How much overdrive should I run?

MadMikeyL

SCCoA Member
I'm putting my 89XR7 back together, and I'm wondering how much overdrive I should run. I got a 94/95 blower, and I took it apart and ported it and the inlet pretty heavily. I also have a FMIC, cam, ported stock valve heads, and some 42lb injectors that will be going on the car. Right now the blower has a 10% pulley on it, but I'm wondering if that will be enough, or should I get a 5 or 10% JS pulley too?

Oh, and the bottom end is stock with all new bearings and rings, and some MLS head gaskets.
 
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put it all back together and see what your max boost is and let us know. you should be able to move alot of air with the stuff you have done.

i'd say 15% should get you where you wanna be. but then you may be looking at the coating peeling off the rotors at those speeds.
 
Ported late model and ported heads and good exhaust with 10% od i see 13/14psi with a stock early model pulley it barely made 10psi. 15% might be to much without a tune... I have a 10% crank pulley i thought about playing with but i dont want my engine to go boom.. I'd say 10% would be perfect without a tune but since you have bigger injectors id get a tune and run about 15% and see what happens.
 
I will definitely be getting a tune when I get everything back together. I just wasn't sure if I would start losing more in heat than I would gain from ODing it that much. I went pretty far with the porting, but I know it is still not going to be as efficient or take as much abuse as an MPX, so I didn't know if I should leave it alone at 10%, or go for a little more. I guess I'll look for a 5% JS pulley too now.
 
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