BMW/Titan LSD Viability

[Geoff Brown]

Tom#348 - All part of the service, member to member & no blushes from me!

Irrespective of the rebuild & the probability that the Titan has sintered plates it would be best to bear in mind the service interval that Titan recommend. To possibly extend the Titan life carry out the prudent checks of wheel rotation & pre load pull off. Also an annual oil sample to check the colour. Anything but clear is worth investigating. Grey going on black is a sign of imminent disaster!

Oil to use is a thorny issue. Multi grades like 75/140 etc gives protection but aids plate slip & reduces noise. The oil as recommended by RR & SPC is an SAE90 GL5 LS oil -  RRs own or something like Castrol B373.

After going through all the motions with a good outcome I hope the diff lasts a healthy amount of time.

[Tom Scanlan]

Hi Geoff and Scott

Thanks for your advice, I will be keeping a close check on it going forward. Road and Race confirmed that it has the sintered plates and hopefully they will prove a lot more durable. Having a warranty was both a blessing and a curse, as if I was paying for it myself I would definitely have gone down the SPC route but with the claim that wasn't really an option.

[DJ.]

Geoff Brown said:

Also an annual oil sample to check the colour. Anything but clear is worth investigating. Grey going on black is a sign of imminent disaster!

I think you will lucky to get clean/clear oil from a diff with a plate lsd fitted. My diff oil has always had particles in it at 2 year/10,000 miles oil changes. It didn't change much between brand new Titan fitted to 30,000+ miles, but it never looked completely clear.

Duncan

[ScottR400D]

#351 Geoff, the way it’s been explained to me is that the oils that give better results, in terms of noise with the Titan sintered plates LSD, do so because they’re loaded with friction modifiers which enable the plates to slip under light load but tight turning. 

The problem is that if the formula isn’t exactly right, particularly if there were too much additive, it can hinder the functioning of the LSD. 

Turning that round, the same oil could give varying results depending on how the LSD is set up. A diff with a high initial preload might take a while to quieten down but might then last well; another that’s quiet from the start might not retain its locking capabilities as long. 

This makes sense to me. Many report that the use of the R&R oil made a big difference to the noise. In my experience with a freshly rebuilt diff it didn’t. I tried a few different oils, different makes and grades, including the R&R but the LSD was horrifically noisy in any case. 

Surely it’s better to engineer the LSD properly so that it doesn’t rely on any particular oil to function well? 

[aerobod - near CYYC]

Titan recommends 75w140, specifically Motul (which is an ester based synthetic), although I couldn't get that specific Motul oil here, I used Redline 75w140 which is also ester based and has the required friction modifiers in it. BMW also recommends 75w140 in their LSD equipped diffs. My diff has been quiet.

[Geoff Brown]

With my original, now dead, gone & forgotten Titan  I used Castrol Syntrax 75/140 & a lot of good that did!

I agree ScottR400D #354 engineer the component correctly in the first place & do not try to hide the inadequacies with formulated multi grade oils.

The Titan was designed & built to a budget as I related to in #343 a quote on the RR home page;  'The rest of the design was focused on reducing rotating mass, and reducing manufacturing costs. By reducing manufacturing costs they are able to pass on the cost savings to the end user,' 

So what does one expect ??

 

[Rob Walker]

Strange I have found exactly the opposite when I used the super duper GL5 lubricants in my plate diffs i found that I lost drive in  right hand corners when pushing hard.  I have had the best results using Castrol Hypoy LS which I think is a GL4 lubricant.

[7 wonders of the world]

Hypoy LS is now renamed as Castrol Z which is a GL5 90 grade mineral LS oil,

B373 is rated as GL6+ again 90 grade EP for LSD (although GL6 is no longer used)

Odd you only lost drive in right handers though....?

[Geoff Brown]

DJ #353 - I understand that Steve Perks of SPC employs Moly plates in his LS unit. According to him the oil should always be clean when checked so my warning about change in colour still stands?

[ScottR400D]

Geoff, I can see how the oil might discolour with carbon plates but wouldn’t think it would be the same with sintered or moly plates. At least not to the same extent. 

Then again, I’m not sure what material the Titan plates are made with, I’ve read it’s sintered bronze, so black discolouration may well be possible from the copper element  

I’m just going to change the oil every year and filter the old to see if there’re any bits in it and keep a check on the mag plug for ferrous bits. 

[Rattie]

Quaife ATB now in and test driven. I had to overhaul the rear calipers, having spotted a seal weeping on one side while reinstalling the DD ears.

Works great, nice and smooth. Looking forward to a trackday in the new year.

[John Vine]

Re #322:

This included the following test for the presence of a Quaife ATB :

1. Lift the drive wheels off the ground
2. With the engine off, put the car in any gear.
3. Rotate the Drivers wheel clockwise. The passenger wheel should rotate counter clockwise.
4. Block or lower the passenger wheel so it cannot turn.
5. Try to rotate the Drivers wheel. It should not turn but about 1 inch in either direction.

My 2008 R400D came with the Quaife ATB, so I've just conducted the same test:

1. Raised the rear wheels.
2. (In neutral) Rotated one wheel -- the other rotated in the same direction.
3. (In gear) Rotated one wheel -- the other rotated in the opposite direction.
4. Locked off one wheel by lowering it onto a block of wood.
5. (In neutral) Could rotate the other wheel easily.
6. (In gear) Could not rotate the other wheel at all (other than to take up transmission slack).

