Well, if your check my profile you see that I was suposed to get the header put on today. Didn't happen. Since I just have the top, I've got make the rest and I ran into some problems today. No rods for my uncle's plasma cutter, and no saleen for my dad's tourch. Freakin sucked. I need to cut the flange out of the steel. I've got a question for the one's who know. I am putting this on with my stock sized exhaust, the 2 inch. I don't have a resinater, and I have a strate through muffler. I thought the size would help keep the noise and price of my exhaust down. My dad seems to think that it's a really bad idea to leave the 2 inch pipe there. Should I go ahead and up for the 2.5, or is it not worth the cost? I'm not sure how much it will cost, but I might go ahead and make it while I'm getting the pipes bent Thursday for the collector. I'll post pics when I'm done.

2.5 is excessively large for a 2.2L naturally aspirated engine -- you simply don't produce enough exhaust gas to use that much pipe efficiently.

2.25" is considered about as large as you want to go, and that's if you keep the RPMs up.

Now, if you're replacing your exhaust, 2.25" isn't that much more. However, a good resonator (an actual one, not the mid-muffler or glasspack design most people mistakenly call a resonator) will not impede flow but will smooth the tone considerably.

So, sticking with the 2 inch wouldn't be too bad. I've heard a couple people using 2.5. I haven't heard of anyone actually using the 2.25. Everyone has said since I can remember that it's the best size, but no one actaully gets it. Most exhaust shops don't cary haff sizes either, I think.

if your staying n/a, i wouldnt go above 2.25" piping.

Put the headers on and see how it performs. I bet money that the 2" exhaust will be fine.

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This is what I'm guessing right now, but the thing is if I've got it jacked up to fab the connection to the stock exhaust, I thought it'd be the best time to put whole new exhaust on. If it looks like it'll be cheap, I'll see if I can't run the 2.25. Our stock exhaust is 2 outside too. So that's like maybe 1.7-1.8 inside?

I run 2.5" on my exhaust, but i was using nitrous and was flowing more exh. As for you straight through muffler, take my advice, ditch it and get one with baffles. Once you get the header on there and resinator off, you're going to sound like a ****ty honda. I would know, I chopped out my resinator and am running a straight through muffler. It's not horribly bad, but I'd def do it different if i did it again.