn't designed for oil/fuel premix, factory has a separate tank that injects oil but is removed cause of common recall issues), 3) have injectors sent out to be cleaned 4)Add fuel pressure regulator to keep fueling optimal for such a finicky particular 2 stroke engine design. I say that cause with carbs they were always picky on my goped and now with EFI premix is picky so setting base pressure or even increasing pressure could eliminate hesitation issues etc and allow to dial in/tune better. 5)Add AFR gauge and make sure its at least 10.7-11.7 AFR rich underload. Any thoughts?
That crank induction is so cool! You would have more power in higher ambient pressure for the same reason you lose power on pikes peak. The number of moles of 02 that you can fit into the combustion chamber directly dictates power production. Displacement, forced induction and nitrous oxide, are all about burning more fuel. Also, rolling resistance is liner, so higher gravity is net positive (Eg: trains/trucks work).
This video is addressing the idea of a 2 stroke, there are other problems too, like reed valve stresses (fluttering etc) and others. With regards to the oil feed system, you can always just add an oil pump from a regular 4 stroke and have it belt, gear or chain driven off the crank - good comment though - matt (p.s - there will be a follow up to this and your point will be included, I can see there being load of questions from this video)
The Workshop if the premix can lube the crank, wouldn't the oily exhaust vapor be enough to lube the turbo? That's how expansion chambers work, in that they reuse the unburned vapor. thoughts?
lol no. The turbo requires oiling at the bearings within the turbo body where the shaft is. All you would do is oil the blades of the turbine, which would do nothing, apart from slow down the turbine slightly due to the weight. Expansion chambers use the high pressure combustion wave.
great vid mate! i personally have always been amazed with 2stroke engines, my first vehicle was a 75 rd 350, there power production per cc in those days were unmatched, seems to me thou that a geared charging system rather than a turbo would be easier to deal with the expansion chamber issues. but after seeing what Suterth-cam.com/video/0leUj-p43uU/w-d-xo.html has recently done with the MMX500 engine ( with combustion chamber the size of the bottle i'm drinking out of ) putting out 200hp (and more now from what i have read) in a bike that weighs 280lbs, whats the point? i mean really, how much craziness can somebody handle? LOL th-cam.com/video/O5NUEwwwtgs/w-d-xo.html
You do not say so explicitly but a 2T engine with a turbo where the turbine is at the end of the tuned pipe, with a correctly sized turbine and waste gate gives an engine where the pressure after the compressor and before the turbine is raised the same ratio above atmospheric so all the normal tuning values is applicable except the pipe temperature is a bit higher so needs to be longer to be tuned for the same point. So no extra losses out the export etc.
awesome video !! Great points and explanations . dont understand going thru the madness of turbocharging a 2stroke. it just takes away the simplicity of the engine . only reason i could think of is someone just wants the bragging rights of being able to say " i have a turbo 2stroke" but still an awesome concept lol
In your video you are explaining that the pressure in the crank case builds up when the piston comes down, and the reasson this pressure drops in the cylinder is mixture escaping into the exhaust. But even in the case the pressure back pulse prevents any of the fresh mixture escaping into the exhaust the resultant pressure in the cylinder at the moment the prots close will not be higher than atmospheric. This because the volume above the piston enlarges with an equal number as the volume under it (the crank case) decreases when it moves down, so the amount of mixture displaced from the one side to the other keeps the same pressure, there is only a momentary raise in pressure caused by the resistance of the pipe/port connecting the cylinder with the cranck case, but the mixture expands in the cylinder to fill the space. Even with the exhaust port blocked off you would be able to turn the crankshaft freely without pressure building from the moment the intake opens untill it is closed again, as long as the intake is open you just move gasses from one side to another.
"But even in the case the pressure back pulse prevents any of the fresh mixture escaping into the exhaust the resultant pressure in the cylinder at the moment the prots close will not be higher than atmospheric." - not really, fresh charge enters the exhaust pipe and is then forced back in, until you reach the rpm range the exhaust has been tuned for. "This because the volume above the piston enlarges with an equal number as the volume under it (the crank case) decreases when it moves down, so the amount of mixture displaced from the one side to the other keeps the same pressure, " - but your forgetting that the tranfered charge also has momentum, as does the exhaust gases expanding into the exhaust. This causes a flow path out into the exhaust. Don't get me wrong its not all of it, around 15-20% depending on the timing and port design. Good comment though - matt
I would make a kind of mech valve just after the exhaust port, and raise the inlet ports as hi as the exhoust maybe even further, then drive the turbo with a big brushes motor 3turn at 160 Amp
An exhaust-driven turbine could work if it fed power back to the crankshaft directly instead of pumping extra fuel/air mixture into the engine. The Wright R3350 aircraft engine (admittedly a four stroke) used this technique, and they called it "turbo compound". However you may then have lubrucation issues if the crankshaft was turning too fast for the amount of fuel/oil mixture going through it.
The turbine wheels in turbos don't 1) have enough mass 2) the energy of the exhaust gases in small 2T bike engines isn't enough to provide enough power to the crankshaft to make it feasible. If you look at the size of the trubines in turbo compound engines they are quite big - cool comment though - matt
I was thinking about the Wartburg 2-stroke car engine of 991cc... however you rauise a valid point. The only other way I can think of to use exhaust gas pressure is to have a turbine attached to an alternator or dynamo, providing power to electric motors on the wheels.
i cant recall the engine shop i was at but they had a very old and weird 2 stroke that was a turbo feeding a blower ( blower was acting as intake ) but it did not feed into crank case it was right to the cylinder wall. only thing different was there was a crank driven " valve " that blocked the exhaust port shortly after both holes were exposed. Keep in mind this engine was floor mounted and ran a generator or pump of some sort i think the man told me and was built to run at a set RPM and never never change. they had a hole data sheet on it about the reason why it was better than a four cylinder for the torque at the goal RPM output. i recall doing some research when i got home and some outboard motor company did this as well where it was blower driven intake with a valve to close exhaust at a set time and had greener out put from the tail pipe than a 4 cylinder of same CC. if memory servers me right it was all most twice as good. but there to same thing really built to only run at a set RPM and never really change, example warm up RPM and Work load RPM. Any way just figured id put this info in here as i found it as good brain food for thought on engines i have played around with
what if you instead used crank pressure routed through a turbo then back to the cylinder? better atomization, less heat. would the turbo even need oil? make a less cc crank area to get better pressure.
what makes turbos spin so fast is the pressure from the heat expansion from combustion process.... though you could spin a turbo from crank pressure it would result in lost energy as you would be using compressed mixture to spin the turbo and also pull from the turbo i do not think there would be any bonus at best i think you would have power loss and weight added. is why the mentioned above method was used and is used today still on high torque level load 2 cycle engines ( really only diesel applications ). while two strokes idea would have more power per CC the problem is you loose compression ability due to a valve less motor. a valve on the exhaust side with forced induction set to close once the air fuel mixture hit's the port give you back compression however then you run into seal problems with running to much pressure not to mention you are burning oil witch leads to not so green exhaust. a quite neat idea to over come this and staying with a valve less set up is a rotary engine ( Wankel ). but it has a larger problem that is not talked about much other than the wear on the " rings " to seal the cylinder... all though the Wankel fires once per 360 degree of rotation like a 2 cycle the rotor it self spins 4 times for every rotation of the crank. so as a idea the Mazda RX-8 has a Wankel engine with a red line of just past 8,000 RPM and at 8,000 RPM of the crank the rotor is spinning at 32,000 RPM. now the Duke engine beats this problem but has more rotating mass and is also a valveless engine. problem with the the Duke is there is all most twice the friction area. all though quite a nice idea has a problem like the other odd balls. reason i bring up those two engines is the main bonus to a two stroke engine is the instant power light weight among other things. end goal of perfect engine is non stop instant power two stroke is closer to this than four how ever when pushed to the max CC per CC a tuned turbo 2 stroke will never make the same power as a 4 turbo can. with out adding the weight back to a two stroke set up to handle higher pressure adding back a lot of mass your back to a four stroke minus the intake valve and no oil burning with " stand alone " oil in crank case. hate to say it but electric motors are going to win the power delivery war every time. the huge draw back to electric is the battery weight if you want it portable and charge time. but if not needing to be portable and you can plug into a power grid,,, well this is why all booming factories use electric motors as power is instant and steady now power then cost then power then cost then power just straight power 100 percent of the rotation. good way to test this as we did in shop class in school get a 5hp engine of any type but jet engine and a 5hp electric motor put at 4 foot bar on each and spin them both at there power rpm you can grab the bar on the engine and stop it but not the motor . jet engine only good at one RPM and a lot of power loss in thrust if not being used. this is why we do not have jet engine cars no one wants the pain and glass on there wind screen melted while sitting at a stop by the person in front... sorry for the long post but i wanted to cover the question in entirety to put it to bed, as i have toyed with this multi billion dollar question a lot and have come up with some good ideas but noting suits every problem as no engine has yet and battery and motor all suits with weight aside and batteries are getting smaller and lighter every year and at this point the only draw back is charge time. and cost of replacement when battery wears out before motor.
