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« on: December 29, 2023, 01:16:54 PM »
If folks want an opinion - - just stop fixating on DCR.
It's sometimes useful to keep you out of trouble if your combination is "way off in the weeds" somewhere.
But it's damn near useless for determining real world fuel tolerance. It does nothing - nothing - to account for the variables in combustion chamber configuration, piston dome contours, intake port and manifold configuration and charge/flow efficiency, exhaust port and system efficiency, fuel chemistry, fuel charge cooling effects, or a host of other things. Your 13:1 engine is gonna be a 13:1 engine at peak torque even with a cam oversized enough to murder power below torque peak. And it'll rattle on junk fuel at an RPM where you won't hear it until the parts bounce off the pan.
90% of the folks reading this should dedicate time to good process, solid parts selection, and comparatively conservative compression choices - and not fixate on optimizing an arbitrary formula trying to find an unquantifiable 1% improvement. I have seen and measured a +/-4% difference in peak power going from 9.8:1 and 10.8:1 - that's roughly 20 or 25 horsepower in a 445. Does anybody honestly think that pushing it to 11.1 or some other arbitrary value to gain DCR would be worth the sacrifice or risk in a street cruiser where 98% of it's life will be at part throttle?
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