Compound Turbochargers Explained
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- เผยแพร่เมื่อ 28 ก.ย. 2024
- Why do Compound or Twin Turbos work so well? Watch this simple explanation (by a Diesel Power Source turbocharger expert) of how Compound Turbochargers work.
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This was straight to the point and super easy to understand! Thank you for this video!
Good video. Short, sweet, and to the point.
so. i wanna do two of these, mounted on either side of an iron block LS. who's with me?
Me too whats up
A race team is doing compound turbos with 3 and shooting for 3000hp on a 4 banger. that alone shows the potential of compounding turbos
@@d3tach3d just watched Shane's interview on HP academy.
@@imty8774 right on, thats where I saw the first vid. Then watched the dyno videos on their test setup
Quad-turbo LS?
Sign. Me. Up.
This was very informative. Well explained. Thank you.
Great video. Can you do this for every mechanical and electrical component on these trucks and specific for each manufacturer? Thanks that would be great🤣
Why would you not have the smaller turbo as primary to feed large turbo on cold side, and have manifolds go into smaller turbo then fron there into the larger turbo? To me, going from large to small seems restrictive
🤦🏻♂️
I'm assuming it would be the same way or at least similar with the triple turbo kite made for diesel trucks
Where do you get those castings for the compounds. You sel them?
For anyone Curious of the ratios in terms of compression he’s talking about the small turbo being between 74.69%-82.67% of the big turbo. Might give some people an idea of where to start if you’re thinking about compound, turboing something😅
For the reverse of above the large turbo needs to be between 20.97%-33.87% bigger than the small turbo 😅
What aspect. The compressor or turbine or what.
@@akassasin5768 The compressor/intake side
Brilliant video!! Very easy to understand you
Good video, great explanation
I feel smarter now. Thanks!
Would a wastegate on the secondary turbo be necessary?
,,sir, do compound turbo is good for long trip? and any sugestion turbo for 2.0 desiel engine,,? thank you and God bless
Do you still use a wastegate for each turbo or just one for the larger turbo?
doesn't small turbo make the restriction for the larger one in intake ?
I'm not an engineer, but the answer would be NO. Simply because if that was the case, jet engines wouldn't work
Depends on how much you want from them,guys getting 2000hp from a 2l engine are using a 106-112mm turbo into a 76mm and pushing over 100psi through it but its bound to be excessive wear on the 76mm though,modded housings bigger bearings its own oil-water pump or just wait for it to whine and smoke then change it out.
Great explanation! Here's a theoretical question. Say you have a gasoline 4-banger (2 liter). If I wanted to run a supercharger AND a turbocharger for maximum boost throughout the rev range, would I feed the turbo into the SC, or make the SC feed the turbo? What would be the best way to route them if space was not a problem?
Kryndon64 turbo into supercharger is generally better because superchargers are better for low rpm power, while turbos are happier in the higher rev range. thso way, the supercharger doesnt run out of steam at upper rpms if it had to feed the turbo. with the turbo feeding the supercharger, it wont run out of steam as it doesnt have to suck in the huge cfm amounts of air as the turbo does. it just compresses already compressed air
ti1355 i never throught of using a supercharger to spool a larger turbo, than open up the turbo to the atmosphere. very good idea
Sc will ruin out of air bf it spools the turbo, as mentioned if you do that you have to bypass it, ie the engine basically runs off the sc at low rpm then switched to turbo at high rpm can't actually feed the turbo with sc bc it Will literally run out of air, look at spool speeds and you'll see why
Mikel Bentley Yes it's true that a supercharger will run of breath when the turbo spools BUT it's very easy to bypass it. All you need is a one way valve parallel to the supercharger. As long as the supercharger is pumping more air than the turbo is sucking in the pressure in the supercharger outlet is higher than the inlet pressure. Once the turbo spools the pressure drops because the supercharger can't keep up with the flow requirement. The one way bypass valve opens and air goes past the supercharger, the supercharger just free spins with minimal parasitic loss.
