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Old 03-19-2014, 12:19 PM   #81 (permalink)
oil pan 4
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The problem with gasoline engines is the more you increase static compression, the cylinder is scavenged more completely. The engine tries to run more efficiently and make more power, but then the throttle gets closed more, lowering dynamic compression, making it less efficient again, because the is no demand for more power.
Thats why compression increases on gas engines net little to no measurable cruising improvement.
If you run a 8:1 compression ratio or 10.5:1 to 1 and reguardless of elevation your dynamic compression is always going to be between 3 and 4 to 1 as you drive down the road.
You need to understand the isobaric expansion process. You have up to 2 horsepower worth of wasted power that can be used to pull air through an air filter or restrictive intake during normal driving.

The idle air control has nothing to do with this.

If you want to play "cram more air into the engine" and have it actually do some good get a diesel. Where more air and clean air filters actually means something.

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1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
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