No Posi-Traction either.

Much Better

DRIVER OST vs BULLITT Steve McQueen Is The Wheelman

(05-11-2012, 06:28 PM)John L Wrote: No Posi-Traction either.

On which car?

Ford doesn't use Posi-traction. They use a limited slip differential.

(05-11-2012, 06:41 PM)Twitchin Kitten Wrote:

(05-11-2012, 06:28 PM)John L Wrote: No Posi-Traction either.

On which car?

Ford doesn't use Posi-traction. They use a limited slip differential.

'Posi-Trac' and 'Trac-Lok' were basically the same thing, with a few differences so as not to break patent codes. And Porsche actually invented LSD before both started using it.

And by the 1970s, Posi-traction had become the generic name for it all, like 'Band-aid' and 'Scotch-Tape'. But the point was that the chase Mustang did not have it. When he had to halt, back up and then peel out again, he left a solid tire line on his right rear tire, and nothing on the left rear.

If I recall, that was what the technology was made to eliminate, by giving equal torque to each side of the differential.

To hell with generic names. I am correct either way, Posi-traction provides energy to both wheels evenly to the rear differential while Limited Slip does not.

That looks to be a '68 Fastback but depending on the time of year it was built, LSD was still an option and not standard on the Mustangs. The late '68's had it standard.

The studio probably cheaped out and took the no traction option. Doesn't matter who invented it, Ford uses it as SOP on all their rear wheel drive cars now.

I cannot speak for the other manufacturers who use Posi-traction as to when they or if it's standard equipment.

TRUE positraction would be full time drive from BOTH wheels. This would cause you to do a burnout every time you turned a corner or rounded a sharp curve. It would also make it difficult to steer almost anything but straight ahead.

Ford did use a version of a locking differential that provided full posi called the Detroit Locker which was manufactured by Dana Corp. and was a vacuum locked differential. You could flip a switch and lock it to full locked drive or disengage it to limited slip. It was good for those who wanted to drag race their street cars and have the advantage of a spool type differential on the track.

Most Detroit Lockers were manufactured in the Ford 9 inch configuration but were also available in a Chevy 12 bolt and Dana 44 (Chrysler's choice) version as well. They also made it in a Dana 60 housing for heavy duty trucks.

"It's a 1949 Buick Roadmaster. Straight 8. Fireball 8. Only 8,985 production models. Dad lets me drive slow on the driveway. But not on Monday, definitely not on Monday. "

Now can someone find a better clip of the best shotgun scene in a movie?
I like it from the beginning when he buys it in the hardware store.

http://www.youtube.com/watch?v=pDlNIPCirLk

(05-11-2012, 07:22 PM)Twitchin Kitten Wrote: To hell with generic names. I am correct either way, Posi-traction provides energy to both wheels evenly to the rear differential while Limited Slip does not.

That looks to be a '68 Fastback but depending on the time of year it was built, LSD was still an option and not standard on the Mustangs. The late '68's had it standard.

The studio probably cheaped out and took the no traction option. Doesn't matter who invented it, Ford uses it as SOP on all their rear wheel drive cars now.

I cannot speak for the other manufacturers who use Posi-traction as to when they or if it's standard equipment.

hey, that's fine with me. I learned decades ago that women are always right, so I will defer to your wisdom.

Dana owned the name 'Detroit Locker' before? It's Eaton now. And as it's a Limited Slip Differential, it does allow for cornering with no tire scuff.

And a 9" Ford with a Detroit Locker is still the bullet proof choice for racing and even off road. Unless you have the $$ to go exotic.

Yeah. Dana developed and first marketed it and Eaton Fuller bought the design for use as a heavy truck differential as it lends itself very favorably for use in a tandem drive axle with interaxle differential lock configuration.

Most class 8 tractors are using the Eaton.

The secret to the Detroit locker as opposed to a straight spool is planetary drive spider gears with a "lockup" plate.

As for "exotic" I think Richmond no longer fits that name since they have become rather common even among lower buck racers.
Strange and Moroso are still "fairly affordable" and not uncommonly seen on better built street/strip cars.

Quite a few years ago a friend did a V8 Vega for street/strip and went with a massive Dana 60 using 4.56 Strange and custom 12" Strange axles. Damn thing was totally bulletproof even when turning a set of Mickey Thompson N 50 15" Sportsman Radial street tires mounted on Centerline reverse offset wheels.

The funny part was when you looked at the car from the rear it was all tire and pumpkin!