I know I;'ve had a few posts about this before >> but yeah i'm finally getting it done, just making sure of some last minute things (big things), I'm getting a 2.5" cat back and I've had the celi checked that it will all fit, but will 2.5" give me less back pressure, enough to give a power loss? i need ideas fast >>

i don't think 2.5" should hurt your power, thats like the line for an N/A car so you should be good i thinks

okay thanks! does anyone have 2.5" on their celi? (with pics if possible?)

Well yeah u'll have less back pressure, but thats cuz you have a larger exhaust.

Less back pressure hurts your low end, improves your top end. But your really not going to feel anything in your car.

assuming your SX is the 1.8l 7afe, I wouldn't go any bigger than 2.25 inch. backpressure is one issue, but its also completely pointless unless you are going turbo in the near future.

I have a 3'' catback.

Stock ST185 exhaust is 2.25'' to give you an idea.

2.5" should be just fine. Almost perfect for an NA celica. I've done lots and lots of research on this.

As far as backpressure goes, please read this:

After reading that- what you're saying is that for cat back, a 2.5" would be better. What if one went the way of the N1 dual, and split it into two smaller pipes?

Would it do what the N1 Dual claims- retain scavenging power but also add on more free flow?

and where is this scavenging power most needed? If it's just splitting off after the cat...

You're reading a little too much into it (or taking a little too much from it >>). I shouldn't have quoted the last part, its not totally correct. If you read on in the thread you'll find this guy (who is also right):

You are speedtoe, thanks to my HS and college physics classes >> I had the base I needed, it was just putting things together.

Thanks VERY much for the dual vs single exhuast tip- I didn't find it anywhere else on this site (I could just be stupid tho >>


--Sean

PS: I know that Bosal 92-95 Camry headers are supposed to fit on my 5S-FE engine.. is this a 4-1 header, a 4-2-1 header? or will it even fit at all? Is it best to have a custom 4-2-1 header made? What should I ask for/look for? THanks >>

-gh0st_d0g+Apr 7, 2004 - 4:27 PM