Backpressure isn't the issue. Exhaust gas flow velocity is the issue. Ideal piping size is that which causes the fastest flow through it for maximum power. Too small piping chokes the system. Too large piping slows down exhaust gas velocity.
correct!!! and his cup and paper trick is crap....if it was atmosphere pressure keeping the card on as he indicated then wouldnt it also do the same without the water in the cup....i think he has other forces at work like vaccum and sticky h20 not a good example....and forced induction would not even apply to his world...but it would in your explanation of choke points and gas velocity.....the exhaust is an extension of the heads really
I think the guys at Summit need to stick to selling parts and not making misleading videos. As an engine builder, you strive to tune the exhaust system so that negative pressure waves hit the exhaust valve as it opens in order to make the pressure at the exhaust valve BELOW atmospheric pressure to get more pressure differential and more flow. "Backpressure" just hinders flow and makes the engine less efficient in every way.
@18 RLX FJBLGB question I have a 4 cylinder sedan with a muffler delete and Spec-D exhaust welded on if I did a resonator delete would I be hurting my engine if so how?
@@FullSendFabrication The pressure wave is relevant no matter how long it is, it just has a smaller effect the longer the pipe is past the 3-4ft of header needed to get a good tuning effect. The pressure waves work like a tuning fork, it will start at your exhaust valve, travel all the way to the exhaust tip and hit atmospheric pressure and then reflect and go back to the exhaust valve as a low pressure wave. The longer the pipe is the more waves are in the pipe at the same time and the less effect they have. Kind of butchering the explanation but that's the most concise way I know to put it.
It boggles my mind that a business like Summit would consent to let someone who doesn't understand fluid dynamics instruct people on exhaust systems. Summit, please consult an expert. This just propagates myths.
This "back pressure" wise tale has been passed around for over 50 years! "My grand paps great grand fathers brothers sisters ex husbands son inlaw said that he lost torque on his Model A street rod when he added dual exhaust... so naturally the loss of torque was because he removed the beloved back pressure... as soon as he added the smaller exhaust his back pressure returned and he made more power... LMAO! I honestly dont understand why more people dont have the slightest grasp on basic fluid dynamics... just a slight grasp would do wonders for most.
Mateo Gomez Gomez it is vacuum along with the vescosity of the water causing a seal at the edges of the glass to the paper. water is heavier then air it pushes down on the card. water is to thick and heavy for air to be pulled threw the edges. causing a vacuum
If back pressure helped in ANY type of way then NASCAR would run it, pro stock, top fuel or any other racing would all use some sort of back pressure... But they don't... Scavenging is different and it has to do with pressure pulses working together to produce a small vacuum, not "back pressure". That's it. End of story. Point blank.
Johnny SIX4 !! Very simple. You have street applications and race. With racing you spend most of your time at high RPMs therefore the flow will be greater thus requiring less back pressure. Im street applications, since the RPMs will be lower most of the time, you need it so the scavenging effect takes place. Otherwise you'll have no torque on the low end and only extra horses on the top end like race cars. As a result you lose low end torque and ability to pull through the lower gears and RPMs. Let's not mention fuel economy loss. You NEED back pressure to create the scavenging effect more so in trucks. It's a large vehicle that requires torque to get the large body moving, not horsepower. Horsepower takes effect at the upper end of the spectrum where torque isn't required as much. Mustangs are light and have high output motors. Stop and go traffic will destroy your fuel economy BUT with a free flowing exhaust, your horses will be higher so in race applications where you're at almost redline, you'll notice the benefits. I don't know very many people that spend that much time at high RPMs while driving to work, so it's not the most economical. You choose how you want your pocket book to go. Poor fuel until you hit redline or decent fuel the way the car was designed and sacrifice the upper end. Take your pick, you can't get both. How that answers your questions and clears your confusion....
Sofa King , NO, NOT BACKPRESSURE, YOU OAF! VELOCITY, AND ONLY VELOCITY. You're wrong because while backpressure will create velocity, it comes with parasitic pumping losses that are created bc the exhaust isn't working good enough, so the engine has to FORCE the exhaust out, hence pumping losses, but at least the pressure creates velocity. If you use proper size pipes, use mandrel bends, a proper balance pipe for dual exhausts, as few of bends as possible, as gradual of bends as possible, and as short of a system as possible (except doing open headers on a stock or mild build). Those will keep your velocity high AND cut backpressure too. You don't need one to have the other! You just need to get the right stuff! Geez
Choosing the right diameter exhaust pipe is to make sure the exhaust gas temperature and velocity stay up. Back pressure is created when your engine is pumping out more air than what your exhaust can handle, as opposed to the partial vacuum created by exhaust scavenging...duh
Basically your engine has to FORCE your exhaust out, so your engine loses some power because of that, particularly at upper rpm. Backpressure is a myth that people just keep believing. 😔😔😔
For those bringing up NASCARS, etc. let's explain something so you understand how motors work. Johnny SIX4 !! Very simple. You have street applications and race. With racing you spend most of your time at high RPMs therefore the flow will be greater thus requiring less back pressure. Im street applications, since the RPMs will be lower most of the time, you need it so the scavenging effect takes place. Otherwise you'll have no torque on the low end and only extra horses on the top end like race cars. As a result you lose low end torque and ability to pull through the lower gears and RPMs. Let's not mention fuel economy loss. You NEED back pressure to create the scavenging effect more so in trucks. It's a large vehicle that requires torque to get the large body moving, not horsepower. Horsepower takes effect at the upper end of the spectrum where torque isn't required as much. Mustangs are light and have high output motors. Stop and go traffic will destroy your fuel economy BUT with a free flowing exhaust, your horses will be higher so in race applications where you're at almost redline, you'll notice the benefits. I don't know very many people that spend that much time at high RPMs while driving to work, so it's not the most economical. You choose how you want your pocket book to go. Poor fuel until you hit redline or decent fuel the way the car was designed and sacrifice the upper end. Take your pick, you can't get both. How that answers your questions and clears your confusion....
Velocity is created BY back pressure. The more pressure you have, the more velocity you have. It's basic fluid dynamics. The less back pressure the better. If an engine actually makes more power with increased back pressure, something is fucked up.
Sorry, but this video is an absolute joke!!!!!! You want back pressure because of the valve overlap?????? Thats 100% absolutely false. Combining back back pressure with valve overlap will reduce power which the last time I checked, it the primary reason why most people what to change their exhaust is to increase power. I'm quite disappointed that Summit Racing and the Company that they are would even put out this video. To anyone why believes that you want even any backpressure, I suggest that you educate yourself on what exhaust scavenging is and how it effects cylinder filling and why we attempt to design exhaust systems and headers to have maximum scavenging (particularly in the region where the cam(s) create the most power) ...
Look all engines react different to exhaust changes. On inline 4 and 6 if your piping is too big then the torque down low will be gone and feel sluggish but High rpm gets a little bump. V8s seem more forgiving but it is true that you need the correct pressure and velocity to have a good ballance of low end torque and output. This I have found on NA engines not boosted and from experience not reading books.
Back pressure in the exaust system require's the engine to work harder period. Back pressure kills efficiency and performance , no ifs and's or butts. What increases efficiency and performance in a exhaust system is Exhaust gas velocity. And thats where pipe size comes into play. To big of pipe reduces the scavenging effect of the exhaust system by decreasing velocity. To small creates back pressure slowing velocity. So a correctly sized exhaust system with a correctly located crossover or X pipe is what most important on a street driven vehicle. Race tracks......less means more. So open headers are king
No engine needs back pressure! Its all about exhaust flow and velocity within the system. Go to small in ID and gain back pressure, go to large and lose velocity. The perfect exhaust would be sized to eliminate any "Back-pressure" and maximize velocity. Back pressure is exactly what it implies, its a restriction! Velocity on the other hand is what creates the scavenging effect from the cylinder. Every NA cam is designed with an overlap. The overlap is a small duration built into the cam where the exhaust valve is closing and the intake valve is opening, for a short duration both are open at the same time. An exhaust system that promotes velocity will have high vacuum on the exhaust side which literally tugs at the intake side giving the intake a running charge into the cylinder just as the exhaust valve snaps shut. This is called the "Scavenging" effect and most all cams are intentionally built with this overlap in order to take advantage of the scavenging effect. The quickest way to kill the Scavenging effect is to add back pressure! Long story short... dont believe everything you hear on the internet... like the video above, you are bound to be mis informed by people who claim to know what they are talking about... So dont take my word... get informed with the theory of operation and become a better Hot Rodder!!!
I'm sorry guys, but your theory on back pressure is wrong here. On the board you are holding up at 2:12, the cylinder is at the intake stroke, i.e. the piston is moving downwards. If we assume that both intake and exhaust are infinitely big and have no flow resistance, then the pressure in the cylinder MUST be lower than in both the intake and exhaust. Air will therefore flow from outside through the intake into the cylinder, and exhaust would flow from the exhaust back into the cylinder. Air would not flow straight through the cylinder and out the exhaust port. This is a common misconception though, that stems from people confusing back pressure with gas flow velocity. The reason you don't want too big exhaust pipes is that you will reduce gas flow velocity, thereby not gaining adequate scavenging of your combustion chamber. Back pressure in an exhaust system is never desirable, since you would then use energy from the engine to push the exhaust gasses through the exhaust system. Google it, plenty of info out there on the subject :)
Summit Racing , could you respond to the above comment? I also think that air would move from the exhaust into cylinder rather than outwards from cylinder during the downstroke. I do think back pressure is important ( as I have experienced performance degradation when I had an exhaust leak) however, I'm not sure if you have provided the correct reason for its importance in your video. Thanks!
