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Old 01-12-2013, 07:02 PM
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Originally Posted by prostcelica View Post
Hey guys

I think I know the answer but I thought id ask the guys that will know for sure. Say you had a 13:1 SBC but had a huge cam in it that made your dynamic compression ratio between 8-8.5:1 would it run on pump gas with out detonation. it is to much cylinder pressure that causes detonation right?

PS Im not planning on doing this. I just want to fully understand DCR
I have no practical experience calculating DCR for such lofty SCR's, but yes, you're understanding it like I'm understanding it.

Yes, cylinder pressure determines the fuel. Fuel determines the detonation resistance.

Using a 355 Chevy built at 13.00:1 SCR combined with an intake closing point of 70 degrees @0.050" tappet lift generates a DCR of 8.45:1 on the KB calc. Here is the cam I used to calculate this....
Crane Mechanical Roller Camshafts 118471 -
Theoretically, the motor should run on pump gas, but like I said in the beginning, I have no practical experience concerning these numbers. If someone could present a valid argument against the results I have shown above, using science and math to convince me, I would yield to their way of thinking.