BMW/Titan LSD Viability

[Tom Scanlan]

Apologies for the stupid question but to perform the wheel rotation check suggested in this thread, should the gearbox be in neutral or in gear?

[ChrisC]

Neutral, the propshaft will turn once the preload is overcome. 

[Geoff Brown]

I am overwhelmed by the response to my original post & do not regret raising the subject. It just shows that my original 'iceberg theory' has proved to be correct.

Steve at SPC is obviously about to be inundated with dead BMW/Titan diffs! Well done Simon for taking on the franchise & the pressure off Steve P.

I am glad that this thread has planted doubt in the minds of those about to order a Seven with LSD & persuaded them otherwise.

From what I have garnered as has ScottR400D is that the SPC LS unit is robust, well designed, engineered & enduring. How enduring is hard to say but I hope more than the Titan that might see out three years for an average road mileage Seven or less if you add a few track days per year. 

Hopefully my diff should be ready for pick up next week - fingers crossed! Then the rebuild starts. In fact that is the other factor about dropping the diff periodically, there are incidentals that one would otherwise be unaware of unless it was obvious while the car was still on the road. Nuts, bolts, bushes & bearings that mysteriously require replacing once everything is dismantled. My bill for incidentals is now north of £180.00.

But I suppose that is the challenge of owning a Seven.

 

 

[Doctor]

Hi all, I have been through the pain of Quaife ATB, Tran-X  and Titan LSD until I discovered (via Simon Rogers and Dave Gemzoe) Steve at SP Components with his Tracsport diff. It has been a long journey with a lot of pain and I (not working in automotive) have been forced to learn a lot of things. Steve has kindly asked me to sum up my experience and post it here. Not keen to start with, I've agreed, so hopefully over the weekend. Loads of misconception in this thread.

[Rattie]

Doctor, interesting you mention "the pain of Quaife ATB...". What was the pain point for you with that diff? I only ask, because I started out with a Sierra based ATB and apart from the CW&P mesh noise, I actually liked the behaviour of the ATB. Obviously it becomes an open diff if one wheel is free of the ground, but is there some other showstopper that you found?

[Wrightpayne]

Re ATB if you lift a wheel when competing, when it lands has a tendency to snap driveshafts.

[Rattie]

Yeah, I understand that is the received knowledge. It strikes me that it's more of a FWD danger, where you can lift a driven wheel under power. In RWD, the only way I can think of doing it is by taking a sausage kerb shortly after the apex, while putting the power down. Very much a racer specific scenario, fair enough.

The other thing is, how would this be any different to on open diff? I'm assuming the damage is due to an airborne wheel spinning up to a crazy speed, then suddenly decelerating to ground speed as it lands. Am I missing a difference in this scenario between ATB and open?

The reason I ask is I'm considering flipping the table and going back to ATB, since after 3000 miles (approx half on track) our BMW Titan is down to about 2lbft of preload, i.e. toast and I don't want to have to revisit the diff more than once. I didn't notice any trackday benefits of the plate LSD over the ATB we had in the original Sierra units, and I'm not a racer and don't intend to race this particular car ever.

So please fill in my gaps if I'm missing something, I'm still not fully decided on my course of action, but I'm definitely erring n the side of a fit and forget option that I've had previous good experiences with.

[DJ.]

The reason I ask is I'm considering flipping the table and going back to ATB, since after 3000 miles (approx half on track) our BMW Titan is down to about 2lbft of preload, i.e. toast and I don't want to have to revisit the diff more than once. I didn't notice any trackday benefits of the plate LSD over the ATB we had in the original Sierra units, and I'm not a racer and don't intend to race this particular car ever.

That's what I'm considering. The only bad report I have had of the Quaife ATB was a friend who broke two, in very little mileage but he did have 440bhp!

[CtrMint]

Honestly I'm nearly crying into my keyboard with this thread.  Seriously it never stops does it.  

[7 wonders of the world]

DJ

For track use you need a decent plate and the Tracsport is the best out their, the Quafie will never lock up and therefore will limit ultimate performance but also induce shock loads into the driveline as you will suffer engine flare up on kerbs or whenever on rear wheel is unweighted.

Steve did and always has carried out proper real world R&D on his unit for over 4 years before releasing it fr general sale, it's been subject to hard use and is a proven design.

 

 

 

[Englishmaninwales]

Just pulled the invoice - my Titan LSD is an early one fitted by R+R in 2009 into a Ford diff. The car has done 8k miles since with many hills an sprints. Relative low power and torque (Supersport) throughout. About 2 oil changes in that time. Preload yesterday is 22 ft lb.

Malcolm

[Simon.Rogers]

Malcolm

I think the Titan is supposed to be 40ft lb.  ("I think")  Just try to find out.

[revilla]

From Mankee Cheng:

 

My Ford 7” Titan is around year 2011/2012. Checked with Titan using the serial number and it came with 30/60 ramps and 20 lbft preload. Checked the preload myself yesterday as well and it was 42 nm/31 lbft. Seems to have worked fine over the past 5 years as far as I can tell.

