Help with exhaust (backpressure)

[EgFanatic]

Hi guys

I have a 2 1/4 inch piping with 4-2-1 extractors on my car with a stock cat.. I have a spoon n1 tip, my problem is that at lower revs cars sluggish around till 4k rpm then it pulls, i want bit more torque at lower rpms.. so i was thinking of getting another muffler to compansate for the backpressure loss due to my current setup.. Any one here can reccomend a nice muffler for low and mid rpms? any help would be greatly appriciated..

thanks

[trism]

1. Backpressure is a myth, at least in the way youre talking about it.
2. Its not the exhaust. Its just a characteristic of the engine.
3. Sounds like the engine just needs a good service. Old fouled up plugs and old heat damaged leads will give the symptoms youre describing.

[hmetro24]

Honda has a problem with low end torque, you can get 4-1 headers and get low end torque. Also it possibly you engine need a service. Hot/ humid weather will also effect the performance of the engine.

[EK1 Civic]

4-1 will push the torque and power to the 5.5k+ rev area. Stick with the 4-2-1 headers. Smaller exhaust diameter gives you more low end to, but you bottleneck the engine up top.

[dougie_504]

Get a high flow cat and drive it harder.

Also please change the name of your thread to something more appropriate, it's very vague.

[pat88c]

Back pressure is not a myth
How do explain that a R32 gtr makes more power and toque with oem exhaust (around 2'5" to 2.75") that bends in and out with press bends conpair to stright 3" exhaust ?
(that with basic mods injectors, intake and cai)
Been done few times in mags and online

Another example is J racing intake pipe the small to big to small
Some of the k series boys use a similar style intake pipe
I can name few more too

Maybe it not something you notice but back pressure is need sometime there to make more power

yeh as most people say do major service on engine and fit high flow cat last after the service to help with bit of flow as stock audm cats are not as good as jdm or aftermarket cats

[EgFanatic]

thanks for the replies guys, i think the back pressure like pat88c said is really not a myth.. because when i put the silencer on the spoon n1 i get better response at lower rpms to mid... but at top it bogs down.. i have actually serviced the car recently, checked and gapped all my plugs and cleaned them accordingly, my problem is that with the spoon n1 silencer installed the car sounds like shit but goes actually alright lol.. so yea

[dougie_504]

I have changed the name of your thread because you didn't when I asked you to.

Sounds like you need to take your pick. Crap drivability or crap sound!

[usaco]

You need to go to a 2" pipe with hi-flow cat.

[akira]

its the same with me....i installed xforce catback with 2 1/4 piping (oem headers and cat) and i felt a slight increase in performance. Then i installed xforce headers and hi flow cat and got the same result as you, sluggish low-mid range and then power in top end.

[trism]

So when you installed a cat back, you felt an increase in performance because it was bigger and less restrictive than the stock exhaust, and therefore wouldve been more responsive, and made a few kw more power.

When you installed the headers and highflow cat, it had the effect of moving the power curve futher up in the rev range. So while people connect this with a loss of power, in fact the maximum power produced is probably more, but its higher in the rev range, and down low is the same, or slightly worse than it was before.

When its a daily car, and most of your driving is low revs, it feels like its slow as fark, and down on power, which is partially true, because it probably is, at these lower revs.

All of those that believe in back pressure, you can please explain to me exactly how having more resistance inside an exhaust, can make more power?

[Drifter995]

I increased my exhaust from a 1 1/4inch pipe to two mufflers over to a 2inch pipe with one lukey muffler at the end, and my car produces more power. Backpressure theory broken.

[curtis265]

Back pressure is not a myth
How do explain that a R32 gtr makes more power and toque with oem exhaust (around 2'5" to 2.75") that bends in and out with press bends conpair to stright 3" exhaust ?
(that with basic mods injectors, intake and cai)
Been done few times in mags and online

Another example is J racing intake pipe the small to big to small
Some of the k series boys use a similar style intake pipe
I can name few more too

Maybe it not something you notice but back pressure is need sometime there to make more power

Anotherone who's confused.. let me try explain

You need to choose an appropriately sized pipe to produce the fastest possible airstream for your desired RPM. Pressure in the exhaust system is inversely proportional to the square of the velocity. in other words, the higher the velocity the lower the air pressure in the exhaust system which is good as it pulls the air out of the cylinders giving your engine more torque, rather than your engine having to apply torque to 'push' the exhaust gases out

The velocity through a pipe is related to the volumetric flowrate and the size of the pipe - the larger the pipe the slower the air. A pipe too big a results in the air moving slower resulting in not enough negative pressure in the exhaust system.

I don't know wtf is up with that G32 GTR, because i'm quite sure a lot of them are going for 3" exhausts.. even some H22's are using 3" for high RPM applications.