High lock diffs

[matt]

I can get OS Giken diffs if anyone is interested. We also build high lock-up stock BMW diffs with 2-4 clutches. Not for $850 though. It's $500 just in machine work to do a 4-clutch setup.

[FredK]

I'm pretty sure the Kaaz 1.5 way is actually around $1600 or so. The OS Giken is a little cheaper; I believe you can get it for around $1400.

[Jean]

^ link for more info? thanks

[e30 gangsta]

Kazz makes a 2 way for e30's I think. Iirc its about $650.

[FredK]

I don't enjoy the chi associated with imbalance.

I hear you.

There isn't any other way to get slightly more lock, though, right, besides going to a 3 plate/disc combo?

Have you done any mods to the carrier to change the ramp angles?

[Jean]

pm sent

[Wanganstyle]

Wanganstyle - how many diffs have you done? Is this something you can do for me, 40-60% lock with fresh clutches.

Thanks!

Yes. Check your pm's :)

Been doing diffs on different cars close to a decade now, rally/drifting/tracking needs :)

[Jean]

http://forums.bimmerforums.com/forum.../t-562940.html

prices on the site appear to be much higher than on the link above...

http://www.performancegearing.com

http://www.performancegearing.com/specifications.php

http://www.metrixmotorsport.com/

[Jean]

Wanganstyle - how many diffs have you done? Is this something you can do for me, 40-60% lock with fresh clutches.

Thanks!

[Jean]

Car is on dot r 30 treadwear tires, not slicks...they are v710 tires. This is in autocross, and the diff might be worn as I don't know it's history.

[Wanganstyle]

Diff in my car can't put the power down on both wheels coming out of the corners if I am getting on it with Dot R tires...guys that work the corner stations were telling me I am spinning one like crazy....

OBX is gear diff... not sure if it's even worth the hassle of trying one or just look for these, but then again it will be 25% lock so...

You have probably worn out the stock LSD in your car. Stock LSD in all BMW's are 2 clutch, 25% locking.

Torsen from Z3 is gear and has leverage ratio instead of Locking % as its rating, from driving them in my cars (both e36 and e30 have Torsens installed), it feels about a 30-40% lock, but only on accelleration- you have to THROTTLE out of corners to activate the torsen's usefulness. Change approach to corner to allow Throttle application near apex point

IF your car is spinning a tire and the corner workers are telling you, are you autoXing? or do you have very friendly tower workers at your track events?

I'm assuming the car is running Slicks?


Torsen LSD = open diff when one drive wheel is in the air. I have to avoid jumping berms with my e30 in the mountains for this reason, with a Clutch LSD diff (assuming it has enough lock up) you can 3 wheel it off the candy cane and still be on the throttle putting down power - turn 5 skyhook Laguna Seca.


If the Motorsports vehicle is set up stiff enough to lift rear wheels airborne while the driver hangs on to the throttle, Torsen is not really suggested as it will shock lock when you land the other wheel, this style of Car+Driver should use a Clutch style high lock diff.

you can get a real high performance diff from OSgiken, or Kaaz or Cusco.....etc

OR you can have your current worn LSD reconfigured to higher lock.

2 discs = stock 25% lock
4 disc keeping the hard items stock geometry from the factory = 60% locking, its rather aggressive.

Many sub companies that build and market "special" oem factory diffs with special build lockup; people have different opinions on who they like.

IMO as a Track driver and guy who does his own diff's (my last e36m track car had a 60% locking 2 way clutch in it for lap time attack), the configuration of a stock to high lock is the max effort that one should assert for the result, Organic discs in high locking 4 disc configuration will still wear out in 2-3 track seasons (full track seasons, i.e. track car with cage and stickers) - requiring another rebuild.

Porsche guys have this problem with 997 GT3, its stock LSD just Dies after a season or two.

If the car is a HPDE vehicle and not competition, its much different- a stock clutch unit if in good shape is actually fine, and 4 discs @ 60% lock may be too much for it.


companies market and play with 3 disc combinations as well, but the geometry of the ZF LSD design already overstresses one side more than the other.........................I don't enjoy the chi associated with imbalance.

[Jean]

Diff in my car can't put the power down on both wheels coming out of the corners if I am getting on it with Dot R tires...guys that work the corner stations were telling me I am spinning one like crazy....

OBX is gear diff... not sure if it's even worth the hassle of trying one or just look for these, but then again it will be 25% lock so...

3.15: 2.8L Z3 may work perfect with future m62 swap
3.46: 3.0L Z3 AT and 2.5L MT , close to what's in the car now

http://cgi.ebay.com/ebaymotors/OBX-H...Q5fAccessories

[rwh11385]

diffsonline. My buddy works for them. probably one of the biggest diff companys in the bmw world.

Biggest doesn't mean best necessarily...

Anything else out there? diffsonline is pretty expensive from the quick look

Not to mention the diff I got there had wrong shit on it. (M coupe bushing I didn't ask for, wrong era sensor) For the money paid, I'd expect the crew not to be high while handling the differential. Whoever ran it seemed nice, but seemed like full of empty promises and slimy after delivering poorly.

I would not recommend them, at all.

[FredK]

Pretty sure it's 25%.

Here's a quick and dirty list for medium case helical diffs:

3.07: 3.0L Z3, MT
3.15: 2.8L Z3
3.46: 3.0L Z3 AT and 2.5L MT
4.10 2.8L Z3 AT

And yes, for the exact reasons nrubenstein described, you may want to consider a clutch-type diff.

[nrubenstein]

I run a Z3 diff in my swap car. It has pluses and minuses. The big problem is that if you lift a wheel or get in a very low traction situation, a helical/torsen/quaife diff goes open. You can abuse the parking brake to put some load on it if you need traction help in the snow, but it's not great in performance situations.