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Title: CR (Check my math) Post by: louisb on July 25, 2007, 17:09:29 pm Someone check my math please and let me know if I am doing this right.
Bore - 94 Stroke - 82 # Cyl - 4 Deck Height - .06 (copper gasket) Head Volume - 51cc (What is the volume on a stock VW head?) Compression ratio - 12.07:1 (And yes I know that is high) Thanks, --louis Title: Re: CR (Check my math) Post by: Lids on July 25, 2007, 17:19:53 pm thats what i make it.
use attached file to see, rename from txt to xls, as it is actually a MS Excel file Title: Re: CR (Check my math) Post by: j-f on July 25, 2007, 17:24:53 pm I use a calculator on the net. Check flat4ever.com (http://www.flat4ever.com/?page=rv)
With your indication and translating the .06 (I suppose Pounds) in millimeter = 1.62mm the result is 10.14 cr. Title: Re: CR (Check my math) Post by: louisb on July 25, 2007, 17:35:58 pm thats what i make it. use attached file to see, rename from txt to xls, as it is actually a MS Excel file Okay thanks for the work sheet. I use a calculator on the net. Check flat4ever.com (http://www.flat4ever.com/?page=rv) With your indication and translating the .06 (I suppose Pounds) in millimeter = 1.62mm the result is 10.14 cr. The copper gasket is .06mm. Sorry i should have been more specific. Thanks, --louis Title: Re: CR (Check my math) Post by: j-f on July 25, 2007, 17:57:36 pm I find 12.07 cr also with this calculator.
I don't know very much in mechanics,but 0.06 for the deck height is not a too small ? Title: Re: CR (Check my math) Post by: The Ideaman on July 25, 2007, 18:01:01 pm Aren't the copper gaskets .060 inch? If so, then the compression ratio is 10.2 to 1.
http://www.cbperformance.com/enginecalc.html Title: Re: CR (Check my math) Post by: louisb on July 25, 2007, 19:38:30 pm Humm, maybe it is inches. That would make more sense. I was surprised to get such a high ratio with that large of a head volume and a .06 deck. so to get close to 12:1 I would need something like a .04 deck and a 45cc head. Sounds pretty tight.
Thanks, --louis Title: Re: CR (Check my math) Post by: alex d on July 26, 2007, 10:38:15 am check the shim thickness with a micrometer, you never know ::)
Title: Re: CR (Check my math) Post by: The Ideaman on July 27, 2007, 01:30:08 am 41cc's with .060 inch deck gets you 12 to 1.
Title: Re: CR (Check my math) Post by: louisb on July 27, 2007, 01:46:00 am Wonder if you can get a VW casting down that much.
edit: actually with a 5 cc dome that puts me a 46cc which isn't too bad. --louis Title: Re: CR (Check my math) Post by: The Ideaman on July 27, 2007, 03:32:35 am I had a set of VW castings with 28cc's in 'em. Made for a 13 to 1 1776.
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