On Wed, Aug 27, 2008 at 10:26 AM, Kitterer Bob <bkitterer@mac.com> wrote:
Question - - why not open the ports on the Judson SP-1 manifold to match a
1275 head?
That is not the problem... The problem is obtaining enough atmospheres of
pressure with the limited volume that the SP-1 produces. The SP-1 was
designed for 948cc. It has to be overdriven for even a stock 1275, even more
so for a 1380! The bearings on the SP-1 are only rated for 5800 - 6000 RPM.
If you overdrive it, that puts the bearings way over design limits. In order
to get the effective boost, the Judson desgined for a 1500 would work so
much better. That would eliminate the heat build up problem too. Trying to
compress the necessary volume of air exudes a lot of heat that is pushed
into the cylinders.
Many have tried to use the SP-1 on a 1275 with resulting heat issues. Just
ask Cap't Bob! That's why I want to build a 2" main 948 for it. Right size,
better strength and great fuel economy with the power of a good running 1275
in addition to the timeless classic look of a supercharger!
--
Kent
1960 Bugeye
1973 Midget - donor card signed in front of a notary!
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