Backpressure: The myth and why it's wrong

[eXe]

Any mods willing to sticky this for future input?

["Ridge"Racer]

im originally from frederick, so im just going to agree with you because there isnt really much else to do up there other than research stuff. alot of what was stated is true, notice the skunk2 mega power r isnt the best for our n/a cars.

+rep

[eXe]

Originally Posted by "Ridge"Racer

im originally from frederick, so im just going to agree with you because there isnt really much else to do up there other than research stuff. alot of what was stated is true, notice the skunk2 mega power r isnt the best for our n/a cars.

+rep

My thoughts exactly, ive always felt that way thats why im kinda leaning back on the putting exhaust on atm. Thanks for the rep!

[soxfan143]

Sweet info dude. Repped.

[reaper702]

good info, but i will stick to mega power r thank you

[mrdimsum]

i always thought, what? backpressure is good? b/c i thought backpressure hinders the engine from forcing out the gasses in the engine combustion, thanks for the info, knew i was right. hahah

[tomasro]

backpressure is only good for higher liter motors who's exhaust gas has a substantial amount of uncombusted fuel. the backpressure keeps the exhaust gases in the combustion chamber for higher efficiency.

the R18 engine has its own EGR valve that does this already, but the backpressure does help to keep up the fuel efficiency.

So if you want a performance civic, get an Si and put a big exhaust on it and anything else you want. If you want efficiency, get an R18 and leave it alone.

[Johannes]

Good write up!

[eXe]

keep the comments comin! I like reading all your inputs

[Si2Typ3R]

Very nice info. Backpressure is most certainly the devil.

[adamhoud]

Makes sense, you have to find the right balance....if you go putting a skunk2 on your car sure you might gain a couple hp up top, at the significant sacrifice of your actual realistic driving power range. It's why I went back to stock so many times.

Same thing goes for my firebird, you don't want to go larger than 2.5" until you are making 5-600hp otherwise it really hurts your powerband. It's also why you can actually gain quite a bit over open headers by just putting on a couple exhaust pipes.

[eXe]

Originally Posted by adamhoud

Makes sense, you have to find the right balance....if you go putting a skunk2 on your car sure you might gain a couple hp up top, at the significant sacrifice of your actual realistic driving power range. It's why I went back to stock so many times.

Same thing goes for my firebird, you don't want to go larger than 2.5" until you are making 5-600hp otherwise it really hurts your powerband. It's also why you can actually gain quite a bit over open headers by just putting on a couple exhaust pipes.

Your a very smart person. Im glad you completely understand why I posted this information. Also glad you made the terms of science easier to understand

[eXe]

[DanDB64]

If only we had tunability... The RSX-S has HUGE gains using a 3" exhaust N/A... K20's LOVE flow... But with our lack of KPRO and our crap ECU tune, we wouldn't benefit much from 3", but I doubt we would lose any in our powerband (5800+), either... I should guinea pig this idea, just to do it

[eXe]

Originally Posted by DanDB64

If only we had tunability... The RSX-S has HUGE gains using a 3" exhaust N/A... K20's LOVE flow... But with our lack of KPRO and our crap ECU tune, we wouldn't benefit much from 3", but I doubt we would lose any in our powerband (5800+), either... I should guinea pig this idea, just to do it

Sometimes I still wish I got the Type S but they stopped making them in Eastcoast when I was going to buy the car.

[Si2Typ3R]

Originally Posted by eXe

Sometimes I still wish I got the Type S but they stopped making them in Eastcoast when I was going to buy the car.

Yeah but once Hondata comes out with tuning solutions for our Z3 you would be saying this Im so impatient but it shall be worth the wait

[redline8500]

nice write up exe that is the best way i have ever heard it. I come riding dirt bikes and the reason that two stokes have that big exhaust pipe is because, it literally sucks the gas out of the crank and into the combustion chamber then it does it all over again. for those of you who dont know two stokes dont have valves so the piston does not move the air and fuel

[eXe]

Originally Posted by redline8500

nice write up exe that is the best way i have ever heard it. I come riding dirt bikes and the reason that two stokes have that big exhaust pipe is because, it literally sucks the gas out of the crank and into the combustion chamber then it does it all over again. for those of you who dont know two stokes dont have valves so the piston does not move the air and fuel

[jdmkid88]

thanx. this was very insightful...

[bmnorm2]

Originally Posted by "Ridge"Racer

im originally from frederick, so im just going to agree with you because there isnt really much else to do up there other than research stuff. alot of what was stated is true, notice the skunk2 mega power r isnt the best for our n/a cars.

+rep

Im from Ijamsville! right next to frederick MD
But neways, ive had 3" inch custom piping and 3" straight through muffle w/ stock cat. It is louder then any companys especially since theres no resonator before muffler.... The point is.. i def lost power up to about 3500-4000 RPM..
At this point my exhaust note actually gets quieter "flowing better" possibly? And has ridiculous response and power from 4 to the end. Just a note of my experience with extremely big exhaust on NA w/ a CAI.. PS planning on SC this summer which is y i went so big
My .02 cents for this car NA would most def be 2.5" unless u like to keep ur rpms high as exhaust velocity is determined intially by the combustion in ur engine and so no exhaust piping is the best for all of your powerband. Good luck