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rsfruitbat Alfa Sprint
Joined: 13 Jun 2007 Posts: 241 Location: Kidderminster
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Posted: Mon Jun 18, 2007 7:41 am Post subject: 16V engine build |
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Does anyone know for sure what the compression ratio is as standard on a 33 16V engine? |
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rsfruitbat Alfa Sprint
Joined: 13 Jun 2007 Posts: 241 Location: Kidderminster
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Posted: Wed Jun 20, 2007 1:56 pm Post subject: |
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I am reliably informed from an Alfa specification that the CR is 10:1.
However having measured the various components I have come up with a compressed volume of 47.5cc. I have got this from cylinder head 29.2cc, head gasket 8.6cc, piston crown 9.7cc. Thisworks out as being 9:1. Can anyone explain this? |
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hugh jinjin Alfasud
Joined: 04 Sep 2004 Posts: 68 Location: Glasgow
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Posted: Thu Jun 21, 2007 9:51 am Post subject: |
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measurements are about right but your calculation is wrong What you have calculated is the ratio of swept volume to static volume, not the compression ratio.
cr is the ratio of uncompressed volume to compressed volume ie swept vol PLUS static volume to static volume or add 1 to your calculation to get the correct cr of 10/1. |
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rsfruitbat Alfa Sprint
Joined: 13 Jun 2007 Posts: 241 Location: Kidderminster
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Posted: Thu Jun 21, 2007 5:06 pm Post subject: |
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Thanks for that. Feel a bit stupid when its something that obvious. Appreciate your help. |
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