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Coyote Series Engines
9.5:1 flat tops or 11.5:1 domes for turbo?
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<blockquote data-quote="twistedneck" data-source="post: 13709710" data-attributes="member: 130159"><p>If we are on E85 what will make more power and torque safely and with less heat.</p><p></p><p>9.5:1 dished pistons with very nice smooth tops and almost no valve cut outs - along with 22lbs boost.</p><p></p><p>11.5:1 domes with big ugly cut outs, but only 15lbs of boost?</p><p></p><p>the smooth 9.5:1 piston crowns helping flame travel and removal of hot spots. the 11.5:1 increasing efficiency, torque, and rpm, requiring less boost. Assume the system is not boost limited i.e. 88mm single turbo, sleeved block, huge fuel system, etc..</p><p></p><p></p><p>There is of course a limit to reducing compression too far to allow for big boost, but lately I've seen a trend for high compression and medium boost over the old standards.</p><p></p><p>indycar is 12.5:1 with 22.4lbs boost and no DI. F1 with DI will be in the range of 13:1 compression ratio with 50lbs of boost!</p><p></p><p>However, top fuel is only 6:1 compression ratio and they have 60+ psi of boost (80 Psi or more with the new blowers).</p><p></p><p>What is the JPC record car doing for boost?</p></blockquote><p></p>
[QUOTE="twistedneck, post: 13709710, member: 130159"] If we are on E85 what will make more power and torque safely and with less heat. 9.5:1 dished pistons with very nice smooth tops and almost no valve cut outs - along with 22lbs boost. 11.5:1 domes with big ugly cut outs, but only 15lbs of boost? the smooth 9.5:1 piston crowns helping flame travel and removal of hot spots. the 11.5:1 increasing efficiency, torque, and rpm, requiring less boost. Assume the system is not boost limited i.e. 88mm single turbo, sleeved block, huge fuel system, etc.. There is of course a limit to reducing compression too far to allow for big boost, but lately I've seen a trend for high compression and medium boost over the old standards. indycar is 12.5:1 with 22.4lbs boost and no DI. F1 with DI will be in the range of 13:1 compression ratio with 50lbs of boost! However, top fuel is only 6:1 compression ratio and they have 60+ psi of boost (80 Psi or more with the new blowers). What is the JPC record car doing for boost? [/QUOTE]
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9.5:1 flat tops or 11.5:1 domes for turbo?
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