Ok, Im getting ready for my LS-VTEC build and was wondering if I should go with the oversized p30 pistons or stay with the stock bore. When you get new pistons you have to have the block honed anyways right? So should I just get it bored out and use the oversized pistons? Also, what size pistons should I use? .20 0ver .25 over? And the last question if Im only boring the block out this small amount my stock sleeves will be fine right?

 

Oversize P30's will be 0.25mm over or 81.25 mm. Stock sleeves are fine at 0.25 mm over. If the block is o.k., boring is not necessary. You could bore it anyway if you want to pick up a little more displacement.

 

Thanks, I'm gonna go with the over sized ones then.

 

What kind of gains would i be looking at with boring .25mm over? Anyone one have an idea?

 

You're really not going to see any gain, may be .1 higher in compression or so. The main purpose of going over bore is to round out the cylinder, displacement gain is minimal.

 

You will go from a displacement of 1796.454288cc's to 1807.560625cc's. A difference of 11.106337 cc's. Worth a couple of horsepower, maybe up to 5 more hp ?

 

ok, I think I'm gonna go oversized than, for the slight gain, and I want to make sure the block is good and clean so Ill smooth it out in there and run the oversized pistons. Last question (I hope), would you go with the pct's over the p30's? I know I will have to have my rods machined to fit them, but I'm worried I'm not gonna be satisfied with skunk 2 stage 2's in the future and dont want to tear into the block again to up the compression to take advantage of a bigger cam. i know im the one who has to make the decision but I'd just like some outside input. go with the pct's in case i ever want to step up my cams? or stick with the p30's?

 

P30's will be fine. You will only pick up about 0.4 points compression by going with the PCT's. Whatever works for you. There are other things to consider-engine management, throttle body,header, exhaust, etc. Pick components that match each other and your goals.

 

oh, ok, I thought .04 difference was a lot more, I'll just keep it simple and stick with the p30's. Thanks for your help