2.5" str8 exhaust with no cats?

[SHAGwagn]

how much of a hp gain can I expect? I currently have the hiboost kit and an HKS hipower exhaust which I plan on having repiped.

 

[Matthew]

i dunno i was looking to do the same thing, since i have a similar setup (turbo+hks) but i had to allocate the funds elsewhere.

 

[SHAGwagn]

did u ever get your car running right?

 

[Matthew]

i figured otu the problem...its a bad FMU. see thread in FI section...

 

[AlbinoMuntjac]

I don't know about straight through. A little backpressure is more benefitial than most people think. Don't forget about the sound too. One silencer may be perfect.

 

[MazdaManic5]

werd, a little back pressure is good for quick spool, a lesson learned from rally racing.

 

[AlbinoMuntjac]

It also helps scavenge exhaust gases and keep the flow a little more consistant.

 

[crashed]

What? That's the opposite from what I've learned about exhaust and I have never seen a track car without an open exhaust. Also, no exhaust rep I've spoken to in SEMA have ever told me that some back pressure is good for performance. I have a turbo and it spools up much quicker with an open exhaust. Faster the exhaust exits through the turbine faster the spool up.

 

[Douggie]

What? That's the opposite from what I've learned about exhaust and I have never seen a track car without an open exhaust. Also, no exhaust rep I've spoken to in SEMA have ever told me that some back pressure is good for performance. I have a turbo and it spools up much quicker with an open exhaust. Faster the exhaust exits through the turbine faster the spool up.

You lose low end power but gain in the high end when you have low backpressure and high flow. When you're racing on the track, you're always revving at high rpms (at least try to), so it makes sense to have as little backpressure as possible

So for daily driving, yes, a little back pressure is good.

 

[AlbinoMuntjac]

You lose low end power but gain in the high end when you have low backpressure and high flow. When you're racing on the track, you're always revving at high rpms (at least try to), so it makes sense to have as little backpressure as possible

So for daily driving, yes, a little back pressure is good.

(mswerd) Thanks for typing it so I didn't have to.

 

[Iconoclast]

is 2.5 the diameter your asking for the piping or the liters or your engine?

cuz if you found a stroker kit for a p5-please gimme the skinny

 

[Douggie]

(mswerd) Thanks for typing it so I didn't have to.

You're welcome