S pipe downpipe

[CarlM2]

Does anyone know the size of the downpipe outlet?

Also, has anyone tried increasing the diameter when implementing a custom exhaust?

I'm just trying to figure if there's enough metal to work with to increase the outlet size to match the exhaust I'm planning on making.

Thanks,
Carl

[DiscreetSpeed]

2 1/4 is the diameter, there are some companies trying to make some, no one yet.

[CarlM2]

Awesome. Thanks for the info. I think I can ream .25" more out of it to match the 2.5" dp. Or, I could just go 2.25" all the way back with no cat. hmmmm

[Striker187]

2.25" is a little small....2.5" or 3" will be much better.

[DiscreetSpeed]

Originally posted by CarlM2
Awesome. Thanks for the info. I think I can ream .25" more out of it to match the 2.5" dp. Or, I could just go 2.25" all the way back with no cat. hmmmm
i thought about it too just boring it out but that peice looks solid at hell.

[KyRaceFan]

stock exhaust is 2.25 all the way back with 2 cats.
Go 2.5 with no cats for a big increase....
3 is overkill, but wont hurt anything.

[CarlM2]

Originally posted by KyRaceFan
stock exhaust is 2.25 all the way back with 2 cats.
Go 2.5 with no cats for a big increase....
3 is overkill, but wont hurt anything.

That's most likely what I'll do. This would be 'phase 2' of my mods. Phase 1, I'm installing Joe's MBC and a boost gauge... just waiting on them to come in the mail.

I wanted 2.5" all the way back originally. My goal is to spend the least amount of money with max amount of benefit. A custom exhaust with no cats shouldn't cost much. The O2 cheater is free because I have the parts lying around to make one. If I find the right tool, I'll probably bore the S-pipe out to 2.5".... also free... I wish I had a flow bench to test the results.... I doubt it'd be much. But, right now I have time and I'd like the exhaust inlet to match the downpipe outlet for technical reasons that I cannot put into words at the moment. I will dyno before and after... just takes time....

Thanks for the info and tips....

[KyRaceFan]

a guy i know here with an msp got a local shop here to make a 3 in exhaust, from the s pipe back , for about 350. No cats, and mil eliminator's for no CEL. He used the stock racing beat muffler, but is going to get an canister style muffler later.

[Striker187]

wow, that's pretty cheap. what material was it? cause i paid $325 + tax for my 3" ss catback. woulda be $225 for aluminized.

[jred321]

the s pipe is cast, isnt it? so you'll need a carbide bit and air tools unless you want to take a few days grinding it away. i say a company should make just that piece so people can buy that piece and then get custom beyond that, but that won't happen for a long time.

and i never got the point of stainless exhaust, especially in warmer weather climates where it will never see road salt. oh well...

[Striker187]

yeah i know, but my car deserves the best :D

[CarlM2]

Stainless looks cool but, it's not worth the expense to me. I rarely keep a car longer than a few years.... plus, I think SS weighs more than aluminum... Also, even if I keep the car long enough to warrant another exhaust system, I won't mind paying for a new aluminum one based on whatever I've learned between now and then.

I was thinking the s-pipe back would cost well under $300... probably closer to 200. I'll find out when I get a quote.

As to the boring boring process... I have access to air tools and I may be able to get it done at a machine shop very cheaply. Doing it the hard way with a carbide tip on a Dremel or whatnot is beyond my threshold for tedious work.

[iON Performance]

CarlM2 - you get what you pay for with aluminized piping. It won't retain heat in the pipes as well as ceramic coated mild or stainless steel. This may affect the longevity of some of the rubber hoses around the exhaust area.