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Title: Combustion Chamber Volume 149/161 Head Post by: FB_MAD on November 30, 2007, 02:52:13 PM Can anyone tell me the combustion chamber volume for a 149/161 kidney shape small chamber head??
Or.... compression ratio with a 149/161 head on a 179?? Or........................ a chart with the combustion chamber volumes of various red heads and I'll work it out meself?? Did have a chart 'ere at home with various head volumes years ago but wouldn't have a clue where it is now. And I'm too lazy to go and cc the head meself so hoping someone already has the figures to save me the trouble. Cheers, Terry. Title: Re: Combustion Chamber Volume 149/161 Head Post by: oldjohnno on December 01, 2007, 06:50:51 PM As far as I know 149, 161 and 173 are 45.4 cc.
The 179, 186 and 202 are 53.5 cc (except the XU1 which has the smaller 45cc chamber) and also I think the 202 EFI has a smaller chamber too. Title: Re: Combustion Chamber Volume 149/161 Head Post by: FB_MAD on December 02, 2007, 09:13:26 AM Thanks Oldjohnno,
Based on that I'm looking at around 9.6 to 1 ( or so ) comp ratio with standard chamber 149 Yella Terra head on flat top pistoned 179. Thanks for taking the time to reply...... appreciated, Cheers, Terry. Title: Re: Combustion Chamber Volume 149/161 Head Post by: oldjohnno on December 02, 2007, 11:57:35 AM You're welcome. The figures actually came from an old post of Dr Terrys. At the risk of teaching you how to suck eggs, here is the formula - maybe someone else will find it useful. (One cubic inch equals about 16.39cc)
CR=(D + V + DC + G + CC) / (V +DC + G + CC) CR = Compression Ratio D = Displacement of one cylinder V = Piston Volume (will be a negative value with a domed piston) DC = Deck Clearance Volume G = Gasket Volume CC = Combustion Chamber Volume |