Diff input appreciated

[jdstuff]

Hello everyone, this is my first post:

I was just curious on what differentials everyone uses and why. Most teams seem to use the basic Zexel Torson. We have been using it the past several years with decent results. It seems to be fairly reliable, if assembled properly, and has much pontential to be lightened up. Our approach is basically throwing away the original housing and machining one that fits our needs. There is one major con, however, in that if you break half/stub shaft, it becomes an open diff and you go nowhere (zero / torque bias = zero). Quaife's also act in a similar fashion. Although unlikely , I dread the thought of something like this happening at competition.

I've been doing a lot of reading on different types of diffs, and I'd appreciate eveyone's thoughts/reasons why you chose your current setup.

Jason- U.Akron

[jdstuff]

Hello everyone, this is my first post:

I was just curious on what differentials everyone uses and why. Most teams seem to use the basic Zexel Torson. We have been using it the past several years with decent results. It seems to be fairly reliable, if assembled properly, and has much pontential to be lightened up. Our approach is basically throwing away the original housing and machining one that fits our needs. There is one major con, however, in that if you break half/stub shaft, it becomes an open diff and you go nowhere (zero / torque bias = zero). Quaife's also act in a similar fashion. Although unlikely , I dread the thought of something like this happening at competition.

I've been doing a lot of reading on different types of diffs, and I'd appreciate eveyone's thoughts/reasons why you chose your current setup.

Jason- U.Akron

[Charlie]

This won't help you diff selection much, but I would not list the fact that a diff won't let the car drive one-legged as a 'con'. Obviously first off don't break driveline parts. But even if you do, that's it, you are done regardless. If you break an axle, and it isn't retained on one end, it will continue to be driven by the wheel and destroy everything it can whack into. If you run a spool it will continue to be driven by both ends and that terrible possibility is even more likely.

Basically I beleive if you break an axle, 99% of the time you will be out regardless of your differential setup.

[Flash]

We haven't built our first car, so I could be way off, but diff selection is something we have been considering.

Initially I wanted to use an ATV diff, being a much lighter duty item (at least I would assume) than a road car, and therefore lighter weight. Looking into to it though, we felt a plate/clutch type diff would be too "tight" (not sure how too express that in terms of torque bias yet) for such a short wheelbase/tight course, without designing the car to unload the inside rear. I'm sure this could be modified to a certain extent, and I believe many teams use them to good effect, but it seems to be inherent of the design to some degree.

This is why we have come back to the torsen. I doubt we will lift a wheel, so should allow easy turn in, and drive through the corner.

All in my very humble opinion, and nothing new im sure. My thoughts may change totally in 6 months, but at least that has been our thought process this far.

Matt Houston
Chief Engineer
University of Auckland

[Mike Shaw]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Charlie:
This won't help you diff selection much, but I would not list the fact that a diff won't let the car drive one-legged as a 'con'. Obviously first off don't break driveline parts. But even if you do, that's it, you are done regardless. If you break an axle, and it isn't retained on one end, it will continue to be driven by the wheel and destroy everything it can whack into. If you run a spool it will continue to be driven by both ends and that terrible possibility is even more likely.

Basically I beleive if you break an axle, 99% of the time you will be out regardless of your differential setup. <HR></BLOCKQUOTE>

unless you get lucky like UMC and break your axle at the road & track competition, finishing enduro, placing in the top 5, but losing in the R&T challenge.

one more week of testing at home could have caused them to loose the axle on lap 20 of the endurance race, putting them out of the top 25...

[farmgirl]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Flash:
We haven't built our first car, so I could be way off, but diff selection is something we have been considering.

Matt Houston
Chief Engineer
University of Auckland <HR></BLOCKQUOTE>

Hey, are you kiwi's gonna have a car for FSAE-A 04? Your website doesn't say much. I'm a kiwi from Palmerston North originally, hence the farmgirl (that'll only make sense if you jafa's know where Palmy is http://fsae.com/groupee_common/emoticons/icon_wink.gif). It would be good to see you guys here...

[Flash]

Somewhere south of the bombay hills, isn't it http://fsae.com/groupee_common/emoticons/icon_biggrin.gif.

We'll be at the 04 event, but it will be tight. We are still designing at the mo, so we are a bit behind. The website should be getting an update soon, its one of many things on our list to do.

Look foward to meeting you there,

Matt

[farmgirl]

Yea.. pretty much. http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

If your to do list is as long as mine, I won't hold my breath! Good luck ah.

Kate