Vinzent Dk I absolutely agree, Vinzent. This demonstration is way off. During the intake stroke, the cylinder is going down and creating a vacuum to suck in the fuel/air mixture. There is no way that exhaust gas can also be flowing out during the same cycle. Al is correct that the exhaust valve stays open during intake but this is to 'artificially' increase the horsepower and efficiency. Here's how: - - - Allowing some exhaust to flow back into the cylinder increases the volume inside the cylinder without increasing the fuel/air mixture. This increases the pressure at ignition which makes the fuel more explosive and you get maximum efficiency out of the fuel. (Yes, it takes more power to create more compression, but the increase in explosion is well worth it.) If there is no back-pressure, you get less pressure inside the cylinder at ignition. This creates a longer, less efficient burn, and (because the exhaust valve opens during the tail-end of the ignition stroke), you could get burnt exhaust valves. This only applies to stock setups. If you're running a turbo, who cares. If you're racing, who cares, but if it's a daily driver, messing with back-pressure is going to cost you. IMHO
Ron "There is no way that exhaust gas can also be flowing out during the same cycle. " Actually, there is, but only during the end of the exhaust stroke or cycle and beginning of intake stroke. It has to do with the momentum of the gases durring overlap, when both valves are open there is exhust flowing out and air flowing in, the tail end of the exhaust flowing out helps draw in fresh air (scavenging) by helping to create a low pressure area on top of the piston. Exhaust flowing back into the cylinder (exhaust reversion) is actully a bad thing as it deludtes the fresh intake charge (this is what EGR do to lower combustion temperatures and reduce NOx emissions, dump a measured about of exhaust back into the intake). This is part of the reason cars with "big cams" idle so crazy. The late closing of the exhaust valve at low rpm lets exhaust back into the cylinder to mix with the fresh air charge which results in erratic combustion (sounds cool though). This clears up at higher engines speeds as there is less time for the exhaust to be drawn back into the cylinder.
Enrique Montero 3" single, and for dual, either a true dual 2.25 or 2.5 will work. This video was one whole pipe size off on his duals. He gave sizes for catback, not true dual. A true dual 2.25 can handle up to 400, so it's great for getting torque out of your motor. If you're mostly after the gains in the upper half of your rpm range, then go for the 2.5". It'll even sound a bitter burlier too, tho trust me, 2.25 can sound mean AF when done right (check out my vids and tell me how NOT redneck my truck sounds even tho it's a stock cam & everything). 2.5 will also leave you more.room to grow if you realistically plan on going above 400 horsepower. Otherwise personally I would go with 2.25, but 2.5 will also work fine if you want. Your choice.
Think of it this way..the smaller displacement 4 bangers rely on a little back pressure to speed up the velocity. And those same 4bangers with 200 horsepower now rely gradually less on back pressure and more on velocity created from the thrust the engine put out originally without relying on back pressure as much as lower horsepower cars...same thing with 6cyl and 8cylinder.. but add a half inch to diameter of exhaust on the 6cyl standard setup On a low hp v6 to make up for displacement gain.from 4cyl to 6cyl... now use the same principal going up in power in the v6 as I Explained in the v4... while going into v8 territory add another quarter inch to standard diameter piping for exhaust and use same principal... blah blah blah. Just read this shit and let common sense take over I’m confusing my self at this point 😂🤣🤣🤣🤣
This is all b.s. If this was true, explain to me why top fuel dragsters are completely straight piped. The free-er flowing the exhaust is, the more power you will put out. Also, the number of variables in exhaust size is more than just horsepower.
I lost all my low end torque when i moved up from 2.25" to 3". You actually want to do some research on a car forum. Learn from other peoples mistakes.. or it will cost you up to $500. According to the video above, I should be at 3.5". The sweet spot is 2.5" for me.
It works best when the whole system is the same size. Here is a link to an exhaust size calculator. www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/
actually, the water stays in the cup because there's a vacuum formed when you turn it upside down and the air can't expand enough to let the card off the rim of the cup, has nothing to do with back pressure lol
+PC Pro vacuum is negative pressure which is lower than the atmospheric pressure ... therefore the atmosphere pressure is the force that keeping for you information pressure is force divide by area. area is constant for the cup for both sides. the pressure in the cup is lower than the atmospheric pressure which mean the force that holding the card to the cup is the atmospheric force!
Sounds good, but you're wrong. The force in the cup is actually greater than the atmospheric pressure which really has nothing to do with the card staying up. The suction of the vacuum inside the cup exceeds the gravitational force being exerted on it.
Ahh the classic "yOu nEed A LiTtle BIt oF BACkpReSurE fOR bottOM eNd ToRQUe" myth. NO, you want to maximize VOLUMETRIC EFFICIENCY. Too small diameter and you will lose power from backpressure. Too large diameter you lose exhaust velocity, you probably won't lose power but you'll definitely be leaving some on the table. With that goldilocks diameter you'll get the fastest exhaust velocity and with it, scavenging. FOH with that backpressure bs.
Summit, I have a degree in automotive high performance and I know this is not how exhaust flow works, the story is about velocity. There is a specific formula for how big and long each tube needs to be in your exhaust system, this has to do with pressure waves and flow. The idea is to have a vacuum in your exhaust not pressure, pro stock dragsters actually have a measurable vacuum at the exhaust port and pressure at the intake port that equals around 7psi of “boost” combined on a naturally aspirated engine!!! This is due to the inertia of air.
actually you're wrong. there is no vacuum present. how is there vacuum if you didn't suck air or water out before or after putting the card over the cup? exactly, you didnt. vacuum is negative pressure from removing something (air or water) from a sealed volume. get a clue. LoL
Vacuum is actually the absence of pressure, it can't do anything. There is a partial vacuum that is created inside the cup in this situation but it's the relatively higher outside pressure that's responsible for holding the card in place.
The chart is great. The guys theory is wrong. It's all about flow rate. The faster you can force air in and out the more power. Meaning to small pipe will choke it out, to big and your engine wont be able to push all the air that's in that pipe out slowing velocity. The perfect size will help power at all rpm ranges. To big you'll loose torque to small you'll loose top end horsepower. That's where I'm at. My truck made 225 hp and ford decided a good size pipe is 2 1/4 SINGLE exhaust. I changed it to 2 1/2 but now I'm making a little more and it definitely feels choked up after 3k rpm. Engine is a 302 btw.
Right now designed and put in a custom header 4-1 with high flow cat, 2.5” pipe and a 19” oval Borla proXS Into a 2011 Chevy colorado 2.9L stock engine with some upgrades Do i make ok?
What is also important is scavenging of exhaust correct exhaust sizing will help "pull out" the exhaust pulses from the other cylinders (my explanation sucks) to big or dual exhaust in some cases reduces this effect some vehicles do better with a 3" single vs two 2.5" duals
It's very simple. Let's say you have a Honda. You run a 3" straight pipe with no cat or muffler, you will move all of your power up high and loose all of your low end power. If you ran 2.25" and have a muffler and cat, you will loose high rpm power and gain low and mid-range power. You want to match your cars exhaust system with the build of your specific engine. If you run a huge camshaft and close ratio gears, you want high rpm HP and huge exhaust. If you have a low duration camshaft and tall gear ratios and a tow hitch, you want more torque. So buy the minimal size needed for your engines hp. I've built many cars, and there are some exceptions to this such as turbo cars. And this guy's numbers are way off. I made 550 hp on a GTI with only 3" single pipe exhaust. My station wagon makes 365hp on 2.25" exhaust. Just remember, exhaust does NOT create HP, the engine creates it and the exhaust supports it and moves the power around.
Hi, any advise for me please? I do have a Tiguan Mk1 2.0TSI , I plan to make it around 300hp. Which size of exhaust system is recommended, I do think of 3"?
@@kyorix_SDF the stock exhaust is 2.25" and more than enough to support 300hp. Being a turbod car, I would recommend removing the catalytic converter and get a high flow downpipe. When you do this, you will need a tune to get rid of the check engine light. With just a downpipe and ecu tune, you can make about 255-275hp and 325-350tq on your engine depending on the tune you choose and fuel quality. 300hp would require a bigger turbo such as a Borg Warner K04-064. That turbo is capable of making 350-380hp with a proper tune, high flow downpipe, and bigger intercooler.
@@Josh-py2in Thanks for the advise, I am currently studying on crucial parts as well which including K04 you have mentioned. I was wandering if F23t is better. Intercooler and the rest of supporting stuffs are much easier to choose. I currently have a stable aftermarket suspension system.
@@kyorix_SDF the f23t is a essentially a modified k04. I have ran both, and the f23t can make 400hp and 400tq with an agressive tune and high octane fuel. There are a problems with the f23t though. They tend to over boost and surge. This is due to the small housing and upgraded wheel. This makes tuning a giant pain in the ass. You will likely need a custom Dyno tune to make it run properly. Also, they're not as reliable as a k04-064. Both turbos will usually cause a problem will valve float at 5000 rpms and above. This is because they have small housings and are being pushed way past their efficiency range. This will cause excessive back pressure and push the valves open at high rpms. The fix for this is expensive as it requires upgraded valve springs. My advice is a k04-064 and an APR tune. They have a new revised tune that will avoid the valve float at high rpms by lowering boost and raising ignition timing above 5500rpms. You should have no problems making over 300hp with that setup. Also, if you want big power and no issues with valve float. Look at the gtx2871r TSI kit. It runs about the same price and will make well over 400 and have no valve float issues. This turbo would require a 3" exhaust to make good power
Hi, I own a 1994 Dodge Ram Cummins Turbo Diesel. The garage just welded a smaller exhaust pipe and muffler into the existing pipe.. Total hack. What will this do to my truck? Thanks.
You guys still can't get your math right. This is the second time I've called you for bs on your quick facts which is wrong as usual. I get so tired of simple high school physics being represented wrong and you giving misinformation to paying customers. Air pressure isn't holding the card on. It's vacuum from the headspace above the water. The water provides a seal and their is no way for air to get in. So essentially the water pulls a slight vacuum because it drops the pressure above the water inside the cup. It's why the top of the cup sucks in. It's basic simple physics and you got it wrong explaining a parlor trick. Second point resistance to movement is Newtonian physics the air from inside the cylinder is pressing against the non moving air. So it doesn't explain why back pressure is needed(as a matter of fact you do not want any backpressure) which is misnamed it's essentially a restriction in the system causing resistance to pressure movement. It's why open exhaust makes more power then muffled exhaust(or does it.. think a correctly sized x pipe system on a v-8). Seriously you guys sell products so sell them but do not use parlor tricks to incorrectly explain a concept that has nothing to do with your explanations. If you guys want ask a high school science teacher to educate your script writers and presenters at least.. the information will be accurate. You can safely run 4-500hp engine on a 2 x 2.5inch system if built correctly. Read David Vizards books on making horsepower before you present vacuum as back pressure and maybe your presenters will actually sound presentable to the more (high school) educated people. You guys still sell them right?
