Advice on exhaust selection needed

[aleccolin]

Okay, time to choose an exhaust. I'm planning on taking advantage of RnR's sale and getting a standard turbo back. I am going to spring for stainless everything I just need advice on sizing.

First, my goals for the car:

92 GSX, bone stock now (recently acquired). Future mods will not exceed an EvoIII 16G, EvoIII manifold and O2 housing, walbro 190, adj. FPR, 550cc injectors, and whatever other supporting mods including eventually a FMIC, but the sidemount will remain in upgraded form until absolutely necessary. I'll be happy with 350 crank hp and the car will be driven often, though probably not daily.

That said, my questions center around downpipe and cat-back piping sizes. I'll be getting the high flow cat, which I'm assuming is 3", but will call to verify.

Given my goals for the car, and that it will be mainly street driven, do I get a 2.5 or 3" downpipe?

The 3" cat-back is a freebie (though extra for SS) so I figured I'd def. go with that. If the cat is 2.5" I'll def. get the 2.5" downpipe, but if it's 3" I need know if the 2.5" dp will support my goals for power output and how it might affect drivability as compared to the 3" downpipe.

I've come to rely on the experience of the members of this site, so I just want to say thanks in advance for sharing your knowledge; that's what makes the dsm community so cool and so much fun.

 

[me612]

either will give you gains. 2.5" will probably work, but you'll still more then likely get more outta the 3". Evo owners are seeing higher numbers with 3" systems and they come with 2.5" stock. If you have the money, go for it. I like to mod right the first time, that way I have no regrets or doubts in the future. What if you do get a bigger turbo someday, you'll really wish you had a bigger downpipe. All I can tell you is what I'd do, and I'd go with 3". Good luck man!!!

 

[aleccolin]

You know, I was kinda going with the whole "bigger is better" thing in my head - I just wanted to see if there was any downside to using the bigger downpipe. It's pretty easy to understand how pressure differential can play into a turbo's performance (output, spool, etc) I'm just trying to make sure I take every factor into account. Thanks for the input!

 

[meh]

bigger is better, less back pressure=faster spool.

 

[Generation1JeY]

dude aleccolin i'm with u, i just bought a 92 GSX almost stock, and i'm just about to upgrade my exhaust with rnr's turbo back sales, whatever u end up getting u gotta let me know how it works out to send me in the right direction cause as of right now i'm confused with all exhaust parts.

 

[aleccolin]

It's really not too difficult. With the turbo back deals you either get an O2 eliminator (eliminates the O2 housing) or a standard which just bolts up to your O2 housing. They give you options for downpipe and exhaust piping sizes (either 2.5 or 3) materials (standard galvanized or stainless steel), high flow cat, and muffler/tip. More than likely I'll be getting the all stainless 3" dp, high flow cat, 3" catback, with stainless muffler and 4" tip. Pretty damn expensive, but will last forever and is a lot cheaper with the sale. RnR has a good reputation so I trust them for a quality product.