Date:         Sat, 6 Dec 1997 15:00:41 -0400
Reply-To:     mark keller <kelphoto@BRIGHT.NET>
Sender:       Vanagon mailing list <Vanagon@Gerry.SDSC.EDU>
From:         mark keller <kelphoto@BRIGHT.NET>
Subject:      Autotrans as a stall converter!
Content-Type: text/plain; charset="us-ascii"

I believe that the VW autobox on my  bus, 91, but they're all the same from
about 87 I think is using a "stall"  torque converter.

The engine is allowed to rev to about 2800-3200 Rpm before the torque
convertor begins to take significant effect. Drag racers have used em for
years.  You can read about them in any performance hop up book.

On the bus the main advantage is that the motor produces more horsepower at
3000 RPM than at any lower RPM . So the stall converter allow the automatic
bus's engine to stay at 3000 or so why the stall converter accerlerates the
vehicle.  It's similiar to a boat propeller that pushes at the same force
until the boat's speed catches up to the force being generated.

You can see this effect by starting from a stop and "hold the rpm at 3000
rpm. The auto trans will shift into 3rd before your at 30 mph, but the car
will continue to accelerating to about 50 mph before you need to increase
your RPM to go faster.  You'll also notice that the engine quickly revs to
about 3100 RPMs and the won't go any higher even with a lot of throttle.
This is because the stall converter is slipping very little after this RPM.

Manual engine bus setups are not at the same advantage in second fourth
gear, unless the driver holds the Rpm shift points above 3000, and then the
engine is making similiar horse power.

I don't think that a well driven manual is slower, but probably takes less
skill technique whatever, to make a auto bus go quick. I've driven a few
manual shifts, with nice tight linkages, and it still my preferance to the
auto box.
Especially at stop and start driving where a lot of gear changing takes place.

My box is at 130,000 miles.  It's good to hear that they hold up. By the
way the Van seems to be faster than the GTI bus of my friend's, but then it
was diesel gearing I think.  I do know that it will go seventy by the end
of most freeway on ramps and that's enough for me. It also seems quite will
to rev up and go 85 plus when passing those real nuts you meet every now
and then on the highway. BTW the weight of individual Buses probabley
varies quite a bit. I keep mine pretty empty at about 3700 with me and gas
and etc.

Sincerely Mark
91 Carat WE
"Lazarus"