Winter Project - Titan LSD project

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aerobod
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From my Titan carbon plate diff experience, I would say the carbon plate wear is possibly the biggest culprit requiring premature service (excessive plate wear may also cause the Belleville washers to move out of their normal optimum range, inducing fatigue cracking), although I did still get over 30,000km out of the original carbon plates with some very hard use (such as well over 100 5,000RPM+ starts with relatively wide slicks on the rear, for autocross runs).

The Titan internals and plates have been used in a wide range of classic Ford cars, I expect that there is a significantly larger install base outside the Caterham one, but I don't see any longevity discussion elsewhere on the Internet. Time will tell with my sintered plate rebuild, I expect 2,000km of hard track use each year going forward, so we will see in a few years time, with it being easier to check oil contamination now that I've threaded a drain hole in the bottom of the diff casing for a magnetic drain plug.

James

CtrMint
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Guys, 

I'm really not sure how to respond.  

Caterham 420R S3 Lotus Toxic Green,  Caterham 620R S3 Exocet Red. Blog: https://www.caterham7diaries.com
Shortshift
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Mark

I would echo the line of thought that you should be looking to a Tracsport LSD from Steve Perks at SPC, near Redditch. 

In my R500D (so not so different from your 420) I had a failure of the Bellevile washers that meant I lost all LSD functionality.  On stripping, to our (mine and Steve's) surprise we found that my diff was, like yours, fitted with sintered plates and not the carbon ones.  They looked pretty much unused - but the point is that a failure elsewhere in the diff (the Belleviles) meant that the diff was rendered unserviceable and, also, that this failure also explained the as-new plate condition.  It seems to me that whilst the Titan diff concept is fine in the physically larger Ford Sierra final drive, the design is fundamentally compromised (and inadequate for function) in the smaller BMW diff unit.

Honestly, I would 110% urge you to change your order with CC and ask them to ship a bare/open diff to Steve at SPC and ask him to fit one of his Tracsport LSD's to it.  You will not regret doing that!

James

aerobod
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Titan diff concept is fine in the physically larger Ford Sierra final drive, the design is fundamentally compromised (and inadequate for function) in the smaller BMW diff unit.

All the Titan LSD moving parts in the BMW 168 and Sierra 7" diff are exactly the same. It is the same rebuild kit for both: https://titanexpress.co.uk/products/lsd-rebuild-kit?variant=32355122020434

James

CtrMint
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Guys, 

I feel like I've inadvertently reopened Pandora's box, specifically the debate over the Titan and that wasn't my intention.  I do appreciate your support and guidance, but I'm going to stick with the direction I've taken.  CC have actually delivered the diff too.  

A large portion of what I'm looking to do is learn, and while the Tracsport maybe more reliable it's not going to provide a like for like comparison and opportunity to learn.  Over time I'd hope to be sufficiently experienced to truly understand some of the technicalities some of you have mentioned. Ultimately I may also end up agreeing, the Titan is only suitable as a large paperweight, but I want to reach that decision for myself through understanding.  

Could we avoid the discussion over which is best and how bad the Titan might be, I will need your assistance, but focussed on the disassembly and evaluation.  Hope you don't mind.

One thing that does confuse me, if the diff is so bad, why aren't the competitors in the Caterham UK series up in arms etc.  Surely they're having a bad experience too. 

 

Caterham 420R S3 Lotus Toxic Green,  Caterham 620R S3 Exocet Red. Blog: https://www.caterham7diaries.com
Dave J
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maybe becaus they use the Ford 7" and not titan 

aerobod
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maybe becaus they use the Ford 7" and not titan

The race units with the Sadev sequential are using the Ford 7" diff which has the Titan LSD in it (same as the 620R, AFAIK), This has exactly the same Titan LSD moving parts in it (plates, shims, Belleville washers, spider gears, side rings) as used in the BMW 168 diff, only the mounting flanges for the crown wheel and side bearings and spline configuration in the side gears is different.

James

David_Long
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I'm a 100% with you on the learning bit. Much better to do that from the real thing than pay too much attention to one person's opinion, or another. All mechanical devices can fail from time to time, and someone's bad experience needs to be seen in context. 

In terms of the race cars, there's simply isn't a durability issue in the race environment. The limited slip bit (the clutch bit) works very much harder when the car is driven gently. Race cars that are cornering at high throttle use slipping tyres to provide the differential action. The differential is locked up and is pretty much doing nothing in a race. You could race the cars with welded up diffs and they'd drive pretty much the same. LSD's are really about allowing a differential action at low speed and low power - that's when they are working hardest.

aerobod
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The slow speed LSD usage with no tyre slip is more wearing than when the diff is fully locked, but the plates are only clamped with the preload clamping force in that case and there is no movement of the Belleville washers. To get the plates to be fully locked with the full clamping force there has to be enough torque on the spider gears from differential movement to walk them up the ramps on the side rings to pressurise the plates beyond the preload. In hard use the slippage of the plates may be brief until the tyres break lose, but the forces are much higher and change more violently at the plates and Belleville washers until both wheels are turning at the same speed.

James

Shortshift
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If you just stand the Tracsport (SPC) unit next to the Titan, you'll get it...

James