You can also do it the other way with the turbo feeding the supercharger but it's a bit harder to controll such a system.
Would a hx35 spool a 75mm turbo ? I have both and might build a compound set up for fun
Yes we sell that kit all the time. If you already have both Turbos, we have a piping kit you may be interested in.
How does this affect the compressor map?
They say to "split" them aka average but I honestly don't think that's 100 percent because when they do those tests they use atmosphere.
Mapping the intake flow, compounds should make a steeper ramp up the pressure scale.
what's preventing overspooling of the stock turbo...Is it wastegated at a certain pressure into the large?
We still use the factory wastegate valve. But on compounds it does split the load between the two turbos, so the individual turbo stress is reduced.
Cooler denser air?
Hi, what about compounding a common rail diesel with variable geometry turbo, electronicaly controled? Any setup ideas? Thanks in advance.
I wouldn't think that there is a benefit to compounding VGTs. Compound turbos are used to reap the benefits of faster spooling without the vanes of a VGT.
@@83ED9 Hello, I got a suggestion coming from Australia, that I should use the original VGT as the first small one, and a Garrett GT30 with internal waste gate as the big one. Or with external waste gate.
I could see that working better than compounding 2 VGTs.
How to control those 2 turbos with electronic controller? Possible?
In effect a common rail or any electronic injection control already is controlling the turbos by either supplying more or less fuel. More fuel makes more heat which makes more drive pressure and thereby more boost, opposite for less fuel. If the load increases, temp of exh goes up forcing boost to go up to a point, then you add fuel to keep moving and around it goes where it stops, who knows.
Im bit simple,
say i had an internal wastegate on my smaller turbo set at say 17PSI... would the larger turbo pushing air in the small turbo make my external wastegate open too fast?..I'm so confused... Do i need my wastegate pressure set the same for both turbos?
We generally set the wastegates over 35 psi.
So bassicly im converting ny dodge to a f 15 fighter jet is what you are getting at.
How do you control the boost?
How do you reference your wastegate?
That's what I was wondering. I see the reference comes from the big compressor to the wastegate. I guess that has to do with the pressure differential.
According to DPS they said the secondary’s wastegate opens when the primary hits 35 psi of boost
Why big turbo first and not the the other way around?
How safe are rubber boots ?
The charge pipe on the cold side between the turbos is Not a rubber boot, it is a special Kevlar/Nomex lined Silicone low-pressure charge pipe that provides superior flow and fitment compared to metal. The couplers on the kit are made of the same Silicone material. Between the turbos on the Hot side we have a cast iron hot pipe that holds everything nice a firm along with a support bracket.
I didnt understand how compound turbos worked until I watched this video.
Does the smaller turbo still get choked out just like it would if it were that smaller turbo only or is the excess exhaust diverted to the larger turbo? would it be possible to bypass the smaller turbine at higher RPM?
Small turbos wastegate opens then the big one goes to work more.
2:25 Benefits; Cooler air; Please explain.
Cooler, denser air burns more efficient than hot light air, in turn gives better power and torque throughout the power band
@@jamestaylor-qb9wo yea but it goes through a turbo an heats up. And then that hot air goes through another turbo. Then the cooler
@@bburnnone exactly what I was thinking
Its denser and cooler because the bigger turbos not working hard to compress the air that hot because of the volume and it s just shoving it down the little ones throat,so then it becomes on how efficient the little one is on its maximum rpm.
whats the difference between Compound Turbochargers vs twin turbos?
Nothing ! Unless you are using one turbo for one bank and another for the other bank in which case it's simply a twin turbo setup. It's when you stack them on top of each other they are true compounds. The first one in line with the exhaust compounds and is compounded by the second as the flow path of the moving air and gas is reversed, hot from small to big and cold from big to small. When drive pressure goes too high exh. is bypassed to the big turbo adding more free flowing drive pressure to spin it harder which relieves load on the small turbo. The primary purpose is to get boost up faster than you would with just the big turbo. This keeps smoke emissions lower.