Here for you guys in the real world and not the advertiser's world, take a plastic cup and a piece of stiff cardboard like he has(plastic sheets works really thin steel sheets work also if it's perfectly flat) do like he does in the parlor trick place the sheet against the lip of the cup with the water and invert the entire setup wait a sec for the water to fill the imperfections in the interface between the 2 surfaces and take your bottom hand away the top of the cup sucks in and the card is sealed to the cup. Water has a surface tension and cap only be made so small so the holes/gaps in the surface are essentially sealed from outside air. This is vacuum or a reduction in pressure above the waters surface inside of the cap wont allow the card to release since there is a negative pressure inside of the cup. It's can't release. It's physically impossible for them to separate. this is how you can explain pressure drops inside of intake manifolds. Not pressure waves and thermodynamics inside an exhaust system. Get your shit right summit. To go beyond this poke a hole in the cup. IT'S BULLSHIT Summit. Put a vacuum gauge on the cup if you do not believe me. Got it summit or are you going to mislead your buying public some more?
Just to mess with summit even more to prove a point and beat the proverbial horse, once more take a plastic dixie cup a flat table surface and a little water on the tables surface. invert the cup place it flat on the surface open face down and squeeze the cup a little move it around on the surface of the table and get the entire cup rim beaded with water now let go of the cup and try to knock it over. the key is squeezing the cup slightly so when you release it it creates a slight vacuum inside of the cup. The water provides a seal and wont let air in and sucks the cup to the surface. Good job summit you just described how an intake manifold works well done on that but this is a discussion about exhaust systems. Stick to selling parts not misinforming your buying public.
Hi guys...from Australia...Love your products and your range..our cost of freight to here is sad like the price of thfe product which turns $1000 to $2000 ...Anyhow i have a 1949 ford single spinner coupe utility...with a 302W old type or flowed mild work heads..or a 347..possible 5.0 mustang motor due to engine number here no one knows and id sure like to know..A fmx auto prior to C4 stage two shift modified standard torque convertor (starter motor Rh to Lh adaptor plate).....9 inch detroit locker and 4.11 gears..b and m pro ratchet..its nice to hmm 100mph..had to 160...but craving more sound ..Anyhow due to constriction in engine bay i have to stick to standard headers pipes (which i have previously flowed via die grinder to gasket size on a 302C that everyone thought i had a 351C due to wow...did you do an engine change?..I sure did...haha..i used to have it in a 1975 ford.....my 49 ute has lukey mufflers and no x or h pipe..2 1/4 inch system one end to other...i just cut back to rear of seats (1.7 metres/ 6 feet) of pipe to rear of utility/ pickup) and it still sounds..a bit boring..not happy....im guessing it has 250-300HP which in video im guessing suffice...its a street rod not a drag car 1500HP monster truck...Advice please and mega thanks for a weekender looks good and want it to sound AWESOME....H-E-L-P...Thanks guys n gals and beer time..Daz from Oz..also gear drive noisy jackson to A gilmer belt..The sounds and Hp variants?.or just a double row chain....im looking...for sound..i cant do top speed..its a COOL😎 75 year old rod..LIKE ZZ TOP ELIMINATOR..I WANT THAT SOUND AND NASCAR LIKE sounds in my coupe ute....thanks heaps 👍.
I have a big big big question, I'm wondering if you guys could please help me out. I have a 2015 dodge ram 1500 Hemi. I had a muffler shop cut ONLY my muffler off. The stock exhaust is a 3inch pipe all the way to a Y-pipe towards the rear of the truck and then goes 2.25 from there to each side. But the exhaust shop added about a 3ft section of 2inch exhaust pipe BEFORE the aftermarket y pipe then to the Y and out to the two pipes. So what I'm asking is where they added that 3 ft section of 2 inch right into the 3 inch pipe BEFORE the split at the Y will that hurt anything? They said no (The muffler shop) but I wanna see what you guys say. They connected the 2 inch right into the 3 inch welded it and said it's fine. Please let me know thank you guys!!!
I’m installing on my 02 540i E39 BMW a Borla exhaust from axle back, Im told it came off a bmw I can tell you it wasn’t a E39 and possibly not a 540 but it sounds so good !!that’s why I’m hell bent on installing it. But it’s dual exhaust and there’s no room on the rear passenger side so I’m going to delete that side and go with the single exhaust but in order to do so I have to increase the pipe diameter to 3 1/2 “ diameter for a 282 horsepower car (+nitrous add 100 more) do those figures sound right ? I’ll need 3 1/2 “ diameter ? Where can I get 3 1/2 diameter pipe and have it mandrel bent ? And do I go all the way to the exhaust tips
Question: I have a 2001 Sierra 1500hd I installed long tube headers x pipe 3inch exhaust. No cats. I definitely lost power is this because I have not enough or no back pressure? Or does it just need tuned? I’d assume both it definitely got an increase on the high end of things but on the low it’s much slower and according to my scanner I lost torque.
It didn't explain much. When it comes to freer exhaust people think of removing components that are connected inline such as a catalytic. Tube diameter explanation is fine but incomplete because of not mentioning cat's back pressure.
That's not back pressure, it it pressure differentiation that creates velocity or flow. too much or too little is bad depending on your engine. Eliminating all BACK PRESSURE is good, you just need the correct amount of pressure differentiation to create flow.
my car has 300hp to the crank..its a DOHC 4.3L v8…my exhaust system is 2.25” and i was wanting to run a 3” with an xpipe from my cats with a 2.25-3” adapter…is that safe or ok?
Oh my... right. We could try and explain performance gains with smaller diameters... of course the explanation falls apart once you go too small. ...so maybe it's that back pressure makes power (it doesn't) or maybe there's another factor at play, somewhat related to backpressure but in no way interchangeable, that actually explains what's occurring. Scavenging. It's not black magic. the SAE has plenty of reading you could do. ...or maybe we need to get with those topfuel guys and tell them what they really need is some back pressure if they want to unlock the potential of their engines.
So if you make 800+ what would be the diameter? Im sure not 9-10" exhaust is the answer. Im sure there's an actual scientific formula that involves volumetric efficiency, runner lenth, desired or max rpm, camshaft timing Im sure Its not that simple im 100% positive there's way more variables to the situation.
I got a 2.25 exhaust pipe and I just installed a 2 inch inlet/outlet Magnaflow turbo muffler...Is that going to slow my car?...Or it doesn't really matters?...Thanks in advance for your help
So don't buy summit racing equipment is that what your saying.... 😂 stick to selling parts mate Christ. considering 1000hp drag cars use like 3inches on 3inch with no muff straight from the block 😂 😂😂😂 I'm with stupid 👉
Hello have a 74 camaro 461 bbc holley sniper dynoed at the crank to 481 horsepower have true dual 2 1/2 already some shops say stay 2 1/2 some say go 3 inch who's wrong who's right?????????
“Hi I’m Al.” Sorry sir, that doesn’t convince me that you are qualified to teach me about automotive engine performance. The myth that all engines need back pressure has been proven wrong in numerous dynamometer tests. Also other variables must be considered before assigning tube diameter such as tube length and number of restrictions such as bends and muffler/cats.
Please, please, kill the difference between, turbo, supercharger, & na. Can I run a chambered flowmaster super 40 or super 44 maybe, on my supercharged 02 lightning, aprox 600hp
Heool I have a 3inch downpipe reduced to a 2.5inch decat and a 2inch custom r32 rep exhaust system will that be on ?? I have a mk4 golf 1.8t pushing just under 200bhp ??
I can't believe Micky Mouse is trying to tell me about back pressure, Micky why don't you take some oranges and stick them in your exhaust, I will drive open header and we will see who wins. Then at the finish line you can tell me about back pressure.
Too bad back pressure is a myth the exhaust flows one way it wouldn’t even make sense where’s the back pressure going back to the cylinders that are pushing out exhaust all the time 🥴🤦🏾♂️
@SummitRacing I own a 2015 lifted Scion xB. And since i only have a TRD sport muffler and a 23” length cherry bomb glasspack. The inlets are weld between 2.5” and factory are 2”. It creates a nice mature exhaust note. Now I am planning to get a full custom exhaust 2.5”. With 2.5” magnaflow high flow cat, and a 2.5” vibrant ultra quiet resonator. This will give much deeper tone and better performance, and also better breather correct? Along with headers included since why I am gettin a high flow cat. No sport muffler from axle back bytheway. So instead of sport muffler axle back, to glasspack, to factory cat. Switch to no muffler on axle back, the vibrant ultra quiet resonator, and high flow cat.
Lol back pressure kills performance....its scavenging that you need....your exhuast needs to create a low pressure wave that allows the exhuast in the cylinder to completely evacuate the exhuast otherwise your not getting a pure air fuel mix on the intake stroke meaning instead if just air fuel you get air fuel exhuast and that creates a poor burn....get the low pressure right it let's the engine evacuate the exhuast properly....all this video is doing is trying to take money out if your pocket.
Ive installed exhaust cutouts on my 2005 mustang gt right at the downpipe , so that eliminates pretty much all thr back pressure. Now im confused , alot of people ran on the dyno with cutouts and they got better hp.can u please explain? Thanks
HI mehio hatab, Most information regarding this subject assumes that a full exhaust must be used due to noise or emissions laws. With that in mind, being able to minimize back pressure is what they focus on. It should be obvious that when you visit a race track and see a dedicated race car, that they are not running a full exhaust, but usually just a set of long tube headers to direct the exhaust out of the engine compartment. Even there, back-pressure can never be totally eliminated, just minimized!
