lockers and LSDs

[fusername]

Hello folks, I was curious if anyone here is willing to educate the dumb massess as to what options are available to those of us who want to upgrade from a one wheel wonder. I have seen LSDs for sale for 091s and bug transmissions, but at 1400 a pop, they are out of my price bracket. Sure you can weld something in your diff and have a locker, but you can also spell "understeer" with those letters. I am really curious if anyone has managed to rig up a full locking differential which can be turend on and off like in modern cars. Can it be done(has it been done) with a reasonable amount of machine work, can modern parts be adapted, what does it take, etc?

Thank you to anyone who trys and pick up this topic and help me make heads or tails of it.

[Pablo]

For starters, there are 3 basic types of "locking/locked" diffs: http://images.thesamba.com/vw/gallery/pix/238566.jpg

Despite Quaife's revamped web description, a TBD is not a true LSD, and could more accurately be described as an advanced version of open diff.

VW swingaxle LSDs and TBDs are more difficult to manufacture than VW IRS, and the old ZFs for swingaxle are more difficult to find in serviceable condition than IRS.

Quaife TBDs for swingaxle are the only NEW swingaxle locking diffs presently available (although GT-brand TBDs and LSDs for swingaxle are presently in the works).

For IRS VWs, there are quite a few old stock ZF LSDs floating around (talk to Bruce).

If you install an 091/002 hybrid trans in your Bug (or whatever you have), then the Syncro Vanagon fully locking diff could be installed (along with the vacuum actuator system to operated it). Keep in mind that this diff has two settings: open & fully locked. It is not a partially locking diff like an LSD or a TBD, so it's of little benefit for every day road driving.

To further discuss a specific application, we would need to know what the application is. Bug? IRS? Drags? One last point: ... until various VW locking diffs are made in China, $1,400 is cheap.

[fusername]

applications varys, but all for offroading in mud and dirt. I have a 091 box in my bus, and SSC IRS in my rail. I would love to be able to use the open/locked syncro parts. I will link to this thread from the offroad forum, becasue we are always looking for better options than pulling the e-brake.

[Pablo]

Well ... even better than the OE Syncro diff is Gary Peloquin's TBD with full locking option. Gary made these so that Syncro guys could retain their fully-locking option when installing one of his TBDs.

Installing the vacuum actuator system for these diffs in the standard 091 will require some mag welding on the main housing.

The best option for your rail (since it's already IRS) would be to convert to 091.

[ntsqd]

If (big word there & no experience with them) the Quaiffe unit is based on the Wisemann design and is a faithful rendition of it, then it is better than any LSD and is truly a TAD.

As to the Synchro parts, based on the parts that I saw at Weddle's some time ago I do not believe that welding is required. What would be required is the use of the Synchro bell housing and likely it's input shaft. From the looks of the actuating parts I was convinced that going to a Morse cable modification would be well worth my time. The method used by the later OX-locker "shifter" would be a good design to copy for the control lever assembly.

[Sneaks]

What is the truth on the AW code for Thing trannies? I read on another site:

"Every Type 1 IRS LSD I have found inside a gearbox came from a 'box with code AW. That is the code for a Type 181 with a ZF LSD. AV is the code for a Thing trans with an open diff."

My baja is a swing but the Rally Bug is IRS, I have no idea what it has in it. I'm hoping to get in touch with Bruno Kreibich eventually and see if he remembers anything about it but I don't have a lot of hope in it.

[Pablo]

The Torque-biasing differential (also called Torsen, Automatic Torque-Sensing, ATB, and more) was originally developed by Gleason corporation in the 40's. Zexel-Torsen is the successor to the that original company. Zexel has by far the widest range (varying styles) of Torsen diffs. Quaife (and perhaps a half dozen other companies) make a more basic version of TBD.

Rear-engined Porsches and VWs have always performed better with true LSDs than with TBDs, because LSDs have decel lock-up and TBDs don't. TBDs are more suited to front or mid-engined cars.

Any original VW ZF with over 20,000 street miles has worn-out friction discs. The original discs were junk to begin with, as those LSDs were made at a time when ZF was experimenting with friction materials. When LSDs are fit with today's high quality discs and plates, they rarely need rebuilding. I'm obviously not talking about the the various Chinese-made LSDs or Porsche's "Street" LSDs, as these all run lousy carbon discs ... but rather I mean discs from the Motorsports division of Porsche (or those found in 915 and 930 ZFs made from '75-'94).

[ntsqd]

I spelled the name wrong.

http://www.weismann.net/

[Glenn]

If you want a ZF... turn your head and cough.

http://www.thesamba.com/vw/classifieds/ ... ?id=889745

[fusername]

yeah whenever i check the classifieds to see if something new came up for sale I see that thing, just laughing at me.

[Bruce2]

If you want a ZF... turn your head and cough.

http://www.thesamba.com/vw/classifieds/ ... ?id=889745

That will be there a LONG time. Swing ZFs don't even go for that much.

[Bruce2]

What is the truth on the AW code for Thing trannies? I read on another site:

"Every Type 1 IRS LSD I have found inside a gearbox came from a 'box with code AW. That is the code for a Type 181 with a ZF LSD. AV is the code for a Thing trans with an open diff."

Whoever wrote that is a pretty smart guy.

[Bruce2]

Any original VW ZF with over 20,000 street miles has worn-out friction discs.

I have to disagree with that statement. I've been inside a pretty big statistical sample, and when you're talking IRS ZFs, the discs simply don't wear out. It could be that the stock 1600 VW put behind the gearbox doesn't have enough hp to hurt or wear out the diff. It could also be the low lockup.
The only wear I see is the axial thrust washers for the side gears, the housing, and the splines on the inner friction discs.

[petew]

how about home made then?

http://z31.com/mods/drivetrain/phantomgrip/

a guy over here in Oz put me onto these. he made a homemade version for a swingaxle beetle rally car that he reckons works great. it looked a lot less complex than the bought one above. just two steel plates and two valve springs out of a 2l mitsubishi engine. he raved about it. he said it worked really well on throttle and on trailing throttle. I think too much power would be an issue though. He also had to do some custom (read homemade) stuff with shims etc to get it perfect. phantom grip don't make em for beetles, but it can't be that hard. when I get some time, I'm gonna make one for the stoke 091 diff I have here to try it out.

btw, if you have the cash, the peloquin 091 unit is a work of art and it's cheaper than a quaife beetle diff.

[Pablo]

I admitedly had the swingaxle (not IRS) VW ZF on my mind when stating that virtually all friction discs are worn out. (I don't think I've ever seen a serviceable disc in a used swingaxle ZF.) Replacement discs are readily available for the IRS, but unfortunately not for swingaxle (the ZF type that really needs them).

The Phantom grip has been around for years, and is certainly a step above the "Poor Man's posi" concept ... but a far cry from a true LSD. They definitely "do something" at lower speeds, but not enough to add much performance at higher speeds. Greater surface area and/or better friction materials are required for true performance.

As always, just my opinion ...