Scruff Vette

have Kooks headers installed using the stock cats with no x-pipe??

Chevy dealer can install them using the existing cats and no x-pipe and claims no tune needed and no codes will be thrown. Price is $1,500 for headers shipped and installed.

The alternative is to use hi flow aftermarket cats, x-pipe (more $$) but also the tech. claims I would then need to get a tune to keep codes from being thrown which would cause it to fail PA OBDII emissions testing.

Any advice is appreciated.

csun213

How would they be able to use the stock cat? I would interested in doing the samething. Can the stock cat be used with LG header or just the Kook? Thanks

LS1LT1

Sounds like a good idea but part of the gains from doing long tubes comes from using high flow (or none at all) cats in place of the more restrictive stock ones.
I would think using the above method would help (and might help in the event of an emissions spot inspection) but one is still leaving some potential gains on the table as well.

csun213

Here in Ca emissions is my main concern. Does anyone know how much hp would be lost by using the stock cat?

andreas g.

It's a federal violation to move the cats from there location in which they were certified. Your dealer is full of crap. I don't think he wants to be hit with a large federal fine for tampering with the cats.

andreas g.

welcome2try

I installed the kooks LT, x-pipe and hi flo cats, B&B route 66 cat backs.. No codes appeared. Then I installed the Vortex ram air. Still no codes appeared. Finally prior to installing 4.10 gears,. Chuck cow performed a lap top tune and showed me the parameters, and he clearly showed me via his lap top, that I was on the verge certain codes appearing.

So just because the codes don't appear, it doesn't mean that all is fine and dandy with the motor, nor does it mean that it is running efficiently. If you install headers only, don't worry about codes. At any rate I would do full exhaust and tune, if I was you, and if headers only, I would still do a tune.

LS1LT1

True, even in keeping OEM cats but simply moving them is technically illegal, moving stock cats is likely no more legal than installing high flow cats in a position other than stock. In fact, I would bet that installing aftermarket high flow cats in the stock cat location (not possible with long tubes of course) would more legal than having the factory/OEM cats in a 'non stock' location LOL.

burtonbl103

The stock Cats will not work with the kooks !!!
I have the kooks setup

tbyrne

(always wanted to use that )

You also shouldn't have any codes after installing this package. The complete package is the way to go.

Tom

cbrf4i1

the dealer is full of $hit and has never done it to know better.

30YR W8T

Except, If they are damaged or you have cause to believe they are faulty. Hmmm, damaged?

glennhl

The OEM cats are so large there would be no room for them underneath the car after you install long tube headers.

'06 Quicksilver Z06

And thats assuming that anyone would even go to the effort to cut them off from the original hardware.

opus1111

Second that. Dude, assuming you're after performance with the headers installation, you're going to want the tune!! You'll see as much performance gain (not just peak hp/tq- throttle response, etc. too!) from the tune as with the headers, probably more from the tune assuming it's a quality one.

My Kooks LTs w/ HF cats and xpipe should be here tomorrow!

LS1LT1

Yes but even then they'd still have to be OEM style (or actual OEM) put back in the stock location...this all based on one wanting to remain 100% legal of course.
I have yet to hear of anyone getting in trouble for having aftermarket cats on their vehicle though, be they in the stock location or otherwise.

Max@Cartek

After that type of expense on a set of parts I would want to get the most out of it. You should really look into a tune for the setup. When done right you gain more than just an increase in Hp on the dyno, but also performance through the reduction of torque management. We do this install all the time, give us a call and we'll be more than happy to run you through all the options and costs.

Max
908.317.4496

30YR W8T

They don't have to be exact, but meet or exceed OEM specs. However, the aftermarket cats come in all different shapes and may be difficult or impossible to install in the stock location.
So to your point, "I have yet to hear of anyone getting in trouble for having aftermarket cats on their vehicle though, be they in the stock location or otherwise." I completely agree.

achilds

Stock cats won't fit. Use the high flows and get a tune. The car will pass the sniff test for smog and most places won't even notice that the cats have been relocated.

Oli1313

I have the kooks with x-pipe high flow cats. I was throwing codes until I found some o2 simulators and had cbrf4i1, a fellow forum member, tamper with them and modify them. Now, no codes!!!!!!!!
By the way, I cannot see how your dealer shop would be able to fit the headers and the original cats . BUT if they are willing to install the headers with the x-pipe for you GREAT, then no chance of them giving you crap about warranty issues.

0GANGSTERMIKE

I agree. Chuck at Corvettes of Westchester installs LG longtubes all the time, and with the header package comes the high flow cats. It is alway's a good idea when doing headers to get a good tune. After the headers, although with a stock tune you may not throw any codes right away, your air flow tables in the pcm will be off (now your car is breathing alot better) and a good tune can add much more power than just headers alone. Plus, your car will be fully optomized and SAFE!! Just make sure you go to a good tuner (like Chuck at COW!!!! )