Short exhaust port duration with shallow, wide bridged ports is what I would do then the exhaust becomes less critical in scavenging. And as used on the BUB 50 landspeed bike, I'd go with methanol to control temperatures, especially with the wide exhaust port pumping heat asymmetrically into the cylinder. If you ran the turbo into a plenum chamber you could control that with a disc valve and straight into the transfer ports. That'd stop you knocking the seals out, then it's a case lubing everything up as you are not running the petrol/oil mix through the crankcases.
I did it , what do want to know ? The crank case seals normally won't handle more that 9-12 psi. Replace them with heavy duty industrial sealed type bearings, throw the carb. away, install fuel injector and new ignition system and a throttle body
the "supercharging" doesnt occur in the crank. it occurs from the design of the pipe causing resonance and forcing extra fuel/air mix back into the combustion chamber. thats what causes the "on the pipe" feeling of a 2 stroke...the powerband. because its operating in the right frequency to get that air/fuel mix forced back into the cylinder
"the "supercharging" doesnt occur in the crank. it occurs from the design of the pipe causing resonance and forcing extra fuel/air mix back into the combustion chamber" - this is n't correct either. How is it supercharging if your trying to recover what you've lost out of the exhaust? Video on this - this weekend
With a 2-stroke engine you create a vacuum in the crank case so not 14.5psi. A turbo only adds air and not a mixture. Since a 2-stroke engine uses a carburetor you can not regulate the extra full to match the extra air of the turbo as it spins up. A carburetor uses a jet and not like a injection engine that measures the air intake and add the extra full for the correct mixture.
U missed the Turbo oiling bit, since the 2 stroke has a dry crankcase so oiling will be an issue and the the gearboxoil wont suit the turbo... separate oilfeeding
You missed that Rotax snowmobiles do not use a performance resonator type of exhaust, it's just a straight pipe. I think the reason for that is that if you stick the turbo on the end of the confuser of a resonated exhaust, the continuously spinning turbo will not let the exhaust "resonate" i.e. change pressure directions on every engine revolution. If you have a spinning compressor wheel, the momentum of it will just even out the pressure waves, thus, eliminating the resonator effect. You might aswell have a simple straight pipe then. I don't think high-end powers are better with turbo engines because of that, but they may equal to NA 2-strokes, with a broader torque curve and resistance to altitude changes.
I imagine there could be some sort of effect on the turbine wheel absorbing the head end of the exhaust pulse, and sizing your turbine is probably pretty important to make sure to conserve as much of that pulse as possible without building excess backpressure, but this is interesting! And it certainly works in a very different way to 4-strokes.
Use a Sprintex Super Charger then inter cooler then fuel inject. Like a Diesel 2 stroke set up.Just make shore the the exhaust closes off to trap the high pressure air coming in.Leave the sump below in a vacuum for less drag.
What if you drive a turbine with the revolutions of the crank shaft and inject the mixture with that power just before the ignition? You could get rid of typical 2-stroke problems AND benefit from missing a carburetor... It's hard to explain, but I would build it like a 4-stroke, where the crank shaft is separated from the cumbustion chamber. So there wouldn't be the typical 2-stroke ducts BUT a 4-stroke sealing piston ring. At the end you can get 4 strokes per revolution: injection, compression, ignition, blow off, repeat.
Crankshaft is spinning the turbine. By getting rid of the typical ducts (I don't know what they are called, anyway) the only duct would be for the exhaust. So if the piston comes up and the duct is closed, the injection could start until the ignition. So that's already available, hm? ;-)
Skidoo offers a factory warranty 850 2 stroke twin turbo. So ya it’s being done reliably in mass. Bikeman performance has tunes for it just like it’s 4 stroke cousins.
a 2 stroke by nature has to by forced air intake or the exhaust would blow out the intake ports. Thats why the exhaust port opens before the intake ports to relieve the majority of the exhaust pressure then the intake pressure can force itself in despite the exhaust still exiting the cylinder. Th expansion chamber adds horsepower by pulling some of the intake charge into the exhaust then pushing it back into the cylinder before the piston closes the exhaust port raising the intake pressure above atmospheric thats why 2 stroke make typically 1 third more power then an equivalent displacement 4 stoke engine. They are supercharge (forced air) already by the piston going down forcing the air from the crankcase up into the cylinder and a reverse wave of pressure coming in from the expansion chamber before he exhaust port is closed. yes a turbo charger or super charger to aid the forced air will work.
Hello mate, I have a few points about your comment 1 - "They are supercharge (forced air) already by the piston going down forcing the air from the crankcase up into the cylinder" - This extra pressure isn't supercharging. Supercharging is when you add more to a standard cycle. This is part of the cycle as standard. The pressure increase is used to move the charge, any gains that the charge below the piston gains in energy is used to move the charge. Its not adding anything to the net product. Not only that but it any gains are lost due to the resistance the piston moving on the power stroke. 2 - "thats why 2 stroke make typically 1 third more power then an equivalent displacement 4 stoke engine." - 2 strokes have 'more power' due to the fact that it fires every 360deg instead of every 720deg that a 4 stroke does. 3 - "before the piston closes the exhaust port raising the intake pressure above atmospheric" - the pressure wave from the exhaust is all about charge recovery. I have a video about that here - th-cam.com/video/j8mCVoPWUaM/w-d-xo.html cheers for the comment - matt
Pressurize the air box. You need over pressure rubber reed type windows for over pressurizing the air box and under pressure reed windows that will open up in the air box when more air is needed till you figure out the 12volt muffin fans that feed the air box through a throttle positioning sensor.
Hi - Interesting Video - I am just building a race car in UK using a V8 - 3600cc two stroke + CVT transmission (about 350hp) AND looking to fit a turbo. I am converting to EFI using a Megasquirt ECU. Why fit the turbo? - noise reduction mainly since its 145db on open exhaust and I need to get down to 105. So I will experiment with the available turbo charge added air whilst engine on dyno. Engines are currently tuned to 600hp so not too worried about component failure.
Hello Peter mate, lol This is my channel, you contacted me through work and we were emailing each other then I didn't hear from you? Hows it coming along? - matt
A Napier T9-29 two stroke diesel engine was both supercharged and turbocharged! Not only that it had an odd number of cylinders and twice as many pistons...and a 3rd as many cranks! All 1950s technology too!
