| The missing part of the puzzle is the timing map. In high compression engines you would have to run really low ignition to prevent detonation, interestingly a lot of ignition retard allows most of the energy to escape into the exhaust manifold which promotes quicker spool up. Turbos spool up due to the difference in heat / energy pre and post turbine wheel / housing. If you can build up enough heat the spool up will be there. HOWEVER, high heat in the manifold has a detrimental effect on exhaust valves and the manifold itself. Assuming the valve materials are capable of handling the heat and the manifolds don't crack I guess all is good. With E85 you can get away way with high compression due to its resistance to detonation allowing you to not retard the ignition to ridiculous levels. Still have to retard the timing but not as much. In short, hi compression by itself is not helping spool up, retarded timing resulting in high exhaust energy in the manifold is. I have no idea how they are running 700 + whp on 91 octane, IMO should not be possible unless they are running almost -ve timing with very high egts. The valves better be very good or sacrificial to run 91 oct. also don't know about their physical cam timing. Lots of details needed.... Just my thoughts Harry
Formerly yellowzxtt
|
