Anybody with experience in collector/ exhaust sizing on modded CRVTEC (high comp, cams, etc.) - 2.5 vs. 3.0 diameters??

 

I'm going with 2.5" diameter. Stock is around 2.25" I believe and a shop that tested really didn't find any advantage to going over that on a mild engine. I'm aiming for what sounds like your setup, and we will need to move the air a little faster than normal. 3" is usually reserved for a high horsepower turbo car. Don't think you'll need to go that big.

B96v6

 

3" collector will eat away at your low and mid-range torque, and will likely benefit your top end power either. As mentioned above, 3" are usually best on FI applications.

 

Talk to Dave at SMSP. If my memory serves me, I believe his B20/VTEC headers were using a 2.75" collector.

 

yea, that is the move...prob 2.5 or thereabouts best...

 

it really depends on what kind of racing you are involved in. a big collector is good for drag racing because you are always in the top of your rpm band, yes you will lose some bottom end but you are usually lanching at a high rpm anyways. so again it depends on your situation.