Whisper wrote:se7en wrote:
170-175psi is normal for curved neck ze I think....
As far as I know the difference between the curved and straight neck ZEs is the cams and obviously the IM. Don't see why there would be a difference in compression. A DE would have lower compression.
Just for the record, cranking compression is dependant on a few things.
For instance:
the compression like you stated(obviously of course)
the camshaft profile(overlap, duration, lift, etc)
and of course, adjustable cam gears and valve lash(on mechanical user adjustable solid lifter cams)
To explain, camshaft has a large affect on cranking compression because it can let extra compressed air escape if it has a lot of overlap(beneficial in high RPM). Also, like in turbo cams, it can trap more air in be closing the intake valve sooner, thus having less overlap and more compression shiwing on the gauge.
Mostly it just says that, the longer the valve is open, and not overlaping with the exhaust valve, the more cranking compression an engine can make with a said amount of piston compression.
Now cam gears and valve lash can affect cranking compress the same way. They both can affect how and when the valve is opening(albet on a less grand scale).
I hope that clears everything up.
7
1992 mx-3 GS-T, 10-12psi, T3/t4 hybrid, Turbosmart WG, AFPR, SSAC TURBO pipes, MSD Blaster coil, K&N, AEM W/B, MSnS(full standalone), 225Whp street tuned(10psi), 245Whp (12psi)(300bhp!!!)
1992 Fairlady Z(JDM RHD) 2+2 TT black(done!)700whp+
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