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12:1 compression ratio

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Old 04-28-2010 | 02:02 PM
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Default 12:1 compression ratio

just finished rebuilding the first of two 502 engines for the cafe racer. Since there are no dynos in panama and all i have to go by is the compression ratio, was wondering what kind of hp would the engine put out considering 12:1 compression? no blowers, just naturally aspired.
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Old 04-28-2010 | 02:25 PM
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Originally Posted by CafeRacerPTY
just finished rebuilding the first of two 502 engines for the cafe racer. Since there are no dynos in panama and all i have to go by is the compression ratio, was wondering what kind of hp would the engine put out considering 12:1 compression? no blowers, just naturally aspired.
Need a lot more info than that; Heads, cam, carbs? also @ 12:1 can you say "The Pin Has Been pulled." That is A LOT of compression in a boat engine. You running straight race fuel?
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Old 04-28-2010 | 02:33 PM
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Hope there is lots of GOOD gas in panama !!!!!!!!!!!!!
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Old 04-28-2010 | 02:38 PM
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!!!!BOOM!!!!! I say way too high!
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Old 04-28-2010 | 02:38 PM
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big compression like that you are asking for trouble.looks like you will be burning the realll expensive stuff.i can only imange how much race gas cost in panama.
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Old 04-28-2010 | 04:17 PM
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gas in panama is 91 and 95 octane at the marina.
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Old 04-28-2010 | 04:34 PM
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then it doesn't matter how much it costs because you are only going to use about 3 gallons before the pistons melt.

if you are locked into 91 /95 then you better get it down to 9.5 or so or start buying pistons in bulk.

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Old 04-28-2010 | 04:48 PM
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Yup................. Im at 9.8 and on the teeter of oh $hit.
-Mike
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Old 04-28-2010 | 07:39 PM
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started the engine for the first time , runs nice, but on JET FUEL... guys were right. as usual. will jet fuel cut the cheese?
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Old 04-28-2010 | 07:44 PM
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i would think you would need aleast 110-115 octane to support that kind of compression,maybe more.
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