Quote:
Originally posted by Speedtek
The crankshaft was not fully counterweighted. The counterweights were very thin and strange looking.
They looked like blades. I was told this was to reduce drag.
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Typically the 2.3/2.5 crank has 8 counterweights on it. in order to reduce inertial mass 4 of these were removed from the EvoII crank.
Less inertial mass requires less energy to rev up and down. this makes it easier/faster for the engine to get to the sweet spot in the powerband. It also helps the engine drop revs faster.
This was all accomplishable because machining technology had gotten to the point where they were able to be far more precise and could afford to 1/2 the number of counterweights