100%LSD lock too much?

Post Mon Sep 12, 2005 6:55 pm

'Ello!

Well, Brown's not a million miles away from being finished and I can't help thinking that an LSD might not be such a bad idea.

I've seen these Kaaz ones which seem to have a million plates in them and can do upto 100% lock. Sounds like it could be fun in corners, but does anyone think it might be a bit much.

I'm also looking into building myown (well, to myown design anyway) which would be a constant lock type where the locking action is the same irrespective of the relative speeds of the rear wheels but the Kaaz one might end up being cheaper.

Whadda people think?

http://www.kaazuk.com/technology.php

Post Mon Sep 12, 2005 7:30 pm

Imo 100% lock is a no-no, 40% lock can give you understeer and anything higher is likely to be a nightmare.

100% lock is like having a welded diff and welded diffs do not like to corner unless it's sideways.

Steer clear,

Iain T

Post Mon Sep 12, 2005 7:42 pm

Well, the Kaaz might still be in the running as it says they can be easily adjusted.

Ooooo! Just seen the price!

Post Mon Sep 12, 2005 8:07 pm

driftworks.co.uk email the admins they can sort some deals on kaaz diffs, or john at zoom might be able to get them cheaper than the extortionate price they are.

100% lock is kinda pointless unless your using it as a drift mobile, are the kaaz's 2way for bmw's?

Post Mon Sep 12, 2005 11:23 pm

i think 25% would be fine for u, as Iain said 40% can be well lairy and especially for your car in the wet it would be. And i'm sure ure going to want to drive fast round bends and not have the constant threat of the arse end trying to overtake u!

Hartge did some 40% jobbies and i believe some were fitted to various E30's too

But find one!

Post Mon Sep 12, 2005 11:32 pm

40% sucks MOREEE but if the kaaz is a 2 way that might be a pain in the ass if its adjustable to a 1.5 way setup then run a fair amount on acceleration.

got to be able to put the power down.

Post Tue Sep 13, 2005 8:27 am

Cheers for the link, have just e-mailed them for a price and the adjustability of the diff.

Cheers for the input chaps!

Post Tue Sep 13, 2005 10:32 am

Not sure I understand the 100% locking bit, surely that's the same as a welded diff. Adjusting the LSD cluster pre-load is not the best way to do it imo.

The standard BMW unit can be cheaply modified to give more ready locking, but agreed that this can be undesirable on fast corners. It can also easily be set up to give different locking with power on or overrun.

Depends what you want TB, I use a 75%ish equal 2 way locking diff with 4 plates, which is a riot,

but can be a bit lairy on fast corners, or can encourage understeer.

Post Tue Sep 13, 2005 10:49 am

I have a BMW 4.1 LSD that was used in the touring cars out here so it has been adjusted slightly to allow a bit more locking and also has a bit more preload (90lbs I think, and I think standard is about 50lbs?). It seems to work great in my 323i and not cause much understeer (my car has very little understeer). It also seems to work great on the dirt. I don't know how it would go with a lot more power and I don't have much experience with other LSDs either so I'm not the best judge.

Aston

Post Tue Sep 13, 2005 11:09 am

I have a BMW 4.1 LSD that was used in the touring cars out here so it has been adjusted slightly to allow a bit more locking and also has a bit more preload (90lbs I think, and I think standard is about 50lbs?).

I think standard is about 60lbs, we use 70lbs for tarmac diffs and 80lbs for gravel, which only 'tightens' the cluster slightly but speeds the reaction.

We use modified pressure rings to adjust the locking, which isn't an exact science %wise, but can be set up to work differently or equally in opposing directions, and is 'kinder' to the LSD cluster.

Aston, afaik most of the Touring car diffs used modified pressure rings, and most drivers preferred a set up with less overrun locking.

Post Tue Sep 13, 2005 11:30 am

M3Compact wrote:I think standard is about 60lbs, we use 70lbs for tarmac diffs and 80lbs for gravel, which only 'tightens' the cluster slightly but speeds the reaction.

We use modified pressure rings to adjust the locking, which isn't an exact science %wise, but can be set up to work differently or equally in opposing directions, and is 'kinder' to the LSD cluster.

Aston, afaik most of the Touring car diffs used modified pressure rings, and most drivers preferred a set up with less overrun locking.

I just checked the info from the guy that did it for me and it was set to 90lbs. I don't know much about LSDs but I have read what you said, that it means it locks up slightly quicker but can also cause more understeer and make it a little snappier (if that's a word, goes sideways quicker with less warning). I do a bit of gravel racing so the higher preload is probably good and I like the way it works.