My friend use to have a 500hp 2 stroke mercury v6 outboard... so it can be done not easily what I've learned from him is that you need a way to increase the fuel in regards to the boost aka fuel injectors and adjust timing at the same time
After/during combustion, there is a lot of cylinder pressure, (much much more than the supercharger can ever do), that makes the hp of the engine, and that all "blows down" in about 30 degrees of crank rotation, after the exhaust port opens before the transfers open so they can do their job and fill the cylinder. Unless you can trap the pressure of a supercharger, (which we have not done yet), to keep the pressure from blowing out of the exhaust port, the only benefit you are going to get from supercharging a two stroke, is less "exhaust gas mixing" in the cylinder, (which will make a bit more power), but you will be wasting fuel out of the exhaust pipe. You will not need upgraded fastener hardware, like head studs. Supercharging, it the only thing that makes me like a 4-stroke.
As a matter of fact, two strokes have been made effective with both turbos AND superchargers on the same engine- the catch that it must be a diesel. At least one form of boosting is actually necessary on a two stroke diesel, as the intake charge is used to completely flush out the exhaust, and being a diesel, no fuel is wasted in doing so. Note-this is generally only suitable for multi-cylinder two- strokes, and ideally for diesels only, as gas engines would dump fuel into the exhaust.
Wouldn't the spinning exhaust turbine prevent the backpressure needed for the combustible mixture to reenter the chamber? If the turbo was in optimum position ie; close to the cylinder. So the engine might run until the turbine spools producing even more forced induction, then the engine starves for fuel because the air-fuel is spraying out the arse end of the pipe.
![BOWKYLION - วิงวอน (ex-change) [Official MV]](http://i.ytimg.com/vi/cLdnZWDaO-w/mqdefault.jpg)
I can honestly say I didn't learn a damn thing from this video, BECAUSE... I'm very familiar with most engines. I have studied and built two strokes for years and have always been amazed at the looks I get when trying to explain how they operate to those who are unfamiliar. Every time I thought there was going to be something you left out, you covered it 3 seconds later. Hours of my life arguing over this same subject in the past. I agree with everything you said and you explained it so well that I could have gone to some other video after 5 min but watched the whole thing anyway. Very well explained, keep up the good work.
Cheers dude - welcome to the channel
So, it would work... but it's alot of work.... turbo weed eater go kart time!!!!😂😂
no way i was also thinking that
guess I'm putting a turbo on my weed Wacker
Use the turbocharged weed wacker to supercharge your snowmobile.
Don't forget the VTEC
Sure gonna win the hill climb if u slap n dab the wacker
th-cam.com/video/_gYCaLDKxNY/w-d-xo.html I've got you beat. I am the greatest in the world, and the only man in the world that can convert four stroke engines to two-strokes retaining the stock piston/rods/crankshaft. My family made them in 1910, the 'Roberts aluminum boat/aircraft two stroke.' You are wrong. Cylclic dispersion takes over. Small port two strokes run exactly like four strokes when run rich. There's a four stroke combustion schedule in fast two-strokes. Try again..
th-cam.com/video/_gYCaLDKxNY/w-d-xo.html
To sum this up, the greater the difference between input pressure and ambient exhaust tip pressure becomes, the lower the efficiency of a 2 stroke will be. At no time is a 2 stroke sealed, to maintain any kind of reasonable efficiency it completely relies on equalibrium.
Definitely the best explanation I've seen online completely correct with common sense included!
Thank you for putting that too bed for all of the naysayers. In the western US we have been running turbos on our 2 stroke snowmobiles for years and the performance gains are incredible, especially when you are talking about elevations from 6-14 thousand feet. They do work and they do work very very well. I have a skidoo summit 850 that is 165hp stock and at just 8psi boost it is about 225-240hp depending on elevation and fuel used and absolutely incredible. The funnest thing you can experience in my opinion.
Can you upload vídeos of your turbo setup ? I would like to see , seems hard to find videos of turbo snowmobiles
@@rodriguezfranco3839 th-cam.com/video/GJQj38ifZao/w-d-xo.html
Think it would work on my 1999 KTM EXC300? I’m 19 building a supermoto build with the ktm and my dad has a turbo laying around from when he did it to normal bikes. But do you think I could actually well put it together and turbo the ktm 300?
done for years on snowmobiles, boondocker are making complete plug and play turbokits to ALL 2 stroke sleds, the upside with the new sleds are that they have EFI and have a lot more tuning capabilities. I've personally built turbo 2 stroke sleds, 2004 ski doo rev 800cc was my second turbo 2 stroke, my first was a 97 rotax 580, both carburetor engines. my biggest problem was jetting. and maintain a good air fuel mixture. I used adjustable powerjets so I could rejet on the run, when there was a temperature change or altitude change. otherwise a completely stock engines, pipes and so on. on the 800cc I had to change reed blades to handle the extra flexing caused by the boost. let's take the rotax 800cc etec for example, 150 stock hp, 2 cylinder, with 5 psi boost by a turbo, and it gets around 200hp on crank, a bit less on the track(wheel). some Swedish students turbocharged a AM6 50cc to 30 hp and they also turbocharged a yamaha tzr 125 with stock engine, and doubled the power. my experience with turbocharging 2 stroke engines that uses carburetors are a pain in the ass to jet, and to make it work 100% all the time. if anyone wants to turbo a 2 stroke, go foor a EFI fueling setup, ecotrons.com have EFI kits for most engines up to 800cc, and you'll save a lot of time on the tuning part, because that's where the problems start ;)
I turboed my switchback assault, the boondocker 2860 turbo is actually to small for 800cc in my opinion. I went for a 2873 kpa turbo, it was so much better for temps over all, cooler engine, more fun on higher boost etc. Had that sled for years with no issues, engine took it well, was never under 10-11 psi. With the big turbo i went for 18.3 psi, that was a kicker, still no issues lol. 2 stroke turbo`s is so much fun, not hard to get right either with a little bit of knowledge or help. Today, kits and pull and go.
@@abccba2344 how many miles did you get out of that engine. Did u ever get to tear it downn to see what kind of wear and tear the turbo did to the engine
@@joshlaquerre3197 rebuilding an 800 costs me around 1k in parts. i have a 2013 m800, i converted to the alpha 1 suspension (video on yt), i put a speed works turbo kit on and im sitting around 230hp on the crank. i rebuild it every other year, like any good two stroke owner should do, and have no issues.
what about electrically controlled carb?
1:00 that just looks like bong with extra steps
😂😂😂
Great video! I'm playing around with a supercharged two stroke idea involving a secondary piston or drum valve to control exhaust timing.
FYI - check out the McCulloch BP-399-T engine from the 70's, that was going to be for snowmobiles .. production was canceled, only a few were made .. it had a small piston opposing the main combustion piston/cylinder ... that small piston was used to pump / supercharge the fuel/air mixture and to also balance the motor. IMO, its almost as complicated and costly as a 4 cylinder 2 stroke, so why not just do that? 2 strokes are simple, adding parts and complexity is almost always a step backward.
2STROKE STUFFING u just need a special porting
Use very low port timings. Something like 110 deg transfer, 140 exhaust.
it isnt that insane to think about since most of the detroid 2stroke diesel engines depend on superchargers to work
There where more companies who where experimenting with this design. I have a moped which also uses this double piston design. The air pump piston has a very large diameter with a very small stroke. The piston is also ludicrously heavy to balance the system. Check out the Motobecane 99z engine. You can find photo's on internet of this engine. This engine was mass produced somewhere between 1976 en 1982 I think (I don't know the exact dates).
everyone's using the Detroit diesel 2 strokes as an argument for turboing 2 strokes, but those engines and gasoline 2 strokes are completely different. on the Detroit, the fuel doesn't go through the crank case, it goes straight into the cylinder through ports in the sleeve. you must supercharge them, or else the exhaust wouldn't be forced out and the new air/fuel wouldn't be forced in.