Eita um desse no punto tjet ia da pra fazer sera ?
vai desmanchar o motor kkkk
@@luizbruno2010 ia anda aguenta de boa heheh
Does it affect the small turbo spool time?
The small turbo will determine how fast the compounds spool up.
What about boost control?
Theres the wastegate flange on the dump pipe.
Power on the intake stroke?
Yes, we've actually ran a substantial amount of CFD testing, which has demonstrated this, then backed it up with real world tests. With positive pressure ratio (exhaust to boost), and a well ventilated crank case, we can and do produce more power on the intake stroke than the exhaust stroke robs. We're behind on getting this video out, but will be producing a video shortly showing some of the actual tests.
top!
i always thought the small turbo fed the large turbo to remove lag?why does the large turbo feed the small one
what would it take to obtain a compound setup for a 3.0 Liter Mercedes Diesel engine?
Not much just design and build it, then get a fuel pump that will supply enough fuel for whatever your desired power level is. And make some good intercoolers. And fit it all under the hood.
I'll take one for my forester.
That's not a bad idea....if you have the TF it's a great choice for a small turbo in a compound set up
I'm sorry to say but this is not a compound turbo.
It's a serial twin turbo.
Compound turbo is something completely different.
en.wikipedia.org/wiki/Turbo-compound_engine
th-cam.com/video/9PbxmRA9vbs/w-d-xo.html
does top turbo oil return line go into bottom turbo feed
Sam Ward probably not. it would get too hot that way and break down
Chuck an intercooler between the two compressors and then it'd work even sweeter
Compound turbo setups are not as popular as they should be, because it's all the benefits of a turbo while hugely reducing the drawbacks. Namely lag.
Woooowww
That giant rubber boot between turbos. Not the best should be metal. An the air filter set up looks cheese dick.
This is like a 2 spool gas turbine.
That's exactly how I'd design my twin-turbo set-up because that saves space and weight.
Compound turbos and twin turbos are not the same thing. You lost me in the first 4 seconds of the video lmao
compound turbo is a type of a twin turbo configuration
@@luizbruno2010 no it is not. Compound turbos scavenge rejected air and push it to the crank to give the engine an additional “50 horsepower”. Although the design never worked and the turbos are almost always switched or removed.
@@jewwinfrey6460 if you say so
@@luizbruno2010 lmao not really an “if you say so” kinda thing. Sorry you’re uneducated on the different types of turbos buddy lmao
@@jewwinfrey6460 ur saying to me that compound turbos doesn't work. i don't have anything else to say.
I used to work at Williams International. They made a "turbo compounder" for the military. It doubles the horse power of a tank diesel. It incorporates the compressor section of a small gas turbine engine to make boost.
Before this video for some reason I couldn’t picture why it works. Now that I heard to turbine engine comparison, it makes total sense to me.
Great video. I'll have to watch it a couple times because I'm an idiot sometimes, but you did a great job of explaining the operation and advantages of the system.
If the exhuast gasses run through the small turbo then won't that ultimately determine peak hp? How is the big turbo helping? It seems like the small turbo works @ 100% And the big large turbo only being used say 15% to spool a little faster?
Wastegate!!! The small turbo cant handle more than say 70% of the exhaust flow. When the wg opens it dumps the extract flow aka energy into the larger turbo. That spools the larger compressor! Boom, more air flow.
Also listen to the video again. Turbos are pressure devices! Input x 2 or 3 is the unusual. If The large compressor makes 25 psi then the smaller compressor will take 25 x 2 =50 psi. More pressure than either turbo can produce alone.
Wastegated to push that fresh exhaust energy straigh to big turbo like he said^.
