2056 build compression ratio dilema |
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2056 build compression ratio dilema |
jjs3rd914 |
May 8 2018, 08:44 AM
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#1
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Member Group: Members Posts: 124 Joined: 8-August 04 From: Sarasota, FL Member No.: 2,476 |
Building a 2056, want good low end torque and drivability. Car has AC. Targeting 115-125 HP
GA 2L case, stock 2L crank rods, new AA 96mm pistons, biral cylinders New AA 2L heads with 44/36 valves Webcam 086 cam Weber 40IDF dual carbs After numerous searches seem like 8.5 is optimal compression ratio (CR) and the build should get me the targeted HP. BUT finding during assembly, with a deck height of .065" (with .010 barrel spacer) 60 cc head volume which includes 2CC for the piston valve recess, I am only getting 8.1. So option are to leave alone and go with 8.1CR or Machine heads to loose about 6CC or machine barrels to reduce deck height. Was told must use a barrel spacer and am using the thinnest I can find at .010. To get the targetd HP do I need to get to a CR of 8.5, or will 8.1 get me there.? Am really confused about the whole CR optimal number for what I want. Thanks jjs3rd914 |
McMark |
May 8 2018, 05:02 PM
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#2
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
You're not going to get where you want with 8.1CR. And I don't think you're going to get there with that cam. It's not a bad cam, it's just not gonna get you there.
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jjs3rd914 |
May 8 2018, 06:52 PM
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#3
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Member Group: Members Posts: 124 Joined: 8-August 04 From: Sarasota, FL Member No.: 2,476 |
You're not going to get where you want with 8.1CR. And I don't think you're going to get there with that cam. It's not a bad cam, it's just not gonna get you there. I am stuck with the cam now, so if 8.1 will not get me there what CR should I shoot for with what I have for optimal performance. Appreciate all the replies thus far. For more info, here in FLA we do have REC (recreation), gas for boats lawn mowers etc, which is alcohol free. It has a posted pump octane rating of 90. That's the gas I would like to use and do use in other older cars. I use it in the 914 now which is a rebuild bone stock 1.7L with original D-Jet and runs great, just not very peppy. Thanks jjs3rd914 |
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