Torsen Diffs

[Brandon C]

we are a first year team and are looking at diffs right now. ive looked at Taggart Performance Engineering's diff, but it was around 4 grand. I see that torsen has a university special based on their T-1 diff. Here's my question: Can we simply(with slight rigging/engineering)bolt a sprocket on or do we have to use a drive shaft? Because if we can go with torsen, we will save a crap load.

[Brandon C]

we are a first year team and are looking at diffs right now. ive looked at Taggart Performance Engineering's diff, but it was around 4 grand. I see that torsen has a university special based on their T-1 diff. Here's my question: Can we simply(with slight rigging/engineering)bolt a sprocket on or do we have to use a drive shaft? Because if we can go with torsen, we will save a crap load.

[Bowtie Man]

Brandon,
there is no ring gear flange on the university special, so you'll have to design a system to transfer the power from the sprocket to the diff casing. A lot of teams drill and tap into the casing, but last year i made a part that gripped the outside of the casing. It would probly be a good idea to search this topic as it's likely been discussed quite a few times. email me at umgroen0@cc.umanitoba.ca if you want to see what I did last year

Luc

[Agent4573]

I know a few teams will take the university special, yank the gears, and make a new housing for it that allows sprocket/brake rotor mounting.

[Psychosis]

i wouldn't recommend the custom housing route if you are a new team. my advice as mentioned is to buy the torsen, drill 3 taped m8 holes and 3 dowel holes each side. this way you can first fit an aluminium blank to each side, joined by a large diameter tube to create the diff casing. on top of which you have the sprocket and discs. hope that helps.

[SnailRacer]

Or another option is a Quaife chain drive diff. Retails for about $900, but I think the FSAE price is about half that. It's already sealed and has a flange for a ring gear or sprocket, and you can get your output shafts, tripods, and axles from Taylor Race (ain't cheap though).

This is a bit easier than the zexel, but all and all will be heavier and more expensive (than the zexel option done RIGHT).

[Daves]

Snailracer, where can I find more information about the chain drive Quaife differential for $900?

You said it is sealed. Must differential fluid be pumped to it?

How is it different than the Taggart/Quaife differential that Taylor Race markets?

[Chris Clarke]

Not much info, but I am sure you can contact them.

http://www.quaife.co.uk/catalogue/page87.htm

You can see all their products here, including their sweet twin hayabusa V8.

http://www.quaife.co.uk/catalogue/index.asp

[SnailRacer]

Check out http://www.quaifeamerica.com/ in the states.

The diff is grease filled, there are about 8 or 10 small threaded holes around the perimeter used to fill it up. All you have to do is fill it and plug the holes.

I think the Taggart set-up uses the same internals as this one, but has a smaller housing and different drive mechanism.

[Brandon C]

Here's my update on my research from your help. I emailed Ken Taggart at TPE and he told me to call Scotty at Taylor-Race at (800-922-4327) because i was looking for the COMPLETE assembly;ie half shafts, diff, brake and rotor flanges, wheel mounts(either 4 bolt or center lock), plus a whole bunch of shit i didnt know existed since this is the first time ive delt with something like this. Well Scotty gave me an invoice like list of everything that we would need. It was just shy of $4000. Not bad considering TPE was going to charge $3700 for the diff and trapez. He was really helpful. I think we are going to go this route.

[PedalOnTheRight]

Being a fairly new team ourselves, we went with a Quaife set-up last year and were in contact with Taylor-Race for some parameters of the design. Quaife diffs are really easy to work with, although a bit on the heavy side in comparison to other options. I'd be careful with your tripod design. I dont remember which we usedf from Taylor Race, but we ended up tearing one of the tripod rings off during testing. The tripod has three circular rings on the end held on by metal O rings that are pressed on and flared to keep the rings steady, but the O rings broke off pretty easily. Maybe a fluke, but something to note.

[GTmule]

How can yall justify 4 grand for a dif and axles? I mean, yes, it's really nice stuff, but if that's the "retail" cost report price, wow. Our final cost report price last year was like 13 grand, a third of that was NOT diff and axles.

Again, I'm not knocking the stuff, I'd probabally use it if I was building my own DSR or something, but for these cars, it just seems excessive.

Mabye I'm just jealous.

[Brandon C]

im always looking for cheaper parts. Im using that figure as a starting point. Im sure if i look long enough i can find cheaper parts. I just needed to know all of the parts i would need to look for. Now that ive got a complete list, i can look for cheaper parts.

