2 1/2 inch-3inch exhaust question

[Bigglesworth87]

Hey all, Ive got a few questions regaurding my current exhaust setup. First of all my current setup is a midas special 2.5" cat back with a glass pack muffler. (Dont laugh, it all cost me 40bucks and a 12 pack of beer) Anyways, I have noticed that my car is really holding back on its performance due to the restricted exhaust. From the turbo to the cat is stock and I have been laggin on buying a downpipe. Anyways, I might have a sweet deal on a megan racing downpipe I just have to wait until they finish redesigning it. I have been debating on buying a thermal catback for now until the downpipe is finished. So will this new catback be less restictive then the 2-1/2" catback that i have now? Will that extra 1/2" diameter really make that much of a difference? Should I save my money and just wait it out for the downpipe? I have the money to get the exhust but do I really need it? Thanks guys!

 

[97gstnick]

patience is a hard battle that people have trouble winning. be patient man, just save and save and save until you can buy a full 3 inch. in the end, you will be very happy. trust me.

 

[Bigglesworth87]

PATIENCE!! AHHHHHHHHHHHHHHHHHHH DONT HAVE THEM AHHHHHHHHHHH

 

[doug]

Will that extra 1/2" diameter really make that much of a difference?

With your current mod list, no. If you plan on going biggie turbo, then yes.

 

[Bigglesworth87]

So then I should wait until the downpipe is finished so i can buy that?? I just want to rid most of the restriction.

 

[doug]

If your long range plan is this downpipe mated to the Thermal, go ahead and get the downpipe, I suppose. You'll want a high-flow cat in there as well, since you will still have to pass emissions.

 

[Bigglesworth87]

well so far the long term goal is to make over 300hp, now wether or not i go with a fpt28 or a larger turbo like a 50trim or something along those lines. I just want to rid of the restrictions until im up to the point of upgrading the turbo....I know a full 3inch is required.

 

[2GeNTSi]

I've read that people said that 2.5" is sufficient enough for mild upgrades. I don't have any experience with 2.5," only my 3" catback and downpipe. I've since taken off my 3" downpipe but I'm going to put it back on this weekend (I just took it off for smog). The 14B spools a bit slower without it but I can still spin 1st a bit, w/ the downpipe it spins a lot easier in 1st. That and the exhaust tone is much crisper.

You say that you have a 2.5" catback with a glasspack muffler, do you have any resonators on it anywhere? If not and you just bolt a downpipe to it, it'll be ridiculously loud (to me at least). My friend with a 1G GSX, had a 3" turbo-back, no neckdowns/resonators/cat and it was way too loud...I'm sure there is worse but it just didn't sound right. My setup had two resonators on the catback, wasn't too loud for me and I loved the tone that having no cat gives it. You have to deal with clearing the CEL every now and then as well as the smell of fuel but you get used to it.

So unless you can deal with the decibels right now and a few more from the downpipe, I suggest you get another catback with some resonators to keep the noise to a minimum.

**UPDATED**Well I looked at your gallery, and it looks like your tip is just welded to the end of a resonator, so I would imagine it's not too loud...

 

[Bigglesworth87]

Well I guess what my main concern was that if a thermal catback would be sufficent enough to solve my restrictions for the time being until i can get that megan dp or would it be like using the same exhaust. Would getting the dp be my main concern for now or what? Which would be the better dp to go with the thermal?

 

[2GeNTSi]

If it were me, I wouldn't even bother getting a different catback. Unless yours has an unusual amount of bends, then it should be fine. The Thermal system is nice of course but I don't see any reason to buy it in your case unless you just want it because it looks nice.

I don't get what you're getting at asking if it'll resolve your restriction. I'm guessing you're concerned with being catless for emissions reasons but you still want the performance of being catless? Going with 3" will help freeing up some restriction in that case but you still have a smaller diameter downpipe and cat keeping some power from being freed up. If this is what you are saying, then I suggest getting an RRE downpipe and swapping between a testpipe and a hi-flow cat. Also if you are doing this in preparation for bigger mods, then of course going 3" would help as opposed to your 2.5" catback.

Correct me if I'm interpreting the situation wrong.

 

[Bigglesworth87]

You are exactly correct. What I mean about the restriction is just that I can tell that its being held back. So a RRE down pipe should help out and thats the answer I was lookin for. Thanks

 

[92awdgsx]

When you do the cat back, get the straitest one you can find. It makes a big difference.

 

[2GeNTSi]

You are exactly correct. What I mean about the restriction is just that I can tell that its being held back. So a RRE down pipe should help out and thats the answer I was lookin for. Thanks

Yeah, it's kind of pricey but I would get it if I had the money...

http://roadraceengineering.com/eclexhaust.htm