Hypothetical Question

[GreyGoose006]

i know this may not be the right place, but what would be the best kind of limited slip diff to use when trying to minimize power oversteer while turning at or near the limit in a powerful RWD car.
i was thinking a standard clutchplate at about 80% locked.
would a totally locked diff work better? how about a viscous fluid type diff (forget the proper name)

[curtis73]

both of those options would make a pretty tough parallel parking situation

Any kind of limited slip would try strongly to return to center, getting stronger as you go toward the limit. That can have the effect of increasing oversteer since its trying to keep both wheels moving at the same speed. Usually the inner wheel ends up turning faster since its unloaded and you lose the little bit of grip that it started with.

Torsens offer full differentiating with a 50/50 torque split, so they would probably offer the least oversteer at greater steering angles.

[2.2 Straight six]

quaife ATB maybe?

(automatic torque-biasing diff. mechanical, not clutch/viscous type.)

[GreyGoose006]

yeah. that makes sense.
i've been playing around on Grand tourismo and another racing game i have.
in GT4, best results seem to be with stiff sway bars and a strong limited slip (clutch type)
in the other game, best results are with a weak viscous type and no rear sway bar.

the problem with the weak viscous one is that althoug it offers the most grip at the max speed, straight line stability is shot.

how does a torsen diff work exactly?
ive seen the cutaways, but it would help if you explained it, or had an animation of one in motion (i'm a visual learner)

[curtis73]

I haven't solidified how the torsen works in my brain yet so I can't really describe it.

I do know that I was contacted by a few game companies to help setup the games and it seemed like they were a bunch of monkey/nerds that couldn't really get organized. I went as far as touring their offices but the actual consultation never happened. They said that the game was coming along slower than expected, then next thing I know the games are all out and on the shelves with surprising inaccuracy.

I guess what I'm saying is, don't let the real world affect your choices in the game. They won't be accurate

[psychopathicdude]

Originally Posted by curtis73

I guess what I'm saying is, don't let the real world affect your choices in the game. They won't be accurate

Did you mean: "don't let the real world be affected by your choices in the game."?

[GreyGoose006]

i think it was an exercise in a little thing called sarcasam...

[curtis73]

Exactly... I don't know where I would be without the game voices telling me what to do.

[GreyGoose006]

back on topic, i stared a torsen diffs for an hour and fifteen minutes today (chem lecture) and may have figured it out.
the driveshaft turns two seperate halves of the rear axle, which have been geared so that they will accept a worm gear. the worm gear meshes with the axle on one end, and on the other end, there is a normal gear that connects it to the other half of the axle.
if both are turning at the same rate, then all is fine and dandy.
if the right one is beginning to slip (torsens *never* slip apparently) and only has the capability to hold 200 lb/ft of the 400 lb/ft being supplied, then the left wheel gets 800 lb/ft of torque. (not quite sure how this is possible, as the engine only supplies 400, but meh, w/e)
torsens are great because they are purely mechanical, so there is no slip and the wheels remain intact with the road at all times.
the major flaw in the original design is that if a wheel is in the air, for example, then the other wheel gets no torque. it has to do with the fact that the diff is really a torque multiplier, and 0 times anything is still 0.

torsen solved this problem by pre loading the diff so that there is a minimum of torque available at all times (not sure how much, but i'd guess its enough to get you some grip)

bad news is that for some reason, torsen does not sell difs to the public?
not sure why, but thats how it is.

and no.
i dont work for torsen.

[psychopathicdude]

Originally Posted by GreyGoose006

i think it was an exercise in a little thing called sarcasam...

ya got me...had the "sarcasm detector" unplugged...oops.