So i really don't know much about FI, so this may be dumb. I'm looking to purchase a supercharger kit, but i also just purchased an Asura 3" exhaust. To match the exhaust I was going to buy a 3" HFC.

Is this too much in terms of diameter for a S/C kit? Should I leave in the stock cat? Buy a 70mm or 63mm HFC??

 

anyone have insight on this??

 

No. If you've got it, use it. It may be loud though to a comparable turbo car.

 

Depends, how much are you going to boost?

I'm running 10 psi, 3" piping, no cat w/ straight-through muffler. It's very very loud/ear piercing

 

yikes, hope its not too loud, the asura got some pretty good reviews on sound

 

On a supercharged S the stock exhaust w/ a 63mm test pipe works great for +400whp.
You might make slightly more power (10whp) with a larger exhaust, but thats not enough to warrant the ear bleeding noise IMO

 

I'm running the Asura 3 inch dual. It was a major improvement over a 70mm system in horsepower and noise.

It is a solidly built unit with good flow.

Three inch exhausts are inherently loud.

The Asura unit is one of the quietest 3 inch systems available.

Use the big cat and make lots of boost.

 

Great i was just getting ready to put it up for sale until this post! Do you think the exhaust will help on a comptech kit with stock boost? I'd be proud to get above 300whp

 

I agree

Op- SC is really loud with stock size exhaust ...and its going to be ear bleeding with bigger. Your not going to see much improvement until you get to the upper range/meat of what your blower can put out. With stock boost, I wouldn’t be surprised if you actually lost some trq and response in all but the very top end of the powerband. I may be mistaken, but I believe Sideways was already making well over 400whp with a ported top end when he switched to this exhaust. I’m afraid that’s when your going to really see any worthwhile benefits.

 

I switched out my stock cat with a test pipe when I went FI. I originally had a comptech exhaust which had similar diameter to stock. I switched it out for a 70MM single but it is now much louder. I do believe switching to the 70mm added more power though. Maybe 5 -10 rwhp over the the comptech. I am at 12PSI though.

I don't' think you need to upgrade your exhaust however you will probably see some good power gains if you up the boost on the supercharger. It will be loud though. I can stand it noise but it is very loud.