got a question about exhausts

[synz]

ive got 2 people telling me 2 things..but... for a cat-back (im having one made), what is better..... 2.25 or 2.50 stainless steel?

[litdevil316]

i think 2.25 would be plenty. but if ya gonna fix up the car some, the 2.5 wont hurt. there more ppl here that can help. i read lot of their posts and see what they say

[03xGAxSE]

v6- 2.5, I4-2.25 mandrel bent or 2.5 crush bent

[whitegase]

i have a ga w/ a 4cyl... and the guy who did my exhaust ran 2.25" piping catback... it flows and sounds better... i think originally it was 1.75"......... (this is for a 96 se)

[RamAirGAGT]

Having 2.25 before the cat and 2.50 after is pointless unless the 2.50 has better bends.

[whitegase]

Originally posted by RamAirGAGT
Having 2.25 before the cat and 2.50 after is pointless unless the 2.50 has better bends.

i am confused on what you mean....i understand it would be pointless to run a full exhaust @ different sizes....but a catback system will be larger than stock... i got 2.25" catback w/ dualexhaust on my 4cylinder and it sounds better than all those civics etc.... go to my webpage @ cardomain to view......

http://www.cardomain.com/memberpage/472641/3

[Themeneea]

i am confused on what you mean....

theres a bottle neck befour the cat of 2.25. you exhuasts restrictiion is at the smallest point

[coupe]

I have SnS headers and from the headers back to the cat it is mandrel bent 2.5" piping hooked to a SLP cat-back also 2.5" mandrel bent piping. If your not gonna upgrade your engine all that much save your money and just get a muffler and keep your stock pipping.

[RamAirGAGT]

Is the stock piping mandrel or crush bends? Your headers have a 2.5 collector?

[AznGA]

I would go with 2.5 mandrel bent.

[Pte Socks]

hehe SEARCH BUTTON WORKS GOOD! stock piping is pressure bent and gettin 2.5" MB piping will not hurt your car and you will notice SIGNIFICANT power increases with just getting a cat-back exhaust.

[synz]

i didnt feel like doing a search since i was running out my door immediately after to go to work. i have a 2.4l engine, btw... i just dont wanna go and get the wrong thing and have it become a problem later on down the road when i do other things to my car, is all. im not engine-literate, i only know about electronic stuff. im just a girl what do you expect :l

[whitegase]

most likely the stock collector is 2" maybe.. and 1.75" exhaust crush bent stock piping... i have a96with a 2.25" catback dual... and it flows nicely ... a half inch will make a difference in the future... with other mods

[wang]

gonna sound like you're farting in a coffee can amanda ;D

[synz]

uh no it wont, stop replying to my threads, thanks.

[white04ecoGA]

I had to go check out my stock piping after reading this, and I measured it. It is 2" from the manifold back. Also, I was extremely surprised to see that it wasn't compression bent anywhere. When did GM stop using compression bent tubing? Given that it is a true 2 in all the way back, would I see any gain in replacing my stock muffler? I plan on an AEM cold air soon as well. Oh and will the slp catback bolt up to my car, or is the ecotec se totally different?

[95-GT]

BTW..Stainless steel will cost a lot more then a simple mild steel will. You dont need stainless as mild will work just as fine.

[BBT]

Originally posted by Neo-Blue99GASE
hehe SEARCH BUTTON WORKS GOOD! stock piping is pressure bent and gettin 2.5" MB piping will not hurt your car and you will notice SIGNIFICANT power increases with just getting a cat-back exhaust.

How significant would that be? Now tonight I watched Horsepower TV and they dynoed after doing each change on a Camaro Z28. First they did a CAI and went from 231 to 239 wheel hp. 8 more hp is a 3.5% gain. Then they did a complete new exhaust, INCLUDING headers and a new free-flow cat, mandrel bent pipes, no resonator, and performance Edlebrock muffler, not just a cat-back, and got another 22 wheel hp. That is a 9.2 % (on 239 hp) or a 9.5% (on 231 hp) improvement.

Translate those, loosely, on a current GA GT. 3.5% on 175 hp = 181 (crank, not wheel). A 9.2 % increase on that adds almost 17 hp, or 9.5% added to the base 175 hp. Now you're up to about 188 crank HP. That's not a bad increase, at the crank, but not all that significant overall, and just a cat-back wouldn't be near those numbers on our cars.

What I'm saying is that a simple cat-back on these cars does not add a lot of power, if the example on Horsepower TV is any indication.

[95-GT]

Cant really use those as a transulation, as the camaro z78 is a RWD V8, much differant from a FWD V6. Like take a cam for out cars, and then a cam for the 5.0 Mustangs. The 5.0 will show a bigger gain then we will. Also, was it a LT1 camaro, cause those numbers seem very low to be an LS1.

[akeller]

Originally posted by synz
uh no it wont, stop replying to my threads, thanks.

Wang :owned:

[BBT]

Dunno what the Camaro was, older model (not really up on them).

My point wasn't so much that we could expect those numbers, notice I said to 'loosely' translate them to our cars. More specifically I was rebutting the claim that a simple cat-back on our cars would give 'significant' hp boosts, which I sincerely doubt, given what a more elaborate exhaust set-up did for a more powerful, and arguably more responsive to tuning, car. I would expect that gains for our cars would be lower % numbers, further lowering the actually hp numbers gained.

[Pte Socks]

Ok, its dyno proven that a CAI + cat-back exhaust will give you roughly 18 WHP. A cat-back exhuast will give you 12 WHP. The significant power gains I mentioned was the high-end power I noticed take a huge leap from the exhaust. It really shoves you back when you punch the rpms to 5000. Also, the statement that SS is much more expensive and not worth it is IMO, stupid. SS will last the time of your car. Getting mild steel will rust away within a few years. Why waste money?

[95-GT]

I am sorry, I wasnt thinking. I mean aluminized steel.

[mthegodfather]

I would definately go with the 2.5. You will kick yourself later on if you have to pay to have it done again because you didnt go large enough.

[Pte Socks]

Well like WEve all mentioned many times before, Unless you plan on extensively modding your car, 2.25" in the V6 is plenty. Only if your putting serious money in should you go with 2.5"

[RamAirGAGT]

You did a custom 2.5 all they way back, right?
If so, did you just reuse your stock cat?

[Pte Socks]

No, I knew for my car of 160 000 kms on it, the stock cat- was probably wearing out. So I just spent the extra 100$ to get a high-flow cat. Supposedly, our stock cats are quite good.