Oh and also ill repair this one:
"Large compressor makes 25psi of boost ,so it is working on pressure ratio of 2.7, then it is multiplied by smaller charger by pressure ratio of 2, so total pressure ratio is 5.4x -> 65psi.
valves my friend valves
Wastegate bypass to the large turbocharger only improves gas flow, and the small internal wastegates on most turbochargers aren't up to the task of bypassing gas flow when you really start cranking things up. I've seen Australians take a Primary 50mm-60mm wastegate and plumb it into the center section of the manifold junction, then pipe the bypass gasses directly into the large turbine inlet, that usually fixes exhaust choke points for high exhaust gas flow rates.
when they say they turbo everything so they turbo the turbo...
Then turbo that turbo that’s attached to the turbo
@DieselPowerSource....It probably has been asked before but my question is in regards to the smaller turbo receiving boosted air from the larger turbo. As the compressor wheel is usually driven from the exhaust side and is compressing external air that is at normal atmospheric pressure, are there any extra stresses placed on the journal bearings of the smaller turbo due to receiving boosted air, rather than air at normal AP? I'm assuming this is combatted by running ball bearings rather than the usual bearing found in standard car turbos. It looks a superb setup in any case and can see that it would eliminate turbo lag due to both turbos spooling at the same time.
That is NOT a compound turbo setup. What you have done is a two stage turbo setup.
A compound system is when the turbo shaft drives directly the crankshaft of the engine
i thought it was from small turbo to intercooler to engine until enough exhaust built up then it would spool up big turbo with excess exhaust gases that would then spool small turbo more due to higher compression resulting in more boost
Same thing with a 2 stage air compressor big piston then second smaller piston.
Great video thank you.
Wouldn't it make more sense to have a smaller faster spooling turbo feeding a big one ?
It’s all about the transfer of energy. It would take more energy for the small one to make the big one run for less power. The big one pushes and compresses more energy to the smaller one and because of the rate at which that energy is transferring it creates a more defined and quicker rate of the release of that energy which in turn creates more power for the engine.
Think about a water hose. The water can come out normally or you can put your thumb on it so the water becomes more defined and sprays out stronger with more power because it’s going from a larger hole to a smaller one at the same speed
Adamantium Life you’ll get more pressure but less volume isn’t the point of a force inductor to get more air volume
This is what the original youtube was about.
i would have thought to spool the smaller turbo off the motor 1st to help spool the larger one.
The original compound turbo was used in the 1950s on triple tail Connie it put the shaft power back to the engine crank output
You are 100% correct on that.
can I stuff this into a Volvo 240 Wagon
How much that compound turbo?
has any one ever put an inter cooler between the turbos ?
michael harris yes check out the hoonigans channel they got someone's on there with old ford truck with a Cummings. It has a water to air inter cooler between the turbo. The truck makes 1233hp to the wheels with 2000 ft/lbs.
Technically, that's the only situation where you have a literal "intercooler". If it's between the turbo and the engine, it's an aftercooler, if it's between one stage of compression and another, it's an intercooler.
I used to do maintenance on some big quarry trucks that ran dual supercharged and quad turbocharged V16 engines. Each cylinder bank was plumbed (Air cleaner->Air Filter->Supercharger->Turbo->Intercooler->Turbo->Aftercooler->Intake) I guess that used to be the cheapest way to make 5,000 Horsepower.
Hey guys. International trucks did put an intercooler in between the turbos on the maxxforce engine. It pre-cools the air before it goes into the smaller turbo. It works great. Look for the maxxforce 13 engine. Most drivers will complain about it but they're comparing the power of a 12.4 liter to a 15 liter. I love my 12.4 engine and I own them both.
I saw a race motor that had air to water imbetween
@@MakingCentsInTrucking u r the only person to ever say "I love my maxforce" lmao. They r the worst engine out there!
So basically sequential lol
Click this link to see some Compound Turbos: www.dieselpowersource.com/compound-turbos-2
DieselPowerSource Just wondering if it would be feasible run the cold side of a small turbo in to the hot side of a large turbo to get the large turbo to spool fast like a small turbo?