I think the subject needs to be about scavenging. I'm not gonna go into detail, but if you read about exhaust scavenging, you'll be able to better design an exhaust system for your setup.
1 have a 2003 ford f250 5.4 2v and i have shorty headers for it and want to h pipe it but dont know what size piping to use im trying to get all the low end and mid range hp and tq i can cause i haul cars can u help me out
the atmospheric air pressure is 14.7 psi at sea level. what he was trying to explain with the cup, water, and cardboard is you have 14.7psi atmospheric air pressure looking at your tailpipe and if it is too big and not enough adequate flow pressure to overcome it, the 14.7psi aap *causes* back pressure on the exhaust. if the exhaust flow is lazy, it has to fight the atmosphere to come out.
i have a 1999 Camaro SS and its all stock, and thinking of removing my resonator only, because i want it a bit louder, will it effect my gas mileage or back pressure by removing it or effect my car in anyway besides the sound being louder?
i like summit racing, dont get me wrong but back pressure is bad. thats the short part. if your engine has to work harder to expel exhaust gases, youre killing power, end of story.
Old school had it that a certain amount of back pressure was needed to help transfer heat from the exhaust valves? And if not then why use any exhaust? Maybe along the lines of the thermostat concept?
Your cup experiment is not back pressure. That's vacuum pressure. Totally different. It has to do with the atmosphere inside the cup. It has nothing to do with the atmosphere on the outside...
I can not believe you are representing summit racing and telling people they need back pressure This is absolutely horse shit stop spreading propaganda Engines do not need back pressure. Wow man this is so sad.
Back pressure existing everywhere isn't a legitimate reason as to why it's good for an engine. Such a big company should be able to explaining this a lot better
Soooo, The pressure does not come from the atmosphere it comes from the air pocket inside the cup and that the water is denser than the air. Not the same as an intake and exhaust system. You are right that you might not want open 4 in headers but you also dont want a 1 in exhaust system or your car will not breath right. This did not help me at all.
put any kind of x pipe h pipe or whatever kind of system you want to create your back pressure run it on the fun I then compare it to zoomies and zoomies with the least to no back pressure makes more power every time. y is that????
Hi I have A 2015 Mustang V6, I Believe The OEM Exhaust Pipes Are 2.25 Inches, I Wanted To Put The Flowmaster Outlaws On, The Gt Ones Which Are 3 Inch Diameter Axel Backs. My Exhaust Shop Would Have To Use An Adapter To Fit It. The V6 Outlaws Are 2.5 Inches, But I Want To Install The 3inch. Will That Work? Or Will I Lose Low End Torque? Thanks In Advance.
+Publius Gatt , For best power throughout the RPM range, the 2.5” pipes would be best. Without any testing it is hard to predict how the car would react with the 3”.
If this guy is telling the truth then some of the manufactures are putting in the wrong diameter piping. Yes. I know every manufacture restricts their engines for better mpg but those numbers are high.
I have a 496 ci chevy i want to build a custom exaust do you have every thing i need im wanting to go out the back side by side about 8 in apart i have a fuel cell
Hi! I would like to ask you which is the best exhaust diameter for an Opel astra h gtc turbo 1.6lt with 250 ps? The exhaust now is the stock one but it’s full decat with stock middle muffler and and an aftermarket rear free flow muffler. The stock diameter now is 63mm downpipe 60mm after that goes to 55mm from the middle muffler and then with a 60mm rear free flow muffler...the Downpipe is decat also there is no precat in it and the second cat is decat also. I tried once to make my stock exhaust full 60mm after the downpipe till the final muffler with a new and shorter stainless middle free flow muffler but after a year with this setup because of big noise that was producing I decided to return to my previous stock exhaust 60 to 55mm exhaust...my problem is that I have tuned my ecu with the full 60mm exhaust and now i turned it to stock exhaust I didn’t retuned the ecu...the motor is an GM ECOTEC 1.6 turbo remapped and produces 251ps. 60mm is about 2.25 inches and 55mm is about 2 inches
With forced induction the least amount of backpressure the better. There is a tradeoff with noise though and the bigger the exhaust the more noise typically associated with that. I would suggest going as large as you can without it being to loud
I am running D16Y8 with and D16z6 pistons, maybe putting up a little more than 250hp for now, I just removed my resonator (straight pipe from headers till muffler) and I experienced a power loss, it it because of the reduction in backpressure? Since there is no restriction now for the exhaust flow, I am using 2.5inch piping, please help, should I get the resonator installed back again or use 2 inch piping instead of 2.5inch?
Humayun Shah, By doing this you’ve increased airflow through the motor and could have potentially leaned the motor out reducing its power output. A dyno session and retune of computer programming is in order here!
I have a stock 2004 Tundra 4.7 V8. I spend a lot of time off road and wanted to add some sound plus some more torque. My idea was a x pipe after the cats, dual mufflers and then step down to 2 inch tailpipes dumped right above the rear axles with turn downs. I wanna keep it high up and stop it just after the axles for clearance. How would that affect backpressure going from stock single with 2.25 to duals at 2 inch?
ok question. I have a ford falcon Australian car with a 302 Windsor v8. its a stock car making 248hp or 185kw. I went with a dual 2.5 exhuast setup with X pipe and amd single muffler on each pipe setup. I'm guessing this is an over kill for my car?
+Mr Tickles, According to info published by Flowmaster, dual exhaust systems for motors over 400 horsepower can benefit from dual 2.50” pipes. Smaller motors making 250hp should use 2 - 2.25” pipe sizes.
I have a 1999 F150, 4.2 V6. I am keeping the resonator's and catalytic converter's as well as stock exhaust pipes. I am looking to replace my worn out stock muffler and I like the sound of the thrush glasspack. I am just wondering if the straight through design will damage my motor. I use it for towing and I don't wan't to lose low end torque.
Hi I am waleed from Bahrain . I have shelby gt500 2009 and l like to replace exhaust system size from 2.5 inches to 3 inches with x pipes magnoflow . do you think the hours power slightly will increase . Now without replacing the exhaust system the hours power is 515 at rear wheels
Hi Waleed Shaheen, Below are two links to the parts you’ve requested. The addition of these parts will increase power but, only a dyno and some computer programming will reveal it! www.summitracing.com/parts/mpe-16433 www.summitracing.com/parts/mpe-16674
more air in and out and more fuel in makes more power and if there is backpressure you lose power. not sure who came up with that ya need back pressure.
I have a BMW 523i which has an in-line 6 cylinder emgine putting out about 170hp.. its currently on stock exhaust. What is the best piping that i could use to gain more power but not mess up my fuel economy too much?
Macky Camesa, Opening up the exhaust system will allow more air into and out of your motor. By doing this (more air) you will also need more fuel so it doesn’t lean out and damage the motor. This extra fuel will impact your economy in some way, therefore, you have to decide if you would be willing to make that sacrifice.
Thanks, I installed a 4.5 Inch exhaust system on my 99 caravan
I hope true duals :-D
i just cut mine off. sounds really cool now
I put a 4.5" system on my Honda Odyssey because I wanted 1000HP....
Don't forget your X-pipe.
I laughed at this
Backpressure isn't the issue. Exhaust gas flow velocity is the issue. Ideal piping size is that which causes the fastest flow through it for maximum power. Too small piping chokes the system. Too large piping slows down exhaust gas velocity.
too large also adds extra weight and noise
THX!!!!!!!!!!!!!!!!!!!!!!
correct!!! and his cup and paper trick is crap....if it was atmosphere pressure keeping the card on as he indicated then wouldnt it also do the same without the water in the cup....i think he has other forces at work like vaccum and sticky h20 not a good example....and forced induction would not even apply to his world...but it would in your explanation of choke points and gas velocity.....the exhaust is an extension of the heads really
Hit the nail on the head
Facts.
You're a good magician. Poor engineer.
Because of this video I just bought a 3” exhaust system for my 1.6l sohc motor because I want to sound like a fast vacuum
I think the guys at Summit need to stick to selling parts and not making misleading videos. As an engine builder, you strive to tune the exhaust system so that negative pressure waves hit the exhaust valve as it opens in order to make the pressure at the exhaust valve BELOW atmospheric pressure to get more pressure differential and more flow. "Backpressure" just hinders flow and makes the engine less efficient in every way.
@18 RLX Vibrant 7 DCT The scientist couldn’t haven’t said it better.
@18 RLX FJBLGB question I have a 4 cylinder sedan with a muffler delete and Spec-D exhaust welded on if I did a resonator delete would I be hurting my engine if so how?
@Honda K24 fJBlgB hey help me out. 2jzgte single exhaust system straight with on aero muffler putting out 700 whp how many inch piping?
@@FullSendFabrication The pressure wave is relevant no matter how long it is, it just has a smaller effect the longer the pipe is past the 3-4ft of header needed to get a good tuning effect. The pressure waves work like a tuning fork, it will start at your exhaust valve, travel all the way to the exhaust tip and hit atmospheric pressure and then reflect and go back to the exhaust valve as a low pressure wave. The longer the pipe is the more waves are in the pipe at the same time and the less effect they have. Kind of butchering the explanation but that's the most concise way I know to put it.
2:45 Looking at this , all the 1500-2000hp Supra should get 15 in exhaust lol
It boggles my mind that a business like Summit would consent to let someone who doesn't understand fluid dynamics instruct people on exhaust systems. Summit, please consult an expert. This just propagates myths.
+unharmonix agree!!
Wow finally found another smart human
hotrodsurplus are you telling us that you’re an expert?, it’s possible , you can be any kind of expert while pecking on your keyboard 🙄
So is this complete video unreliable for power-size ratio?
This "back pressure" wise tale has been passed around for over 50 years! "My grand paps great grand fathers brothers sisters ex husbands son inlaw said that he lost torque on his Model A street rod when he added dual exhaust... so naturally the loss of torque was because he removed the beloved back pressure... as soon as he added the smaller exhaust his back pressure returned and he made more power... LMAO!
