a technical discussion, engine efficiency |
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a technical discussion, engine efficiency |
r_towle |
Aug 15 2005, 08:27 PM
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#1
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Custom Member Group: Members Posts: 24,624 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
so, I have been thinking (not always a good thing)
If an engine is basically an air pump, and the objective is to make it as close to 100 percent efficient, why is the exhaust valve so much smaller than the intake valve? Forget emmisions, forget fuel delivery, just want to understand why this is so...it is so on most engines... Rich |
Bleyseng |
Aug 18 2005, 10:26 PM
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#2
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Aircooled Baby! Group: Members Posts: 13,036 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
The other fly in the onintment for this 2.2L is the supply of intake charge with the stock system. Several engineers have pointed out that if you get much bigger than a 2056cc you will have to enlarge the runners(one runner should be equal to the volume needed to fill the chamber) and the plenum(what size I can't answer other than bigger).
Large valves can get in the way of the intake charge slowing it down but smaller valves can benefit from a good cam timing. I have always wanted to try to build a larger djet motor just to see what happens. Hmm, I still might get the chance.....if I can find all the time I have misplaced.... (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) |
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