Compression ratio?
Thread Starter
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Joined: May 2009
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From: Woodstock Ga.
Compression ratio?
I have read many times about the CR of a hybrid being 10:1 using a 85/86 block with euro heads.
Does anyone know what the same block would be using US heads?
Does anyone know what the same block would be using US heads?
Race Director
Joined: Sep 2004
Posts: 16,271
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From: Stockton, CA
the stock 5.0 32V pistons have a CC of about 6.5...but will add a touch more with the two valve cutouts...the USA head vs the Euro 16V is 3.5cc more so it will be a touch less compression....
Man of many SIGs
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Joined: May 2005
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From: Florida, USA
If Brians correct, adding 3.5 cc's to the combustion chamber will yield a comp. ratio of 9.35:1 by my calcs. I wish I had seen this thread sooner. I just dropped a pair of US 4.5L heads and a set of Euro S heads off at the machinist this afternoon. I can cc them when I get them back.
#'s used were:
Head Gasket @ 1.5mm thick X 100mm diameter
Piston: -6.5 cc's ( this number will increase in your application due to the necesity of larger valve reliefs.
Chamber: 56 cc ( I arrived at this # by adding 3.5 cc's to the known Euro S #'s of 52.5 cc's )
#'s used were:
Head Gasket @ 1.5mm thick X 100mm diameter
Piston: -6.5 cc's ( this number will increase in your application due to the necesity of larger valve reliefs.
Chamber: 56 cc ( I arrived at this # by adding 3.5 cc's to the known Euro S #'s of 52.5 cc's )
Pro
Joined: Jul 2002
Posts: 658
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From: Kristiansund, Norway
I know we have argued about this before Mark, but I am sure there is difference between Euro S and "S2" (84-). I have two sets of Euro S heads(from 1980), all 4 measures 52,5ccm. I am pretty sure the 47ccm heads came in 1984.