I honestly dont understand why more people dont have the slightest grasp on basic fluid dynamics... just a slight grasp would do wonders for most.
did this guy really just show me a test of vacuum and try to use that to talk about back pressure????
Yes, he did.
daniel velez it's not vacuum, the same amount of air is still in the cup when he flips it over
Mateo Gomez Gomez it is vacuum along with the vescosity of the water causing a seal at the edges of the glass to the paper. water is heavier then air it pushes down on the card. water is to thick and heavy for air to be pulled threw the edges. causing a vacuum
Lmao I said the same thing wtf Chuck
Yup! I almost clicked out of the video at that point but it was like watching a train wreck... I just could not look away.
this guy has no idea what he is talking about vacuum is not back pressure I'm going to have to start my own channel
If back pressure helped in ANY type of way then NASCAR would run it, pro stock, top fuel or any other racing would all use some sort of back pressure... But they don't... Scavenging is different and it has to do with pressure pulses working together to produce a small vacuum, not "back pressure". That's it. End of story. Point blank.
Johnny SIX4 !! At least someone is informed, there is so much misinformation in the industry because of videos and "internet experts" like these
Johnny SIX4 !! Very simple. You have street applications and race. With racing you spend most of your time at high RPMs therefore the flow will be greater thus requiring less back pressure. Im street applications, since the RPMs will be lower most of the time, you need it so the scavenging effect takes place. Otherwise you'll have no torque on the low end and only extra horses on the top end like race cars. As a result you lose low end torque and ability to pull through the lower gears and RPMs. Let's not mention fuel economy loss.
You NEED back pressure to create the scavenging effect more so in trucks. It's a large vehicle that requires torque to get the large body moving, not horsepower. Horsepower takes effect at the upper end of the spectrum where torque isn't required as much.
Mustangs are light and have high output motors. Stop and go traffic will destroy your fuel economy BUT with a free flowing exhaust, your horses will be higher so in race applications where you're at almost redline, you'll notice the benefits. I don't know very many people that spend that much time at high RPMs while driving to work, so it's not the most economical. You choose how you want your pocket book to go. Poor fuel until you hit redline or decent fuel the way the car was designed and sacrifice the upper end. Take your pick, you can't get both.
How that answers your questions and clears your confusion....
Sofa King , NO, NOT BACKPRESSURE, YOU OAF! VELOCITY, AND ONLY VELOCITY. You're wrong because while backpressure will create velocity, it comes with parasitic pumping losses that are created bc the exhaust isn't working good enough, so the engine has to FORCE the exhaust out, hence pumping losses, but at least the pressure creates velocity. If you use proper size pipes, use mandrel bends, a proper balance pipe for dual exhausts, as few of bends as possible, as gradual of bends as possible, and as short of a system as possible (except doing open headers on a stock or mild build). Those will keep your velocity high AND cut backpressure too.
You don't need one to have the other! You just need to get the right stuff! Geez
Back pressure doesn't create the scavaging effect the fucking sonic wave does its a fucking harmonics thing not back pressure smfh
My hero.
Choosing the right diameter exhaust pipe is to make sure the exhaust gas temperature and velocity stay up. Back pressure is created when your engine is pumping out more air than what your exhaust can handle, as opposed to the partial vacuum created by exhaust scavenging...duh
Basically your engine has to FORCE your exhaust out, so your engine loses some power because of that, particularly at upper rpm. Backpressure is a myth that people just keep believing. 😔😔😔
For those bringing up NASCARS, etc. let's explain something so you understand how motors work.
Johnny SIX4 !! Very simple. You have street applications and race. With racing you spend most of your time at high RPMs therefore the flow will be greater thus requiring less back pressure. Im street applications, since the RPMs will be lower most of the time, you need it so the scavenging effect takes place. Otherwise you'll have no torque on the low end and only extra horses on the top end like race cars. As a result you lose low end torque and ability to pull through the lower gears and RPMs. Let's not mention fuel economy loss.
You NEED back pressure to create the scavenging effect more so in trucks. It's a large vehicle that requires torque to get the large body moving, not horsepower. Horsepower takes effect at the upper end of the spectrum where torque isn't required as much.
Mustangs are light and have high output motors. Stop and go traffic will destroy your fuel economy BUT with a free flowing exhaust, your horses will be higher so in race applications where you're at almost redline, you'll notice the benefits. I don't know very many people that spend that much time at high RPMs while driving to work, so it's not the most economical. You choose how you want your pocket book to go. Poor fuel until you hit redline or decent fuel the way the car was designed and sacrifice the upper end. Take your pick, you can't get both.
How that answers your questions and clears your confusion....
You need Velocity not back pressure. Too big gets rid of Velocity.
Velocity is created BY back pressure. The more pressure you have, the more velocity you have. It's basic fluid dynamics. The less back pressure the better. If an engine actually makes more power with increased back pressure, something is fucked up.
Sorry, but this video is an absolute joke!!!!!! You want back pressure because of the valve overlap?????? Thats 100% absolutely false. Combining back back pressure with valve overlap will reduce power which the last time I checked, it the primary reason why most people what to change their exhaust is to increase power. I'm quite disappointed that Summit Racing and the Company that they are would even put out this video.
To anyone why believes that you want even any backpressure, I suggest that you educate yourself on what exhaust scavenging is and how it effects cylinder filling and why we attempt to design exhaust systems and headers to have maximum scavenging (particularly in the region where the cam(s) create the most power) ...
Question for you, is there any benefit of additional collector length in a 480-520 hp street car ?
@@Moparmaga-1 only if the collectors are open to atmosphere, which is not practical on a street car.
@@cw6371 okay thanks.
if you have 500 horsepower to the wheels and had a single exhaust period you most have a sleeper on purpose.
Look all engines react different to exhaust changes. On inline 4 and 6 if your piping is too big then the torque down low will be gone and feel sluggish but High rpm gets a little bump. V8s seem more forgiving but it is true that you need the correct pressure and velocity to have a good ballance of low end torque and output. This I have found on NA engines not boosted and from experience not reading books.
the sience experiment worked. theorie behind it didnt.
Back pressure in the exaust system require's the engine to work harder period. Back pressure kills efficiency and performance , no ifs and's or butts. What increases efficiency and performance in a exhaust system is Exhaust gas velocity. And thats where pipe size comes into play. To big of pipe reduces the scavenging effect of the exhaust system by decreasing velocity. To small creates back pressure slowing velocity. So a correctly sized exhaust system with a correctly located crossover or X pipe is what most important on a street driven vehicle. Race tracks......less means more. So open headers are king
That’s it. I am officially moving to jegs.
No engine needs back pressure! Its all about exhaust flow and velocity within the system. Go to small in ID and gain back pressure, go to large and lose velocity. The perfect exhaust would be sized to eliminate any "Back-pressure" and maximize velocity. Back pressure is exactly what it implies, its a restriction! Velocity on the other hand is what creates the scavenging effect from the cylinder. Every NA cam is designed with an overlap. The overlap is a small duration built into the cam where the exhaust valve is closing and the intake valve is opening, for a short duration both are open at the same time. An exhaust system that promotes velocity will have high vacuum on the exhaust side which literally tugs at the intake side giving the intake a running charge into the cylinder just as the exhaust valve snaps shut. This is called the "Scavenging" effect and most all cams are intentionally built with this overlap in order to take advantage of the scavenging effect. The quickest way to kill the Scavenging effect is to add back pressure! Long story short... dont believe everything you hear on the internet... like the video above, you are bound to be mis informed by people who claim to know what they are talking about... So dont take my word... get informed with the theory of operation and become a better Hot Rodder!!!
better. I still got no clear size formula. I calculus required ? That's ok.
I'm sorry guys, but your theory on back pressure is wrong here. On the board you are holding up at 2:12, the cylinder is at the intake stroke, i.e. the piston is moving downwards. If we assume that both intake and exhaust are infinitely big and have no flow resistance, then the pressure in the cylinder MUST be lower than in both the intake and exhaust. Air will therefore flow from outside through the intake into the cylinder, and exhaust would flow from the exhaust back into the cylinder. Air would not flow straight through the cylinder and out the exhaust port. This is a common misconception though, that stems from people confusing back pressure with gas flow velocity. The reason you don't want too big exhaust pipes is that you will reduce gas flow velocity, thereby not gaining adequate scavenging of your combustion chamber. Back pressure in an exhaust system is never desirable, since you would then use energy from the engine to push the exhaust gasses through the exhaust system. Google it, plenty of info out there on the subject :)
Summit Racing , could you respond to the above comment? I also think that air would move from the exhaust into cylinder rather than outwards from cylinder during the downstroke. I do think back pressure is important ( as I have experienced performance degradation when I had an exhaust leak) however, I'm not sure if you have provided the correct reason for its importance in your video. Thanks!
Vinzent Dk I absolutely agree, Vinzent. This demonstration is way off. During the intake stroke, the cylinder is going down and creating a vacuum to suck in the fuel/air mixture. There is no way that exhaust gas can also be flowing out during the same cycle. Al is correct that the exhaust valve stays open during intake but this is to 'artificially' increase the horsepower and efficiency. Here's how: - - - Allowing some exhaust to flow back into the cylinder increases the volume inside the cylinder without increasing the fuel/air mixture. This increases the pressure at ignition which makes the fuel more explosive and you get maximum efficiency out of the fuel. (Yes, it takes more power to create more compression, but the increase in explosion is well worth it.) If there is no back-pressure, you get less pressure inside the cylinder at ignition. This creates a longer, less efficient burn, and (because the exhaust valve opens during the tail-end of the ignition stroke), you could get burnt exhaust valves. This only applies to stock setups. If you're running a turbo, who cares. If you're racing, who cares, but if it's a daily driver, messing with back-pressure is going to cost you. IMHO
Ron "There is no way that exhaust gas can also be flowing out during the same cycle. "
Actually, there is, but only during the end of the exhaust stroke or cycle and beginning of intake stroke. It has to do with the momentum of the gases durring overlap, when both valves are open there is exhust flowing out and air flowing in, the tail end of the exhaust flowing out helps draw in fresh air (scavenging) by helping to create a low pressure area on top of the piston.
