You need the rod to stroke ration to be about 2:1 to start seeing big
differences. If you hover around 1.8:1 you won't see much. Makes great sense
for cams to be expressed that way except that the cam manufacturer would
have to know a lot about the engines and the installer would need a very
long stroke dial indicator.
-----Original Message-----
From: Larry Young [mailto:cartravel@pobox.com]
Sent: Wednesday, June 15, 2005 6:08 AM
To: Bill Babcock
Cc: fot@autox.team.net
Subject: Re: 225hp
I've played with the numbers in the spreadsheet, and I can't get much
difference even when the stock length is less. For example, a stock SBC is
5.7, long rods are about 6.2. The arguments about weight and friction are
more believable.
I already had this spreadsheet laying around. Long ago valve timing was
given as piston positions rather than angles. It makes more sense when you
think about it.
Bill Babcock wrote:
>Hey, that's really cool. You're as nuts as I am. Of course right there
>is the problem I was talking about. For our engines it doesn't really
>matter--you can't get even close to the numbers you need for it to matter.
>With short stroke motors and really long rods it makes a small
>difference without changing displacement. And in F1 motors (and MotoGP)
>a tiny improvement can be the difference between first and second,
>which is the difference between winner and first loser.
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