1fastLT

I have an 08 Z06 that I want to add some headers to, and I'm torn as to which war I should go on the X pipe. The headers will be one of the first steps to my modding plans. I have a Killer Bee and after the headers I plan on a tune then in a year or so it will be a cam, springs, rockers, exhaust, and maybe a port job... The County I live in has never had emissions so that is not a concern.

I'd love to hear the pro's and con's of the catted vs. off-road x pipes, and to the folks that have the off-road pipes do you regret your decision? For those with Cats do you wish you had gone the other way?

Thanks for all input.

ChargedC6

if you want it loud, i say no cats and every ONCE in a while you will get a wiff of fuel but its in rare occasions. i would go catless and free up all the pressure if you have no emissions laws.

Im in cali (the worst for smog) and im blown with headers and catless x-pipe i have the B&B bullets and its LOUD but sounds mean as hell and is mellow when in low RPMS.

I say go Catless

1fastLT

I'm leaning towards Catless, but I wanted some input...

dgreer26

Just put kooks headers and cat-less x-pipe on mine two 2 weeks ago. Definatley no complaints here.

1fastLT

I am getting the headers coated, do you think it's worth doing the cats?

For what I will save on getting the cats I could do both and still come out ahead...

PowerLabs

I've done the catless thing on 2 cars... Extremely illegal, easy to spot, car smelled terrible; the exhaust fumes burned my eyes if I had the engine running and had to unload the trunk.
But I had a good reason: I was running a lot of turbo boost and I needed to reduce the backpressure.
On my C6 I decided that catless was NOT worth it. My main deciding factor was noise: Headers are loud, my GHL exhaust is REALLY loud, and to take the cats off and make it all louder would make for a pretty miserable highway ride... I got 1 3/4 JetHot coated Kooks (the coating is very much worth it in my opinion) with a catted X pipe and couldn't be happier. This combo + a CAI was good for 395 at the wheels on an eddy current brake dyno on California 91 octane gas. I find it very hard to believe that catless would have netted any more power.

Mike V.

People are being too gentle here, going catless will be way to loud. It will sound like 60's hotrod with glasspacks. It will be fun for 5 minutes & then reality will hit. This will get increasingly worse as you mod the car. I have 450rwhp from a cammed LS2 w/ headers, cats, 3" x-pipe, 3" back to flowmasters & I'm going to tone it down w/ NPPs or Z06 mufflers w/ a mild to wild swicth. Without cats even the mild to wild won't tone it down. The only justification for this is if this is a race only car, if that's the case, fine, if not, don't save money by bypassing cats, skip the coating. You will not enjoy driving the car for any length of time especially if you want to bring someone along to enjoy it w/ you.

ChargedC6

i aggree/disagree with the loud statements. its not that loud and it dosnt smell as bad as some make it sound.

I live in the worst place when it comes to smog/cats and all my cars are catless i have no issues if you keep your foot out of the gas the car is mellow but at WOT it sounds like a race car.

Your going to get many many many different opinions so either way you go you will be happy

06.Z51.MontRed.Vert

I can't stand catless cars, like one of the ops above said the smell is awful to the point that it burns your eyes. It isn't just you it affects its the people behind you (in addition to the environment). Keep the cats.

sacsrpc

I would say it depends on what your intentions are.

If you are trying to squeeze out every last but of horsepower on your setup go for catless.

For Me - I am throwing the cats back on my 99 turbo FRC for two reasons.

1) I am not after a max power setup and this is my daily driver. With the cats back on I am sure I will still be making enough HP to overpower my street tires.

2) There is a smell tradeoff. Not noticeable when you are moving, but stop the car to unload your golfclubs at the bag drop, get stopped in traffic etc and you will notice the smell. Stand around the car long enough with it running and the smell sticks to you.

HoleInOne

What is the "smell" everyone is talking about? I always thought the cats were responsable for an odor.

Ragtop 99

Good hi-flow cats should only cost a few HP over straight pipes. Do the right thing and get them.

GMuffley

The effect on the environment is not worth the minimal performance gains.

Smoke20

o0 zeno 0o

It smells horrible.... If your not smelling it, the people around you are. You're not going to get any real gains by not getting them, you'll just be making everyone in a convertible hate you.

C6400hp

I do not understand why you want a stinky and illegal car that ***might ** have an additional 3 HP over the one with cats.
Guys, it does not matter what your state smog laws are, having no cats is a federal offence, illegal in all 50 states with huge fines that can be imposed. The price of cats is chump change compared to the fines you will pay when you get caught.

PowerLabs

The smell is from unburnt hydrocarbons:
Because of the very short timespan combustion takes place in an engine the fuel injected is never combusted completely. The left over gasoline, under the high temperatures present in the combustion chamber, breaks down into smaller hydrocarbon molecules; these then recombine to form all kinds of absolutely nasty chemicals; alkanes, alkenes, dienes, cyclo-alkanes, cyclic hydrocarbons, aldehydes, ketones, etc... That is where the horrible smell comes from.
Incidentally, a lot of those chemicals are also known carcinogens. Catalytic converters aren't required by Federal law because the government wants a chunk of platinum underneath your car.
The platinum honeycomb in the cat, once up to operating temperature, recombines these hydrocarbons with carbon monoxide in the exhaust to produce C02 and water vapor...

carpe dm

huckleberrydude

not on purpose, but I'm catless now because they broke down and clogged and caused a blown head gastket. It may have had something to do with the tune and a combination of heat and boost. I will go back to cats if I can figure out the problem. The smell hasn't bothered me and with the borla touring the sound is plenty bearable. I'll have the electric cutouts on this weekend for when I want noise.

LsJuan25

Whenever someone rode with me and we were sitting still at the light they would cough and get teary eyed go with the Cats catless sucks!