Hi,
I am interested in straight piping my car.....anyone done this before??? any stories to tell?

 

I experimented with my 545 exhaust in stages a bit before ultimately putting it back to stock and going with a B&B muffler.

Note:
545?s come with a vacuum actuated flap on 1 of their 2 mufflers. And have 3 resonators?2 are up front a little bit behind the cats and the 3rd is a large suitcase style resonator in front of the 2 mufflers
Here?s what I did:

Stage 1-
Weld open flap on muffler

Results:
Minimal sound difference?no noticeable performance difference good or bad

Stage 2-
Weld open flap on muffler
and
Remove front two resonators

Results:
A bit more throaty vs. stock?no noticeable performance difference good or bad

Stage 3-
Weld open flap on muffler
and
Remove front two resonators (run dual pipes all the way to mufflers)
and
Remove rear resonator

Results:
Unpleasant tinny sound, I think the run from the cats all the way back to the mufflers was just too long?no noticeable performance difference good or bad


Stage 4-
Put everything back to stock and replace 2 rear mufflers with B&B

Results:
Perfect?no noticeable performance difference good or bad


So the only option I didn?t experiment with was leaving the front 2 resonators in place and replacing the large single rear resonator?hope this helps

 

I did it accidentally with my 540. The pipes came loose behind the catylitic converters and produced the most beautiful sounding V-8 music I have ever heard. So, to get the best out of the 545, I would think straight piping out of the cats would be the ticket.

 

Most of the time I hear "straight piping" it is to replace the cat converter with a pipe...hence, straight pipe. If this is what you're talking about, DON'T do it. I know of many people who have and the additional increase in power is not worth the hastle when you have to get the car smog checked. You really only gain a little more power on the top end while losing some low end acceleration.

If you're talking about straight piping behind the cat converter, I would just get a manufactured exhaust system with full muffler systems or else you stand to lose a great deal of low end acceleration due to the lack of back pressure. Remember, too much back pressure (OEM systems) helps with acceleration but hampers top end speed. Too little back pressure (ie. too free flowing) and you stand to gain top end but compromise low end speed. In extreme cases (of too little back pressure), you can actually damage an exhaust valve in your engine if the OEM exhaust valve springs are too weak.

 

Damn now I'm confused....