[Geoff Brown]

I get the opinion from some posts here the Ford/Titan seems to be wearing well. Is this due to a difference in the installation, the internals, its size, set up or something else tangible compared to the disaster that appears to be happening with BMW/Titan combos? Taking into account carbon faced plates..........

Surely the Titan recommended service interval applies to either installation? 10,000 road miles, annually or a race season. With any track day time also taken into account? 

[Nigel B]

I was talking to Steve Perks earlier in the week & he was of the opinion that there isn't any difference in longevity. He said the internal parts are the same in the BMW & the Ford versions & he rebuilds plenty of both types. 

[ScottR400D]

I don't think we have enough information to be sure about why some diffs last and others don't. I can't see why a different housing would make a difference.

I would think that, and it seems to be, IME, that power outputs are the main factor, type of use is important and the time when the diff was built and with which components, though the latter is impossible to quantify. It does appear that there have been a number of component and material changes/developments made to the Titan over the years, for better or worse, but there's no way of being sure. 

Having said that, I wouldn't be at all surprised if there are quite a number of cars running around with non or only partly functioning LSDs, with cracked or broken components, with the owners simply unaware of that but assuming all is well. It certainly appears that several members have found that to be the case after being alerted to the possible problems by this thread and the earlier ones on the same issue. (You included, I think, Nigel?)

 

[Nigel B]

Yes, you're right Peter. I had suspicions that something was amiss at the end of last year, as my car didn't feel as confidence inspiring as it had initially. Under power it felt a bit erratic. 
 

I was aware that the Titan didn't have a very good reputation for longevity, but I'd assumed, naively, that if the plates wore out it would simply act like an open diff. I didn't realise that was a sign that it was on the verge of catastrophic failure & was likely to break up & cause very expensive damage to the crown wheel and pinion!

[james marsden]

I have a newly acquired 2017 420R SV with what I guess is the BMW LSD. I am changing all the fluids so I know what is in there and especially following this thread see that new Diff oil is a good idea (it is a little noisy) but Caterham are now suggesting a different spec (75W-140) to the cars handbook (EP80W90) and there seems to be little consistency of what to use on various forums. Can anyone give me their view (and why) - my car use will be split between trackdays and touring. Much appreciated !

[aerobod - near CYYC]

Titan recommend Motul Competition 75w140:

Motul Oil Spec: https://d23zpyj32c5wn3.cloudfront.net/images/product_descriptions/technical_data_sheets/108/Gear_20Competition_2075W140_GB.pdf?1492016023

[Bricol]

I'm not quite certain what is trying to be measured here when there is talk of "torque".   With a rotating component, you aren't getting a true reading by winding a normal "click" type torque wrench up or down until it "gives" as you turn it.  Even how you apply it will give a different reading - a jerk may cause it to "give", when slowly applying it won't.

To measure a rotating preload, you need a dial indicating type, rotate it smoothly  - you will get a peak reading that settles down as you continue to rotate.  Not many people have them as they cost a bit more than your more common "click" types.

[aerobod - near CYYC]

A cheap way to measure the torque is to wrap a rope or strap around the tyre and pull from the bottom rear to register the load on a hanging scale, then multiply by the tyre radius to give the torque. The ideal scale to use is one of those cheap digital ones for weighing suitcases.

[ScottR400D]

It doesn’t matter how you measure torque if there isn’t any........

[Nigel B]

That was what I found. There was no preload left to measure!

[Geoff Brown]

On the subject of which oil to use in the BMW LSD - CC/Titan recommend a 75w140 which I had in my sorry looking LSD. But if one talks to SPC or R&R they recommend a good SAE 90 GL5. In fact R&R produce their own oil to this spec.  

When I get my diff back from SPC I intend to install Castrol B373 SAE 90. It is specified as a GL6 but this standard is no longer recognised as GL5 is the adopted highest standard (allegedly).  So the diff should receive all the benefits of a GL5 +.

I think the watchword is irrespective of cost, mileage or use change the oil annually & check the colour.  That goes for ALL  LSDs but especially Titan!

The number of owners innocently driving around with their Titan merrily on it way to destruction or causing the whole diff to implode must be immeasurable. With all the background noises attributed to driving a Seven it can be difficult to know when the diff is trying to tell you something. Fortunately mine 'spoke to me' with noises I could not ignore catching it just in time.

It is just a shame that CC neglected to inform owners at point of sale or in the Owners Handbook the service requirement for such a delicate piece of equipment.

Could we as owners possibly compile the number of Titan problems/failures?  Date, car model year, type of diff (BMW or Ford) & failure outcome. I don't mind taking this on board. So either PM me or use my club in box.

[Wrightpayne]

Is there a drain plug on the bmw item? Not one on the ford diff. I had to use my machine mart oil syringe to evacuate the old oil