question? i am going to build my bottom end this jan. i have spec b's and a bunch of other ****. a guy where i live has some stock bore je pistons and he wants to work out a trade. they are 12.5 cr, will my vafc, and maybe 410 injectors be enough to tune with, or do i need power fc? also is 12.5 going to be to high for pump gas ?

 

410 is too big. Prelude injectors should be as much as you'll ever need.

Warren

 

I have a set of 290cc prelude injectors, OBD2.. Will sell them cheap..

 

Many people are currently running 12.5 on pump gas. Look at the compression ratio calcualtion listed on this board and determine your actual compression with these pistons. With stock gasket & deck height, you may not be reach a true compression of 12.5 without decking the block.

You will have a fuel issue with that compression! You will probably need to upgrade to 310 injectors at least. Since you are going to depend on the VAFC for fuel tuning, getting a fuel pressure riser and gauge probably won't be a bad idea either. Since you may need to lower static fuel pressure, these will help with that.

Lastly, the biggest concern should be using stock bore pistons. A simple honing may no be enough for proper ring sealing if you have mileage on the engine(25k+). It would suck to do this and then need to pull it apart again because it didn't seal!