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Thumbs up High CR = Better fuel economy

10 MPG!!!! What kind of mileage do you get?
Old 03-29-2005, 04:36 AM
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Oh God, more CR please! My next pet peeve is deck height. I've had guys ask me if they can run a .250" deck. Combustion no longer occurs in the "combustion chamber", but fully within the cylinder. No wonder they run hot, get poor fuel economy, and make no power :-)

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Old 03-29-2005, 04:59 AM
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Why would someone want to run a quarter of an inch in deck height? Or is that a typo? That'd be like 4/1 CR.

BTW, I really hope you're not bagging on Grady Clay. He's the real deal.
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Old 03-30-2005, 12:07 AM
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No, i'm serious about the .250". Some vw guy building a turbo engine and didn't know how to get the compression ratio down and thought that a quarter inch of deck height was acceptable.

As quoted by Grady in that other thread, "Today I would raise the CR even more, have twin plugs, smaller valves, and Nikasil cylinders. I would also apply most of the race engine "tricks" because they typically reduce losses." He's totally on it. I wish more people were of this mentality.

Charles Navarro
LN Engineering
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Aircooled Precision Performance
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Old 03-30-2005, 05:32 AM
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Charles I would have to agree about using race engine tricks in a road engine. You end up with a much sweeter road engine, they are smoother, more responsive, better performing, and usally more economical!

Regards Mike
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Old 03-30-2005, 05:48 AM
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Which is why most of today's road engines owe an awful lot to Keith Duckworth, Mike Costin and their DFV.
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Old 03-30-2005, 08:55 AM
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Increasing the compression ratio is one of the few things that will increase both power and fuel mileage due to increased thermal efficiency. Unfortunately, our engines have a lower upper limit due to combustion chamber design and the lack of a second spark plug (my engine anyways).

Sherwood
Old 03-30-2005, 11:51 AM
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Quote:
Originally posted by cnavarro
No, i'm serious about the .250". Some vw guy building a turbo engine and didn't know how to get the compression ratio down and thought that a quarter inch of deck height was acceptable.

As quoted by Grady in that other thread, "Today I would raise the CR even more, have twin plugs, smaller valves, and Nikasil cylinders. I would also apply most of the race engine "tricks" because they typically reduce losses." He's totally on it. I wish more people were of this mentality.

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

O.K., cool. I misunderstood your post.
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Old 03-30-2005, 12:59 PM
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