I want to change my pulley and I want to know if the 3.25 is to small .I have a Thrasher CAI and a 180 thermostat with 1 heat range colder plugsand a reworked exhaust with 2 Flowmasters.Would I be better off with a 3.4 pulley? Any help would be apprecited.

My gut tells me that you won't be able to get away with that until you go with headers. Someone more familiar with the S2 will have ot confirm that. 3.4 is the common size for the mildly-modded S2.

The 3.25 is definately too small. With your mods, I would actually not be suprised to see you getting KR with the 3.4 pulley. 3.4 is definately the smallest I would go with your mods. To go to a 3.25 you would probably need rockers AND headers, or a cam, on top of your existing mods.

Shawn

Even with rockers or headers, a 3.25 can still cause KR. I wouldn't go below a 3.4. I plan on staying with this pulley even with my ported manifolds. And if I do rockers, I will probably stick with the 3.4 .... maybe a 3.3.

Thanks for the info guy. I guess I'll go with the 3.4.There just was a Pulley Boys 3.25 on E-Bay for $45.00 that I thought might work.

If you run at the track regularly, a 3.25 MPS would be nice, toss in Race gas, keep her cool, and just do a few runs.

You should definitely stick with the 3.4" until you free up the exhaust a bit more.
With headers, you can go to 3.3" and with Rockers drop to a 3.2".
A cam will allow a drop to 3.0".
Going to a Gen5 Supercharger will allow a .2" drop in size.
An Intercooler will allow a .2" drop in size.

+102 high octane fuel will allow a drop of .1" or .2"
Outside temps below 45*F will also allow a drop of .1"

Beware, these recommendations are generalized.

The only way to know for sure is to scan the car on an accel run to check for knock.