ok i have a question on if my apexi n1 3 in exhuast will hurt my performance. My setup is a 1.8 b series motor that pushes out 190whp and 132 torque. I use a jdm ITR header with AEM 3in CAI. i got a really good deal on it and i figured it would be better that my 2.5in custom CRUSH BENT exhuast. Please don't flame me for this topic i just would like to know what some of the gurus think. thank you in advance

 

3" is too much ... 2.5" crush bent is fine for now ...

greg

 

anybody else's thoughts?

 

anyone?

 

try it.

i mean if open header nets better results, pls explain how a bigger exhaust would be "too much"

 

very good point! see i need more feed back like that. thank you. I thinkin it has something to do with lack of back pressure but see i don't know for sure, thats why i'm asking anyone else?

 

after the header, backpressure is a myth IMO.

edit: awhile back someone asked something similar..and supposedly some guy responded with he tried it and gained power all over the place on the dyno.

 

well i can tell u right now. that when my ehaust broke right after the header. it di not make any more power. it was a complete dog. i couldnt believe the amount of power it lost.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99b18 &raquo;</TD></TR><TR><TD CLASS="quote">well i can tell u right now. that when my ehaust broke right after the header. it di not make any more power. it was a complete dog. i couldnt believe the amount of power it lost.</TD></TR></TABLE>

so was that an open header? or did you leave part of the exhaust broken off your header??

 

Dont do it. Dont need it for a turbo car with anything under 350, and you dont need it for your car.

But, since you asked, user NAb20C5 made 189whp with a 2.0 ITR, Toda B, Power FC, on his turbo exhaust he had. Fuel was taking the biggest **** at vtec crossover, so we all believed it would have made upwards of 210 or more.

Still, dont do it.

 

if it's free or cheap, try it! you can sell it easy to turbo guys if you don't like it.

 

why not 3 in? b/c it slows down gas velocity too much; especially for your mods.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DefiantGSR &raquo;</TD></TR><TR><TD CLASS="quote">why not 3 in? b/c it slows down gas velocity too much; especially for your mods.</TD></TR></TABLE>

Exactly. Exhaust gases cool as they exit the system, and this slows velocity. This is why people put heat wrap on their headers--to keep the temperatures up inside the exhaust. Running a 3" on your basically stock engine seems like overkill. It might give you crazy gains at certain narrow RPM bands, but overall it would probably be as bad as your crush bent system.

IMO, buy a quality 2.5" catback + hi-flo cat.

 

3" is really good on big engines....i.e 2.0+.
I'm in search of a 3" exhaust for mine, right now. I have a 60mm Espiler JGT500, and it's holding me back BIG TIME.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EVOL &raquo;</TD></TR><TR><TD CLASS="quote">if it's free or cheap, try it! you can sell it easy to turbo guys if you don't like it.
</TD></TR></TABLE>
good point

 

edit:

then why does open header gain power? no exhaust gases cooling? just exiting?


Modified by EVOL at 9:46 PM 8/25/2004

 

open header may gain power but down low it loses alot.
im daily driving my car right now open header there is a real shitty amount of low end torque right now and it sucks so bad. i have to drive to work like this and come out smelling like gas.
but its fun when you want to scared the **** out of people hahah

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hayabusa160 &raquo;</TD></TR><TR><TD CLASS="quote">open header may gain power but down low it loses alot.
im daily driving my car right now open header there is a real shitty amount of low end torque right now and it sucks so bad. i have to drive to work like this and come out smelling like gas.
but its fun when you want to scared the **** out of people hahah</TD></TR></TABLE>

I've driven every car I have ever owned open header @ one point. Even if it was just to the exaust shop and all except my b16 felt much slower. I can't explain the reason for this but, the b16 felt like it was uncapped when I would pull the exuast off.(It had a 2.5" crush bent btw, no cat!) I am thinking of taking the b18b hatch to the track this weekend open header just to see how she will do.

Phil

 

you wouldnt benefit from 3 in exhaust b/c you are not making enough power. 2.5 is plenty big for an all motor setup. you need to keep backpressure in order to get h/p gains. 3 in tooo big

 

i wouldn't do it... if your crush bent 2.5" was done well i think your better off with that.. i think to an extent crush vs mandrel bent is overrated.. NOT saying mandrel isn't better in every application but if you have a good muffler shop and you have a pretty mild street car bent is fine...

the guy that does mine starts a bend then cuts it and welds it in the middle on the start of the next bend so there's not actuall crushed spots it looks like a mandrel bend very good job