Finally, I don't have to state the obvious - cheers dude - matt
The Workshop lol finally did something right in my life
metallicakid83 correct and they are oil lubricated like a four stroke.dont always need a blower they made one way clutched turbos that would spool at idle until the exhaust would build up past idle and spool the turbos
Joe Cameron how would it spool enough to accomplish the scavenging and intake at idle? never heard of them ding that before
metallicakid83 they only need a few psi of boost to idle till the turbos take off on exhaust.look up emd motors im pretty sure some detroits were only turbo charged to with no blower
You're quickly becoming my favorite mechanical style channel. The simple fact that you give the TL;DR at the beginning for 5 seconds. Watch the rest if you want. You're informative, easy to understand, and funny at spots too. I love it. Cheers brother
This guy's brain is super charged. It must weigh 52 pounds. Hat's off to his mastery of the topic and his superb ability to communicate it in a manner we mere mortals understand. Genius.
I can understand where you're coming from for 2 stroke engines I'm general, but for snowmobiles you'd be suprised how big of a market after market turbos are. On most modern 2 stroke snowmobile engines, 1 psi from a turbo is 7-8 hp and most engines will handle up to 11 psi on pump gas. So for most engines you will go from 150-160hp on a 800cc twin to 220-240 hp. You may think that's not worth it but it most cases where people use turbos it absolutely is worth it lol.
70hp is more than many cars have. that on top of 150? almost 150%? who the fuck says it's not worth it?
Great explanation, I have been a 2 stroke mechanic since the late 60's, my father was a McCulloch dealer, raced go cart's and even set a track record in the single engine class at 127.5 MPH, the engine was only 5 cu.in. or 80cc.
Turbo charging isn't worth the trouble, you are better of "stuffing" the crankcase (filling all empty space in the crankcase that you can, Now McCulloch had a prototype snowmobile engine BP-399 and a chainsaw BP-1 that used a balance piston to not only balance the engine but to draw more fuel/air mix in and compress it just that much more these engines put out insanely high power and RPM for their size. my BP-1 would turn 15K rpm and practically vibration-less. here is a video I found on the BP-399 that scares the daylights out of me because where on earth are they going to find a clutch that will stay together at 16,600 RPM? enjoy th-cam.com/video/c7eTGDn8mmk/w-d-xo.html
Back in the late 80s I had a tuned Honda VT250 (4 stroke) and that reved to over 12,000. There was a racing series in Japan, so you could get parts if you had money, it did blow up a lot though. I think I red lined at 13500 but that is from memory and with a lot of tuning parts and work.
Try F1 clutch. They proven to be working at 20k so I didn't see the problem of running it at 16k
Yet another person that doesn't get how a two stroke turbo works. I.ve seen over thirty five lbs of crankcase pressure with a turbo, never seen ten by stuffing.
we have been turbo-ing our 2 stroke Arctic cat (suzuki) snowmobile engines since 2006 with fuel injection and we get from 300 to 400 h.p. on our 1000-1200 and 1300 c.c. cat engines with excellent engine life. change pistons every 2000 miles and run them from 11-16 lbs. boost all day long. we do some mild cylinder/head mods to enhance turbo performance. one other note is that a 2-stroke will use a much larger turbo than a 4-stroke cc to cc we use garrett gtx3076r turbos on our big bores and they work. 2-strokes forever!!!
LOL sorry but "change pistons every 2000 miles" isn't excellent engine life. You do know that the piston is part of the engine???
"one other note is that a 2-stroke will use a much larger turbo than a 4-stroke cc to cc"
- of course you do - you burn double the fuel............
2000 miles is excellent piston life for a turbo engine running race gas boost and we change them at that interval for maintenance NOT because they are wore out, you obviously know nothing about a 2-stroke engine but thanks for your uneducated reply
2000 miles for an engine is shit andthe whole point of the reason why 2 strokes are shit. The phrase "engines with excellent engine life." then followed by "change pistons every 2000 miles" is shit.
Excellent = 2000 miles? I get what you mean but that's just madness. That was the point I was making - but you got all 2 stroke butt hurt about it.............
I would like to see you run a yzf450, crf450, kxf450...ANY race 4-stroke run 2000 miles without changing the piston. You would fail and destroy the engine... so 4-strokes have their downfalls also.
The reason why any off-road dirt bike dies is because you revving the nuts off the engine and not really going anywhere. Take that same bike onto the road and race around and you'll be fine. Heat saturation is what kills these engines.
the part you are overlooking in this video is the expeller of the turbo acts as a constantly fluctuating valve. it's rotatiomal movement, or lack there of creates the pressure in the exhaust pipe to cause the reverb of pressure back into the cylinder as the exhaust gas pushes on it's vanes... and the open, 2-stroke system is actually the better option for spooling a turbocharger, you can put a bigger turbo on a 2 stroke than a 4 stroke because it moves twice the air at a given rpm...
Hey look, a guy who actually knows what he's talking about. You should have done the video, instead of this knob.
William Ward yeah, we run gt30 turbo on 800cc 2 strokes, and it spools faster then a gt28
thank god I wasn't the only person sitting here screaming at my screen because he OBVIOUSLY doesn't understand turbocharging...thank you
It moves twice as much air assuming a VE of 1.0 at any given RPM. Never disregard friction, my friend.
William Ward. I fully agree with what the other comnenters are saying. You need to produce your own video.
turbo cr500 supermoto come on. someone do it
Supercharge it
What wrong with you!!
The CR500 is crazy enough as it is...
One of the big reasons to turbo a sled is altitude. Air gets thin at high altitude, so even with perfect jetting, the 150 hp your engine makes at sea level is knocked back considerably. With a turbo you can gather more of that thin air and keep your power.
An excellent explanation of the basic pros and cons of 2-stroke turbocharging.
A lot of the problems can be solved by having an exhaust valve instead of an exhaust port -- but that's more complexity, and the whole point of 2-stroke engines is to make as much power as possible with the least complexity possible.
Very true
thank you for answering the question in the first second of the video. High quality shit mate
I love 2 strokes, and I love turbos, this video combines them, awesome. Thanks for making this vid, keep up the good work.
Chears matt. Great channel
l understand how you feel. I worked for a company full of delboys with a delboy line manager.
After paying to go to Australia for some experience (couldn't find any one willing in Scotland) and paying to go to college for two years to achieve two asme 9 qualifications and finish top of my class. I found myself in Fife welding copper boilers for a company(fantastic work)
Unfortunately I only lasted 2 years before having a mini breakdown.
This was due to the relentless bullshit, lies and fukin morons that I worked beside.
To give you an idea, the company had a cad system, used the cad system on a daily basis, but my "technical" drawings came from Microsoft word with no measurements and not to scale.
I've been working delivering pizzas on minimum wage since I left, and that was 3 years ago. I love fabricating and welding, but can't shake the massive dent in my confidence in the industry ( I worked a couple other places for a couple of weeks and they were the same sort of thing)
If you have any advice I'll take it. (or a job)
If not, I hope this helps explain why people like dell are a bad influence and shows the effects they can have on people as well as there chosen profession.
FAKIN CANTS
Damn good explanation. at 9:18 i wanted to know about the turbine's backpressure on the cylinder having any effects but you cleared that up later.
Glad that I answered your questions - thanks for the comment - matt
did you cover the pressure rise in the exhaust from the turbo. if your turbo provides boost it will provide back pressure. say a 1.5:1 ratio. if you have 10psi of boost youll have about 15psi of back pressure on the hot side of the turbo. youll get exhaust reversion with a turbo you wont piss away the intake pressure when the intake and exhaust ports are open together, you have the chance to fill you intake with exhaust instead.
this is a good example oh a supercharged instance not a turbo.
I guess it depends
On intake the piston scavenging may be enough to offset the backpressure of the exhaust
On exhaust the chamber has just fired and it will be at even higher psi than the backpressure because it is so hot, blowing the backpressure and exhaust out through the turbine together
It seems from your explanation that the biggest issue is the exhaust geometry? I think it’s a good rule of thumb to thoroughly research the tolerances of any engine before modifying it.
