well here is the story, for those who dont know, i am in the process of building a D16 and turboing it. its all in the HCF project section, anyways...

my current exhaust is a 2.25 inch SS catback with a huge can. now this thing is very loud, even with the resonator, and of course the local cops think so too. ive been pulled over twice now. and i do have the scilencer, but it sounds so ****ty, and bad response. apperently they are cracking down on any non stock exhaust, which is bs cause there are tons of trucks and stangs arounf here with exhausts just as loud.

1.) this brings me to my main question, i am going to be upgrading to a 2.5 exhaust when i go turbo, but i have a chance to trade my 2.25 for a 2.5 even, within the next few weeks, quite awhile before i go turbo. now i know you shouldnt run that big on n/a, but do you guys think it would be that bad for the 2 months i will be n/a?

2.) the exhaust would be fabed up on my car, our mechanic can mandrel bend 2.5 inch pipe, and then a muffler like this one, link, i heard that they sound like a magnaflow. this would be with out a resonator too. how loud do u think this would be, i think since it is a real muffler it should be a bit quieter, and not so raspy/farty

3.) and one final question, i could have him get a high flow cat too, but would it ruin it if i put it on my current engine that is running rich, and has a lot of soot cause of low compression?

 

im running a 2.5' catback NA, and its perfectly fine

 

its not gunna hurt your car at all to have 2.5 on an n/a engine. you're just gunna lose low end torque. thats all. so if thats nota big deal to you.. go for it. make sure your high flow cat is legal tho or you'll be in trouble. = )

 

cool thanks guys, now do you know if it would ruin a new cat to run it on my current engine, it runs rich and there is alot of soot, would this clog a highflow cat? the one we were looking at was this one. LINK

p.s. i like the sig billy

 

Forty04 ran 2.5" on NA for a while before he boosted and he said it was just fine, both NA and boosted.

The cat should do fine, i dont think exhaust diameter has much to do with ruining the cat, specially if its just a header bolted up to the cat and then bigger piping behind that.

 

oh, im not talkign about ruining the cat from the larger diameter, im thinking my engine might ruin it cause it is in such rough shape right now, with all tha soot it is spewing right now, i would think it would clog any cat?

 

oh....that might be a problem then, older cats will go bad, not sure if the cat itself gets old or the engine is putting out soot, but they do go bad for some reason