Date: Sat, 21 Nov 1998 10:47:13 -0600
Reply-To: Blue Eyes <lvlearn@MCI2000.COM>
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: Blue Eyes <lvlearn@MCI2000.COM>
Organization: Vexation Computer
Subject: Limited Vanagon content: using reverse running transaxles
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Another of my mind candy offerings:
I'm reminded of a friend's project car from years ago every time I see a
comment describing how installing transaxles from front wheel drive cars into
rear wheel drive vehicles typically reverses the vehicle direction produced by
each gear. Vern ran an auto repair shop which developed quite a reputation
for building quick street cars back when 400+ inch street racers seemed as
common as fleas. He wanted to built something that was really unusual,
wouldn't attract unwanted police attention, yet would blow most of his
customer's cars into the weeds in an acceleration contest. Not an easy design
goal. He said, "it had to be light, sticky and powerful, but not attract much
attention."
Well, he installed one of his "pressure maker" Chevy V-8s in a 2 door
Corvair. For the benefit of readers who weren't born when the Corvair was
made, let me explain. It was a small light low profile Chevy powered by a
noisy air cooled rear mounted 6 cylinder engine coupled to a rear drive
transaxle. Corvair front/rear weight distribution gave them a nasty tendency
to "swap ends" if a driver tested its cornering limits. I personally did this
once in a 'Vair (short affectionate oral term of the period), and I can tell
you that once a spin starts, it's NOT correctable by driver intervention.
You're just there for the ride. Blush.
But that very front/rear weight distribution which caused a cornering safety
liability turned out to be a great benefit for then popular stop light to stop
light street racing. (Of course nobody does that today :) I knew of two
Corvairs whose owners installed high pressure super chargers. With all that
weight over their larger sticky rear tires, plus the temporary rearward shift
of weight on hard acceleration, these machines would cover the first hundred
feet with their tires smoking like few other streetable cars I ever saw. They
launched more like a motorcycle than a normal car.
Vern put his V-8 where the Corvair back seat normally existed, so he had a
true mid-engine car. But the engine was facing backwards bolted to the
Corvair transaxle, so it would have driven the car backwards. Sound like our
familiar Vanagon transaxle application problem? Obviously it's similar.
His solution was to order parts to reverse his motor's rotation. I recall
that it required a different camshaft and some starter modifications. But
really was NOT a big deal. Back then, apparently there was enough market
demand for special purpose reverse spinning motors for marine applications and
who knows what else that parts vendors supplied reverse spinning parts by just
placing a prepaid special order.
I'll bet that if we had a time machine and Star Trek's Dr. Spock to do a mind
meld with the right VW designer, there was a VW designer's decision made
between
1) making only one transaxle series that could be interchanged between front
and rear wheel drive vehicles by making both "right" and "left" spinning
motors,
2) making only counter clockwise spinning motors, but compensate for this by
building and supporting different transaxle designs.
I wish he had elected to support two rotation directions for each motor rather
than to support two transaxle series. If only they had asked me. . . . We
would now have a much wider pallet of easy interchange options. I'm not
suggesting that reversing motor rotation is the best way for Vanagon owners to
match available transmissions with their vehicles. But if someone wants a
super low final drive ratio or a six speed transaxle from an Audi, reverse
spinning appears to be our least resistance design path. Money/choices/mind
candy.
What would it take to make a reverse spin kit? Asking a cam supplier to feed
reverse grinding instructions into their controller computer for a short
production run would be one requirement. How tough would it be to get a
reverse sprague clutch for a VW starters? What else would it take? When I
start thinking about $1650 to $2000 for new transmissions, I'm compelled to
consider this wider universe of options.
In my opinion, Ken Wilford's $1650 US offering of brand new stronger SA
transaxles with their 3.73 final drive ratio (5th .816:1 times differential
4.57:1 = 3.73) sounds damned attractive to me. For anyone repowering with a
strong gas motor, that appears to be the obvious transaxle of choice in my
opinion.
John