I appreciate you taking time to explain to the average person what to expect when turbocharging a two stroke!
The biggest issue is that 2 strokes are very sensitive to intake pressure and velocity, adding a turbo just makes thing worse
@@dirtygarageguy Got it, I totally overlooked the intake side of things.
Back in the 80's we used to "turbo the crank" of our 2 stroke motors. This consisted of machining deep groves on the outer edge of the crank flywheel to pick up more fuel mixture from the case like a fan blowing straight into the intake port. To this day I have no idea if it actually had any benefit, we thought it was pretty trick.
You tell us? Did it make a difference?
@@danielg6967 We didn't have access to a dyno back then, so any "difference" was measured only subjectively. Was it a significant night & day difference, no. That said, having a psychological advantage of my magic secret weapon did improve my competitive confidence.
I was just looking at some of the comments you get. OMG. You have the patients of a saint. Thanks for showing my bike. The 750turbo. I am a member of Lorcan's site.
Always been curious about this due to crank case pressure.
Not run off crank new skidoo 2020twin turbo fuel injection triple
Another thing is that a turbocharged goes on the exhaust first then exhaust fumes spin the turbine and then the air made with that goes in to intake, thous getting higher pressure in engine, which Would require to tune to run more fuel as well to even out the a/f ratio
Thing is a 2-Stroke is relatively simple, powerful and
light, so adding a turbo to it seems like you don’t get a lot of pay-back? Now it is more complicated, more powerful and
heavier. And as said they were being fased out because of emissions.
To be honest the last time I rode a Turbo was the 90s, and
it wasn’t fun on a motorcycle.
@@arnehurnik depends on the setup titanium mani weighs less than full ss. bigger snails definitely weighs more than smaller one
its to bad that the two stroke engine is slowly dying out. love the sound of them. you learn us so much. wished there where more channels like yours. cheers
Main problem is they kinda stop developing them .
Imagine if they put the same amouth of money in 2 stroke that company put in 4 stroke ....
Direct injection could help a lot 2 stroke performance .
Snowmobiles have been doing it for years
This is why power valves became the choice for manufacturers to increase horsepower reliably. The part about increased heat and pressure forces the manufacturer to use better quality parts which increases cost.
and snowmobiles use 2 cylinder 2 stroke engines now a days, the picture you showed was a skidoo 3cyl 1200 cc 4 stroke turbo.
Yeah my bad, editing is so hard lol (smallest violin)
the way I see it, four-stroke engines have completely isolated intake and exhaust cycles, so you are free to add pressure to the intake (to an extent). In two-stroke engines, intake and exhaust cycles overlap, so if you add pressure to the intake, a lot of fresh air/gasoline mixture will rush out of the exhaust port (something that already happens to some extent in regular two-stroke engines)
the Detroit must have the supercharger to run. some have turbochargers added on top of the blower .the torque curve is pretty flat no lugging power
Detroit Diesel engines don't run the intake air through the crank case to pressurize it. And they also exhaust valves in the head.
Could you tell me why Detroit can't use VGTs?
Some can spool their turbos with a gear train on the turbo shaft for starting
no 2stroke detroid diesels depend on a supercharger to work and use ports not valaves
I think you mean the Detroit Deltic (greatest engine ever) which had opposing cylinders and ports at the bottom of each stroke, detroit engines with one crank and a head would use valves 2 or 4 for exhaust and ports for intake
I don't know why but I always watch the whole video when it answers my question in the first 5 seconds... Quality Video, great explanations 👍
Did you build your shed over an old graveyard , random breezes , ghosts knocking stuff over and a raven perched above your chamber door
the graveyard he build it on is called great britten
@The Workshop It is supercharged. It has a volumetric effeciency of greater then 1. meaning it is able to process more then it's static displacement per revolution.
You don’t understand i “need” to Turbo my 2 stroke 1/5 rc!
That's would be awesome! can you imagine those alx eninges turbocharged? The alx 80 look crazy already would love to see that!
Look new turbo skidoo 2020 will blow everyone mind
cleared a few things up that i have been thinkink about for quite a while, great vid dude thanks
what about the forced induction forcing open the reeds on the downstroke when the inlet port is uncovered ?
A similar thing happens with normal 2 strokes, although this is compounded when using a turbo system. This is called reed valve flutter and I'll go into more detail in the next video on this subject - good comment - matt
cant wait to watch it, its been on my mind for years
rotary valve 2 stroke bruh
Jacob Westphal that's the 1st thing that came to my mine was the old rotary valve 2 strokes
Best way to make power on a 2 cycle
Lol...first 3 seconds, says entire video. I stayed for the honesty. My man
So I can turbo my Husqvarna?
I agree with everything your saying, on a stock engine, charging (super or turbo) a 2 stroke can work and work really well, but only with porting arrangements that suite it, ie way less overlap in the intake and exhaust porting, I've done a little RnD work with a local two stroke dirtbike engine builder, and he has built one two stroke that worked well with a turbo, the problem he finds with most is that the porting arrangement needed to work can't be archived with the stock cylinder castings, there isn't enough material in the right places, and he kept having to cut port's to close to water jackets and in every case completely lost the ability to run the power valve, making them unridable except for drag racing (who drag races a dirtbike?), adding turbo lag to no powervalve makes a KX60 seem like a chevy big block in terms of power curve.
The one engine he's made work well was a maico (or ATK if your in north america) 700cc he built for an attempt at the dirtbike top speed record, eventually making 140hp, but again, it was completely useless for anything else and unreliable as well.
Everything I have turboed had untouched porting and worked perfectly. My very first project was a 4 cyl outboard motor that made 40 hp. The very first dyno pull showed 85 hp with more to go.
I owned a 2 stroke, the exhaust kept clogging up, I can't imagine adding turbo without adding exhaust valves
What engine is it?
The Workshop uhm, it was just a 50cc. And it was the reason because the next street bike was a 4 stroke 250 instead of an aprila 2 stroke
The Container Vessel I am working on has a 2-Stroke Main Engine wich is turbocharged, so the answer should be yes.
I see your point, but I can not fully agree.
I'm seeing alot of 'Detroit Diesels are supercharged'. No, they are not. The blower is used as a scavenge pump to pull exhaust/ push air through the engine
Quite true, that was coming up in the next video to this subject, but you've beat me to it lol Technically is known as artificial aspiration. - great comment - matt
Correctly put. Roots ts3 engine is a very good example.
I clicked this video intending to make my second rude youtube comment in ages. This one is a lot better than your E-Tec video, though.
You might want to clarify that this applies to gasoline engines designed for natural aspiration. I fiddled around with a Wichman 3DC just the other day; it has factory turbocharging and works quite nicely.
Its alright, you'll get over it. I have a part 2 that I'll put up tomorrow that makes it all a bit clearer
I'm 3 min in to this and I am very interested.. lol, thank you. I've subscribed. never learned motor works but like to pretend I can understand what all these # are.
Thanks for the comment dude and welcome to the channel - matt
Is it a bird, is it a plane? No! Its More than Normal Man!
Very well explained, subbed.
lol welcome to the channel dude - matt
the first thing you said: can you turbo 2-strokes, yes. can it be down well, no. on that fact is a turboed snowmobile putting out around 160hp stock naturally aspirated. turboed they put out over 300hp. doubling your horsepower isn't good enough to be considered well? it's only the thousandth time I've heard some youtuber spurge bullshit on a topic which they didn't research well enough
The Workshop look up skidoo 800 etec aerocharger. running around 14lbs of boost with a the intercooler and 110 that's what they achieve
The Workshop no need to even build it from there. because power is such a high priority for snowmobiles running at the high elevation the precision fit of the parts are much more spot on than a normal car. that's why 800cc produces 160hp
I second Ross.
I agree, there are many manufacturers making turbo kits for sleds that work great and have amazing power increases...
Nothing uncommon about that at all.
