I was thinking about running at the track with no exhaust and just have a dump after the DP so its dumping in the middle with a special dump tube I had made. My DP is 3" from the 3586 turbo and I have no cat.

Has anyone made any gains in HP just from ditching their 3" exhaust? I know I'll save a little weight.

Mods in sig.
Currently running 10.1@142

 

I ran faster with my exhaust off. Only .2 though.I did it mainly to save weight not gain power

 

.2 is impressive. What exhaust are you running and are you running a cat?

 

I plan on doing this as well, but with an exhaust cut-out on my testpipe.

 

I notice some power gains without an exhaust

 

I have read in a book about a guy that did some back to back testing with 3in exhaust and 4 in exhaust and he surprisingly recorded some gains. This was a "semi" stock turbo car but I would imagine the gains would be more substantial with the power levels you are at.

 

It was a hks hi power with test pipe. So I ran my down pipe and test pipe for the night. Honestly not sure of it was the exhuast or if we cleaned up the tune but regardless it did spool faster.

 

I'd be stoked to gain .2 since that would be put in the 9's. Again, this is just for the track. Thanks!

Regarding the larger exhaust, I have read that Buschur had dyno tested a 3" vs 3.5" exhaust and he did not see get any gains. Both exhausts had similar straight through mufflers.

 

I think it may help you some. All race cars run short exhaust and or cut outs.

 

Shoot I first read thread on my phone and didnt see your sig. the only power mods my car has is a intake and that exhaust. My best with the exhaust on was 12.8. with the cat back off I went 12.6 but that was on a different tune. I only retuned because I ran a different fuel the last time I ran. So will taking your catback off give you .2 in a quarter mile prob not lol. But it may have for me.

But hey its not going to make you slower and its only two bolts and two hangers so give it a try

 

My guess is unless the 3" exhaust is really choking up the power then removing the exhaust would probably provide minimal gains.

 

Definite power gains.

 

Are there any dyno comparisons to back up these claims??

 

i think the stm richer just runs a full 3in exhust

 

I don't have the graphs right now I'll post exact numbers later but I made at least 15 whp after taking it off and a retune