Im running an all motor R with over 200whp, but am still on the stock exhaust. I dont want to spend 700+ on an exhaust when I can just build my own. There is a racing shop near me with tubing, but only has 3" tubing, and I really only wanted 2.5". You think 3" is over doing it?

 

2.5 should be fine.

 

they dont have 2.5 dammit!

 

How does a "race shop" not have 2.5 ?

 

domestic race shop...since when have you seen a big *** V8 with 2.5inch tubing lol

 

a lot of dual exhaust setups run 2.5" piping.....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rob :190: &raquo;</TD></TR><TR><TD CLASS="quote">a lot of dual exhaust setups run 2.5" piping.....</TD></TR></TABLE>

ok wise *** I think you know what I meant!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RTW DC2 &raquo;</TD></TR><TR><TD CLASS="quote">

ok wise *** I think you know what I meant!
</TD></TR></TABLE>

This guide of diameters was posted way back when by Dave Stadilus (SMSP) IIRC:

"2-1/4" up to 210HP @ the flywheel (about 180-185 whp)

2-3/8" (60mm) up to 235HP @ the flywheel (about 200-207 whp)

2-1/2" up to 265HP @ the flywheel (about 225-235 whp)

2-3/4" up to 325HP @ the flywheel (about 275-285 whp)

3" big for big HP (Forced Induction: &gt; 275 whp) "


Here is also a chart showing flow for the available HF cats at the time (just found it recently on my work PC HD):

"Cat Convertor flow rates


1) Catco (metal core) 2.25" 223.8 cfm
2) Catco (metal core) 2.5" 271.9 cfm
3) Catco (std. core) 2.25" 338.2 cfm
4) Catco (std. core) 2.5" 388.0 cfm
5) Random Tech 2.25" 297.1 cfm
6) Car Sound 2.25" 342.7 cfm
7) Test Pipe 2.25" 407.1 cfm
8) Stock NSX 242.1 cfm
9) Stock Type R 223.6 cfm
10) Stock Integra 218.3 cfm"

Although I forgot who posted it and it also doesn't list the 2 1/2" Carsound. But thought since I'm in such a sharing mood lately. What the Hell.

 

Thanks Anton

 

Whatever your opinions of Dan (of Godspeed), I recall he once posted his findings regarding tests of a 3" exhaust system on an ITR. His basic conclusions were that, although quite loud, the 3" system did indeed yield gains over the smaller systems he tested. If you're prepared for the noise, I don't think you'll have a problem with the 3" piping. Just be sure to select quality resonator and mufler components.

 

Christian Ran/Runs the 3" thermal on his crazy Integra.

You might want to ask/talk to him.

 

yeah Ill ask Christian and see what he thinks.

Noise is a DEFINITE concern I have, I DO NOT want a rediculously loud exhaust. I love being able to drive the car and hear the motor rather than the exhaust. I planned on running the same muffler SMSP uses in conjunction with a decent resonator of the same ID/OD as the rest of the piping.

 

Noise is a factor of the muffler, not piping diameter. Less restriction is better, 2.5 is good enough for most setups but 3 should be ok if thats all you can get at a good price.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dr Pooface &raquo;</TD></TR><TR><TD CLASS="quote">Noise is a factor of the muffler, not piping diameter. Less restriction is better, 2.5 is good enough for most setups but 3 should be ok if thats all you can get at a good price.</TD></TR></TABLE>


.....If I had it to do all over again, I'd have gone with 3" piping in the first place.

Actually, I'm still debating doing it anyway... but then I don't want to spend any more $ on exhaust so I think I'll just use a 3" cutout and my current 2.5" mandrel bent custom setup.....

Dammit, I want 3"+!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">

Dammit, I want 3"+!!! </TD></TR></TABLE>

I feel bad for you, is that 2.5 making some people happy?

 

I'm no exhaust expert, but I think 3" will be overkill for your application. I would contact KTeller8 on this board for a 2.5" exhaust system. He uses magnaflow mufflers and mandrel bent tubing..

 

2.5 is good all the way to 350 to the wheels...