A 700cc Polaris with a hair drier on it will put out 300 HP.
Check out the mountain sleds.
I don't understand the dislikes, this was a pretty clear and informative video. Explained your points well and didn't leave me with questions. I thought it was a great video.
aweSome video! super nice and easy explained. did I understood correctly that you said pisses out? :-)
Yes sir I did lol
😂👍
Best explanation I’ve ever seen on this!
Great video, you didn't really explain the reflected pressure wave from the back of the expansion too well for anyone who doesn't understand it, but other than that good vid. I've lay in bed at night and wondered how it would go on a dirt bike but other that, too much fucking around to make it work well, like you say, and the best thing about a two stroker is simplicity and reliability....and they scream their tits off anyway! Leave it alone, mix up some fuel, tip it in the tank and try not to kill yourselves, how fast do you really want to go anyway! Peace bro ✌️
Thanks for the comment dude - matt
There is a 2 stroke v10 japanese diesel tank engine that is twin charged and they had a lot of problems while developing that engine. Its called mitsubushi 10 zf mod 21 which was in their early to mid cold war tank which i currently dont remember its name
you sir, are awesome
Thank you! lol - matt
Sticking the turbo before the expansion chamber is silly because the airflow is both back into the cylinder and forward into the expansion chamber. The stored rotational energy in the turbine would over come the suck back into the engine as a result it would be sucking the unburnt charge into the exhaust thus wasting it.
The expansion chamber on the other hand acts a receiver to provide a constant flow (or what passes for one in 2 strokes) thus providing the turbo with what it needs to compress the inlet air.
Can you nitrous a 2 stroke safely ? what fuel and a/f ratio? what premix ratio?
Great question, it deserves its own video - added to the list
Yes you can i have done it before.
But they get hot so godamn quick.
A/F is hard to understand on a 2 stroke. But if running on NOS you should add a little more oil to your gas.
Would it work on a PWC? My standard ratio of oil to fuel is 30:1 .... what would be the right amount now?...... would I want to have 10.7 - 11.7 afrs under load on pump fuel?.... I am thinking maybe even pump E85 which 9.7 (stoich) and 7.7 AFR under load with NOS.... any thoughts? Engine Longevity? Its just more brainstorming right now.... also now that you said the engine heats up it is concerning but detonation/knock would be more concern..... the engine is cooled from water flowing through exhaust and engine cylinders so I think water temp and ambient temp would play a factor there. E85 is supposedly better at preventing knock/detonation.... I just have to plan to best way like bigger fuel pump(s) bigger injectors ... fuel pressure regulator, NOS and special NOS controller w/AFR gauge.... and of course finding the right oil to fuel mixture..... 30:1 won't cut it lol
2 stroke engines are very temperature sensitive adding NOS always increases the combustion temperature due to the free oxygen. As for engine longevity - its only going down. Alot of the heat is transfered into the piston rings, even more so with NOS included, this is usually what gives up the ghost first. I have seen a couple of drag racers use thicker rings when running NOS to reduce things going tits up.
As for premix etc I wouldn't know to be honest, although it don't think it would be too much of a problem. By the time the oil makes it into the cylinder its done most of its job with the bearings etc. Changing the premix ratio will have an effect on how stable the combustion is, and I don't know what chemical reactions take place with NOS and the oil itself.
As for coolant and knock, the knock occurs during compression, the coolant has little effect with a system that is fixed. Coolant removes waste heat after the fact, and obviously from the power stroke previous. In other words you have to test the heat saturation of the cylinder/head before making any judgements out changing the coolant system. If the cylinder/head is too cool then this could cause condensation, which when running NOS would lean out the mixture.
This would cause combustions temperatures to climb and then knock would occur. So you then cool it some more making it worse.
- matt
What is the base fuel pressure for this 3 cylinder EFI 2-stroke.... is it the same as 4 stroke 43.5psi? Do you think a standard eBay type of fuel pressure regulator would suffice for measuring that set base pressure someone on the forums locally is having issues with hesitation and the like and I suggested 5 tips: 1)upgrade and Hardwire Fuel pump to relay (hardwire cause of voltage drop issues in electric pumps), 2) clean, replace or totally remove fuel pump's filter (fuel pump wasn't designed for oil/fuel premix, factory has a separate tank that injects oil but is removed cause of common recall issues), 3) have injectors sent out to be cleaned 4)Add fuel pressure regulator to keep fueling optimal for such a finicky particular 2 stroke engine design. I say that cause with carbs they were always picky on my goped and now with EFI premix is picky so setting base pressure or even increasing pressure could eliminate hesitation issues etc and allow to dial in/tune better. 5)Add AFR gauge and make sure its at least 10.7-11.7 AFR rich underload. Any thoughts?
That crank induction is so cool!
You would have more power in higher ambient pressure for the same reason you lose power on pikes peak. The number of moles of 02 that you can fit into the combustion chamber directly dictates power production. Displacement, forced induction and nitrous oxide, are all about burning more fuel. Also, rolling resistance is liner, so higher gravity is net positive (Eg: trains/trucks work).
the main thing your missing about small motorcycle two strokes is there is no forced lube system on these engines so you need to add a system
This video is addressing the idea of a 2 stroke, there are other problems too, like reed valve stresses (fluttering etc) and others. With regards to the oil feed system, you can always just add an oil pump from a regular 4 stroke and have it belt, gear or chain driven off the crank - good comment though - matt
(p.s - there will be a follow up to this and your point will be included, I can see there being load of questions from this video)
The Workshop if the premix can lube the crank, wouldn't the oily exhaust vapor be enough to lube the turbo? That's how expansion chambers work, in that they reuse the unburned vapor. thoughts?
lol no. The turbo requires oiling at the bearings within the turbo body where the shaft is. All you would do is oil the blades of the turbine, which would do nothing, apart from slow down the turbine slightly due to the weight. Expansion chambers use the high pressure combustion wave.
Yeah that makes sense. Wouldn't be very hard like you said.
This is one of the best explanations I’ve seen on this topic!
great vid mate! i personally have always been amazed with 2stroke engines, my first vehicle was a 75 rd 350, there power production per cc in those days were unmatched, seems to me thou that a geared charging system rather than a turbo would be easier to deal with the expansion chamber issues. but after seeing what Suterth-cam.com/video/0leUj-p43uU/w-d-xo.html has recently done with the MMX500 engine ( with combustion chamber the size of the bottle i'm drinking out of ) putting out 200hp (and more now from what i have read) in a bike that weighs 280lbs, whats the point? i mean really, how much craziness can somebody handle? LOL
th-cam.com/video/O5NUEwwwtgs/w-d-xo.html
lol I know what you mean, welcome to the channel mate - matt
Hey. Great stuff as usual. Thanks for clearing up some everlasting questions of gearheadom; and for debunking some everlasting bullshit as well.
Video ends 0.06
More like 0.05 lol
The Workshop hahaha yeah, interesting tho, always wondered about putting a turbo on my rs125
lol don't lol after all its not worth doing. If you do your bike test you'll want something heavier
The Workshop no I wasn't gonna bother, when I'm 19 I'll do my a2 and get a Aprilia rs250
You do not say so explicitly but a 2T engine with a turbo where the turbine is at the end of the tuned pipe, with a correctly sized turbine and waste gate gives an engine where the pressure after the compressor and before the turbine is raised the same ratio above atmospheric so all the normal tuning values is applicable except the pipe temperature is a bit higher so needs to be longer to be tuned for the same point. So no extra losses out the export etc.
1 bar is actually 14.7 psi
1 bar is 14.5 psi, 1 atmosphere is 14.7 psi
Jordan Richards you played yourself
Zenkor, why would they have the 2 different terms for such an insignificant pressure difference?
Jordan Richards no.
But Earths atmosphere is 14.7 PSI though lol
I appreciate your view of PCC two strokes not being inherrently "supercharged". Never thought of the terminology like that.
