[Deadmau5]

Any one know if getting the cats removed and switched to straight pipes will trigger cel? I just got my zl1 and I have all the mods waiting to be put on etc but I don't wanna mod a brand-new car out the box I'll give a a few months . So would just cutting out the cats cause any problems or need a tune ?

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[ssrallyred]

Removing the cats will throw a PO420 and PO430 code.

[kwav8r]

Removing secondary cats won't throw a CEL.

[Deadmau5]

Originally Posted by kwav8r

Removing secondary cats won't throw a CEL.

So the ones located after the headers right before the xpipe won't throw a cel?

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[SJFGTO]

Yes that will throw a CEL and you will need a tune.

[kwav8r]

Originally Posted by Deadmau5

So the ones located after the headers right before the xpipe won't throw a cel?

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There are two sets of cats, the closest to the headers is primary. Secondaries are oval and flat and sit aft (some folks refer to them as resonators).

In different terms. The O2 sensors sit in-between the primary and secondary cats. If you pull the cats forward of the sensors you'll throw a CEL. If you pull the ones aft of the O2 sensor you're fine.

[SJFGTO]

Originally Posted by kwav8r

There are two sets of cats, the closest to the headers is primary. Secondaries are oval and flat and sit aft (some folks refer to them as resonators).

In different terms. The O2 sensors sit in-between the primary and secondary cats. If you pull the cats forward of the sensors you'll throw a CEL. If you pull the ones aft of the O2 sensor you're fine.

This ^^^

[Deadmau5]

Awesome thanks guys

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[mlee]

Originally Posted by Deadmau5

So the ones located after the headers right before the xpipe won't throw a cel?

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I assume you mean manifolds and not headers.

Also, not sure why you would want to delete cats on a stock car.

[bigmike32172]

I'm hoping to eliminate at least a hundred pounds and pick up 10RWHP once dropping the secondary cats

[RedHot18]

If you are not going with a full exhaust replacement ie headers on back, I wouldn't mess with taking the cats off. You will also be voiding the warranty. Add a Tony Mamo TB, Green air filter and a Borla, Corsa or who ever cat back and you will have your 10 HP plus a few more.

[EDFHOBBIES]

Originally Posted by mlee

I assume you mean manifolds and not headers.

Also, not sure why you would want to delete cats on a stock car.

nope the Stock manifolds are basically shorty headers you cant tell until there off because the thin heat shield on them. They had me fooled when I took mine off I was like dam! That's why a lot people are just doing the total cat delete tubes. The difference between full header longtubes and these shorties with the both cat deletes are not that much different unlike on the old days of the LS3 Cast manifold.. these tri Ys are not that bad. Of course if your gonna make big power change them every bit helps.

[kwav8r]

Originally Posted by RedHot18

If you are not going with a full exhaust replacement ie headers on back, I wouldn't mess with taking the cats off. You will also be voiding the warranty. Add a Tony Mamo TB, Green air filter and a Borla, Corsa or who ever cat back and you will have your 10 HP plus a few more.

That's exactly what I've done - Tony Mamo TB, Green air filter and Borla 60606. I kept the OEM suitcase muffler (for the NPP) as well as the OEM exhaust manifolds/headers (insert semantics argument here...).

Results - Better throttle response, throatier exhaust, and a little more power as measured by my calibrated butt dyno.

I did all of that with an agreement with the Dealer. Only questionable warranty mod so far has been the Elite E2-X Catch Can.

[Sub]

I gutted the secondary cats on my gen6 SS and never had an issue. It didnt save much weight but made it sound better. I havent done it on my ZL1, its loud enough!