Compression Ratio
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Cargo Master
Joined: Nov 2009
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Compression Ratio
So I have a brand new set of .030 OS flat top pistons that I picked up, and back of the envelope calculations, if I used these, I'd be looking at 10:1 perhaps even 10.5:1 compression with most of the standard FE heads, my big question is, how likely are the FE's going to run into detonation/pinging issues at that sort of compression levels?
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Cargo Master
Joined: Nov 2009
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This cam https://www.lunatipower.com/voodoo-h...8-250-256.html
Doubt I'll ever spin it much over 4000
Doubt I'll ever spin it much over 4000
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Cargo Master
Joined: Nov 2009
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Alrighty, I'll save the flattops for a Fairlane or something, I've got a good set of used. 030 over standard crown pistons I can use
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Cargo Master
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More Turbo
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From: Lacey
I'm running the Comp XE274H (230/236 @ 50; 562/565 lift, 110LSA, 106 ICL) with 2291F flat top pistons with C8AE-H heads at 200ft elevation no issues. The cam is installed straight up too. That Lunati is much more mild so I don't see why it'd have any problems. Calculate your dynamic compression and you could possibly install with whatever degree it needs. Unless I'm missing something 
More Turbo
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From: Lacey
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Cargo Master
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Ok, so with the existing D2TE heads, it looks like I'm looking at 10.386:1 static compression, if I went with the flat tops. How do i determine, based on the cam specs I have, how many degrees ABDC, the intake valve closes?
More Turbo
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From: Lacey
Wallace Racing - Cam Degree Calculator
Wallace is my quick go to for dozens of engine formulas just to try to learn something or out of curiosity.
Wallace is my quick go to for dozens of engine formulas just to try to learn something or out of curiosity.
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Cargo Master
Joined: Nov 2009
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Alright, so confirmed the D2TE are the heads that are on the engine currently in the truck, which using wallace's calculator, tells me I should have a dynamic compression ratio of 8.97:1. I've never really dealt with dynamic ratio before, so what does that mean to me, as far as being able to run it on regular old unleaded without having it detonate?
More Turbo
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From: Lacey
Dynamic is measured off the intake closing which provides a much more accurate "reading" as to how a given cam will operate vs another cam in the same engine. Hence BIG cams specify a minimum static compression ratio to get the engine into "safe" ranges for available pump octanes. Cam timing and distributor timing plays a role as well but in much smaller increments in comparison to the cam characteristics themselves. Do a search on the topic for many more details.
Like I said before that Lunati cam you selected is fairly mild spec-wise and should run happily given proper oil and break in which is a whooooole other ball of wax.
Like I said before that Lunati cam you selected is fairly mild spec-wise and should run happily given proper oil and break in which is a whooooole other ball of wax.