brandobot89

California has some strict *** smog laws, so i'm running a gutted cat convertor because my cat failed. I heard I can actually lose power and whatnot from a gutted cat convertor. What are your recommendations? I'm running DC headers, aem intake, and a greddy sp2. All bolt-ons.

I have extra greddy 2.5" piping that I can have a shop cut and drill holes to make a test pipe, what do you think would be best?

russlan44

in ur place i would keep the cat without gutting it and spend 20-30 bucks on test pipe so when ur smog comes up, u wont have to buy another cat, hope u havent gutted yet, aldo u said ur running it already. Gutted cat is same thing as test pipe.

brandobot89

Its gutted already. The cat convertor failed, check engine light came on and it began to rattle. So i removed it and bashed everything out and put it back in. I got a o2 sensor spacer and the CEL is gone.

But im thinking about getting a test pipe, I keep reading gutted stock cat convertor can slow your car down.

h23siaws

gutted cat doesn't slow you down, it does makes more noise though. you should see your engine revving a lil quicker. slap a good cat-back exhaust on and it will rev like crazy. but you will need new cat for smog test = $350 from dealership

brandobot89

I got a full catback on it also. Thanks!

Finest

I'd go for the gutted cat since they can also do a visual inspection to see if there is a cat present underneath the car. The flow difference between a gutted cat and a test pipe is minimal at best, especially at the level of mods you're at.

98vtec

neither.

ethereal2pt2

just leave it.

Kronn 98SH

My cat also failed and I gutted it. Killed performance obviously. Replaced it with a universal Carsound highflow cat for $55, but I'm not in Cali.

paniaguae640

hi-flow magnaflow

Kronn 98SH

For Original Poster:

Magnaflow and CarSound are the same thing. I think Magnaflow bought Carsound.

autoluder

straight through resonators is the best way to go, and get a po box address on your license from outside county that doesnt have smog testing.

Problem solved.

paniaguae640

I read somewhere that test pipe pollutes the world in which we live in and also makes 1 more horsepower compared to hi-flow and hi-flow does not contaminate mother nature as much. This is a suggestion get a magnaflow or carsound hi-flow and also at the same time buy a normal new california cat. This way when you have to do a smog check just unbolt and put in the new california cat. and once your done unbolt that and put on the hi-flow. This is all just bolt-ons, not welds.