Exhaust flowing back into the cylinder (exhaust reversion) is actully a bad thing as it deludtes the fresh intake charge (this is what EGR do to lower combustion temperatures and reduce NOx emissions, dump a measured about of exhaust back into the intake). This is part of the reason cars with "big cams" idle so crazy. The late closing of the exhaust valve at low rpm lets exhaust back into the cylinder to mix with the fresh air charge which results in erratic combustion (sounds cool though). This clears up at higher engines speeds as there is less time for the exhaust to be drawn back into the cylinder.
So what would you suggest for a 280hp car? suggestion for single and dual please. I have a 350z with just injen short ram intake.
Enrique Montero 3" single, and for dual, either a true dual 2.25 or 2.5 will work. This video was one whole pipe size off on his duals. He gave sizes for catback, not true dual. A true dual 2.25 can handle up to 400, so it's great for getting torque out of your motor. If you're mostly after the gains in the upper half of your rpm range, then go for the 2.5". It'll even sound a bitter burlier too, tho trust me, 2.25 can sound mean AF when done right (check out my vids and tell me how NOT redneck my truck sounds even tho it's a stock cam & everything). 2.5 will also leave you more.room to grow if you realistically plan on going above 400 horsepower. Otherwise personally I would go with 2.25, but 2.5 will also work fine if you want. Your choice.
Where can i buy 8" exhaust pipe? I need a 6" piece for my VW Vanagon.
Home Depot.
HVAC supply get some chimney pipe
I came for answers got a kindergarten science project smh
This guy throws a hotdog down a hallway.
God damn the word "back pressure" gets thrown around so much with so many meanings I with we could just ditch those two words.
Think of it this way..the smaller displacement 4 bangers rely on a little back pressure to speed up the velocity. And those same 4bangers with 200 horsepower now rely gradually less on back pressure and more on velocity created from the thrust the engine put out originally without relying on back pressure as much as lower horsepower cars...same thing with 6cyl and 8cylinder.. but add a half inch to diameter of exhaust on the 6cyl standard setup
On a low hp v6 to make up for displacement gain.from 4cyl to 6cyl... now use the same principal going up in power in the v6 as I
Explained in the v4... while going into v8 territory add another quarter inch to standard diameter piping for exhaust and use same principal... blah blah blah. Just read this shit and let common sense take over I’m confusing my self at this point 😂🤣🤣🤣🤣
3” it is for my Geo metro...thanks Summit!!!
3 cyl? Triple pipe setup? You might want 4" for a beast like that.
🤣🤣🤣🤣💀
1 inch for each cylinder? 😁
Get a 3 to 1 collector that goes to 10"
This is all b.s. If this was true, explain to me why top fuel dragsters are completely straight piped. The free-er flowing the exhaust is, the more power you will put out. Also, the number of variables in exhaust size is more than just horsepower.
those cars have enough power to eliminate the need of back pressure. For a daily driver then thats where youll need it
Why don't you try doing some technical research for yourself. sounds like you could stand to learn something, anything really. loL.
BrapTube i modify engines for a living
+Da Northlander I do to. except I also went to college and studied engineering and physics. lol.
+Da Northlander do you know what " scavenging " is and how it works???
1:05 mind blown
So I was looking into welding a 2.5 or 3" exhaust muffler on my stock 2.25 piping, will there be a significant sound difference b/w the 2?
I lost all my low end torque when i moved up from 2.25" to 3". You actually want to do some research on a car forum. Learn from other peoples mistakes.. or it will cost you up to $500. According to the video above, I should be at 3.5". The sweet spot is 2.5" for me.
Pipes seems a little big for the hp.Is it true you can run a smaller tail pipe and be ok?
It works best when the whole system is the same size. Here is a link to an exhaust size calculator.
www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/
actually, the water stays in the cup because there's a vacuum formed when you turn it upside down and the air can't expand enough to let the card off the rim of the cup, has nothing to do with back pressure lol
+PC Pro vacuum is negative pressure which is lower than the atmospheric pressure ... therefore the atmosphere pressure is the force that keeping
for you information pressure is force divide by area. area is constant for the cup for both sides. the pressure in the cup is lower than the atmospheric pressure which mean the force that holding the card to the cup is the atmospheric force!
+Hamdan Alharbi regardless, it has nothing to do with back pressure which was my original point and you just proved that yourself so thx :)
Sounds good, but you're wrong. The force in the cup is actually greater than the atmospheric pressure which really has nothing to do with the card staying up. The suction of the vacuum inside the cup exceeds the gravitational force being exerted on it.
+Curtis Dodds that's basically the same thing I said, its because of the vacuum not because of back pressure.
+Curtis Dodds I was responding to hamdan alharbi
Ahh the classic "yOu nEed A LiTtle BIt oF BACkpReSurE fOR bottOM eNd ToRQUe" myth. NO, you want to maximize VOLUMETRIC EFFICIENCY. Too small diameter and you will lose power from backpressure. Too large diameter you lose exhaust velocity, you probably won't lose power but you'll definitely be leaving some on the table. With that goldilocks diameter you'll get the fastest exhaust velocity and with it, scavenging. FOH with that backpressure bs.
between 301 and 349 bhp you don't even need an exhaust it's ok
Unless it’s a factory pipe. U what it to breath better and run much smoother.
I have a 2.5" Borla single exhaust and it's sufficient to ~350 hp. Not sure where that"chart" or "rule" came from...
Now i have to check my exhaust back-pressure with a paper cup...
Summit, I have a degree in automotive high performance and I know this is not how exhaust flow works, the story is about velocity. There is a specific formula for how big and long each tube needs to be in your exhaust system, this has to do with pressure waves and flow. The idea is to have a vacuum in your exhaust not pressure, pro stock dragsters actually have a measurable vacuum at the exhaust port and pressure at the intake port that equals around 7psi of “boost” combined on a naturally aspirated engine!!! This is due to the inertia of air.
On an engine that produces 220hp would u recommend 2.5 or 3" single piping??
vacuum holds the paper to the cup, not pressure. . ...duh. haha
actually you're wrong. there is no vacuum present. how is there vacuum if you didn't suck air or water out before or after putting the card over the cup? exactly, you didnt. vacuum is negative pressure from removing something (air or water) from a sealed volume. get a clue. LoL
Vacuum is actually the absence of pressure, it can't do anything. There is a partial vacuum that is created inside the cup in this situation but it's the relatively higher outside pressure that's responsible for holding the card in place.
The chart is great. The guys theory is wrong. It's all about flow rate. The faster you can force air in and out the more power. Meaning to small pipe will choke it out, to big and your engine wont be able to push all the air that's in that pipe out slowing velocity. The perfect size will help power at all rpm ranges. To big you'll loose torque to small you'll loose top end horsepower. That's where I'm at. My truck made 225 hp and ford decided a good size pipe is 2 1/4 SINGLE exhaust. I changed it to 2 1/2 but now I'm making a little more and it definitely feels choked up after 3k rpm. Engine is a 302 btw.
Right now designed and put in a custom header 4-1 with high flow cat, 2.5” pipe and a 19” oval Borla proXS
Into a 2011 Chevy colorado
2.9L stock engine with some upgrades
Do i make ok?
What is also important is scavenging of exhaust correct exhaust sizing will help "pull out" the exhaust pulses from the other cylinders (my explanation sucks) to big or dual exhaust in some cases reduces this effect some vehicles do better with a 3" single vs two 2.5" duals
It's very simple. Let's say you have a Honda. You run a 3" straight pipe with no cat or muffler, you will move all of your power up high and loose all of your low end power.
If you ran 2.25" and have a muffler and cat, you will loose high rpm power and gain low and mid-range power.
You want to match your cars exhaust system with the build of your specific engine. If you run a huge camshaft and close ratio gears, you want high rpm HP and huge exhaust.
If you have a low duration camshaft and tall gear ratios and a tow hitch, you want more torque. So buy the minimal size needed for your engines hp.
I've built many cars, and there are some exceptions to this such as turbo cars. And this guy's numbers are way off. I made 550 hp on a GTI with only 3" single pipe exhaust.
My station wagon makes 365hp on 2.25" exhaust.
Just remember, exhaust does NOT create HP, the engine creates it and the exhaust supports it and moves the power around.
Hi, any advise for me please? I do have a Tiguan Mk1 2.0TSI , I plan to make it around 300hp. Which size of exhaust system is recommended, I do think of 3"?
@@kyorix_SDF the stock exhaust is 2.25" and more than enough to support 300hp. Being a turbod car, I would recommend removing the catalytic converter and get a high flow downpipe. When you do this, you will need a tune to get rid of the check engine light. With just a downpipe and ecu tune, you can make about 255-275hp and 325-350tq on your engine depending on the tune you choose and fuel quality. 300hp would require a bigger turbo such as a Borg Warner K04-064. That turbo is capable of making 350-380hp with a proper tune, high flow downpipe, and bigger intercooler.
@@Josh-py2in Thanks for the advise, I am currently studying on crucial parts as well which including K04 you have mentioned. I was wandering if F23t is better. Intercooler and the rest of supporting stuffs are much easier to choose. I currently have a stable aftermarket suspension system.
@@kyorix_SDF the f23t is a essentially a modified k04. I have ran both, and the f23t can make 400hp and 400tq with an agressive tune and high octane fuel. There are a problems with the f23t though. They tend to over boost and surge. This is due to the small housing and upgraded wheel. This makes tuning a giant pain in the ass. You will likely need a custom Dyno tune to make it run properly. Also, they're not as reliable as a k04-064.
Both turbos will usually cause a problem will valve float at 5000 rpms and above. This is because they have small housings and are being pushed way past their efficiency range. This will cause excessive back pressure and push the valves open at high rpms. The fix for this is expensive as it requires upgraded valve springs.
