AT E-brake turn modification.

[Todd A Erickson]

I like playing around on low traction surfaces, gravel, snow, and ice with
my Legacy Sport. It has an automatic transmission. I was looking for a way
to get my Sport to pivot for hairpin turns. Left foot braking just wasn't
doing it. Two things came to mind. The parking brake and the FWD "switch".

All the non VDC Subaru automatics with AWD can be though of as FWD with a
clutch pack for rear add. The FWD "switch" is a fuse holder on the right
side strut tower with a cap on it marked "FWD". When you insert a spare
fuse the holder, it commands Front Wheel Drive from the AT control unit.
(There is a reference voltage on one terminal and ground on the other. When
you put a fuse in the holder, the reference voltage is pulled low
(grounded)). It is the same action required when running the spare tire so
the AT control unit doesn't try to compensate for off size of the spare.
((Never dyno test with the FWD fuse in and on a 2-wheel dyno. The immense
speed difference between the front and the rear will damage the clutch
pack.))

Then I looked at the parking brake warning lamp circuit. It is a circuit
that is pulled low by the switch at the parking brake lever. The ground side
is also tied into the brake fluid level sensor. Ahh.

So the thought went like this, "What if I tie the fluid level sensor
(parking brake switch) to the FWD request?" For testing purposes only
(wink), I installed a jumper wire; back probed in to the connector for the
brake fluid level sensor and a spade in the FWD fuse holder. Waa laa. Now
when I pull on the parking brake lever the FWD lamp comes on. That shuts the
"rear add" and momentarily locks the rear tires and the back of the car
skips right around.

Todd Erickson
Total Performance Center, Inc.
"Todd the tuner. Can he tune it? Yes he can!!!"

[Bill Covert]

Cool! BillC

[ciper_]

Good idea. Now you need to find a way so that when the e-brake is
disconnected no voltage is sent to the diff while when the e brake
switch is connected you get fwd. You will have a locked center diff that
only unlocks when you pull the lever!