What a bloody terrible explanation.
what a bloody terrible comment - reasons, arguments, examples - if not fuck off
awesome video !! Great points and explanations . dont understand going thru the madness of turbocharging a 2stroke. it just takes away the simplicity of the engine . only reason i could think of is someone just wants the bragging rights of being able to say " i have a turbo 2stroke" but still an awesome concept lol
In your video you are explaining that the pressure in the crank case builds up when the piston comes down, and the reasson this pressure drops in the cylinder is mixture escaping into the exhaust.
But even in the case the pressure back pulse prevents any of the fresh mixture escaping into the exhaust the resultant pressure in the cylinder at the moment the prots close will not be higher than atmospheric.
This because the volume above the piston enlarges with an equal number as the volume under it (the crank case) decreases when it moves down, so the amount of mixture displaced from the one side to the other keeps the same pressure, there is only a momentary raise in pressure caused by the resistance of the pipe/port connecting the cylinder with the cranck case, but the mixture expands in the cylinder to fill the space.
Even with the exhaust port blocked off you would be able to turn the crankshaft freely without pressure building from the moment the intake opens untill it is closed again, as long as the intake is open you just move gasses from one side to another.
"But even in the case the pressure back pulse prevents any of the fresh mixture escaping into the exhaust the resultant pressure in the cylinder at the moment the prots close will not be higher than atmospheric."
- not really, fresh charge enters the exhaust pipe and is then forced back in, until you reach the rpm range the exhaust has been tuned for.
"This because the volume above the piston enlarges with an equal number as the volume under it (the crank case) decreases when it moves down, so the amount of mixture displaced from the one side to the other keeps the same pressure, "
- but your forgetting that the tranfered charge also has momentum, as does the exhaust gases expanding into the exhaust. This causes a flow path out into the exhaust. Don't get me wrong its not all of it, around 15-20% depending on the timing and port design.
Good comment though - matt
They have been doing it to Snowmobiles for YEARS people. Get 800 twins to 350 hp off 10 lbs of boost!
I would make a kind of mech valve just after the exhaust port, and raise the inlet ports as hi as the exhoust maybe even further, then drive the turbo with a big brushes motor 3turn at 160 Amp
An exhaust-driven turbine could work if it fed power back to the crankshaft directly instead of pumping extra fuel/air mixture into the engine. The Wright R3350 aircraft engine (admittedly a four stroke) used this technique, and they called it "turbo compound". However you may then have lubrucation issues if the crankshaft was turning too fast for the amount of fuel/oil mixture going through it.
The turbine wheels in turbos don't 1) have enough mass 2) the energy of the exhaust gases in small 2T bike engines isn't enough to provide enough power to the crankshaft to make it feasible. If you look at the size of the trubines in turbo compound engines they are quite big - cool comment though - matt
I was thinking about the Wartburg 2-stroke car engine of 991cc... however you rauise a valid point. The only other way I can think of to use exhaust gas pressure is to have a turbine attached to an alternator or dynamo, providing power to electric motors on the wheels.
i cant recall the engine shop i was at but they had a very old and weird 2 stroke that was a turbo feeding a blower ( blower was acting as intake ) but it did not feed into crank case it was right to the cylinder wall. only thing different was there was a crank driven " valve " that blocked the exhaust port shortly after both holes were exposed.
Keep in mind this engine was floor mounted and ran a generator or pump of some sort i think the man told me and was built to run at a set RPM and never never change. they had a hole data sheet on it about the reason why it was better than a four cylinder for the torque at the goal RPM output.
i recall doing some research when i got home and some outboard motor company did this as well where it was blower driven intake with a valve to close exhaust at a set time and had greener out put from the tail pipe than a 4 cylinder of same CC. if memory servers me right it was all most twice as good. but there to same thing really built to only run at a set RPM and never really change, example warm up RPM and Work load RPM.
Any way just figured id put this info in here as i found it as good brain food for thought on engines i have played around with
what if you instead used crank pressure routed through a turbo then back to the cylinder? better atomization, less heat. would the turbo even need oil? make a less cc crank area to get better pressure.
what makes turbos spin so fast is the pressure from the heat expansion from combustion process.... though you could spin a turbo from crank pressure it would result in lost energy as you would be using compressed mixture to spin the turbo and also pull from the turbo i do not think there would be any bonus at best i think you would have power loss and weight added. is why the mentioned above method was used and is used today still on high torque level load 2 cycle engines ( really only diesel applications ).
while two strokes idea would have more power per CC the problem is you loose compression ability due to a valve less motor. a valve on the exhaust side with forced induction set to close once the air fuel mixture hit's the port give you back compression however then you run into seal problems with running to much pressure not to mention you are burning oil witch leads to not so green exhaust.
a quite neat idea to over come this and staying with a valve less set up is a rotary engine ( Wankel ).
but it has a larger problem that is not talked about much other than the wear on the " rings " to seal
the cylinder...
all though the Wankel fires once per 360 degree of rotation like a 2 cycle the rotor it self spins 4 times
for every rotation of the crank. so as a idea the Mazda RX-8 has a Wankel engine with a red line of just
past 8,000 RPM and at 8,000 RPM of the crank the rotor is spinning at 32,000 RPM.
now the Duke engine beats this problem but has more rotating mass and is also a valveless engine.
problem with the the Duke is there is all most twice the friction area. all though quite a nice idea has
a problem like the other odd balls.
reason i bring up those two engines is the main bonus to a two stroke engine is the instant power
light weight among other things. end goal of perfect engine is non stop instant power two stroke
is closer to this than four how ever when pushed to the max CC per CC a tuned turbo 2 stroke will
never make the same power as a 4 turbo can. with out adding the weight back to a two stroke set
up to handle higher pressure adding back a lot of mass your back to a four stroke minus the intake
valve and no oil burning with " stand alone " oil in crank case.
hate to say it but electric motors are going to win the power delivery war every time. the huge draw
back to electric is the battery weight if you want it portable and charge time. but if not needing to be
portable and you can plug into a power grid,,, well this is why all booming factories use electric motors
as power is instant and steady now power then cost then power then cost then power just straight power
100 percent of the rotation.
good way to test this as we did in shop class in school get a 5hp engine of any type but jet engine
and a 5hp electric motor put at 4 foot bar on each and spin them both at there power rpm you can
grab the bar on the engine and stop it but not the motor .
jet engine only good at one RPM and a lot of power loss in thrust if not being used. this is why we do
not have jet engine cars no one wants the pain and glass on there wind screen melted while sitting at
a stop by the person in front...
sorry for the long post but i wanted to cover the question in entirety to put it to bed, as i have toyed
with this multi billion dollar question a lot and have come up with some good ideas but noting suits
every problem as no engine has yet and battery and motor all suits with weight aside and batteries
are getting smaller and lighter every year and at this point the only draw back is charge time. and cost
of replacement when battery wears out before motor.
Metric: 1 Bar @ sea level
Imperial: 14,5 PSI @sea level
The Imperial system is so Intuitive...
Short exhaust port duration with shallow, wide bridged ports is what I would do then the exhaust becomes less critical in scavenging.
And as used on the BUB 50 landspeed bike, I'd go with methanol to control temperatures, especially with the wide exhaust port pumping heat asymmetrically into the cylinder.
If you ran the turbo into a plenum chamber you could control that with a disc valve and straight into the transfer ports. That'd stop you knocking the seals out, then it's a case lubing everything up as you are not running the petrol/oil mix through the crankcases.
