Just a quick question. I have a bolt on high flow cat right after my y-pipe. I was wondering if there would be anything wrong with running my exhaust open right after the cat? There is probably 4 inches of pipe after my cat and then a ball joint where I can unhook it. I was wondering because wouldn't it be bad if cold air got up into the cat after shutting the car off with only 4 inches of pipe after it?

 

no...that wouldnt be a problem. If you want to dump the exhaust, I would get some sort of tip that either turns it away from the floor, or dump it out the side.

open exhaust, esp. through the cat sounds bad though IMO.

 

Anyone else have an opinion on this? I would like to run like this at the track tomorrow night but I'm worried that once I shut my car off, cold air will go back into the cat and damage it.

 

I think you'll be fine

 

TTT...anyone else have any input? Will I lose that much low end by running open cats at the drag strip? Any ill effects on the cat after shutting off the car?

 

For a long time i had my exhaust unbolted right before the muffler, with stock manifolds and stock cat. I thought it sounded awesome, and so did everyone else. About the cold air getting back in the cat, never heard anything about that? I would suggest putting a turn down on the end or something, even though I didnt when the muffler was unbolted on mine, nor do I have any on the currect set up (lt's with 18inch sweet thunder tubes)

 

TTT... I know I posted this a long time ago but I was thinking about doing this for real this time and I just wanted to see what anyone thinks? Seems the consensus is that it would be fine.

 

It will be fine, I had it done on my street car for a long time. Sounded awsome..only got pulled over for it once. All it does is allow the car to breath a little better in high RPM. You wont loose a considerable amount of torque, i didnt notice a difference after i got my cutout pipe removed and hooked straight to the muffler so im sure you wont be dissapointed, it will be loud at least :-P

 

I lost 4rwhp and 8rwtq from just opening my cut out, instead of running it through my mufflers. Our cars need backpressure. It sounds mean but kills performance. and I have the dyno sheets to prove it.

 

I forgot I still have factory cats, so you'll probably loose even more power and torque since you have hi flow cats.

 

I would definitely run it open .... What kind of catback do you have?

You may loose a bit of low end, but probably gain it back in the upper RPM range. Cold air hitting the cat after shutdown won't be a problem. I run my cutout open all the time, and have dual high flow Random Technology cats under the passenger's seat. Never had a problem.

If you like the way it sounds/performs, I'd recommend an electric cutout so you can dump it anytime you want to from the driver's seat

Thomas.

 

I have a SLP 2OTL catback. It sounds pretty damned good with a straight pipe and still good with the high flow cat, just not as loud. I'm not too worried about the loss in power, just wanted the sound. Anyways I was just worried about the cold air hitting inside the cat because I'm sure that wouldn't be good.