Differentials

O

opel racer

New member
I'm looking for some direction in deciding what type of differential I use. What's better- a limited slip unit or a welded unit? Is using the stock differential completely out of the relm of possibility? As I have posted before, I am new to this so please be patient!
 
If you're thinking limited slip, I can tell you from first hand experience, that a Quaife will slip. I've heard that the VWMS one doesn't because it's a different design. Problem is, there aren't many around for 020 boxes, and the ones I've heard about are about twice what a Quaife costs.

On the other hand, there are several people who do very well w/ welded spools w/o significant driveline wear/failure. They do take a different style, but they don't slip!

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MARRS #25 ITB Rabbit GTI
SCCA 279608
 
mmmm....traction
biggrin.gif


I love my welded diff, wouldn't trade it for anything. If they paved the paddock at my local track, I'd find one that wasn't haha!

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87 ITB Scirocco
www.geocities.com/highspeedconnectionracing
 
We do give up a little on the slower / tighter corners, and in the rain it's not as good as a Quaiffe, but it's chaper. It also requires a different driving style. You have to be on the loud pedal in order for it to turn.

So, you brake in a straight line, turn in, and get on the gas. No trail-braking.

I broke a hub last year, but that was on an original 19 year old part, that had been re-built, but had almost 300k miles on it. I went through more CV's and transmissions auto-xing my car using an open diff, than road racing with a locker.

My $0.02 worth.

Just make sure that you paddock in a spot that you can make "WIDE" 90 degree turns.

haha



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Tim Linerud
San Francisco Region SCCA
#95 ITB GTI, GP for 2002
http://linerud.myvnc.com/racing/index.html
 
A couple more questions on this topic:

If I were to go with the welded diff & didn't like it; have I ruined any parts that would be required with the quaife?

If so how much $$ are we talking about?

Also, what costs are involved in welding the diff.? BTW I do not weld, so that is an obvious cost to me.

I've run my brother's ITB '84 GTI w/quaife & I think I really need to do something because it handled excellent.

Jason
ITB Scirocco
 
I have run (and still have) each of welded, VWMS clutch-pack, and Quaife diffs. AFAIK, welding does not damage anything later used for the Quaife. I HATED the welded diff on pavement, but I was running Yokos at the time and understand that Hoosiers (which have a much greater slip angle) allow it to work. The VWMS is still my favorite, as it works in all corners, even when my inside wheel is way in the grass (nice on Lime Rock starts
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Unfortunately, it needs to be rebuilt at least every other season and parts are scarce. The Quaife works great as long as both wheels are on pavement and have "some" grip, plus it doesn't seem to wear out (although some people have broken them).
 
Jason,

The Quaife is a total replacement for the stock unit (you do need the ring gear though, and new bolts). I can't see anyone chharging you more that $25 - $30 to weld it up, provided you've removed it from the tranny and cleaned all the oil from it.

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MARRS #25 ITB Rabbit GTI
SCCA 279608
 
or put a spool in....

Chris

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[This message has been edited by shwah (edited September 19, 2002).]
 
Wow, I wish you guys were allowed to use my differential. I weld the differential in the transaxle. Then I cut the right side axle and weld an over-running clutch from a tractors farm implement drive shaft. Basically, the drivers side wheel is full time drive. The passenger side wheel freewheels when you get off the gas. When you step on it, the "ratchet" locks (the dogs engage) and your locked like a welded differential. I'm open going into corners and locked coming out. If you're smooth with the gas pedal, you don't even know the dogs have engaged. If you brake hard and stand on it, the steering wheel jerks a bit, but when you expect it, that's even easy to handle. Works great on an asphalt oval with Goodyear slicks.

Scott
 
Who makes that spool? I have heard of them for Hondas but not for VWs. The decrease in rotational inertia would seem like a bonus. More info?

Kirk
 
I agree that the decrease in rotational mass should be a benefit. Actually for that reason I considered not telling anyone else about it ;-), but in the end I figure that we are more of a community of competitors rather than cut-throat competitors (generally), and that it might be pretty useful to others. Also, since the guys bringing it to market took the time to develop it, it only seems fair to give them some exposure.

APTuning makes it, I am working to get some more details now. Basically it was developed for drag racing, but should really fit the bill for our application.

Chris
 
That spool is a nice looking piece. Is that for a VW 020 box? I'm curious as to how much they are??

BTW, I believe the Detroit Locker style diffs are legal in IT. The ITCS says you can use any diff, as long as it fits in the stock housing.

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MARRS #25 ITB Rabbit GTI
SCCA 279608
 
I run the welded diff and love, I do however think that it is the cheap way about it, I believe the VWMS limitedslip is the way to go, but it is just expensive, But like most things, you get what you pay for. As far as the welded goes I have found that trail braking works great, but it all depends on how your car is set up. And as far as not fast in the rain, As long as there are not puddles try and see if someone can keep up. I think Its lightning in the rain. But again I do think that the VWMS unit is better. OPM offers a clutch type unit as well, and from my understanding of how it works I think it would be a good choice too. I have heard really good things about it. Can anyone tell me how exactly a spool works?
 
A spool is the same thing as a welded diff, but with considerably less mass. Simply put, you have a flange for the ring gear and stubs coming off the flange which mimic the stubs where the Inner Cv joints will attach.

There would be no differential housing, spider gears, shafts, etc. thereby significantly reducing weight and rotational mass. Besides the traction, you have a kind of aluminum flywheel equivalent.

There are many benefits.

The only down sides would be those same ones atributable to the welded diff; to wit, tough paralell parking and extra wear on cv joints and maybe even clutch.

Cheers.
 
OK I got a little more information on the spools. They have not set pricing yet, but it sounds like they will be a good deal less than a quaife.

There are 2 designs. The Gen1 has the stub shafts machined right into the spool. The Gen2 will have replaceable stub shafts. Both will be sold as a kit with new bearings installed and new ring gear bolts. They have the tooling done for the 020 application and are finishing up on the 02A application - so both will be available.

The people that I spoke to were nice, knowledgeable and not only told me what they were doing, but listened to my comments as well. I made sure to tell them that there are plenty road-racers out here that would be interested in the product, and pointed them to this forum so that they can update us once everthing is ready to go.

This should develop into a real nice option for the VW racer.

Chris
 
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