Im about to get a vortech for my G35. Ive seen a lot of good info on the many different brands of catback exhausts, but it seems to all be geared for normally aspirated cars. What do you guys use on your set up? Does adding a catback on an FI car make a bigger difference than installing the same catback on a NA car? I would expect the gains to be even better with FI. Im still trying to decide between stillen/borla/nismo to go with RT cats.

 

I think the biggest difference is seen on turboed cars rather than SC's. Since turbos need a nice free flow to get the turbo wheel spinning, they seem to respond more favorably to less restrictive exhuasts. ACP went from stock exhuast to a Greddy Evo2 (2.5 inch) exhaust and gained about 40 hp across the board, but peak HP remained about the same.

With an SC's, I would think the gains would be comparable to NP, maybe 10-15hp?? I guess it also depends on the other mods you have.

 

fluidz and 12secz run borla td,,,,,,,and they have nothing but good reviews......not to mention sc need some back pressure where as tt need to expel gases fast a possible i think the borla is great for sc cars.

 

Borla TD here.

 

Borla TD and Helix Test Pipes and Never had a CEL yet after 500 miles....

 

The idea is to vent the hot gas out better. More air in (however it gets there) means more exhaust out. It shouldn't really be about the "gains" with FI but about the big picture of getting the hot gas out of the engine which is why I have headers and RT's and TD. As you can see most of us went Borla TD and are happy with it. The gains come from the boost and the tuning etc.