I about to do a internal engine build up using forge pistons and rods. I am pretty clear about rod use. On the other hand, pistons are another story. Since i am running factory internals on my Turbo LS Hatchback, i am confused about the bore of the cylinders etc etc. I am looking to run 8.5:1 compression pistons made by SRP. My question is that they have two sets:

SR-149223 ACURA 1.8LS(B18A/B):81mm/8.5:1
SR-149225 ACURA 1.8LS(B18A/B):81.5mm/8.5:1

I understand that the stock bore of my LS motor is 81mm. If the SRP piston is 81mm, i would think it would not fit? Is honing neccessary for these piston use? Also since i am ni there and have a decent amount of money at hand for my project, would sleeving the block help with fitment of any of these pistons? Any help would be appreciate!



[Modified by Zynentech, 12:00 AM 10/16/2001]

 

I would HIGHLY recommend overboring the motor .5mm (.020") when rebuilding a motor! Go with the 81.5mm pistons! Ideally you will want .003" - .0035" piston-wall clearances on a boosted car!

 

man, I think 8.5:1 is way too low...

 

I agree, 8.5:1 would suck for daily driving. Keep it in the 9 range at least IMO.

 

I personally have 8.5:1 CR on my car! Almost all factory turbocharged vehicles have 8.5:1 CR or lower! Silvia 8.5:1 CR, Slyline 8.5:1 CR, 2nd gen Eclipse 8.5:1 CR, 1st Gen Eclipse 7.8:1 CR! A lower CR will be less responsive on the street ONLY @ lower RPM's but once that tubro spools, It gets nasty! Overall, You will be able to run larger amounts of boost with lower compression! I drive my car on the street everyday and 8.5:1 CR is fine. I have a large T3/T04E (.82 housing StageIII Turbine, 57 Trim .60AR Compressor) and I start spooling @ 3500 rpms and have full boost @ 4400 rpms! Half the time I am in gear cruising around @ 4000 rpms anyways, so spool is right there!

 

Dont get the SRP pistons. Make sure you get the JE pistons.
JE makes SRPs but the SRPs are much lower quality and cannot
stand up to boost and WILL break.