Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) Morgan Plus four - LSD

An LSD can be a lot of fun in the right hands and the right driving situations. For example on a beautiful alpine pass road out of the curves with throttle.
I think Morgan doesn't offer it on CX cars because it is far too dangerous for the average rider in more normal situations.
CX Morgans have no protective electronics. When such a light car with so much power has LSD, you can spin on your own axis when accelerating on a slightly wet but even straight road. It only needs to be different grip on the left and right just for a moment.
Why I know this so well: It happened exactly the same way to me with my Honda S2000 with 80% LSD 17 years ago. It came out of nowhere and without any warning at all. The speed was not very fast, around 40 mph. Fortunately, no car came towards me and it had just gone out without damage. The two cars are comparable because both are without electronic driving aids. Only that the CX with its stronger power-to-weight ratio would say goodbye even sooner.

Interesting answer, looks like some testing of either option was carried out, I wonder if every car used for the many magazine tests was non LSD ?

Thank you, that is an interesting answer and encouraging that they tried both options I guess they chose the safer option on balance.

Hi Heinz

I also drive a Caterham with 500bhp/ton on the road and track and then the LSD comes in handy to put the power down in bad conditions and to find grip coming out of the corners. I have also had a brown underpants moment when the car suddenly lost traction on a painted marker but if your react quick enough it scares you a bit but you'll learn from it. I'm planning to drive the Moggie all year so I was a bit afraid that because most Morgans are only driven in good conditions that it would be quite a handful in bad weather. After speaking with the factory my conclusion is to put winter tires on in the winter and see how it goes. If I come to the conclusion that it would benefit from an LSD I will ask a specialist to install one later on.

I agree re the better passive safety of the open diff on the Plus Six. It came up during the thread around the number of new Plus Six demo cars being spanked.

The open diff allows excess power to break traction and spin away the dangerous power with the lightly loaded rear wheel whilst the other tries to maintain direction. When the LSD sees a loss of grip it locks up and then both wheels tend to break traction and you have a whole new steering system.

I think it would be good to make it a sales option for those who do have experience. If needed Morgan could link it to the "driver training course" that is on the list so people can have a go and make certain they understand it? Quite a few cars have had LSD as standard over the years ask most Jag XJ owners as the salisbury diff was a wonderful thing?

This raises a question: why did every Aero have a LSD?
The only real difference is that the V8 torque delivery is much more gentle, peaking at 3500 rpm or so, whereas both CX cars peak torque is between 1500 and 2000 rpm. So the sudden arrival a lot of torque could a sudden breakaway.

The C63 has a LSD, but it has a mass of electronics to control the stability and traction....

My 2002 Plus8 has an LSD. I like it but.......
Case1. Hit a diesel spill on a damp road exiting a roundabout. An “oofa” moment that made invented some vocabulary. Sudden rear end twitch ( to about 45 degrees) but caught it ok.
Case2. Not long after having the car, again exiting a roundabout on a damp road, twitchy rear felt.
Cases 3 onwards.....similar to Case2 but down to me being over enthusiastic in damp conditions. By learning how the car reacts I have learned to either feed in power more gently or use a higher gear to reduce the sudden torque input.
In dry conditions the car is superb, the LSD helping manage the power through the wheels.
OK, not track/race driving to really test the limits but it improves the enjoyment of driving by allowing momentum to be maintained without hitting the limit of traction. I look on it as extra insurance rather than a temptation to go faster.
I can understand MMC testing both with/without and their decision to go without. I still wonder, though, if the mishaps with Plus6 cars is the reaction of the gearbox/engine rev combination during kickdown being over aggressive for a much lighter Morgan than the heavier donor BMW it was designed for.
Just remembered...at the golf club I use the road in/out has slippery tarmac as you leave the car park. It is very easy to get the Morgan to fishtail up the slight slope. It gets some members to comment!

As a matter of interest does anyone happen to know the ground clearance of this model as it is pretty critical for my drive/garage.

I don't think the Roadster would have managed the incline without leaking vital fluids.

My Plus 8 does as it's fitted with sensible tyres not elastic bands. I think the Plus Four has proper tyres too.

Richard,

you can download the handbook of the Plus Four from the Morgan website.
The numbers there say ground clearance front 125mm rear 135mm. Now, are these numbers correct?
Only owners can tell you.

Regards,
Markus

Thank you Markus, I'll have to have a physical check when I go for a test drive it's a make or break for me.