NSX differential types throughout the model years?

[Niels_at_home]

Hello!

I'm not as well informed as some of you here must be. I'd like to know a bit more about the type of differential used. Here is what I think so far, but it could very easily be very wrong. It seems the first years they used a 'Torque Control Differential' and later they switched to a 'Torque Reactive Differential'..

Torque Control Differential
I struggle to find much about it other than certain preload torque values. Is this all this differential does, i.e. an always present locking torque caused by left and right half shafts being connected by clutch plates that are pressed together with a spring (washer)? Is there nothing else involved? I read here http://www.nsxprime.com/Gallery/press/tidh/tidh-33.htm that the torque is a maximum of 16kgm. This video http://www.youtube.com/watch?v=tn2oF8rT6io mentions at the end the R diff should have 120 .. 150lbs locking, assuming he means not force but torque, 120ftlbs is 16kgm so that could well be true.

But to be sure, is this all it does, a fixed 'breakaway' torque in these diffs? And if 120ftlbs / 16kgm is for the R model, what would the value be for the 'regular' model NSX? No ramp angles or viscous differential type behavior?


Torque Reactive Differential
It sounds like this is a more conventional ramp angles type salisbury differential with ramp angles for 'drive' and 'coast' deciding how hard the clutch plates are pressed together, and the locking torque will be a function of input shaft torque, ramp angles and clutches friction. Possibly with a pre load torque as well.

Is this true and is anything known about differences between the regular and R version of the NSX with such a diff? Are pre loads and locking percentages (or ramp angles) known?

Would be great if I could learn some more..
Niels

 

[Barn Man]

The 91 -94 nsxs had the same diff internals. The 95-2005 had the same internals. Since all the clutches and plates (same number of clutches and plates in the early and late models) are the same part number I can only assume that they improved upon the design of the diff making it a reactive type diff with the gears in the actual planetary gearset.

The 120-150 labs of breakaway torque for the type r are the amount of torque it takes to turn ea shaft in a different direction. Now all that being said....I don't know how much better the 95+ diffs are from the earlier year models. I'm actually in the process of planning a diff rebuild on a 98 diff to beef it up and drop it in my 91. I'm hoping to get more in the neighborhood of 175-200 lb of breakaway torque.... but we'll see what happens.

 

[bullithollywood]

The 1995 model year press release says this about the differential upgrade:

Torque Reactive Differential

A new torque reactive limited slip differential was developed to minimize spinning the inside wheel on NSX models equipped with the manual transmission. This unit uses a multi-plate clutch and new, helical-type planetary gears. When traveling in a straight line, the amount of slip between the rear wheels is controlled by the force of a preset spring-loaded disc imparting a force on the multi-plate clutch. In a tight corner, however, the force of the spring-loaded disc is overridden by the thrust force of the new helical-type planetary gears, thus preventing the inside wheel from spinning and enhancing stability. In testing, this unit improved acceleration time out of a corner by 10%.

 

[stuntman]

No ramp angles. Just the addition of inner planetary gears (which I think) squeeze the clutch plates with load, thus the "reactive" nomenclature:

http://www.nsxprime.com/forum/showt...hich-one-is-the-best-and-why?highlight=torsen

 

[Barn Man]

The number of clutches and plates are exactly the same in both versions. Both use multi plate clutches...don't know why they emphasized that part. But the helical gears are the difference. The more torque applied to them the harder they push on the clutches. I remember reading about it in training class back in the day now that I see the article you posted. Good stuff.