exhaust change. How much is it worth?

[86lance]

Going from stock exhaust(89 daytona shelby) to a 3 inch side exit. Going to stick with the 2.5 downpipe unless someone local has one extremely cheap. Its going to be 3 inch cat and possibly a 3 inch muffler out the side. any idea how much power increase i should see? thanks!

[zshadow]

regardless of what you change yer size to, bigger is better with these cars... i went from a 2 1/4 stock 87 daytona exhaust, to a 2 1/2 catless glasspack out the side exhaust and there was a night and day difference.

estimated ponies i have no idea about, but anything that flows better and its a tid bigger is going to help...

[supercrackerbox]

Sorry, the plans have been delayed due to the purchase of the new SC, but I'm talking to my local dyno shop about getting some hard before/after numbers using the '86. Base pull will be with an '87 TII that's completely stock except for a K&N drop in, then moving up to a full 2.5" system, no cat, and finally an '87 CSX MP computer. Look for the info to be posted sometime this fall.

I'd also like to do a similar thing with the SC, which will be getting a more modified engine and a full 3" system, but not promising anything yet.

[MiniMopar]

Should notice a quicker spoolup and less of a drop-off in power at the top end. This is what I noticed just by replacing the stock exhaust with a 2.25" mendrel-bent cat back system with no muffler on a bone-stock 86 T1. Going from that same exhaust to a 2.5" mendrel-bent cat-back system with a Super-Turbo muffler seemed like a wash, but was much quieter.

Oh yeah...it will be louder which tends to have a mental effect as well. Dyno runs are a great idea and will be interesting.

[ssheen]

3" is 48% bigger than 2.5. That said having a shorter side exit will be better than a full length one.

My boost jumped from 12 to around 18 when I went 3" over stock. May want to watch that if you have a MBC.

[86lance]

yeah i rpped the complete exhaust system of the tona today and drove it to the exhaust shop to have the downpipe bolts torched off to save me some hassle. Man what a ride HUGE difference with only a downpipe. took the downpipe off at the shop and even more of a blast to drive Now im having a HUGE problem getting thos stupid --- downpipe bolts back on! they didnt have the correct pipe to turbo exhaust donut so nothing is working. I dont think my damn downpipe is the stock one and i belive it to be some cheap --- exhaust shop special this looks like it will work crap.. no wonder my damn onut crack in half and went into my converter to begin with!