Cats vs No Cats
Le Mans Master
Joined: Oct 2014
Posts: 8,674
Likes: 2,728
From: Atlanta GA
Even with high flow cats I still get some gas smell at startup because they are farther downstream than the originals and do not heat up as fast ... once they are hot I don't smell fumes but my wife will complain a bit ....
But I don't care , I love the sound and the power ..... I will put up with a bit of fumes ... but I would not ever go without cats .....tto much fumes without them
Racer
Joined: Sep 2014
Posts: 348
Likes: 20
From: Ft. Lauderdale Florida
You will smell the gas/fumes a little bit more without ones. To me was no cats and will do it again in a heartbeat...so...
Burning Brakes
Joined: Apr 2009
Posts: 899
Likes: 209
From: Louisville KY
Ran cats & 1-3/4 Kooks headers for 6 years on my 08 LS3. Always had some exhaust smell in slow traffic. Installed 1-7/8 Kooks headers and removed cats from Kooks mid-pipes. Still had exhaust smell at times in slow traffic in car. I Had the car dyno tuned at Shore Tuning this month and now no gas smell in car anytime. Turns out the low end was tuned pig rich to cover up some slight surging between 1300 & 1800 RPM at steady state throttle I had complained about after getting my initial dyno tune in 2010. Can't say how much HP removing cats added if any because I did other mods at the same time I replaced the 1-3/4 Kooks with 1-7/8 & removed the Kooks cats from their mid pipes. I have stock dual mode mufflers and there is no increase in sound level with the muffler bypasses closed. Doesn't sound like the car is that much louder when they open but there is some increase.
Last edited by jstewart; Nov 24, 2016 at 01:10 PM.
