Exhaust versus Power versus HP

[Paul in SC]

Quote:

from secondchance in previous thread

Re: Group Buy Stainless Works.
With headers, no cats and 94 stock exhaust it registered 1.4 psi @ 6000 rpm.
Same with free flow exhaust (OBX in this case) dropped to 1 psi.

Yun,

Let's start there and the first question I have is what mods and HP for the engine tested?

Thanks for adding comments. I hope you don't mind the new thread.

Paul

[Meanmyz]

From the SW thread... Paul I guess I was asking because I was considering the pros and cons of doing this myself (headers, cats, and stock resonator and mufflers).

So again the question to anybody will to chime in: If Marc H lists 5 HP as the difference between the second design stock exhaust vs. a freer flowing exhaust, does this difference widen as you modify the car for more power, such as 500HP?

...with the answer leading to "yes it only makes sense to also add a free flow exhaust because you are only mitigating the effects of some of your mods" or "no, there won't be a noticeable difference".

[secondchance]

Quote:

from secondchance in previous thread

Re: Group Buy Stainless Works.
With headers, no cats and 94 stock exhaust it registered 1.4 psi @ 6000 rpm.
Same with free flow exhaust (OBX in this case) dropped to 1 psi.

Yun,

Let's start there and the first question I have is what mods and HP for the engine tested?

Thanks for adding comments. I hope you don't mind the new thread.

Paul

94 405 hp stock motor. Headers and OBX exhaust w/ Marc Heibeck chip turned 363 rwhp and 340 rw lb-ft.
OBX is 2-1/2" stainless steel system.

[secondchance]

From the SW thread... Paul I guess I was asking because I was considering the pros and cons of doing this myself (headers, cats, and stock resonator and mufflers).

So again the question to anybody will to chime in: If Marc H lists 5 HP as the difference between the second design stock exhaust vs. a freer flowing exhaust, does this difference widen as you modify the car for more power, such as 500HP?

...with the answer leading to "yes it only makes sense to also add a free flow exhaust because you are only mitigating the effects of some of your mods" or "no, there won't be a noticeable difference".

Conventional wisdom is to go to 3" exhaust once above 450 hp. To answer your question - yes. Difference will widen. Higher hp means more exhaust volume.

[efnfast]

1990, 375 stock hp. Headers, no cats, OBX exhaust, Marc H chip. 353 rwhp.

[1990 quasar blue]

1990 ported plenum/injector housings. SSW headers, random technology cats, flowmaster catback. HAT tune. 390 rwhp/360 rwtq. SAE.

[Fully Vetted]

1994 ported, SSW headers, no cats, Magnaflow catback, Corey Tune. 430 rwhp/392 rwtq

[WARP TEN]

350, Haibeck 510 pkg minus Fidanza and plus ceramic cats. Top end/head porting, 63 mm throttle body, SSW headers, Corsa. 413 RWHP. Fidanza aluminum flywheel would add 13 RWHP and no cats would add another 10 or so.--Bob

[Raptor Twin Turbo]

Stock 405 HP 93'

360 rwhp & 340 rwtq

No port, No headers, stock CATs & exhaust.

MS/Raptor ECM with MS tune.

http://i1132.photobucket.com/albums/m578/rhanselman/corvette356342.jpg

[Paul Workman]

It is all in my signature except to add this re the exhaust


3" dual exhaust (except mufflers...but that is going to change!)

http://i185.photobucket.com/albums/x220/6PPC_bucket/Dyno%20graphs/DynoLT510-19-10.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/Dyno%20graphs/DynoLT510-19-10.jpg.html)