Exhaust Question?

[exdtuner]

I know a lot of you guys put a header and 2.25" exhaust on your cars. I don't really want a header though so I was wondering what you people think about a 2.5" cat-back exhaust and a free flow cat like magnaflow or something like it? Do you think the exhaust being .5" bigger could help performance gains anymore since I will not have a header? My thinking is that since I will be using the stock manifold and no header, I could free up the extra back pressure in the cat and slightly bigger piping for the cat-back. I don't know it's just a thought. Tell me what ya think.

Wow my question must realy blow, 2 and a half hours and not one response. HAHA holy crap come on guys tell me something.

[2003GT]

I was talking to Someone the other day about High flow cats and he told me all newer cars were high flow cats. Any cat with a honeycomb design was high flow. I dont know if he was right. So you are trying to go form 1.75 to 2.5 It might work I dont know if the gains would be substantial.

[exdtuner]

Mother of God................... 8 and a half hours and one single response. HAHAHAHAHAHA I really didn't think the question was that stupid but geesh. If anyone has any input on this whether it's positive or negative go for it. If not, screw it.:bang::bang::bang:

[mesaboogie18]

I'm no expert on this kind of thing but I think 2.5 inches for a n/a 2.0 I-4 is too big. If it were turbocharged, then 2.5 inches would be good, but if it's stock, I'd go for smaller. I think 2.25 inches is just about right for the motor. If the exhaust is too big, you won't get the right back pressure and you'll lose hp and especially torque.

[Matrixloader]

form what others have experienced here 2.5 is good if your boosted, but on a n/a motor you will loose alot of torque. 2.25 is just right for your setup, but a header with the cat-back will net better gains.

[exdtuner]

Finally someone! Thanks messa. I know 2.25" is whats recommended but I wonder if going 2.5" you could get similar results as having a header. An aftermarket header obviously relieves some backpressure and people run a 2.25" exhaust with a header, so it seems to me that with a stock manifold you could get away with running a 2.5" exhaust. I really don't know and I could be completely wrong but to me it makes since.

[PSUsouthpaw]

Finally someone! Thanks messa. I know 2.25" is whats recommended but I wonder if going 2.5" you could get similar results as having a header. An aftermarket header obviously relieves some backpressure and people run a 2.25" exhaust with a header, so it seems to me that with a stock manifold you could get away with running a 2.5" exhaust. I really don't know and I could be completely wrong but to me it makes since.

2.25 with a hi-flo cat and a header will work fine. 2.5 might barely be worth it with a header, but without it stick with 2.25.

[exdtuner]

2.5 with a header probably wouldn't have enough backpressure and result in loss of torque and possibly hp with N/A. With no header and 2.5 exhaust it may do the same but thats what Im trying to figure out.

[cbogg]

Remember, if you drop your backpressure down far enough, there's also a possibility of burning an exhaust valve as well, so don't go too big. 2.25" should be just fine for what you're trying to do.

[exdtuner]

Cool thanks cbogg

[bdiggy]

Some have gone 2.5 here only when getting the exhaust done crush bent vs. mandrel. With the crush bent it does pinch your piping a bit on the bends. If you go the mandrel route then stick to 2.25.

[exdtuner]

It will be crush bent. Baller on a budget baby. I keep my belly full, clothes fresh, pockets fat, and my pimp hand strong. HAHA!!

[cbogg]

Some have gone 2.5 here only when getting the exhaust done crush bent vs. mandrel. With the crush bent it does pinch your piping a bit on the bends. If you go the mandrel route then stick to 2.25.

Trying to one-up me Chef? Don't make me beat you with a saucier. He's right though, crush bent IS cheaper, but if you're going custom exhaust, mandrel is really the only way to go. Crush bent, even if it's bigger but works out to be roughly the same, won't flow as well because the crushed sections will cause more turbulence and disrupt the flow.

It will be crush bent. Baller on a budget baby. I keep my belly full, clothes fresh, pockets fat, and my pimp hand strong. HAHA!!

and the bull**** flowin? lol

[exdtuner]

^ thats right haha

[bdiggy]

Trying to one-up me Chef?

Always cookin' up some marvelous sheet! That's how I roll yo, lol!

[BobMs_wht2k2]

2.25" CRUSH BENT is more than enough for n/a with no header. That's what I've been running for a few months now. 2.5" is just too much.

[exdtuner]

cool thanks man

[SteveHGT]

I'm no expert on this kind of thing but I think 2.5 inches for a n/a 2.0 I-4 is too big. If it were turbocharged, then 2.5 inches would be good, but if it's stock, I'd go for smaller. I think 2.25 inches is just about right for the motor. If the exhaust is too big, you won't get the right back pressure and you'll lose hp and especially torque.

MM. my exhaust is 2.5.. I have lost nothing. No CAI nothing.. Infact my exhaust has improved HP and low end.. so i dont know what you tried. but it failed horribly..