So, the two tests match exactly.

Re #261:

Having never removed a diff before it's been an interesting time. Thanks to John Vine for the guide that I found elsewhere on here, took the trepidation out of it.

Not me guv!  Although I'd be interested to know whose guide it was.

JV

[Dave Hardcastle]

John, it certainly was as I used it as well 

Dave

[John Vine]

Oops, how embarrassing!   I'd completely forgotten about that post.  Put it down to age.

When you said "guide", I assumed you meant a wiki-style contribution in the Guides section (my excuse anyway).

JV

[Bob Shelley]

Just heard back from the very helpful Martin Phipps that my 2008 R400D was fitted with a Quaife ATB. The test in #362 also confirm this.My research has also established that the reason it is so noisy is that CC were fitting non Ford OE crown wheel and pinion sets in that period and they were not made to the same tolerances.

[Dave Hardcastle]

#365 That's interesting Bob. I also have a 2008 R400D, my diff has a very loud whine in the 3-4.5k range. Makes me wonder why Caterham did that? 

[David_Long]

At that time there was a real shortage or Sierra diffs (the reason they moved to BMW in the first place). As I understand it (I have a 2008 R400 and researched it at the time) there was a period when diffs were sourced from Quaife who fitted their own CW&P and ATB diff. I suspect they used the casing from all final drive ratios and possibly the Ford CWP if they contained the correct ratio. 

[Bricol]

Just a thought about the quaife diff test:

1. Lift the drive wheels off the ground
2. With the engine off, put the car in any gear.
3. Rotate the Drivers wheel clockwise. The passenger wheel should rotate counter clockwise.
4. Block or lower the passenger wheel so it cannot turn.
5. Try to rotate the Drivers wheel. It should not turn but about 1 inch in either direction.

My 2008 R400D came with the Quaife ATB, so I've just conducted the same test:

1. Raised the rear wheels.
2. (In neutral) Rotated one wheel -- the other rotated in the same direction.
3. (In gear) Rotated one wheel -- the other rotated in the opposite direction.
4. Locked off one wheel by lowering it onto a block of wood.
5. (In neutral) Could rotate the other wheel easily.
6. (In gear) Could not rotate the other wheel at all (other than to take up transmission slack).

 

If you did this with a "free" diff you would get the same results.

 

[David_Long]

Yes, the Quaife ATB is an open diff when not under load. From my blog . . .

''The Quaife ATB is a Spur type differential. Although there’s nothing new about the design, it does offer some features that can be adapted to provide limited slip action. Rather than bevel gears, it has pinion roller gears, which would normally be mounted on bearings, but in this (ATB) design they run loose and unsupported in a carrier.

The implications of this are that the pinion and spur gear are pushed apart under torque (like any gear set). The pinion gears are then subjected to higher frictional forces against the carrier wall. By putting lots of pinion gears (12 in this design) the friction forces can be multiplied up. In essence there is a limited slip action as torque increases. To ensure there is sufficient torque to enable this process to start there is a stack of Belleville springs between the spur gears to provide some initial frictional forces between them.

The limited slip action is at a maximum when both wheels are turning together at the same speed (pinion gears are stationary). If something should happen to overwhelm the fiction and start the pinions turning then the LSD action can drop rapidly returning it to a more of an open diff mode. This is typically seen when subject to more extreme track driving where wheels become airborne over kerbs. However, limitations aside, it has a good pedigree on road cars and works well as as a fit and forget LSD solution.''

[Geoff Brown]

37 pages, 369 posts,18,337 views & counting. A record?

When first starting this thread in October I imagined it would run out of legs quite early on. But no it still has life. Keep contributing chaps!

Maybe it will still be near the top by the time the Spring comes around & I can fully report on  the performance of my SPC LS unit?!

Merry Christmas & Happy New Year to all those that have contributed positively therefore revealing an awful lot of info & getting to the bottom of the problem.

[Geoff Brown]

I make no apologies for resurrecting this post. 

The problem of the 'variable chocolate tea pot' life of the Titan, especially the carbon clutch plate type has been discussed at great length. Many owners have thankfully nipped the problem in the bud at some expense. Others have not been so lucky.

The problem still endures & I can personally state that even now in the month of March 2021 two more owners have found their diff to be unserviceable & one just happens to be the club vice chairman !

It is lamentable & imo neglectful of CC to have allowed the problem to even exist. If they had generally educated owners including at the point of sale & in the Owners Handbook then there possibly could have been a zero attrition rate.

So....you have been warned ! 

 

[ScottR400D]

What power were those cars, Geoff? Do they fit in with the theory that the Titan is OK up to a certain amount of power/torque, around 175/180 bhp? 
 

 

[7 wonders of the world]

It's more than that Peter,

Whilst its fair to say the Titan cannot handle the torque which is bourne out by the significant number of owners with burnt plates, but there's also the problem of broken bellevillies  which makes them bang like a barn door in the wind, this is purely down to poor design.

[ScottR400D]

I don't disagree Neil, but I have club member mates with 270s/310s with Titans and have done up to 20k miles and they look at me oddly when I moan about the Titan! 

[7 wonders of the world]

have they checked their preload though.......