Is it possible to run a setup like this on a gas engine?
Gas has turbo examples so compounds should work on any engine eg. Lt4 ,vr,2j,...
In about 1978 while working at mack trucks our engineering lab actually built a twin turbo cummins KT400
The larger turbo won't compress the air until it starts to make boost due to the size of the compressor wheel, the small turbo drags in the air from the big turbo because of the small compressor wheel is making boost in the lower rpm
hello i have a guestion what control secon larger turbo boost ? the smaller one have wastegate or VG\VNT system but secon bigger one dosnt have waste gate actuator how it dint owerboosting ???
Uhmm doesn't all boosted air regardless of compound or single turbo set ups give you power on the intake stroke?
What kind of running is needed when installing compounds???
Thinking about using a fleece cheetah with my stock turbo but I’m not sure if I would need to do any special tuning. This is hardly ever mentioned on these videos.
Do these have any horse power benefits over a stock turbo if so how much
Our compound will increase HP by approx. 25% over the stock turbo, if you do thing more than install the compounds. Of course, with the compounds you will have the ability to add ALOT more fuel if you desire, which will increase your HP by even more.
Here are a few video links you may find helpful:
th-cam.com/video/DmWNHoqXjx4/w-d-xo.html
th-cam.com/video/Et7v7DEXuj8/w-d-xo.html
th-cam.com/video/5dzvPzf3u9g/w-d-xo.html
th-cam.com/video/nZBNMB8HQKE/w-d-xo.html
Don't need an intercooler if between turbocharger 1 & 2 using a rubber pipe.
Won't the smaller turbo cause more back pressure and restrict exhaust flow at higher rpm?
Blow off valve dumps what the small turbo can’t handle straight to the big turbo at higher rpm’s.
@@jonellwanger7258 you mean wastegate right? That is actually clever.
U think u guys can do a compound setup for a 4 banger? Say A k03 twin scroll with a Gtx2 ceramic twin ball hearing for a 2.0 or 2.3l?
You can..
What if we use 2 turbos with the same size?? 🤔
Could you explain fine tuning the waste gate say for a 07 5.9 cummins?
Love it
Can I ask some questions sir??
You bet, what would you like to ask?
If someone could donate me one of those kits that would be fantastic =D
Eric the car guy, is that you?
how much a kit like this cost?
I know this is how its supposed to be. But it seems the smaller turbo should spool the largr turbo. Looking at it looks like it would overspeed the smaller turbo. I know this is not so, im speculating on how it looks on the surface
Yeah thats why you have certain sized turbos depending on what you want from it,down low top end power ,torque etc..
Kaikki alkaa pikku turbosta, ei isosta.
what if you engine bay mount the small turbo and rear mount the intake turbo? is there a problem with pressure loss or heat loss to second turbo?? thank you
The rear mounts work good because its built up the pressure in volume to the back and its charge is cooled alot heading back to the front,it be the initial lag to begin with nothing the loading up of the clutch wont fix.
how does it affect the exhaust turbo braking? Thanks
Horrible verbage but....
Do you guys think it's a viable development tactic to design an electric precharcher turbine that takes the place of the first stage turbo on a compound turbo system? If someone can make a precharger spin to 50000+ rpm nearly instantaneously like those dang bmw and volvo electric prechargers, would the price of the r&d pay off soon after people began buying the kits? Y'all seem to be able to make very compact compound turbo kits whereas the bmw, volvo, bugatti systems are all planted upstream via much longer tubing to be able to fit inside much different and compact engine bays. What do y'all think? Could Diesel Power Source make a badass super quick spool compound turbo that feels like a supercharged system that just keeps on building boost?
