squish ratios

[group a supra]

Now for those of you who know how to build good forged engines you will know what i mean and im sure everyone has small preference here and there on the 7m but what do you use i tend to go .8mm just curious

 

[Doward]

Depends on the expansion rate of the alloys you are using (pistons, head - probably stock, right? LOL, gasket, rods)

I shoot for 1mm.

 

[group a supra]

i shoot .8mm on wiesco pistons on my built engines that have to make good power seem to be able to tweak in a bit more timing there but hey maybe its just me lol and all these are on link g3 or g4 ecu's

 

[Doward]

Odd - optimized quench should have you running LESS timing at the same power.

 

[group a supra]

Odd - optimized quench should have you running LESS timing at the same power.

i totaly agree what i meant was i add in even more timing for even more power without detination ie i can add a in a few more degree's than normal without det where i would normaly have to have stopped.

 

[Doward]

And you registered increases in power, on the dyno?

I'm assuming you're talking about extra timing under WOT (full boost), correct?

 

[group a supra]

not on the dyno but its easy to work out from the inj cycle dutys but yes under full boost

 

[Doward]

Gotcha - makes much more sense now! (Usually, with a bunch of boost, you end up with a retarded timing angle vs optimal, in order to keep cylinder pressures from spiking due to low grade detonation)

 

[group a supra]

couldnt agree more its much more fun when mapping cars to keep chucking in the timing with out det 2jz's even stock seem to love it
3s's seem a bit twitchy uless really well built with the squish being spot on
and well 7m's are just 7m's are a rule to themselves lol
But 1g's seem to like a bit