Street Visionz, Inc.

iTrader: (68)

I was surfing some sites the other day when I came across a set of pistons available for those planning on going all-motor. The pistons are forged and they raise the compression to 11.5:1 from the stock 10.3:1. If I get the higher compression pistons, around how much hp increase am I looking at? Also is there any downfall to getting 11.5:1 compression pistons aside from the fact that it would be near impossible to safely turbo the car?

Sosa

iTrader: (1)

Pingage with the CA gasoline/water... It may be too high compression for 91 octane, but you could be the guinea pig!!! If you were to do the pistons, and plan on doing cams in the future, be sure to do everything at once to minimize labor costs. ps... u give up moddin??? Or did you just run away from home Z ya around. -Sosa

Street Visionz, Inc.

iTrader: (68)

Hm. haha nah bro I didn't give up modding but I kind of just want to go the all-motor route and see how much hp I can extract out of the car without getting cams. For some reason I can't get myself to like them. hahah. Anyone else have any info about the 11.5:1 pistons? I think they would work alright with the CA gasoline since the M3's out there in cali seem to be fine and they run 11.5:1 compression.

Street Visionz, Inc.

iTrader: (68)

Anyone else?

D'oh

Keep in mind that the only thing preventing a high compression ratio is detonation, which is dependent on many factors.

Therefore, just because M3's don't have problems @ 11.5:1 doesn't mean the Z will be OK. Things like timing, cylinder temp, etc. all will make a difference. Of course, the fact that other cars are able to handle the compression does indicate that there is a good chance the Z will as well. The higher compression ratio will give you better efficiency, but you aren't really improving the breathing or anything else, so you won't be able to move more air or gas through the motor. Therefore, I'm guessing that the 10% change in compression ratio will give maybe 5% better efficiency which is ... 12 RWHP.

Also, if you are going all motor, I think you will really need to get cams. The Z's torque drops off pretty quickly after 4800 RPM, and to get significant HP gains you want to keep that torque up in the high RPM ranges. The stock cams will definitely limit your potential, no matter how many other improvements you make. Of course, a very important consideration is just how much power you are trying to make, but from what I've seem, going to different cams will make a big difference at the top end.

Anyhow, best of luck and keep us updated. Can't wait to hear how things turn out.

-D'oh!