i have the DC sports 4-1 header and the GMPP Touring Exhuast but i still have the stock cat. what would be better performance wise a down pipe or high flow cat and with either one will it still pass smog?

 

anyone?

 

...a DP has a cat. you can either go catless or not. if you have emmisions you can try and pass with a highflow cat DP.

 

do a catless down pipe and get a o2 simpulator on ebay. it moves the rear o2 sensor off the dp making the extra flow unnoticable to the computer. so no check engine light

 

I say get the whole downpipe with cat becaust the stock downpipe has other restrictions besides the cat

 

what do you guys recommend that are simply bolt on compadable with the GMPP exhuast?

 

Xtc.

 

just gut the cat on the stock dp

 

I just sold my xtc dp, computer didnt like it, and I didnt want to deal with simulators and other crap. I cant even tell a difference honestly back with the stock DP

 

how do you gut your stock cat?

 

you take the dp off and then form the end that bolts up to the header you just get a screwdriver or whatever else and clean all the stuff out of it.

 

Catback before downpipe.

 

I bought a Random Tech DP w/ high flow cat from Crate Engine Depot.It's a direct fit with the GMPP cat back and stock or Extrude Hone manifold.Polished stainless.You might consider that.

 

i haven't found a simulator that works yet, i've tried 2, the one that offsets the original 02 sensor just by spacing it out further and the resistor and capacitor circuit thats wired in.

I had a 2.5" xtc downpipe plus the Cobalt-Addiction header with stock catback which actually felt stronger than my CA header + 3 in catback with original dp. I think it only felt stronger because the torque hit greater at low rpms than it does now, burning out into second was a lot easier before a 3" exhaust. I sold the dp because i hated the CEL i got all of the time.

 

if you gut the cat won't that throw a CEL?

 

yes.

 

If you have hp tuners or know someone who has it they can disable it, if your not going to tune for taking out the cat by bunping up timing and such thats where most the power comes from taking out the cat because you can bump up timing with hp tuners, i would just get a high flow if your not worried about geting thate extra hp, if not go catless its going to be way louder and raspy.

 

Sorry forget the name of the device) but a ob2 from a shop will also turn off cel permantly also.

 

the device is a Tec2 and its something that you can only find at GM dealerships or reputable garages. either way, the people who have this tool are very unlikely to break the law and disable the rear o2 sensor for you.

 

WTF....so the GMPP cat-back exhausts don't come with a new cat?? Is there a downpipe with a high flow cat available that won't void the warranty?
Sorry for the slight thread-jack, but I was just wondering.

 

The gmpp exhaust is just a cat-back exhaust, meaning it bolts up after the cat, and yes there is many d/p with high flow cats on the market, and i highly doubt a dealership is goin to void a warranty over a pipe.

 

I agree 100%. If it cuased some problem and they can prove it was the DP and highflow cat then yes you would be fucked. But I can not think of anything a DP and high flow cat could do to hurt your car.

I think I'm going with the Cobalt addiction Downpipe, 2 and 1/2 inch with the High Flow cat. Where does the AEM wideband sensor go?

 

The wideband bung would be placed after the cat i believe, like 8inches after the cat.

 

Can you buy a DP with highflow with a spot already ready for the AEM sensor?

 

Um iam not sure i think for extra cobalt-addiction will make you a bung.