 Dynamic CR Opinions - WebCam 86b/86c |
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| yeahmag |
 Jul 1 2026, 03:20 PM
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Advanced Member  Group: Members Posts: 2,484 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California 
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My next autocross motor is coming together, but I'm a little hung up on the CR. For your calculating pleasure:
Bore: 96mm (3.77953") Stroke: 78mm (3.07087") Deck Height: 0.045" Cylinder CC: 50cc Connecting Rod Length: 5.325" IVC @ .050": 54 degrees (WebCam 86b/86c) Gas: 91 octane E10 CA gas I get: STATIC Compression Ratio:10.69:1 DYNAMIC Compression Ratio:8.2:1 To get it down to roughly 9.5:1 static and 7.5:1 dynamic CR I need to: * Find 6cc - 8cc in the head or dish the piston * Go to a HUGE DH of 0.085", which I find completely unacceptable Any opinions on 1) how hard it will be to find 8cc in the heads or 2) if putting a small dish in the piston? My calculations have the dish at something like: * Dish Diameter: 82mm * Dish Depth: 1.7mm Thanks! |
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Posts in this topic
yeahmag Dynamic CR Opinions - WebCam 86b/86c Jul 1 2026, 03:20 PM
worn I have built engines but have much to learn. Why ... Jul 1 2026, 04:59 PM
emerygt350 Quench I believe is the term. You really want no ... Jul 1 2026, 05:44 PM  |
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