High comp NA Zetec, how to calculate CR
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Hi all,
Im using a 1.8 zetec head which is not skimmed, 2ltr block with standard pistons and a standard 2ltr motorcraft head gasket and weber alpha 45mm throttle bodies. the engine is built and running in the car! Problem is, its over fueling on a standard 2.0ltr map which im told is going to happen due to higher the C Ratio.
Does any one have the volumes of these to hand or know where i could get them from.
Thanks in advance.
John T
Im using a 1.8 zetec head which is not skimmed, 2ltr block with standard pistons and a standard 2ltr motorcraft head gasket and weber alpha 45mm throttle bodies. the engine is built and running in the car! Problem is, its over fueling on a standard 2.0ltr map which im told is going to happen due to higher the C Ratio.
Does any one have the volumes of these to hand or know where i could get them from.
Thanks in advance.
John T
#2
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I think someone has lead you up the garden path.
What you need is it to be properly mapped for YOUR spec. Also, it'll be a pain to map as those throttle bodies are faaaaaaar too large for the spec you mention above. You'll only have to map about the first 25% of throttle opening and that'll be it!
What you need is it to be properly mapped for YOUR spec. Also, it'll be a pain to map as those throttle bodies are faaaaaaar too large for the spec you mention above. You'll only have to map about the first 25% of throttle opening and that'll be it!
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Ive got cams and ported head on it also but didn't think that would matter.
I need to get it running in a drivable manner as I live in Jersey Channel islands and need to drive it to the rollers on the mainland. I want to get a chip made up for me and sent over so I was thinking If i new the CR it would help them with creating the basic map.
I need to get it running in a drivable manner as I live in Jersey Channel islands and need to drive it to the rollers on the mainland. I want to get a chip made up for me and sent over so I was thinking If i new the CR it would help them with creating the basic map.
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#11
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Aside from the other excellent advice you've been given, as the 1.8 and 2.0 have the same CR when standard, at 10:1, its easy to just back calculate the combustion volume. Although there will be a slight error due to the piston dishing, to all intents and purposes, a 1.8 on a 2.0 gives a CR of 11:1.
As has been said, that won't really effect the fuelling MAP, but check for the spark being a bit too far advanced under load.
As has been said, that won't really effect the fuelling MAP, but check for the spark being a bit too far advanced under load.
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