tourenwagen

LSDs

Mon, 25 Jul 2011 21:44:38 +0000

I was looking for an article describing how the internals of a Quaife differential work. Quaife’s own web site isn’t very helpful.

Rather than using clutch plates as a method of operation, the Quaife ATB uses sets of floating helical cut gear pinions that run in pockets and mesh during normal driving. Should one of the driven wheels start to spin however, the helical gears start to generate a torque bias thanks to the axial and radial thrust of the helical gear pinions in their pockets. The result is a progressive transfer of torque away from the spinning side of the axle to the driven wheel, which is now capable of transmitting a greater proportion of torque.

That’s a summary, not theory of operation.

After reading a few different pages, I started to get a feel for it. I think it goes something like this: Helical planetary gears assume the role taken by pinon gears in a normal diff. Since the planetary gears are helical (at an angle), and are floating in pockets in the rotating housing (”cage”), a torque differential can generate forces that press the planetary gears into those pockets. The friction between the planetary gears and the cage generates lock for the wheel with the most resistance.

I’m still working out the forces. And I don’t yet understand why a wheel that completely slips prevents the diff from delivering power. I’ve read that the differential acts as a torque multiplier. So no torque on the slipping wheel means no torque on the driven wheel. But I don’t yet understand why.

I haven’t digested it yet, but this is the most detailed description I’ve found: Quaife and Guard ATB / TBD Differential Comparison.

A good overview of diffs can be found at How Stuff Works. The article covers clutch based LSDs, but doesn’t really explain why they work. Knowing how the clutches are actuated helps in understanding why custom ramps are awesome. I thought I understood that, but I can’t write a description off the top of my head. So I guess I don’t know it that well.

Don’t get my started on Torsen, which is another kettle of fish. I’m still working on Quaife and clutch LSDs.

The Road America Planning Begins

Wed, 05 May 2010 06:03:00 +0000

Stuff for Road America:

Race car + two sets of wheels
track day car + one set of wheels
easy up
plus usual list (scrubbed)

Wheel Lust

Fri, 26 Feb 2010 07:35:17 +0000

http://www.jongbloedracing.com/process.htm

CA Track Days

Tue, 23 Feb 2010 02:15:05 +0000

Another compendium of California Track Days.

2010 Tentative Race/Practice Schedule

Sun, 31 Jan 2010 09:48:20 +0000

March 19, Sears Point, test day (tentative)
March 20-21, Sears Point, BMW CR with NorCal NASA (tentative)

March 22, Buttonwillow, NCRC/ARC (maybe)

April 5, Buttonwillow, NCRC/ARC (maybe)

April 16, Buttonwillow, test day
April 17-18, Buttonwillow, BMW CR(?) and WERC with SoCal NASA

May 15-16, AAA Speedway Fontana, BMW CR with BMW CCA LA

May 22, Llihrednuht, BMW CR(?) and WERC with NorCal NASA

June 7-8, NJMP, BMW CR

June 12-13, Buttonwillow, BMW CR with SD BMW CCA

June 25, Buttonwillow, test
June 26, Buttonwillow, WERC with SoCal NASA

July 6-7, Laguna Seca, Skip Barber MX5
~~July 9-11, Laguna Seca, BMW CR with Speed Ventures~~

August 7-8, Road America, Skip Barber MX5
August 23, Road America, HOD Great Lakes
August 27-29, Road America, BMW CR

October 1-3, Las Vegas (outside), BMW CR with BMW CCA LA

October 8, Buttonwillow, test
October 9, Buttonwillow, NASA WERC

November 13-14, Thunderhill, BMW CR
November 15, Thunderhill, PDC

November 20-21, Buttonwillow, NCRC/ARC

December 1-2, Thunderhill, test
December 4, Thunderhill, WERC with NorCal NASA