Help regarding high flow cats and headers

[Rabamaro]

So I'm interested in slapping some long tubes on my LS3 or perhaps sticking to high flow cats and upgrading to the headers later. I've got two questions: Besides Solo, are there any other brand high flow cats and is there really any difference btwn the brands? Also, will LTs throw O2 sensor codes if you get the O2 extensions?

I'm not interested in tuning my car just yet for warranty issues. I appreciate any help!

[Fraxum]

If you install non LT high flow cats that fit before LT headers they cannot be used once you get the LTs. So if you buy the cats first the only headers that will fit will be shorties. Shorties are nice but do not seem to add much HP.

Just avoid the tune and you should be OK with the warranty. Get O2 extenders to avoid most CELs. But get a code scanner to reset them when you do.

Some people will tell you LTs are not a good idea without a tune, but while a tune improves drivability and has other benefits, it will only add a few HP. Several owners here run their LTs without a tune and seem to be happy with it.

But you never know with some dealers. So if keeping your warranty is a major concern, just get the high flow cats and get 1/2 to 3/4 of the power LTs and high flow cats give you.

If you are really nervous about your warranty stay away from all of this. In modding you have to pay to play.

[The Stig]

Originally Posted by Fraxum

If you install non LT high flow cats that fit before LT headers they cannot be used once you get the LTs. So if you buy the cats first the only headers that will fit will be shorties. Shorties are nice but do not seem to add much HP.

Just avoid the tune and you should be OK with the warranty. Get O2 extenders to avoid most CELs. But get a code scanner to reset them when you do.

Some people will tell you LTs are not a good idea without a tune, but while a tune improves drivability and has other benefits, it will only add a few HP. Several owners here run their LTs without a tune and seem to be happy with it.

But you never know with some dealers. So if keeping your warranty is a major concern, just get the high flow cats and get 1/2 to 3/4 of the power LTs and high flow cats give you.

If you are really nervous about your warranty stay away from all of this. In modding you have to pay to play.

Correct me if I'm wrong but don't you have to get a tune with LT headers?

[lrc250]

Originally Posted by stieger

Correct me if I'm wrong but don't you have to get a tune with LT headers?

To get the most out of them sure, but you don't have to. Most without the tune will also get the CEL for the rear O2 sensors.

[TBone]

Originally Posted by stieger

Correct me if I'm wrong but don't you have to get a tune with LT headers?

You don't have to get a tune but you run into a few issues if you don't.

You leave HP on the table that you could otherwise be enjoying.

But the bigger issue, if I remember correctly, is that you will be running lean and that can be potentially dangerous to your motor.

T.

[Fraxum]

Originally Posted by TBone

You don't have to get a tune but you run into a few issues if you don't.

You leave HP on the table that you could otherwise be enjoying.

But the bigger issue, if I remember correctly, is that you will be running lean and that can be potentially dangerous to your motor.

T.

I believe the lean condition does not happen with the Camaro by adding LTs. There are threads on this.

[Fraxum]

Originally Posted by lrc250

To get the most out of them sure, but you don't have to. Most without the tune will also get the CEL for the rear O2 sensors.

The O2 extensions that move the rear sensors further out of the exhaust stream help. But I think everyone that has LTs without the tune eventually get CELs occasionally. When you do get them you can turn them off easy. And if you have a CEL it is not good to ignore it so the scanner is needed.

Because we are modifying the emissions control system with LTs or just high flow cats, any emissions warranty related claims can definitely be denied by a dealer. But of course we are buying new cats anyway.

So if the OP is worried about the warranty he should stick to a CAI and a catback. You can pick up 15 RWHP with those mods.