Difference between 2.25 and 2.5?

I have a 99 eclipse gs, and I was looking at ebay exhausts. I can only find 2.5" exhaust, where I think 2.25 would give me better back end hp. Is there a huge difference going to a bigger exhaust? Will I lose hp because its too big? I have no mods to my car right now, Im getting an intake soon.

2.5 is fine. You'll notice a drop with a N/T with a 3inch pipe. I got a 2.5 on mine, and everything runs and feels great. No power loss. More gains. Not being restricted as much as a 2 1/4

Don't bother with an ebay exhaust. Just go to a shop and tell them you want 2.25" piping bent for your car. I would go stainless steel, but others might pick other metals that are lighter or w/e. You will notice quite a bit of low end torque loss with 2.5" piping over 2.25", but slightly higher end. 2.25" is about perfect for a N/T with minor mods, if you plan on going pretty big on mods, then get the 2.5". :2cents:

You really feel it pull through at about 4500rpm, but I also have a header, which helps the fact even more. The ebay ones are good... that's what I got. I would recommend it.

2.5" dude i lost my torque with that. My set up is... 2.25" down pipe to 2.5" piping! no cat. BUt i can tell you when your on the highway you have some power. I noticed a big gain in highend hp.. but my torque.... sucks ass

Thats because you took off the cat, you lost all of your backpressure

Don't start with the backpressure comments again! :D

Thats because you took off the cat, you lost all of your backpressure


so you think my car will have a better gain if i add a high fow catalytic converter???

I wouldn't say a gain......................but you'd have cleaner exhaust :biggrin:.......and maybe more lower torque. It depends. :-/