Willdo
Posts: 500
Joined: 7/31/2003 From: Auckland, NEW ZEALAND Status: offline
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quote:
ORIGINAL: av8tor1977 Well, excuse me but I have the same question. How would a supercharger be any better than a turbocharger on a two stroke engine? The problem of the blowdown period, and losing the charge out the exhaust would still exist. Besides, a supercharger takes power to run it! AV8TOR Surely with a conventionally aspirated two stroke the blowdown problem is the same, - after all the transfer phase is essentially force charging the cylinder - isn't it? A turbocharger also takes power to run it, - you don't get anything for nothing! In a fourstroke with a turbocharger, although some of the exhaust pressure is caused by the residual gas pressure in the cylinder when the valve opens, power is used too when the exaust gases are also pushed out by the piston during the exhaust stroke. In a two stroke, the pressure in the exhaust is again caused by the residual gas pressure in the cylinder as the exhaust port opens, helped by the pressurised fresh charge ( needing power to produce) from the crankcase via the transfer ports. If a mechanically driven supercharger is used, naturally, power would have to be used to drive it. If a turbocharger is being used, then some of the power to drive the turbine would come from the residual pressure in the cylinder, plus the pressure of the fresh charge (supercharge - needing power to produce) pushing the exhaust gases out. So power will be used in one form or another, but what is important is the amount of gain you get from using some of the power. ( this is all beginning to sound like perpetual motion) All very interesting, - maybe my ideas are a little simplistic and if you think that I'm incorrect, feel free to correct me, but make it stick! RON, When you said " properly engineered turbo", you sure hit the nail on the head! CRUSTY, Don't blame you for not wanting to take any responsibility for the construction of the original! One thing is for sure, that machine didn't turn at anywhere near the revs it would be expected to, otherwise there would be schrapnel flying everywhere!
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