Let's see...
Assume it's a 302 with 11:1 compression. That makes the chamber volume,
including all domes, head gaskets, valves, spark plugs, etc.
( 302 / (11-1) ) / 8 = 3.775 cid = 61.86 cc
So going from 54 to 64 cc heads changes the chamber volume to 71.86 cc =
4.385 cid
The new CR is 1 + 302 / (4.385*8) = 9.608
If it's a 289 with 11:1 the chamber volume is 59.198 cc
Go from 54 to 64 cc and the chamber volume increases to 69.198 cc = 4.223
cid
The new CR is 1 + 289 / (4.223*8) = 9.554
So the CR change depends on the displacement (but we knew that, right?)
Theo
> -----Original Message-----
> From: Steve Laifman [SMTP:Laifman@Flash.Net]
> Sent: Friday, January 21, 2000 6:16 AM
> To: Alex MacLaurin
> Cc: Ronak, TP (Timothy); 'Bob Palmer'; 'Tiger News Group List'
> Subject: Re: Performance Tuning the Tiger
>
> Alex MacLaurin wrote:
>
> > With all this talk about compression,I have a question: if a motor has
> 11:1
> > compession with a 54cc chamber and all variables stay the same, how much
> > compression does the engine have with a 64cc chamber?
>
> Assuming your numbers are accurate:
>
> 54 cc. x 11 = 594 original volume
> 594 / 64 = 9.28:1
>
> Compression Ratio = Final Volume / Swept Volume
>
> I've assumed that the deck height and gasket thickness were contained in
> your
> "chamber" volume, but they usually are not, and need to be known for an
> exactly
> correct answer, but this one is close enough for 'Government Work"
>
> Steve
>
> Steve Laifman < Find out what is most >
> B9472289 < important in your life >
> < and don't let it get away!>
>
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