Thread: head upgrade disappointment

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Originally Posted by turbo2256b

Whats your cranking compression?

seeing how he never said were the piston was in the hole or what the real cc of the head was . what bore size or how thick the head gasket was ? who know s ? 10.2???? or i may of miss the post were he said this ? not sure but i think i did ask him this back on page one ?

Originally Posted by pat mccarthy

seeing how he never said were the piston was in the hole or what the real cc of the head was . and what bore size or how thick ? who know s ? 10.2???? or i may of miss the post were he said this ? not sure but i think i did ask him this back on page one ?

Think he posed a comp figure just under 10 to 1. Calculated? Cranking interests me as far as effictive cylinder filling.

i cc every thing way to many variables for my liking on chamber size . this was after you posted tech did not know you did the math

Originally Posted by turbo2256b

Cranking interests me as far as effictive cylinder filling.

It interests me also. CraneCams says that about 165 psi is the limit for pump gas, but I have read of fellows who have run over 200 psi without detonation on pump gas. Never been there myself, but I'm thinkin' there could be no PCV or EGR and everything would have to be de-burred and polished to prevent pre-ignition.

Originally Posted by techinspector1

It interests me also. CraneCams says that about 165 psi is the limit for pump gas, but I have read of fellows who have run over 200 psi without detonation on pump gas. Never been there myself, but I'm thinkin' there could be no PCV or EGR and everything would have to be de-burred and polished to prevent pre-ignition.

egr very well could help with a hirer cranking psi with poor fuel i ran more then 165+ psi on many build. but grade of fuel is ?

Originally Posted by pat mccarthy

egr very well could help with a hirer cranking psi with poor fuel

Perhaps, but I have no interest in introducing burnt gases into the system to reduce the charge density. If you must run EGR from an emissions standpoint, then fine. But if you don't, then the whole contraption is mis-engineered in the first place if you have to use EGR to make it work.

Originally Posted by techinspector1

Perhaps, but I have no interest in introducing burnt gases into the system to reduce the charge density. If you must run EGR from an emissions standpoint, then fine. But if you don't, then the whole contraption is mis-engineered in the first place if you have to use EGR to make it work.

well i do not but you posted it ? its done on new cars every day many make very good HP with it

Originally Posted by pat mccarthy

seeing how he never said were the piston was in the hole or what the real cc of the head was . what bore size or how thick the head gasket was ? who know s ? 10.2???? or i may of miss the post were he said this ? not sure but i think i did ask him this back on page one ?

I calculated it for him with real numbers a while back, 9.80:1 SCR.

Originally Posted by pat mccarthy

seeing how he never said were the piston was in the hole or what the real cc of the head was . what bore size or how thick the head gasket was ? who know s ? 10.2???? or i may of miss the post were he said this ? not sure but i think i did ask him this back on page one ?

This does bring it back to effectively answering the core question.I have never hear of a mid lift correcting a port that maybe too big.I guess that could work along with questioning if the heads actually flow the rated number.I would still question the viscosity of the fuel mix.If that wouldn't just come into the port and be either too lean or too rich.

Currently run a 92 302 just short of 9 to 1 poreted DOOE heads. Cranking is 170. Run that through caculations for dynamic vs static. The other is a 86 460 its 190 cranking static is around 10.2 to 10.5. Wacked the closed chambers on the DOVE heads and didnt have a way to CC them. Ported them also numbers on intake should be about 300 CFM. Couldnt flow them as a motor burned up on the flow bench. Both engines run on premium.
The 460 is in a dually used to tow a 14000 lbs trailer or a car hauler.