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Differentials
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!
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"I love the smell of a welded diff in the morning. It smells like...traction!"
Kirk
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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
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mmmm....traction http://Forums.ImprovedTouring.com/it/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
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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
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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
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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 http://Forums.ImprovedTouring.com/it/smile.gif 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).
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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
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Hmmmm.
<$50 vs. $1,000 ?!?!?
I think I'll try the welded dif http://Forums.ImprovedTouring.com/it/smile.gif
Thanks,
Jason
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or put a spool in....
Chris
http://www.printroom.com/_vti_bin/Vi...d=0&courtesy=1
[This message has been edited by shwah (edited September 19, 2002).]
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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
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VWMS Clutch type diffs are no longer double the price of a Quaife. They have come down in price.
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Bill Sulouff - Bildon Motorsport
Volkswagen Racing Equipment
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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
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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
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Now watch it cost as much as a VWMS clutch-pack!
Kirk
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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
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Has anyone tried the Phantom Grip Diff. I've run a welded Diff, and just installed my third transaxale in three years.
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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?
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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.
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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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From a Google search: http://www.aptuning.com/index.html
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Don Horner
Port St. Lucie, FL
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Is it possible to remove all or most of the weight adding gears, housing, etc. from a stock diff and then weld it? Same benefits, cheaper price?
PJ
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83 Rabbit GTI - future ITB
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>>I'm curious as to how much they are??
The spools are going to cost about $550.
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Bill Sulouff - Bildon Motorsport
Volkswagen Racing Equipment
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Oh yeah - contact information. Although it looks like you guys dug it up.
APTuning 717-272-0916. Talk to Mike or Mark. The pricing for the Gen1 with bearings and a bolt kit installed will be $560.00.
We hope to try one out at a few track days this fall, and plan to build a brace of transmissions over the winter with them (3 ITB cars and 1 G-Prod car).
I am pretty excited about trying this out, because I halfheartedly tried to get a spool made last year, thinking that the reduced weight would be nice. Of course since the 5th gear is loose on both of my transmissions, I need to dig up some other parts before the winter rebuilds.
Chris
(edit for missing word)
[This message has been edited by shwah (edited September 22, 2002).]
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The spool sounds like alterative to welding, but if I'm going to spend 550 plus, why not just move up to the quafe. I ran across the Phantom Grip LSD, their at Phantomgrip.com. Looks like a price of about 300. Has anyone used this in a golf..
Golf/GTI ITB 40
[This message has been edited by loboracer (edited September 22, 2002).]
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No personal experience but reports on the Phantomgrip have been mixed...
Kirk
PS - yeah, I know. I could have googled it myself.
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The pricing is not as close to the Quaife as it appears IMO. The spool has a new bolt kit and new bearings pressed on when you recieve it, while the Quaife is bare.
For those of us who feel that a locked differential performs better than a quiafe this is a good option.
Chris
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Not sure how much the bearings are, but an ARP bolt kit is ~$50. Add that to the $800 or so that an 020 Quaife costs. I gotta admit though, I'm curious as to why the spools cost $560, even w/ bearings and bolts. A Richmond spool for a Ford 9" is only $180, and it's made from 4140 CrMo steel. I'm certain there's an economy of scale effect here, but I don't see a 3x upcharge over common stuff that's out there (yeah, I know it's for a Ford).
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MARRS #25 ITB Rabbit GTI
SCCA 279608
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Well, I'm definitly looking into this as an option for next season, especially since my welded diff tranny grenaded, while I was loading it up on thursday night for our race weekend. Mind you I put approx. 25+ race starts on this with no damage other than a single broken outer CV. I haven't torn it down yet, but on initial inspection through the hole http://Forums.ImprovedTouring.com/it/smile.gif in my bellhousing, it appears the weld didn't hold up. It was arc welded as well.
On a side note, a fellow competitor, who couldn't make it for this weekend was nice enough to lend me his quaife equipped gearbox to try out. And needless to say, I have scratched it off my list of things I might want. IMO, if you want grip, get locked, I was at best a second per lap slower with the quaife than with my welded diff.
The one thing I liked about it was how easy it was getting around the paddock, but who cares about that!
Steve
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87 ITB Scirocco
www.geocities.com/highspeedconnectionracing
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For comparison:
Spools are now $460.00 (yes the price dropped)
Quaifes are $819.00
And VW Motorsport diffs are $1195.00
Diff bolt kits are $44
The quaife is very effective in the rain, on straights and sweeper (carousel) turns. The spool has the disadvantages of a welded diff but will not allow wheel spin in tight corners.
The VWM diff does everything right. The VWM diff is the best (you get what you pay for)
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Bill Sulouff - Bildon Motorsport
Volkswagen Racing Equipment
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Actually the $460 number is for the spool only without the bearings and bolt kit. I asked about this today and was going to post it here, but Bill was right on top of it.
Also for those wondering where the cost is in these peices, I asked about that last week...As you can imagine it is not the material, I mean steel is not THAT expensive. It turns out that the expensive part was the custom tooling for broaching the splines, and thus the machining is pretty pricy.
Chris
[This message has been edited by shwah (edited September 23, 2002).]
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So it's $56 for the diff. bearings?
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MARRS #25 ITB Rabbit GTI
SCCA 279608
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So just for comparison sake, who is the NA dealer for the VWMS diffs? I would like to have a peak at them and read some information about how they work.
Steve
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87 ITB Scirocco
www.geocities.com/highspeedconnectionracing
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Steve,
I believe that Bildon can get them. It's my understanding though, that there is a very limited supply of them. They haven't been made (for an 020 box) for several years IIRC.
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MARRS #25 ITB Rabbit GTI
SCCA 279608
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While I really try to refrain from "advertising" here...yes they are available and supply is no longer a problem.
Check out our site.
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Bill Sulouff - Bildon Motorsport
Volkswagen Racing Equipment
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Has anyone obtained this spool yet? If so, how much did it run you?
Thanks,
Wilson
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There is one disadvantage to the spool/welded diff that no one has mentioned yet. Carroll Smith noted that if you break an axle (or a CV) while under power with a spool/welded diff, the car will turn IMMEDIATELY (and faster than you can react) in the direction of the axle that broke. If there's a wall there, you will hit it. If you are in a corner with the power on, you will either go off the outside immediately or spin to the inside immediately.
Just thought I'd point this out. The other diffs (VWMS, Quaife, OPM, Phantom Grip, etc.) aren't quite as susceptible to this as they will allow the other axle to slip.
MC
#14 GP VW Scirocco
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Mark, that's correct, but it's not as violent as what you describe. During the last race weekend @ ThunderHill, I was exiting thrn 11, and was going down the "back stretch" and when I grabbed 4th gear, the car pulled to the right. I backed off and checked out the steering, everything seemed to be OK, ie no flat tires, etc. Got back on the gas and the car pulled to the right. I slowed down and pitted. Needless to say, the left inside CV joint was gone. During dis-assembly, there was PLENTY of grease inside the boot, but the cage and balls were missing (destroyed). That's the first CV failure I've had with a locked front diff in 4 years of racing. I always rebuild / replace both 1/2 shaft assemblies every winter, and carry each side as a spare.
My $0.02 worth
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Tim Linerud
San Francisco Region SCCA
#95 ITB GTI, GP for 2002
http://linerud.myvnc.com/racing/index.html
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Interesting that it pulled to the RIGHT when you broke a left CV. I assumed it would pull in the other direction. Maybe Carroll Smith wasn't referring to FWD cars? Or maybe the toe-out caused it to pull to the right?
Hmmmmm.
MC