Vervish

iTrader: (4)

I am running gutted with xforce exhaust as well - the smell is really strong, I be adding highflow cats soon.

i had the RR tune and xforce exhaust before gutting cats. The power increase was dramatic when I added the tune. When I subsequently gutted the primaries, I noticed an incremental increase in power but not as dramatic as when I added the tune.

When I add the highflow cats, I expect to lose some of the gutting benefits, but only some of it. Not sure if it worth all the trouble..

Justin727

I can't stand the smell and cant roll the windows down or open the sunroof with it stinking up the interior of my car. I'm not cruising in an old 80s stang 5.0 with turn downs.

Vervish

iTrader: (4)

I ran a pretty heavily modified catless subaru before getting my F, and the smell was not bad at all. This V8 produces WAY more exhaust stink than the suby..

Jondls33

thanks for the info.

I came from a stage 2 suby aswell, 3" turbo back no cats all straight pipe and smell wasn't bad at all and I can sure live with it but im worried about how bad the "smell" that everyone talks about when they gut the primaries.

Vervish

iTrader: (4)

The ISF fumes are much stronger IMO. Maybe get the RR tune and keep the primary cats in place...it's a little more cash, but you will not be disappointed.

Justin727

I agree. I've owned nothing but Supra's prior and the smell be no where near as bad as this. I just chalk it to the way the fuel system is designed and how it burns the fuel differently etc. My ISF is not my DD and the interior is starting to hold on to the smell. Time to fix it.

Vervish

iTrader: (4)

I wonder if stock secondary cats might work...they can't be that restrictive.

msgs350

iTrader: (2)

Isn't the stock cat inlet/outlet about 2.25" versus the 2.50" that's on most aftermarket exhaust systems?

flowrider

iTrader: (9)

^^^^^See my post from another thread:

Lou

Vervish

iTrader: (4)

Looks like they might work..they open up nicely

Vervish

iTrader: (4)

I cannot find any significant flow difference between Gesi and magnaflow.

There are a lot of other factors, but with everything equal, flow is based on the cells per square inch (CPSI). Generally, the more CPSI, the more restrictive the cat is and the better it filters
OEM cats are somewhere between 400-600 CPSI
Most aftermarket ceramic core cats are 300 or 400 CPSI
Most metal core cats are 100-200 CPSI
FWIW - read on some forums, the difference between a 400 and 200 CPSI unit is about 12% more flow.

The Magnaflow and Gesi are higher flow units are metal core and have about the same CPSI (100-200).