Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) LSD on a 2012 4/4 Sport

It's just the diff, it doesn't include the bevel and ring gear. I can't answer any of the BTR questions as mine is a Salisbury axle, but I'm sure Billy Bellinger would know. My axle was rebuilt 10 years ago and at that time it was no problem to get a Morgan ATB from Quaife, but I have no idea what availability is like these days. I'm sure they could make you one though.

Thanks to everyone for their replies.

I was told that LSD became standard around 2014 around the time the adjustable camber was brought in to the front suspension. Although knowing Morgan production methods I didnt expect a definitive answer as the factory was known to 'mix & match' in production.

It appears from replies that LSD wasnt brought in as a standard fitting around 2014. My own car confirms this as it is a September 2012 car and has a LSD and front camber adjustment.

Someone at the factory may well know the reason why some cars have LSD and others dont, in my view likely to be axle supply to the factory. I wonder however if this would happen today under the new Morgan ownership as I am sure Morgan would be happy to charge a premium for the option of a LSD.

The upshot is I can see fellow Morgan owners on here jacking their cars up to check whether they have LSD or not. Its nice to know the spec of our cars and especially useful at service and MOT time.

Yep easy to tell if you jack up the car and turn one rear wheel.
I have now added a post below as I found a video explaining how.

If you look at my link a few posts above Tim/Heinz you will see that Quaife have them in stock for BTR axle.

Lots on yout ube on how to test the diff here

Thank you, Richard. Quite apart from my desire for a shorter final ration, re the ATB differential from Quaife, can anyone be sure that it will fit the latest version of the BTR rear axle? According to SimonH the 2014 axle with 7.7" ring gear. I wouldn't be so sure because the ATB seems to be made specifically for the M76 axle, and that should be the 7" diameter ring gear axle according to SimonH. See my post, the first of page 3 of this thread. Simon: The diff carrier (the pigs head) in the middle of the axle is also physically larger and heavier“.
I do not know if this has an influence regarding the fit of an ATB.

Tim, thanks for the recommendation, I wrote a mail to jb-engineering (Billy Bellinger) concerning all this stuff and will see next week what they will response.

In answer to an earlier post, my 2009 4/4 Sport came with the factory fitted Track Day Pack option and this included roll bar, 4 point harnesses (no conventional seat belts) battery cut off switch and a few other bits and bobs but did not include an LSD unfortunately.
Altering final drive ratios on the 4/4 Sport is a bit of a minefield. Sure you can get a livelier response with shorter ratios, but motorway driving will likely be a drone fest and fuel consumption will go up with little return in performance. I'm not saying it is a bad idea, just that there is much to consider before choosing this route.

With the shorter final gear ratio, I would no longer drive 160 km/h in 5th gear at 4000 rpm, but 145 km/h. That's still OK, since I only drive the motorway with the 4/4 on holiday. The gain is that I can use gears two and three in the wider rev range on the country road. As it is now, I would theoretically drive 160 km/h in third gear at high revs, which affects the driving pleasure.
Regarding the LSD, after a break down of the gearbox in my Lotus Elise in 2021 I now have one out of a MR2 which is 10 percent longer than before which means also that now I drive 145 km/h at 4000 rpm (130 km/h before with the original ratio). It makes sense as the engine power is enhanced and FR was definitely too short. And a huge plus is that I now have a LSD in the Elise. I had to train to drive it under secure wet conditiins not to become surprised and lose the rear on a wet road when flooring the throttle which means driving even more carefully in the wet and knowing the points where it can break out but also being able to catch the car as well as possible. And of course to learn to take advantage of the LSD.

With an LSD, drifting out of corners becomes the norm after a while.

I'd be the first to admit that my 4/4's 4.1:1 rear ratio is not perfectly suited to motorways. 70 mph is about 3000 rpm so it is indeed a bit of a drone. I tend to dial it back to 65 or so where it's all a lot more civilised.

The upside of course is that when one is playing about on windy minor roads, the lower ratio and 165bhp combine to be a right laugh.