Gauging Interest - Rear diff controller

[Turninconcepts]

So if it were possible to build a rear diff controller that would affect the action of the rear diff, who would be interested?

Price would probably be 200-300 for a basic controller. The controller would allow for much more aggressive lock up of the rear diff under certain circumstances to allow for better handling. We could lock it for example under braking to make the car more stable and allow better rotation, play with the power distribution for corner exit...the options are vast.

Please get this out to other boards as well. This can be an international interest request. I am going to post it here and on mazda speed forums.org as those are the two I frequent.

Tony

 

[zinger002]

Like to make the car more towards a 50/50 power distribution?

how about you check your pm's too...

 

[Captain KRM P5]

i'm all for it, i do have concerns about the rear diff's ability to be ... reliable ... long term with such an application.

 

[Turninconcepts]

Like to make the car more towards a 50/50 power distribution?

how about you check your pm's too...

I have no PMs.

 

[tunersteve]

I've been interested in this for a long time. HPA makes them for the VW Haldex systems, and I wonder if we can get something similar.

 

[FORZDA 1]

I've been interested in this for a long time. HPA makes them for the VW Haldex systems, and I wonder if we can get something similar.

Knowing how our coupling unit for the rear diff works, it should be incredibly simple to build up a simple circuit board that would output a variable frequency square wave to the 12 VDC duty cycle commands to the pilot clutch solenoid. You could put a simple pot-type controller knob or set it up with a detented knob for specific duty cycles. I'm thinking it would cost more along the lines of $50.

The only problem I can think of may be the durability of the pilot clutch solenoid with high duty cycles. If you want to essentially "lock in" the rear coupler, just apply 12 VDC through a simple off-on switch and see how long the solenoid lasts while energized continuously.

 

[tunersteve]

Knowing how our coupling unit for the rear diff works, it should be incredibly simple to build up a simple circuit board that would output a variable frequency square wave to the 12 VDC duty cycle commands to the pilot clutch solenoid. You could put a simple pot-type controller knob or set it up with a detented knob for specific duty cycles. I'm thinking it would cost more along the lines of $50.

The only problem I can think of may be the durability of the pilot clutch solenoid with high duty cycles. If you want to essentially "lock in" the rear coupler, just apply 12 VDC through a simple off-on switch and see how long the solenoid lasts while energized continuously.

I think we're on the same page, but the ones I saw for VWs were microchip sets that replaced the OEM unit. I'd imagine that the thresholds and monitoring were still intact, instead of just supplying a stronger signal to the solenoid. I'd prefer to have a unit that monitors and responds to the vehicle sensors instead of a gain controller wired in. Just my $.02

 

[Turninconcepts]

The unit I am thinking about would be a completely separate device with G sensors that would monitor the inputs and adjust torque bias as necessary.

 

[FORZDA 1]

The unit I am thinking about would be a completely separate device with G sensors that would monitor the inputs and adjust torque bias as necessary.

Ok, this is a bit more interesting, but I'm not sure it would be worth the effort. Have you studied the OEM application to see how it works? IMO, it is limited more by the basic hardware design than the activation variables.

Even with the pilot clutch solenoid fully "on", the rear coupling has a ball-and-ramp type setup to vary the drive force (torque) to the rear differential pinion shaft. Basically there is no torque developed unless there is a potential difference in rotation speed. The more speed differential, the tighter it clamps the main clutch pack. No difference equals no pressure on the main clutch ramp mechanism.

I've tested the front/rear bias on a hard launch on dry, grippy pavement and the fronts turn less than a full rotation before the rears are locked in and spinning at what seems the same rate. The torque applied is sufficient to lay 4 black lines as the rear drifts out of line with the fronts a bit. I think it safe to assume that the rear torque developed would be significantly less if the tires were on slippery surfaces.

 

[tunersteve]

Here's the link to the HPA one I was talking about before:

http://www.hpamotorsports.com/haldex.htm

 

[FORZDA 1]

Here's the link to the HPA one I was talking about before:

http://www.hpamotorsports.com/haldex.htm

The Haldex system works significantly different from the Mazda AWD version. Here is a decent top-level on the Haldex. Note that the Haldex clutch pack (and rear diff if included) is positively controlled by an on-board fluid pressure pump whereas the MS6 version is all passive/mechanical past the pilot clutch.

http://www.haldex.com/en/North-America/Applications-Products/Product-categories/AWD/Development/


http://www.haldex.com/en/North-America/Applications-Products/Product-categories/AWD/Design-Info/

 

[Mistersix]

very interesting concept here fellas. so i'm subbin to see what comes of it.

 

[leo766]

super duper interested

 

[waterwagon]

yes please