I notice that Vishnu doesn't have, in their list of staged upgrades, a cat-back exhaust with a reflash. Instead, the closest thing they have replaces everything from the down-pipe back, including the cat. But to stay in SCCA stock autocross class, we can only replace the exhaust behind the cat.

My question is what can be achieved by replacing the exhaust behind the cat, and then reflashing. This is not a question about changing the exhaust sound, I just want to know how much power gain, if any, could be expected.

Mike

 

I'm sure that Shiv will start with the base tune (good for 270 whp or so) and tune it up from there. Even with just a tune, you are looking at 35 whp or so. I would expect cat back to add at least another 5 whp.

 

Howdy-- Our Stg 0 includes a downpipe/cat with a reflash (or XEDE). You can easily substitute the cat-back for the downpipe for a small price adjustment. The reason we opted for the downpipe as the first bolt-on mod was because it didn't effect the exhaust noise of the car. Nothing is wrong with doing the cat-back instead... just as long as you don't mind some more exhaust volume. But for racing specs, that wont be an issue I'm guess

shiv

 

A local guy here gained 45whp w/ a custom tuned reflash and a Perrin catback. He baselined 255whp and ended up at 300whp. Not too bad for only 2 mods

 

FWIW, you can't stay in the stock class if you have reflashed your ECU. That would dump you into BSP if you do not remove the boost pill, SM if you do, or in STU if you choose not to run race rubber.

 

Oh, yeah, you're right, thanks, I forgot.