 2056 D Jet Stock cam, What compression ratio? |
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| DavidSweden |
 Jan 5 2021, 04:49 PM
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#1
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Member  Group: Members Posts: 479 Joined: 8-June 14 From: Sweden Member No.: 17,452 Region Association: Scandinavia  |
What is the recommended compression ratio for 2056 with D jet & stock cam?
Thanks in advance |
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| Mark Henry |
Jan 6 2021, 09:52 AM
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
ROW 914 IIRC was 8.0:1CR, I wouldn't run a whole lot higher with a stock cam.
WEB73 some have run as high as 9.0:1CR, but I'd be a bit more conservative say 8.5 to 8.7:1CR. Big duration cams can run higher CR, but won't work with stock FI. |
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| VaccaRabite |
Jan 6 2021, 03:52 PM
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#3
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En Garde! Group: Admin Posts: 13,465 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
Very much agree with what Mark said. Keep it stock or near stock. A slight bump is fine (say by not using the head gasket) but going above 8.7:1 is going to cause issues.
Zach |
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| porschetub |
Jan 6 2021, 04:24 PM
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#4
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Advanced Member Group: Members Posts: 4,704 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
QUOTE(VaccaRabite @ Jan 7 2021, 10:52 AM)  Very much agree with what Mark said. Keep it stock or near stock. A slight bump is fine (say by not using the head gasket) but going above 8.7:1 is going to cause issues. Zach (IMG:style_emoticons/default/agree.gif) my last build used NOS 411 high comp pistons on carbs I was happy to dial in just over 8:6-1 as a safe margin ,IMO its about keeping max engine temps @ a managed level and that hard with a T4 @ the best of times,higher compression is a trade of for long time reliability unless you run a modern fuel system etc. |
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| 914Sixer |
Jan 7 2021, 02:30 PM
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#5
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914 Guru Group: Members Posts: 8,901 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region 
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I used a custom grind Elgin 330-1 camshaft Slightly higher than stock for 2056 but good for FI. Kept compression 8 to 1.
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| sjhenry1075 |
Jul 14 2022, 01:10 PM
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#6
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Member Group: Members Posts: 268 Joined: 22-July 12 From: Stevensville, MD Member No.: 14,709 Region Association: North East States
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QUOTE(914Sixer @ Jan 7 2021, 04:30 PM) I used a custom grind Elgin 330-1 camshaft Slightly higher than stock for 2056 but good for FI. Kept compression 8 to 1. What kind of performance gains did you get? Is it noticeable? What was it before? |
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