YLOFEVR

I am now running hi-flow cats with LG PRO LT's and Corsa Sport. If I decide to go catless (emissions testing aside), what else do I need to do or consider? eg. Throwing codes, tuning it out, etc. Thanx in advance.

DOUG @ ECS

If you already have high flow cats, chances are the codes for the rear o2's have already been shut off. However I would have the tune checked over for safety.

YLOFEVR

Thanx for the input, Doug. Your advice and experience is much appreciated.

timd38

Basically nothing. As stated previously, you need to have the rear o2's turned off.

Motorhead-47

Increased exhaust odor. I have yet to see/smell a catless C6 that didn't suffer from increased exhaust odor when running a no cat exhaust. Lets be honest in realizing that the cats are there to burn off some of the undesirables. Practically speaking though, on the road, who cares...it is all behind you. Idling in the garage might be a different answer though.

saplumr

That is an understatement. I had the offroad x-pipe pipe for 3 years and hated it from day one. I had ECS put hi-flows on. Sound was great, odor was horrific! Never again!

Amric

You should also turn off Cat overtemp (COT) and CAT warm up in the tune.

Neither of these are neccessary, but they are better off than on. COT can pull power for no reason if you have the cats removed.

ETA

I have the CATs removed and love it, but the NPP sound is much much louder now over 3500RPM. Cops can probably hear me a mile away.

YLOFEVR

Thanx for all the good advice and different perspectives. I hadn't really thought about the smell.

arctic74vette

Smell is relative. My car SMELLS like straight gas. I have a buddy with a cobra with no cats and his car doesnt smell to me. Its really not that bad.

Motorhead-47

Probably the best advice to give is for you to find a Vette that is running off-road pipes and take a whiff for yourself...both at idle and follow along behind him.

FloydSummerOf68

I dont know what you guys are smelling.

My car with catless x-pipe smells like stock. If you dont tune it ever, then sure, you'll smell it because the cars run rich from the factory.

If you tune your car properly then 99% of the smell is gone. I haven't EVER had anyone comment about the smell and have actually had people comment that there WASNT a smell after I told them I didn't run cats.

There is no downside to no cats other than emissions testing, if they look.

The up sides are more power and sound.

Motorhead-47

You are one of the few. Every one I've been near had a distinct "scent"...and ALL were professionally tuned. The cats are there for a reason....the smell is a byproduct of that reason. If it doesn't bother you than great. It's your car...do with it as you please.

To the OP...take a sniff or two before you make the leap.

Stingbill

I don`t have cats and do have a tune and my car do smell !

wbear

These vettes with out cats do not smell more or less than any muscle car 1974 or older. If it didn't bother you then it won't now. Will it have an odor? Of course, its a large engine burning gasoline. In the 60's we didn't make it a point to stand behind the car or inside a garage while it was running and you shouldn't today even with cats since it still produces CO.

If it bothers you that much you can always add the cats later. In the mean time you can save $300, have more power, better sound and a cooler running tunnel.

FloydSummerOf68

My car literally does not smell any different than a stock C6. I can leave it running in the garage for a while and you can't smell anything.



I've had several friends with catless fbodies, and after tuning them they had no smell either. So I dont know what to tell you guys, lol.

saplumr

Obviously from what is being written here....smell or odor is relevant to ones senses. To the post that said it's no worse than muscle cars from the 60's, I say we didn't know any better then, but we're smarter now.

wooden

I don,t notice any oder from mine either, the exhaust is going out the back, really should not be any oder unless you are sittng in the garage with the motor running. the muscle cars of the 60,s ,70,s did not have efi and were not tuned as well, and most of them had exhaust dumping under the car instead of out the back atleast mine did and most the others I was around.

ramrodw30

No downside? How about that it is a violation of federal (and many states) laws and increases pollution for all of us to breath - thanks so much for your self absorbed analysis.

It is very curious why posts about illegal street racing are not allowed but posts about making illegal modifications are aok...

And how much extra power do you get based on dyno results I wonder?

FloydSummerOf68

To your first sentence:
I pass inspection JUST fine

To your second....because it would put a HUGE hurt on vendor sales and crush any enthusiast board as any longtube header violates federal law and aftermarket exhausts of any kind violate many local laws as do many other modifications. We're on a car enthusiasts board...better get used to lots of laws being broken

I would guess around 5rwhp more on a catless system.

C7-Beast

I too used to believe that going catless meant dealing with a bad odor until recently. I have a friend that went catless and I spent a good deal of time with his car recently and I gotta tell you, I could not detect any additional odor from the exhaust.