My advice is a k04-064 and an APR tune. They have a new revised tune that will avoid the valve float at high rpms by lowering boost and raising ignition timing above 5500rpms. You should have no problems making over 300hp with that setup.
Also, if you want big power and no issues with valve float. Look at the gtx2871r TSI kit. It runs about the same price and will make well over 400 and have no valve float issues. This turbo would require a 3" exhaust to make good power
@@Josh-py2in I see, should I upgrade my pistons then? I am worried if they can sustain the 400hp
Hi, I own a 1994 Dodge Ram Cummins Turbo Diesel. The garage just welded a smaller exhaust pipe and muffler into the existing pipe.. Total hack. What will this do to my truck? Thanks.
What about 100 hp?
You guys still can't get your math right. This is the second time I've called you for bs on your quick facts which is wrong as usual. I get so tired of simple high school physics being represented wrong and you giving misinformation to paying customers. Air pressure isn't holding the card on. It's vacuum from the headspace above the water. The water provides a seal and their is no way for air to get in. So essentially the water pulls a slight vacuum because it drops the pressure above the water inside the cup. It's why the top of the cup sucks in. It's basic simple physics and you got it wrong explaining a parlor trick. Second point resistance to movement is Newtonian physics the air from inside the cylinder is pressing against the non moving air. So it doesn't explain why back pressure is needed(as a matter of fact you do not want any backpressure) which is misnamed it's essentially a restriction in the system causing resistance to pressure movement. It's why open exhaust makes more power then muffled exhaust(or does it.. think a correctly sized x pipe system on a v-8). Seriously you guys sell products so sell them but do not use parlor tricks to incorrectly explain a concept that has nothing to do with your explanations. If you guys want ask a high school science teacher to educate your script writers and presenters at least.. the information will be accurate. You can safely run 4-500hp engine on a 2 x 2.5inch system if built correctly. Read David Vizards books on making horsepower before you present vacuum as back pressure and maybe your presenters will actually sound presentable to the more (high school) educated people. You guys still sell them right?
Here for you guys in the real world and not the advertiser's world, take a plastic cup and a piece of stiff cardboard like he has(plastic sheets works really thin steel sheets work also if it's perfectly flat) do like he does in the parlor trick place the sheet against the lip of the cup with the water and invert the entire setup wait a sec for the water to fill the imperfections in the interface between the 2 surfaces and take your bottom hand away the top of the cup sucks in and the card is sealed to the cup. Water has a surface tension and cap only be made so small so the holes/gaps in the surface are essentially sealed from outside air. This is vacuum or a reduction in pressure above the waters surface inside of the cap wont allow the card to release since there is a negative pressure inside of the cup. It's can't release. It's physically impossible for them to separate. this is how you can explain pressure drops inside of intake manifolds. Not pressure waves and thermodynamics inside an exhaust system. Get your shit right summit. To go beyond this poke a hole in the cup. IT'S BULLSHIT Summit. Put a vacuum gauge on the cup if you do not believe me. Got it summit or are you going to mislead your buying public some more?
Just to mess with summit even more to prove a point and beat the proverbial horse, once more take a plastic dixie cup a flat table surface and a little water on the tables surface. invert the cup place it flat on the surface open face down and squeeze the cup a little move it around on the surface of the table and get the entire cup rim beaded with water now let go of the cup and try to knock it over. the key is squeezing the cup slightly so when you release it it creates a slight vacuum inside of the cup. The water provides a seal and wont let air in and sucks the cup to the surface. Good job summit you just described how an intake manifold works well done on that but this is a discussion about exhaust systems. Stick to selling parts not misinforming your buying public.
Hi guys...from Australia...Love your products and your range..our cost of freight to here is sad like the price of thfe product which turns $1000 to $2000
...Anyhow i have a 1949 ford single spinner coupe utility...with a 302W old type or flowed mild work heads..or a 347..possible 5.0 mustang motor due to engine number here no one knows and id sure like to know..A fmx auto prior to C4 stage two shift modified standard torque convertor (starter motor Rh to Lh adaptor plate).....9 inch detroit locker and 4.11 gears..b and m pro ratchet..its nice to hmm 100mph..had to 160...but craving more sound ..Anyhow due to constriction in engine bay i have to stick to standard headers pipes (which i have previously flowed via die grinder to gasket size on a 302C that everyone thought i had a 351C due to wow...did you do an engine change?..I sure did...haha..i used to have it in a 1975 ford.....my 49 ute has lukey mufflers and no x or h pipe..2 1/4 inch system one end to other...i just cut back to rear of seats (1.7 metres/ 6 feet) of pipe to rear of utility/ pickup) and it still sounds..a bit boring..not happy....im guessing it has 250-300HP which in video im guessing suffice...its a street rod not a drag car 1500HP monster truck...Advice please and mega thanks for a weekender looks good and want it to sound AWESOME....H-E-L-P...Thanks guys n gals and beer time..Daz from Oz..also gear drive noisy jackson to A gilmer belt..The sounds and Hp variants?.or just a double row chain....im looking...for sound..i cant do top speed..its a COOL😎 75 year old rod..LIKE ZZ TOP ELIMINATOR..I WANT THAT SOUND AND NASCAR LIKE sounds in my coupe ute....thanks heaps 👍.
I have a big big big question, I'm wondering if you guys could please help me out. I have a 2015 dodge ram 1500 Hemi. I had a muffler shop cut ONLY my muffler off. The stock exhaust is a 3inch pipe all the way to a Y-pipe towards the rear of the truck and then goes 2.25 from there to each side. But the exhaust shop added about a 3ft section of 2inch exhaust pipe BEFORE the aftermarket y pipe then to the Y and out to the two pipes. So what I'm asking is where they added that 3 ft section of 2 inch right into the 3 inch pipe BEFORE the split at the Y will that hurt anything? They said no (The muffler shop) but I wanna see what you guys say. They connected the 2 inch right into the 3 inch welded it and said it's fine. Please let me know thank you guys!!!
I’m installing on my 02 540i E39 BMW a Borla exhaust from axle back, Im told it came off a bmw I can tell you it wasn’t a E39 and possibly not a 540 but it sounds so good !!that’s why I’m hell bent on installing it. But it’s dual exhaust and there’s no room on the rear passenger side so I’m going to delete that side and go with the single exhaust but in order to do so I have to increase the pipe diameter to 3 1/2 “ diameter for a 282 horsepower car (+nitrous add 100 more) do those figures sound right ? I’ll need 3 1/2 “ diameter ?
Where can I get 3 1/2 diameter pipe and have it mandrel bent ?
And do I go all the way to the exhaust tips
Engines need back pressure to make power....no. Stick to selling stuff and stop recommending stuff you know nothing about.
Question: I have a 2001 Sierra 1500hd I installed long tube headers x pipe 3inch exhaust. No cats. I definitely lost power is this because I have not enough or no back pressure? Or does it just need tuned? I’d assume both it definitely got an increase on the high end of things but on the low it’s much slower and according to my scanner I lost torque.
It didn't explain much. When it comes to freer exhaust people think of removing components that are connected inline such as a catalytic. Tube diameter explanation is fine but incomplete because of not mentioning cat's back pressure.
That's not back pressure, it it pressure differentiation that creates velocity or flow. too much or too little is bad depending on your engine. Eliminating all BACK PRESSURE is good, you just need the correct amount of pressure differentiation to create flow.
my car has 300hp to the crank..its a DOHC 4.3L v8…my exhaust system is 2.25” and i was wanting to run a 3” with an xpipe from my cats with a 2.25-3” adapter…is that safe or ok?
Oh my... right. We could try and explain performance gains with smaller diameters... of course the explanation falls apart once you go too small. ...so maybe it's that back pressure makes power (it doesn't) or maybe there's another factor at play, somewhat related to backpressure but in no way interchangeable, that actually explains what's occurring. Scavenging. It's not black magic. the SAE has plenty of reading you could do. ...or maybe we need to get with those topfuel guys and tell them what they really need is some back pressure if they want to unlock the potential of their engines.
So if you make 800+ what would be the diameter? Im sure not 9-10" exhaust is the answer. Im sure there's an actual scientific formula that involves volumetric efficiency, runner lenth, desired or max rpm, camshaft timing Im sure Its not that simple im 100% positive there's way more variables to the situation.
I got a 2.25 exhaust pipe and I just installed a 2 inch inlet/outlet Magnaflow turbo muffler...Is that going to slow my car?...Or it doesn't really matters?...Thanks in advance for your help
So don't buy summit racing equipment is that what your saying.... 😂 stick to selling parts mate Christ. considering 1000hp drag cars use like 3inches on 3inch with no muff straight from the block 😂 😂😂😂
I'm with stupid 👉
Hello have a 74 camaro 461 bbc holley sniper dynoed at the crank to 481 horsepower have true dual 2 1/2 already some shops say stay 2 1/2 some say go 3 inch who's wrong who's right?????????
“Hi I’m Al.” Sorry sir, that doesn’t convince me that you are qualified to teach me about automotive engine performance. The myth that all engines need back pressure has been proven wrong in numerous dynamometer tests. Also other variables must be considered before assigning tube diameter such as tube length and number of restrictions such as bends and muffler/cats.
Please, please, kill the difference between, turbo, supercharger, & na. Can I run a chambered flowmaster super 40 or super 44 maybe, on my supercharged 02 lightning, aprox 600hp
Heool I have a 3inch downpipe reduced to a 2.5inch decat and a 2inch custom r32 rep exhaust system will that be on ?? I have a mk4 golf 1.8t pushing just under 200bhp ??
I can't believe Micky Mouse is trying to tell me about back pressure, Micky why don't you take some oranges and stick them in your exhaust, I will drive open header and we will see who wins. Then at the finish line you can tell me about back pressure.
Too bad back pressure is a myth the exhaust flows one way it wouldn’t even make sense where’s the back pressure going back to the cylinders that are pushing out exhaust all the time 🥴🤦🏾♂️
That rule for a single pipe is so wrong.
my 5.4l engine is pushing 450+ hp through a 3" single pipe.
