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Discussion Starter · #1 ·
What is the difference performance wise with water cooled engines vs air cooled engine,
Ex a 6.2hp polini 911
Be it a/c or w/c your still getting 6.2hp
Does the w/c rev higher ? Another example
A/c c1 does 35mph and w/c version is faster? Why?
 

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No, has nothing to do with modification. It's the production tolerance are smaller. I can only compare the small two stroke engine that I know.
The squish Band on a AC engine is always bigger as on the same layout on a wc cylinder.
 

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When you compare the same 50cc bzm engine one with ac and one with wc there will be about 3-4hp different. The wc engine can run 0,5mm squish we're for the ac cylinder I would recommend 0,9mm. Also the piston to barrel clearance is at the wc about 0,02-0,03mm and at a AC 0,03-0,05mm.
Also the with the better cooling of a wc cylinder you can run a much higher porttime and more blowoff area as on an ac engine.
AC cylinders runs also most a richer carb setting for better internal cooling.
 

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Yes you can run a mutch smaller ring gap when you know your engine won't go over 90c bearing clearance can be mutch tighter as well Les slop = more RPM and a much more refined engine.
 

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Discussion Starter · #8 ·
When you compare the same 50cc bzm engine one with ac and one with wc there will be about 3-4hp different. The wc engine can run 0,5mm squish we're for the ac cylinder I would recommend 0,9mm. Also the piston to barrel clearance is at the wc about 0,02-0,03mm and at a AC 0,03-0,05mm.
Also the with the better cooling of a wc cylinder you can run a much higher porttime and more blowoff area as on an ac engine.
AC cylinders runs also most a richer carb setting for better internal cooling.
Okay so does this mean a if the a/c 911 6.2 is 6.2 hp than the w/c 911 6.2 would actually be more like 9-10 hp?
 

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No but it has more potential to tune it.
The 6.2 engine is a restricted and calibrated engine. When you put on a bigger carb and a better exhaust you can get 8hp.
 
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