Two articles (sidebars) on this subject are currently on your newstands.
1) Hot Rod Car Craft "200 Power & performance tips" page 69 and part of a=
n
article entitled "Power secrets from the Pros". Basically notes "Our
engine experts pretty much agree that long rods can reduce friction,
cylinder wall thrust loading and rod angularity while enhancing ring
stability. Long rod engines tend to have less spread between peak torque=
and HP than short rod engines. Feuling, Duttweiler, Edelbrock, Mondello,=
and Lenard form the long rod lobby but they focus on rod ratio, not pure
lencgth. McClellad, Kaase, Klein, and Sherman are in the "it depends"
corner. Several other sources are noted to feel that short rods (and
ratios) can be better in certain instances while some "experts" admit the=
y
are still trying to figure it out.
2) Muscle Mustang and Fast Fords "5.0 Tech Guide" page 30 as a sidebar to=
the article "Stroke of Genius" notes: .....rod ratios are flat-out
controversial. Again, the sides are sharply divided between the "long is=
better camp" (the marginal majority) and the "it doesn't matter a hill of=
bat guano" camp.
The theory popularized by Smokey Yunick and a cadre of Chevy circle
trackers) is that having more rod ratio engine wear is less, the piston's=
dwell time at TDC is increased (improving power) and the leverage on the
crank is improved.
Rubbish, say others. Some of the most powerful gasoline powered engines =
in
the world (IHRA Pro Mod and Pro Stock) have only "poor" rod ratios (1.1 t=
o
1.3).
Sounds to me that emprical opinion is "slightly" on the side of longer is=
better. =
I'd guess that back to back dyno runs that have inherent 2% to 3%
repeatability couldn't tell the difference. =
Regards,
Jim
B9470139 =
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