with a forced induction built 296 ci engine running about ~12 psi boost on 91 octane fuel, with the option to go to 16+ psi on 100 octane fuel? It feels like you are ultimately power limited by the octane rating of the fuel you are running, no matter what boost/CR/spark combination you try to run. So maybe the question really is how much power will 91/100 octane support, and then what CR is required to achieve MBT spark (or as close as possible) for the amount of boost your blower can produce efficiently. Has anyone worked through an algorithm to solve this type of problem? It would be nice to settle upon an optimum value, rather than choosing a CR that 'has worked OK for others', which I've tried to summarize below anyhow:
Car___________CR____Disp___HP________TQ______Boost__Weight
GT500___________8.4____5.4___500@6000__480@4500__8.5______3920
SLR McLaren_____8.8_____5.5___617@6500__575@3250__?________3732
Ford GT_________8.4_____5.4___550@6500__500@3750__?_______3468
SVT Cobra_______8.5_____4.6___390@6000__390@3500__8_______3665
Crossfire SRT-6___9.0_____3.2___330@6100__310@3500__14.5____3220
As I understand it, too low a compression ratio makes for a sluggish low end throttle response and poor fuel economy, so one should go as high as possible. If you believe the table, the answer is somewhere between 8.4 and 9.0.
Car___________CR____Disp___HP________TQ______Boost__Weight
GT500___________8.4____5.4___500@6000__480@4500__8.5______3920
SLR McLaren_____8.8_____5.5___617@6500__575@3250__?________3732
Ford GT_________8.4_____5.4___550@6500__500@3750__?_______3468
SVT Cobra_______8.5_____4.6___390@6000__390@3500__8_______3665
Crossfire SRT-6___9.0_____3.2___330@6100__310@3500__14.5____3220
As I understand it, too low a compression ratio makes for a sluggish low end throttle response and poor fuel economy, so one should go as high as possible. If you believe the table, the answer is somewhere between 8.4 and 9.0.
