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techtalk:ref:engmech04p [2020/10/05 04:14] hippysmack [REF: Engine Mechanicals - Sub-07D] |
techtalk:ref:engmech04p [2023/12/26 21:44] (current) hippysmack |
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That's why racers with vacuum pumps use multistage scavenge pumps to account for the imbalance to scavenge and improve it. \\ | That's why racers with vacuum pumps use multistage scavenge pumps to account for the imbalance to scavenge and improve it. \\ | ||
- | Regardless, it's evident that some racers use vacuum pumps to increase vacuum pressure in the crankcase of a Sportster engine. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932)) \\ | + | Regardless, it's evident that some racers use vacuum pumps to increase vacuum pressure in the crankcase of a Sportster engine. ((Hippysmack of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/197307-sportster-crankcase-pressure-engine-breathing-wetsumping-and-mods?t=2073932)) \\ |
It's been said that positive crankcase pressure upon piston upstroke gets between the rings and basically causes bad sealing at the ringlands. \\ | It's been said that positive crankcase pressure upon piston upstroke gets between the rings and basically causes bad sealing at the ringlands. \\ | ||
This is also in the high RPM range when ring flutter is present. So there are several things happening then. \\ | This is also in the high RPM range when ring flutter is present. So there are several things happening then. \\ |