Bob,
Thank you for the update. I'm always looking for a challenge. And once I get
something in my head.....It's that compusive disorder that keeps me moving
forward.
I'm still determine to build an adapter to try out an SU on the 948 cc w/
Judson. I have the flanges made. Still need to make the tube. I hope to have
this done this summer.
I'll keep the list posted.
Allen
-------------- Original message --------------
From: "Robert E. Shlafer" <pilotrob@webtv.net>
Allen...
the Spridget-sized Judson is a little short on capacity for the 1275. To get
the expected 40% increase in torque you NEED
the 6psi boost curve. A 4psi curve is what you come up with using the stock
Judson
pulley set-up, which is all show (except for
heat) and no go.
Using a 2.8" blower pulley will give you the
6psi boost curve but not for long as the single V-belt quickly begins
"slipping" around such a sharp curve, treated or not.
(Modifying the crank pulley diameter rather
than a smaller diameter blower pulley would get you by in this respect, though.)
This results in over 7500 blower rpm and the stock Judson blower bearings
aren't up to the load (for very long, anyway:) and the concurrent adiabatic
heat rise experienced by increased blower compression sends combustion intake
air temps soaring,
further decreasing your margin to pre-
ignition/detonation.
(Modification to blower bearings will do, as will a calibrated alcohol/water
delivery or
injection system. This could be "T-eed" into
the stock oil delivery system or by other means.)
By the time you get through, simply installing a modern Moss blower kit would
probably be more cost effective I would think. This would also result in a
minium of
oil entering the combustion chamber which, on today's garbage unleaded octanes
would be a real plus as well.
Might work OK on a stock 1098 though, where far less overdriving of the Judson
would be required for the needed 6psi
boost curve.
But hey...most people can't even get the
Judson to perform well and reliably in year 'round temperatures (summer) on a
948 on today's weaker octanes! So, you've done a good job! :)
Cap'n. Bob '60 :{)
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