I did it , what do want to know ? The crank case seals normally won't handle more that 9-12 psi. Replace them with heavy duty industrial sealed type bearings, throw the carb. away, install fuel injector and new ignition system and a throttle body
the "supercharging" doesnt occur in the crank. it occurs from the design of the pipe causing resonance and forcing extra fuel/air mix back into the combustion chamber. thats what causes the "on the pipe" feeling of a 2 stroke...the powerband. because its operating in the right frequency to get that air/fuel mix forced back into the cylinder
"the "supercharging" doesnt occur in the crank. it occurs from the design of the pipe causing resonance and forcing extra fuel/air mix back into the combustion chamber"
- this is n't correct either. How is it supercharging if your trying to recover what you've lost out of the exhaust?
Video on this - this weekend
it depends on the engine, early Detroit 2 stroke diesels used roots supercharger as well as turbos on top of the roots system and work very well
John McRae they use a supercharger to scavenger the exhaust gases out and air in.
With a 2-stroke engine you create a vacuum in the crank case so not 14.5psi. A turbo only adds air and not a mixture. Since a 2-stroke engine uses a carburetor you can not regulate the extra full to match the extra air of the turbo as it spins up. A carburetor uses a jet and not like a injection engine that measures the air intake and add the extra full for the correct mixture.
U missed the Turbo oiling bit, since the 2 stroke has a dry crankcase so oiling will be an issue and the the gearboxoil wont suit the turbo... separate oilfeeding
You missed that Rotax snowmobiles do not use a performance resonator type of exhaust, it's just a straight pipe. I think the reason for that is that if you stick the turbo on the end of the confuser of a resonated exhaust, the continuously spinning turbo will not let the exhaust "resonate" i.e. change pressure directions on every engine revolution. If you have a spinning compressor wheel, the momentum of it will just even out the pressure waves, thus, eliminating the resonator effect. You might aswell have a simple straight pipe then. I don't think high-end powers are better with turbo engines because of that, but they may equal to NA 2-strokes, with a broader torque curve and resistance to altitude changes.
I'm just glad to hear someone use the term "turbo-supercharger"...and actually understand what each part of it refers to. Yay! Subbing. :-D
I imagine there could be some sort of effect on the turbine wheel absorbing the head end of the exhaust pulse, and sizing your turbine is probably pretty important to make sure to conserve as much of that pulse as possible without building excess backpressure, but this is interesting! And it certainly works in a very different way to 4-strokes.
Great video, i am quite intrigued. It gets my engineering cap on.
Use a Sprintex Super Charger then inter cooler then fuel inject. Like a Diesel 2 stroke set up.Just make shore the the exhaust closes off to trap the high pressure air coming in.Leave the sump below in a vacuum for less drag.
What if you drive a turbine with the revolutions of the crank shaft and inject the mixture with that power just before the ignition? You could get rid of typical 2-stroke problems AND benefit from missing a carburetor...
It's hard to explain, but I would build it like a 4-stroke, where the crank shaft is separated from the cumbustion chamber. So there wouldn't be the typical 2-stroke ducts BUT a 4-stroke sealing piston ring.
At the end you can get 4 strokes per revolution: injection, compression, ignition, blow off, repeat.
This is what we call a jet engine, and you're missing one thing - compression. Is the crankshaft driving the turbine or visa versa?
Crankshaft is spinning the turbine. By getting rid of the typical ducts (I don't know what they are called, anyway) the only duct would be for the exhaust. So if the piston comes up and the duct is closed, the injection could start until the ignition. So that's already available, hm? ;-)
exellent video i allways wonder how a two stroke engine work and you explained it perfect thank loads ste
Skidoo offers a factory warranty 850 2 stroke twin turbo. So ya it’s being done reliably in mass. Bikeman performance has tunes for it just like it’s 4 stroke cousins.
I like a healthy balance of delboy videos.
a 2 stroke by nature has to by forced air intake or the exhaust would blow out the intake ports.
Thats why the exhaust port opens before the intake ports to relieve the majority of the exhaust pressure then the intake pressure can force itself in despite the exhaust still exiting the cylinder.
Th expansion chamber adds horsepower by pulling some of the intake charge into the exhaust then pushing it back into the cylinder before the piston closes the exhaust port raising the intake pressure above atmospheric thats why 2 stroke make typically 1 third more power then an equivalent displacement 4 stoke engine.
They are supercharge (forced air) already by the piston going down forcing the air from the crankcase up into the cylinder and a reverse wave of pressure coming in from the expansion chamber before he exhaust port is closed. yes a turbo charger or super charger to aid the forced air will work.
Hello mate, I have a few points about your comment
1 - "They are supercharge (forced air) already by the piston going down forcing the air from the crankcase up into the cylinder"
- This extra pressure isn't supercharging. Supercharging is when you add more to a standard cycle. This is part of the cycle as standard. The pressure increase is used to move the charge, any gains that the charge below the piston gains in energy is used to move the charge. Its not adding anything to the net product. Not only that but it any gains are lost due to the resistance the piston moving on the power stroke.
2 - "thats why 2 stroke make typically 1 third more power then an equivalent displacement 4 stoke engine."
- 2 strokes have 'more power' due to the fact that it fires every 360deg instead of every 720deg that a 4 stroke does.
3 - "before the piston closes the exhaust port raising the intake pressure above atmospheric"
- the pressure wave from the exhaust is all about charge recovery. I have a video about that here - th-cam.com/video/j8mCVoPWUaM/w-d-xo.html
cheers for the comment - matt
Pressurize the air box. You need over pressure rubber reed type windows for over pressurizing the air box and under pressure reed windows that will open up in the air box when more air is needed till you figure out the 12volt muffin fans that feed the air box through a throttle positioning sensor.
Hi - Interesting Video - I am just building a race car in UK using a V8 - 3600cc two stroke + CVT transmission (about 350hp) AND looking to fit a turbo. I am converting to EFI using a Megasquirt ECU. Why fit the turbo? - noise reduction mainly since its 145db on open exhaust and I need to get down to 105. So I will experiment with the available turbo charge added air whilst engine on dyno. Engines are currently tuned to 600hp so not too worried about component failure.
Hello Peter mate, lol This is my channel, you contacted me through work and we were emailing each other then I didn't hear from you? Hows it coming along? - matt
A Napier T9-29 two stroke diesel engine was both supercharged and turbocharged! Not only that it had an odd number of cylinders and twice as many pistons...and a 3rd as many cranks! All 1950s technology too!
My friend use to have a 500hp 2 stroke mercury v6 outboard... so it can be done not easily what I've learned from him is that you need a way to increase the fuel in regards to the boost aka fuel injectors and adjust timing at the same time
Which one in particular if you can remember? I'm planning on doing a turbo set up on a 1970's merc I6.
After/during combustion, there is a lot of cylinder pressure, (much much more than the supercharger can ever do), that makes the hp of the engine, and that all "blows down" in about 30 degrees of crank rotation, after the exhaust port opens before the transfers open so they can do their job and fill the cylinder. Unless you can trap the pressure of a supercharger, (which we have not done yet), to keep the pressure from blowing out of the exhaust port, the only benefit you are going to get from supercharging a two stroke, is less "exhaust gas mixing" in the cylinder, (which will make a bit more power), but you will be wasting fuel out of the exhaust pipe. You will not need upgraded fastener hardware, like head studs. Supercharging, it the only thing that makes me like a 4-stroke.
As a matter of fact, two strokes have been made effective with both turbos AND superchargers on the same engine- the catch that it must be a diesel. At least one form of boosting is actually necessary on a two stroke diesel, as the intake charge is used to completely flush out the exhaust, and being a diesel, no fuel is wasted in doing so. Note-this is generally only suitable for multi-cylinder two- strokes, and ideally for diesels only, as gas engines would dump fuel into the exhaust.
Wouldn't the spinning exhaust turbine prevent the backpressure needed for the combustible mixture to reenter the chamber?
If the turbo was in optimum position ie; close to the cylinder.
So the engine might run until the turbine spools producing even more forced induction, then the engine starves for fuel because the air-fuel is spraying out the arse end of the pipe.
Plus in a non power valve engine I can raise the exhaust port to change the port timing.