DragBikeMike
Serious Thumper
Offline
SuzukiSavage.com Rocks!
Posts: 4167
Honolulu
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Driveability
This is the area where the high compression pistons really shine. Unfortunately, it is also difficult to measure. It’s subjective rather than objective, seat-o-da-pants stuff. All three setups have excellent manners. They all start right up, idle smooth, have good throttle response, and broad useable power bands. But the high compression setups are crisper. The higher the CR the better it gets. The high compression changes the character of the engine from that of a workhorse to a thoroughbred. It changes from an engine that’s always willing and able to one that is chomping at the bit. Sure, the WOT tests show conclusively that the high compression setups are faster, but the real benefit is at part throttle operation. This is especially evident on the flat-top with its associated tight quench. Part throttle response is instant and crisp. Where the part-throttle to WOT transition is good with the stock piston, it is much better with the pop-top, and excellent with the flat-top. The transition from part throttle to WOT is smooth and predictable on all three pistons, but the flat-top is off the hook. It will kill in the twisties, probably allowing a good rider to run one or possibly two gears higher through turns. It’s makin good power way down low. At part throttle, the venturi vacuum is highest. That results in much better atomization and homogenization of the fuel droplets and air. Throw that brew into a combustion chamber that is more turbulent due to the higher compression and the burn is more uniform and complete. Add the flat-top’s tight quench and things really get stirred up. You get more power from less fuel. More heat is used to do work, less heat is lost to the cooling system, CHT and oil temps go down. I can’t say enough about the part-throttle performance. Yes, both these high compression pistons are faster at WOT, but it’s the part-throttle performance that makes them worth the entry fee.
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