"I have seen a lot of arguments both ways with the "it doesn't help power"
side
having a slight advantage."
Most people are not designing engines but trying to make the best of
existing engines and components so there is not a lot they can do about the
rod length. Using an existing block and crank, extra rod length has to come
from reduced pin height (and there is very little room for change there.)
Longer rods give the pistons longer at the top, less cylinder wall loading,
less friction and thus a higher proportion of the combustion forces
transmitted to the crank.
A Volvo racing guy once told me the optimum and I think it was a little over
2:1.
cheers, derek
Derek White
37/2 Buller's Lane
Colombo 7
Sri Lanka
Tel: 94 1 581175
Cell: 94 777 475955
-----Original Message-----
From: owner-tigers@autox.team.net [mailto:owner-tigers@autox.team.net]On
Behalf Of Frank Marrone
Sent: Tuesday, February 04, 2003 7:11 AM
To: 'DrMayf'
Cc: Tiger List (Tiger List)
Subject: RE: Desktop Dyno Fun
DrMayf,
For what it is worth, the users manual for the desktop dyno software
says that it does not consider rod ratio as an input because the
designers of the program feel it does not effect power output. I have
seen a lot of arguments both ways with the "it doesn't help power" side
having a slight advantage. Everybody agrees it has a lot to do with
cylinder wall loading and hence directly influences red line.
Frank
> -----Original Message-----
> From: DrMayf [mailto:drmayf@teknett.com]
>
> Interesting! Have you all looked at my web site? I have an
> analysis of rod ratio for lots of items there. My conclusion
> is that it really doesn't do an awful lot for you unless you
> are a ProStock crew chief looking for the last once of
> torque. Look at: http://www.teknett.com/pwp/drmayf/analyses.htm
>
> mayf
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