[CMURacing - Prometheus]

torsen "university special": $395 net, $700 retail
rockford CV axles (custom lengths, torsen splined inboard, any splines outboard): $1000.

total cost report price: $1700. a wee bit less than $4k.

[scotty young Taylor Race]

Gentlemen,

GTmule is right, the TRE/TPE chain drive differential is expensive, and is ideal for a DSR/CSR. In fact the TRE/TPE chain drive differential was developed for the DSR/CSR community, and continues to be the only chain drive differential purpose-built to be a chain drive differential. Several FSAE teams have adopted this diff because of its simplicity, size and weight. There are a number of choices of differential for the FSAE car. Here is a partial list of torque biasing differentials, along with what needs to be done to get them into a FSAE car. Any one can function well in the FSAE car, with the main differences being completeness, weight, and flexibility.

1.Zexel Torsen University Spec differential
a. Has the lowest initial cost approximately $700 not including bearings or stub axles
b. Requires fabrication of many parts
1.Housing including seals, as the unit should be oil lubricated
2.Sprocket flange
3.Bearing mounts on differential
4.Chassis mounts for differential
5.Stub axles
6.Brake rotor flange (if inboard brakes are desired)
7.Offset mount in chassis, unless special housing built, as flange is between bearings
8.Unequal length halfshafts if special housing not manufactured

Note: This unit is the heaviest of the three unless a custom center section is fabricated.

2.Quaife Escort or Civic based conversion
a. Mid priced at approximately $1000 - $1200 not including bearings, bearing mount, or stub axles
b. Requires fabrication of
1.Chassis mounts for differential
2.Cannot accommodate brake rotor flange if inboard brakes are desired.
3.Offset mount in chassis, as chain drive sprocket flange is between bearings.
4.Unequal length halfshafts to accommodate offset diff
5.Stub axles for small CV joints or Tripod joints (Optional flange is for 100MM Lobro Joint – Porsche 911)

Note: This unit weighs approximately 21 pounds when CV flanges, bearings, and bearing mounts are included

3.The TRE/TPE Chain Drive diff
a.Highest price at $2756, complete with bearing mounts, CV flanges, sprocket and brake rotor flange (if desired)
b.Requires fabrication of
1.Chassis mounts for differential
2.Equal length halfshafts

Note: This unit weighs 17 pounds complete. The MOI is also lowest, as the differential is just 3.6"� in diameter.


Craig Taylor / Scotty Young
Taylor Race Engineering

[fsae_alum]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by GTmule:
How can yall justify 4 grand for a dif and axles? I mean, yes, it's really nice stuff, but if that's the "retail" cost report price, wow. Our final cost report price last year was like 13 grand, a third of that was NOT diff and axles.

Again, I'm not knocking the stuff, I'd probabally use it if I was building my own DSR or something, but for these cars, it just seems excessive.

Mabye I'm just jealous. </div></BLOCKQUOTE>

a.) Don't forget that some teams have more money than time. Buying something off the shelf in lieu of designing from scratch and fabricating can also free up limited resources on a small team.

b.) Also need to remember that there is something to be said for buying somthing that off the shelf stands a 99% chance of working right off the bat (no schedule delays to deal with, no unexpected problems, etc...).

c.) Also something to be said for heritage, reliability, and risk. For a car that has a one shot chance (can only race your car at each comp once), reducing risk of track failure is something to seriously consider.

How much is the endurance event worth in points? How much is the design event worth in points? Better yet, is your team competing to win design or competing to win dynamic events.

For some teams, the Taylor is the way to go, for others it is not and there is no "Right" answer for choosing one way or the other. They both have their advantages and disadvantages.

[Chuck Maddocks]

I'm designing a new carrier for the university special diff. here's a pic (http://www.wam.umd.edu/~maddocks/pics/lsd.jpg). it's a two piece design (blue screws). now i'm looking into stub axles and half shafts for it. any suggestions from teams that have conquered this task in the past? currently on my radar are:
rcv performance sae axle kit (http://rcvperformance.com/saeaxlekit.html)
paradigm motorsports torsen splines (http://www.paradigmmotorsports.com/html/torsen_splines.html)
taylor race splined stub axle (http://www.taylor-race.com/part.cfm?category=Drive%20Axle%20Components&subcategory1=Differential%20Stub%20Axles&id=4352)

am i missing any, or has anyone used a different stub axle?