@SummitRacing I own a 2015 lifted Scion xB. And since i only have a TRD sport muffler and a 23” length cherry bomb glasspack. The inlets are weld between 2.5” and factory are 2”. It creates a nice mature exhaust note.
Now I am planning to get a full custom exhaust 2.5”. With 2.5” magnaflow high flow cat, and a 2.5” vibrant ultra quiet resonator. This will give much deeper tone and better performance, and also better breather correct? Along with headers included since why I am gettin a high flow cat.
No sport muffler from axle back bytheway.
So instead of sport muffler axle back, to glasspack, to factory cat.
Switch to no muffler on axle back, the vibrant ultra quiet resonator, and high flow cat.
Lol back pressure kills performance....its scavenging that you need....your exhuast needs to create a low pressure wave that allows the exhuast in the cylinder to completely evacuate the exhuast otherwise your not getting a pure air fuel mix on the intake stroke meaning instead if just air fuel you get air fuel exhuast and that creates a poor burn....get the low pressure right it let's the engine evacuate the exhuast properly....all this video is doing is trying to take money out if your pocket.
lol...the example is completely wrong
agree!
So ur telling me my stock chevy impala needs a 3.5 inch exhaust, say fokin less bod
I have a true dual exhaust v8 with 360whp, stock is 2.25 for a cat back dual h-pipe exhaust should I stick with 2.25 or go with 2.5?
Ive installed exhaust cutouts on my 2005 mustang gt right at the downpipe , so that eliminates pretty much all thr back pressure. Now im confused , alot of people ran on the dyno with cutouts and they got better hp.can u please explain? Thanks
HI mehio hatab,
Most information regarding this subject assumes that a full exhaust must be used due to noise or emissions laws. With that in mind, being able to minimize back pressure is what they focus on. It should be obvious that when you visit a race track and see a dedicated race car, that they are not running a full exhaust, but usually just a set of long tube headers to direct the exhaust out of the engine compartment. Even there, back-pressure can never be totally eliminated, just minimized!
I think the subject needs to be about scavenging. I'm not gonna go into detail, but if you read about exhaust scavenging, you'll be able to better design an exhaust system for your setup.
1 have a 2003 ford f250 5.4 2v and i have shorty headers for it and want to h pipe it but dont know what size piping to use im trying to get all the low end and mid range hp and tq i can cause i haul cars can u help me out
the atmospheric air pressure is 14.7 psi at sea level. what he was trying to explain with the cup, water, and cardboard is you have 14.7psi atmospheric air pressure looking at your tailpipe and if it is too big and not enough adequate flow pressure to overcome it, the 14.7psi aap *causes* back pressure on the exhaust. if the exhaust flow is lazy, it has to fight the atmosphere to come out.
i have a 1999 Camaro SS and its all stock, and thinking of removing my resonator only, because i want it a bit louder, will it effect my gas mileage or back pressure by removing it or effect my car in anyway besides the sound being louder?
CamaroWarrior ,
You should consider a new tune for the computer!
i like summit racing, dont get me wrong but back pressure is bad. thats the short part. if your engine has to work harder to expel exhaust gases, youre killing power, end of story.
Old school had it that a certain amount of back pressure was needed to help transfer heat from the exhaust valves? And if not then why use any exhaust? Maybe along the lines of the thermostat concept?
Your cup experiment is not back pressure. That's vacuum pressure. Totally different. It has to do with the atmosphere inside the cup. It has nothing to do with the atmosphere on the outside...
I can not believe you are representing summit racing and telling people they need back pressure
This is absolutely horse shit stop spreading propaganda
Engines do not need back pressure. Wow man this is so sad.
Back pressure existing everywhere isn't a legitimate reason as to why it's good for an engine. Such a big company should be able to explaining this a lot better
Soooo, The pressure does not come from the atmosphere it comes from the air pocket inside the cup and that the water is denser than the air. Not the same as an intake and exhaust system. You are right that you might not want open 4 in headers but you also dont want a 1 in exhaust system or your car will not breath right. This did not help me at all.
Still the myths persist..... what is is ideal amount of "backpressure" then. Hint: It's vacuum.
put any kind of x pipe h pipe or whatever kind of system you want to create your back pressure run it on the fun I then compare it to zoomies and zoomies with the least to no back pressure makes more power every time. y is that????
Hi I have A 2015 Mustang V6, I Believe The OEM Exhaust Pipes Are 2.25 Inches, I Wanted To Put The Flowmaster Outlaws On, The Gt Ones Which Are 3 Inch Diameter Axel Backs. My Exhaust Shop Would Have To Use An Adapter To Fit It. The V6 Outlaws Are 2.5 Inches, But I Want To Install The 3inch. Will That Work? Or Will I Lose Low End Torque? Thanks In Advance.
+Publius Gatt ,
For best power throughout the RPM range, the 2.5” pipes would be best. Without any testing it is hard to predict how the car would react with the 3”.
sounds like this guy been inside a couple of exhaust pipes before
If this guy is telling the truth then some of the manufactures are putting in the wrong diameter piping. Yes. I know every manufacture restricts their engines for better mpg but those numbers are high.
What if your in between 300 and 350 hp
Hahah, you noticed that too.
3.75", duh
+Jake Merritt Haha
I'm more then 350 I'm 380
I have a 496 ci chevy i want to build a custom exaust do you have every thing i need im wanting to go out the back side by side about 8 in apart i have a fuel cell
Good video but what if I want to use a single tube exhaust and the car makes 325 HP? You jumped from 300 to 350. Haha!
Hi! I would like to ask you which is the best exhaust diameter for an Opel astra h gtc turbo 1.6lt with 250 ps? The exhaust now is the stock one but it’s full decat with stock middle muffler and and an aftermarket rear free flow muffler. The stock diameter now is 63mm downpipe 60mm after that goes to 55mm from the middle muffler and then with a 60mm rear free flow muffler...the Downpipe is decat also there is no precat in it and the second cat is decat also. I tried once to make my stock exhaust full 60mm after the downpipe till the final muffler with a new and shorter stainless middle free flow muffler but after a year with this setup because of big noise that was producing I decided to return to my previous stock exhaust 60 to 55mm exhaust...my problem is that I have tuned my ecu with the full 60mm exhaust and now i turned it to stock exhaust I didn’t retuned the ecu...the motor is an GM ECOTEC 1.6 turbo remapped and produces 251ps. 60mm is about 2.25 inches and 55mm is about 2 inches
With forced induction the least amount of backpressure the better. There is a tradeoff with noise though and the bigger the exhaust the more noise typically associated with that. I would suggest going as large as you can without it being to loud
I am running D16Y8 with and D16z6 pistons, maybe putting up a little more than 250hp for now, I just removed my resonator (straight pipe from headers till muffler) and I experienced a power loss, it it because of the reduction in backpressure? Since there is no restriction now for the exhaust flow, I am using 2.5inch piping, please help, should I get the resonator installed back again or use 2 inch piping instead of 2.5inch?
Humayun Shah,
By doing this you’ve increased airflow through the motor and could have potentially leaned the motor out reducing its power output. A dyno session and retune of computer programming is in order here!
I have a stock 2004 Tundra 4.7 V8. I spend a lot of time off road and wanted to add some sound plus some more torque. My idea was a x pipe after the cats, dual mufflers and then step down to 2 inch tailpipes dumped right above the rear axles with turn downs.
I wanna keep it high up and stop it just after the axles for clearance. How would that affect backpressure going from stock single with 2.25 to duals at 2 inch?
Shit I'm using a single 4" with 865rwhp. Best I change it to fit your bullshit recommendations
I will make 4.5" dual exhaust on my car, then i will think about finding a 1000hp engine.
ok question.
I have a ford falcon Australian car with a 302 Windsor v8.
its a stock car making 248hp or 185kw.
I went with a dual 2.5 exhuast setup with X pipe and amd single muffler on each pipe setup.
I'm guessing this is an over kill for my car?
+Mr Tickles,
According to info published by Flowmaster, dual exhaust systems for motors over 400 horsepower can benefit from dual 2.50” pipes. Smaller motors making 250hp should use 2 - 2.25” pipe sizes.
1.3 65hp? 2inch single be okay?
Yes, that would be plenty large enough for the 65hp 1.3L engine.
@@SummitRacing that's for reply , it's classic carbureted 4 cylinder
I have a 1999 F150, 4.2 V6. I am keeping the resonator's and catalytic converter's as well as stock exhaust pipes. I am looking to replace my worn out stock muffler and I like the sound of the thrush glasspack. I am just wondering if the straight through design will damage my motor. I use it for towing and I don't wan't to lose low end torque.
+GREATSWORD1000 ,
By keeping the factory pipe size and converters and simply changing out the muffler, no torque loss or engine damage will occur.
Thank you very much!!
I have a motorbike with 16 hp and i want to know what exhaust should i use because i can't find any table for small bikes
Hi I am waleed from Bahrain . I have shelby gt500 2009 and l like to replace exhaust system size from 2.5 inches to 3 inches with x pipes magnoflow . do you think the hours power slightly will increase . Now without replacing the exhaust system the hours power is 515 at rear wheels
Hi Waleed Shaheen,
Below are two links to the parts you’ve requested. The addition of these parts will increase power but, only a dyno and some computer programming will reveal it!
www.summitracing.com/parts/mpe-16433
www.summitracing.com/parts/mpe-16674
Please take this down! This guy doesn't understand the process of vacuum or exhaust scavenging!
more air in and out and more fuel in makes more power and if there is backpressure you lose power. not sure who came up with that ya need back pressure.
I have a BMW 523i which has an in-line 6 cylinder emgine putting out about 170hp.. its currently on stock exhaust. What is the best piping that i could use to gain more power but not mess up my fuel economy too much?
Macky Camesa,
Opening up the exhaust system will allow more air into and out of your motor. By doing this (more air) you will also need more fuel so it doesn’t lean out and damage the motor. This extra fuel will impact your economy in some way, therefore, you have to decide if you would be willing to make that sacrifice.