Thanks for the info about touring car diffs, I don't know much about mine except the preload.

However it is setup it works great with my car and the driving, I can't say how it would go with a different car but when I get more power I'll definately be trying my diff first before I look for an alternative.

Aston

Post Tue Sep 13, 2005 1:55 pm

Appears that they're Ãƒ”šÃ‚£875 inc Vat from Driftworks and can be had off the shelf.

They say all the BMW Kaaz diffs are 1.5way, which sounds more suitable for road use?

They can't be adjusted on the car though, so it could be a bit of trial and error.

Mabey Quaife is the way to go.

Post Tue Sep 13, 2005 2:36 pm

Turbo-Brown wrote:Appears that they're Ãƒ”šÃ‚£875 inc Vat from Driftworks and can be had off the shelf.

They say all the BMW Kaaz diffs are 1.5way, which sounds more suitable for road use?

They can't be adjusted on the car though, so it could be a bit of trial and error.

That's interesting. If they're fixed at 1.5 way, there's no way they can give 100% locking. To give 100% locking, it has to be done in the cluster, which can't be adjusted for direction. (My guess is that they're referring to the fact that the axle is 100% locked, as opposed to the common interpretation of locking %, which is the amount of slipping torque that the LSD unit will 'bias'/transfer.)

I prefer 2 way for the trailing throttle oversteer, which is easy to transfer in to power oversteer with an uprated LSD, many don't like this tho', specifically the circuit users.

Mabey Quaife is the way to go.

I've used the Quaife ATB diffs, and they're lovely to use. They're not quite as much raucous fun as a plated LSD, because they never actually lock up, but they're very efficient imo. I've been told that they were originally developed for Post Office vans in bad weather conditions.

I just checked the info from the guy that did it for me and it was set to 90lbs.

I'm not sure if 90 lbs would actually affect the amount of torque biasing, but it would certainly make the unit react promptly, it's likely that you have modified pressure rings, if it noticably locks more readily than a standard LSD.

Post Tue Sep 13, 2005 2:50 pm

1.5 way is much nicer, gives you that room for recovery when you start going into a big sideways moment prior to a spin.

pricey but kaaz diffs rock, just remeber to break them in properly and look after them with the right oil etc.

Post Tue Sep 13, 2005 9:52 pm

1.5 way is much nicer, gives you that room for recovery when you start going into a big sideways moment prior to a spin.

I agree that for most users a 1.5 is much more appropriate. For the drift hooligans, a 2 way, increased locking multi plate is the way to go imo.

pricey but kaaz diffs rock, just remeber to break them in properly and look after them with the right oil etc.

Looking at their image, this looks to be a multi plate design of the BMW/ZF LSD unit style, it appears to possibly have the pressure rings machined with assembly options, which could incorperate the adjustable aspect. This means a complete rebuild/set up to adjust the diff.

If it hasn't, the preload is used to adjust the locking, that's not desirable imo.

There's nothing with this unit, that can't be achieved with a pre-determined setting for the BMW unit, at a fraction of the cost. (Decide beforehand and build it for Ãƒ”šÃ‚£200 + a used LSD.)

BMW/ZF units are tried and tested in thousands of competition applications, and are excellent in operation and very robust.

The Kaaz LSD unit seems like an unnecessary extravagance to me.

Post Tue Sep 13, 2005 10:59 pm

Templ8e30 wrote:Imo 100% lock is a no-no, 40% lock can give you understeer and anything higher is likely to be a nightmare.

100% lock is like having a welded diff and welded diffs do not like to corner unless it's sideways.

Steer clear,

Iain T

dose give me under steer especialy with 8j rear.

Post Tue Sep 13, 2005 11:02 pm

Post Tue Sep 13, 2005 11:08 pm

Zaust

Where have you been geese?
Have you seen the "E30 drift day" in the Meets section?

Post Wed Sep 14, 2005 12:17 am

M3Compact wrote:I'm not sure if 90 lbs would actually affect the amount of torque biasing, but it would certainly make the unit react promptly, it's likely that you have modified pressure rings, if it noticably locks more readily than a standard LSD.

The diff was completely rebuilt before it was put into my car and I thought he also adjusted the locking % as well as the preload. I could be wrong though, might be standard locking and just modified preload.

BMW/ZF units are tried and tested in thousands of competition applications, and are excellent in operation and very robust.

Which reminds me that after 1 1/2 years of normal driving and motorsport on dirt and bitumen I should probably get mine checked out. It still seems to be working fine but a service wouldn't hurt.

Aston