whitlcj1 An electric precharger kit is not really practical UNLESS you have a 48 volt or higher electrical system. A supercharger draws a lot of power, we are talking about 10-20% engine power. A 100kw engine would require about 10-15kw of power which means 3-5000 Amps at 12v. By comparison an automotive starter draws 2-3kw of power. That's about 300 Amps. Truck starters with 6-7kw have 24volt electrical systems and also run at about 300 Amps. Now remeber how thick starter cables are. You would need a cable with at least 10 time greater area than that for a 12 volt system. This is extremely unpractical. Also the battery simply can't supply that amount of power. With hybrids it is easy, you already have a higher voltage system that can supply the power. All you need to add is the supercharger itself.
whitlcj1 Also a mechanical supercharger has it own set of problems but they seem to be easier. Since it would be driven directly it's speed would be directly proportional to crank speed. This means that if it was geared for low rpm it could overspeed at high rpm. So we would need a clutch that can disengage it. If it were geared for high rpm then it wouldn't make much boost at low rpm.
The complexity of the belt drive is increased. This system would be very exprensive for what it does. Do you really need full torque from idle, or can you live with it being at 1200-1500 rpm. Do you really mind half a second of delay after you press the throttle. Sure it would be nice to eliminate that but would it be worth it if it costs thousands of dollars? Also modern turbochargers spool faster and have lower boost thresholds than ever. So the requirement for such a system is lower than ever
Yip TH-cam cleetus electric supercharger works great i dont know about 2500$ great though,considering theres 500$ high powered brushless rc speed control and motor sets that easily put out 5kw on 24v 200a and 800a burst the batteries would be the main expense say 150$lipo for 15min runtime but then youll probably only have it going 10 seconds at a time for the initial pick up.
So there are four turbos, and zero compressor units?
there are two turbos. two compressor wheels and two turbine wheels.
Here’s where i loose how this can make any power. Yes the compressor side makes sense, but at the end of the day how does the first turbine “smaller one” not become a restriction at a certain point?
Because the small secondary only stops producing power because it runs out of air . Its at the peak of its map in its atmosphere , the large turbo makes it so that wont happen. It does create a restriction though. I have a 7675 with a s488 compounded. The s488 should be good for 1300hp Ill be lucky to see 850 with the two.
Depends on the sizing of them,these guys running 100psi plus on 2l engines@2500hp are feeding a 112-20mm turbo into a 75-80mm,and thats a pretty big small turbo but thats racing applications though and all the support mods to go with it bigger pumps secondary pumps etc..
The small turbo must have a waste gate allowing relief on the exh. The second turbo changes the intake map of the small turbo letting it work with less loss of efficiency so as long as you can supply fuel to keep the exh heat in range up, it's the same as any other engine, more air needs more fuel more fuel needs more air, increase both and power continues to increase too.
Where can I get the piping from?
Thanks
no turbo lag?, which one should be the VGS, the smaller one?
neither in this case. but guys do run a vgt turbo as the smaller primary and a fixed vane atmospheric turbo. but even with two fixed vane turbos, there is next to no lag because of the small turbos size.
How much for this
Good video lots of good info, im curious what exhaust housing are you using on the s475? It looks smaller then the factory one that came on it
And what would be the size of a factory S475 since that was never offered as a factory turbo? At least not on a Cummins. Cummins used Holset and the S series is a Borg Warner. I could be off on that in the later years. Even Holset turbos came with many different turbine housings depending on what it was installed on from the factory, so what installation are you asking about?
@@brettschacher8644 Thats not at all what he’s saying.... 🤦🏻♂️
Very cool‼️Great explanation
Great video i was wondering dose a compound set up need to wastgates on each turbo.
Generally no, you gate the small turbo to bypass exh. into the larger one which can flow much more. Once the drive pressure is high enough to spool the big turbo it needs to be passed out without overdriving the small turbo. It seldom needs bypassing the final, you don't gain any power doing that.
Any videos on this type of setup in 2012 Ram
Pretty much the same whatever year it is.
All nie and clear :) thanks!
Thanks for the video, informational and short