<VV> 5-speed transmission

Jim Simpson simpson661 at gmail.com
Thu Aug 20 12:26:23 EDT 2020


If someone is going to all the trouble of installing a Subaru or Porsche
5-speed transaxle, then the issue is probably moot, but the Corvair
powertrain, including the transaxle, is integral to the overall handling of
the late-model cars.

US Patent 3,327,803 (June 27, 1967) was pointed out to me some time ago.
This was issued to General Motors and it makes several claims including
"... t*o provide in a vehicle having an elastically mounted driving
aggregate, a  suspension arrangement which is constructed and arranged with
reference thereto so that the vehicle side loads generated in cornering
induces yawing of the driving aggregate relatives to the vehicle which in
turn is kinematically transferred to the suspension structure in such a way
as to induce angular change of the plane of the driving wheels in an
understeering direction*."

This is patent lawyer speak for saying that the Corvair powertrain is
designed to provide passive rear steering to control oversteer.

The patent is available on-line so you are welcome to try to decipher just
how it all works.  The patent description is about as clear as mud, in my
opinion.  But the end result is that the rear wheels actually turn into a
corner based upon the cornering side loads.  But there are no numbers in
the patent so you'd have to find the GM engineering records to see if and
how well it worked.

So if you start fooling with the way the rear suspension is attached to the
transaxle and body, you will lose, or at least change, the passive
understeer built into the original design.  Whether that's a good or bad
thing is up for discussion.

That said, I'd love to have a 5-speed transmission in my '66 Corsa turbo.
A good overdrive gear would make highway cruising a lot more relaxing.

Jim Simpson
Group Corvair


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