I have a thought of dropping the stock exhaust from the cat back and replacing it with a "straight" single piece of exhaust piping.
Anyone ever done this in an S? Some say that our engine needs back pressure, and some say that it would free up some horses. Frankly, I don't really know.
Would a single pipe from the cat back provide a few more horses? For the track, I would like to drop the stock exhaust weight and if a straight, and cheap Midas pipe works to both drop weight and give a couple more horses, then I'd be happy.

Note, that I'd be keeping a test pipe with a resonator in place of the cat - and that this is for track only.

Your expertise and help appreciated.

CB

 

A) Backpressure is a myth.

B) It's been done. No dynos as far as I know, but the weight savings is real.

C) Loud.

We did it on cthree's 2004 OTC car. It was done before that as well by some autocross types (jzr, etc.)

 

Ludedude,
So, would you say YES and do it? Any "butt-dyno" reports?

I've already talked with the Midas shop down the street and the manager says it would be easy for them to make and cheap for me. A custom fitted single pipe would cost me less than a hundred bones.
I don't care about the sound as this is just for the track and I'm looking for whatever edge I can afford for the upcoming time-attack competition.

 

Butt dyno is meaningless as there was other mods done to the car at the same time. You do save about 40-50 lbs of weight and that's significant.

Did I say it was loud?

 

what size pipe are you planning?

 

Iceman1,
That's what I need to know...
What I'm thinking is a same diameter as the exit from the cat-back exit.
What do you all think?
What should be considered is flow and heat and expansion of gasses coming out of my S.

And for the record, I do mods one at a time.
My S is so supurbly set up suspension-wise right now, that all I'm looking for at this time is more power and acceleration out of the twisties.
My S is roughly 200 pounds heavier in the rear right now.
If I can lose the extra weight and maintain a better corner balance while keeping, or increasing the HP, that would just be delicious.



CB

 

Maybe he tried it already and can't hear you

 

Gotta take those bodies out

 

^
Granted, I could stand to lose a few pounds, but for now I'm looking for HP/Weight ratio with what I have now.

 

a 2.75" (70mm) straight pipe would yield you the most gains...VersionJDM did this, but added a Megan turbo muffler to the pipe, and got 14 rwhp gains (peak) OVER the Spoon N1 exhaust. You will defenately pick up some power, on top of some serious weight losses. I say go for it! If I didn't need my hearing for anything, I'd have done it already

I did drive around once with no cat-back attached to the header....It was pretty f'ing cool, but I couldn't hear crap for awhile afterwards. Not a smart move.