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More thoughts:
The NSX has a compression ration of 10.2:1. That actually makes a significant difference in this scenario for multiple reasons. One, the overall cylinder pressures achieved even after boost are acceptable (they will be similar after boosting to the boxster's NA pressures). Two, octane. While it's accepted that high compression engines require high octane, most forget that it's finally the maximum cylinder pressures that really matter in this scenario. Cylinder pressures achieved under even low boost in the boxster will be high enough to cause detonation with pump gas. This will result in an uncontrolled burn and localized rather than steady state dynamic loads. (Steady state dynamic sounds like a contradiction. what i'm getting at is not the dynamics of the engine itself, but the dynamics of the combustion phase. a controlled combustion results in fairly even tempreratures and pressures throughout the cycle. detonation results in local high pressures and temperatures, like on one spot of a piston crown as opposed to even pressure / temp on the entire crown. this is one reason why we see pistons with holes in them).
lux -
you are right in that heat soak could be an issue. you are also right in that high compression engines can run with high boost. there are requirements for this though: plenty of fuel and an engine management system that knows that you are doing this. the spark curve on the boxster will be adjusted if the engine starts to knock, but it changes other things, too. the bottom line is that the TPC system does not account for enough of these variables and as such is an incomplete system. all they do is apply the pressure. with something like a boxster engine, more work is needed to ensure a usable and long lasting engine.
because porsche took these things about as far as they can go without pressure, some of that work has to be UNDONE to use pressure properly. this is costly, and imo not nearly as effective as just dropping in a 996 motor. if you're going to pressurize, don't cut corners. tear the motor down and build it for pressure. the results will be great. the bill will be high.
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