Why don't most performance cars have a LSD?
Discussion
cerb4.5lee said:
I'm a very big fan of a LSD for the improved grip and the added fun factor, yet Lotus/Porsche/Mercedes don't seem to fit them as standard.
Also you only get a LSD on Bmw's full fat M cars, but I think the M140i/M240i would benefit from one, is it purely cost why manufacturers don't bother with them? Or the fact the most drivers maybe wouldn't even notice if one was fitted.
If they put an LSD into an M240i as standard, who would pay for the M2?Also you only get a LSD on Bmw's full fat M cars, but I think the M140i/M240i would benefit from one, is it purely cost why manufacturers don't bother with them? Or the fact the most drivers maybe wouldn't even notice if one was fitted.
?They just need to make it a tick box option, the fact they don't implies it's a cost issue, never mind who can handle it. If you can't don't tick the box. Of course there are other companies making these things which likely perform better than even a cost controlled factory option, but choice would be nice.
cerb4.5lee said:
I'm a very big fan of a LSD for the improved grip and the added fun factor, yet Lotus/Porsche/Mercedes don't seem to fit them as standard.
Also you only get a LSD on Bmw's full fat M cars, but I think the M140i/M240i would benefit from one, is it purely cost why manufacturers don't bother with them? Or the fact the most drivers maybe wouldn't even notice if one was fitted.
C63 AMGs from 2015 onwards all have a mechanical LSD (as does the AMG GT), the C63 S (and AMG GT S, C and R) all have the same diff with additional electronic control. Also you only get a LSD on Bmw's full fat M cars, but I think the M140i/M240i would benefit from one, is it purely cost why manufacturers don't bother with them? Or the fact the most drivers maybe wouldn't even notice if one was fitted.
It's available as an M Performance dealer fit upgrade for those who care enough to want one, but the majority don't notice and won't get much benefit for the additional £2.5-3k (or £100pm extra on the lease/PCP...). It's a factory option for the A/CLA 45 AMGs from memory, which are 4Matic as standard anyway.
Main barrier is cost, but that's justifiable when there's a £15k+ gap between the performance model and the next one down the range, as with M3/4 and 3/440i or C63 and C43 (4Matic renders it unnecessary, apparently - although it's still present in M xDrive on the new M5 and 4Matic+ on the E63/S due to the ability to switch to a RWD only handling mode for maximum fun/driftiness).
4941cc said:
C63 AMGs from 2015 onwards all have a mechanical LSD (as does the AMG GT), the C63 S (and AMG GT S, C and R) all have the same diff with additional electronic control.
It's available as an M Performance dealer fit upgrade for those who care enough to want one, but the majority don't notice and won't get much benefit for the additional £2.5-3k (or £100pm extra on the lease/PCP...)
Main barrier is cost, but that's justifiable when there's a £15k+ gap between the performance model and the next one down the range, as with M3/4 and 3/440i or C63 and C43 (4Matic renders it unnecessary, apparently - although it's still present in M xDrive on the new M5 and 4Matic+ on the E63/S due to the ability to switch to a RWD only handling mode for maximum fun/driftiness).
I will admit I was pretty shocked that the early C63's didn't get one, because that's just the type of car to really benefit from one for me, I didn't realise it was made standard on the later models thanks. It's available as an M Performance dealer fit upgrade for those who care enough to want one, but the majority don't notice and won't get much benefit for the additional £2.5-3k (or £100pm extra on the lease/PCP...)
Main barrier is cost, but that's justifiable when there's a £15k+ gap between the performance model and the next one down the range, as with M3/4 and 3/440i or C63 and C43 (4Matic renders it unnecessary, apparently - although it's still present in M xDrive on the new M5 and 4Matic+ on the E63/S due to the ability to switch to a RWD only handling mode for maximum fun/driftiness).
I do like what Bmw have done with the new M5 making it with a Rwd option as well as Xdrive, the best of both worlds.
We were discussing LSDs at our Lotus Seven club meet last week. My Seven has an LSD, and I would say that since I fitted it, I have found it to be great fun, and definitely the traction is improved in the wet.
I have to admit that when hooning on an airfield day, it can push into understeer if I get a low speed corner wrong. However, when I get it right, it does lead to a predictable slide and It does great doughnuts
.
Anyway, a friend who I respect has a theory that LSDs are behind several crashes that local owners have suffered over the last year. He thinks that on a bumpy road they can lead to unexpected complete loss of traction resulting in a rear end slide, and when the wheels grip again, the car bites suddenly and ends up crashing.
So, I don't think manufacturers are put off by cost, I think they are more concerned that their owners will get into trouble and not be able to get out of it.
I have to admit that when hooning on an airfield day, it can push into understeer if I get a low speed corner wrong. However, when I get it right, it does lead to a predictable slide and It does great doughnuts
.Anyway, a friend who I respect has a theory that LSDs are behind several crashes that local owners have suffered over the last year. He thinks that on a bumpy road they can lead to unexpected complete loss of traction resulting in a rear end slide, and when the wheels grip again, the car bites suddenly and ends up crashing.
So, I don't think manufacturers are put off by cost, I think they are more concerned that their owners will get into trouble and not be able to get out of it.
There is a standard OEM dynamics test that simulates un-even rear wheel traction on a crowned or cambered road. With a (mechanical) LSD, it's actually quite hard to control the car, as if both wheels spin, all lateral grip is immediately lost, and the back of the car quickly slides off down the camber. Without one, just the upper wheel spins, but the car continues on straight. So, for the average driver it's "better" to have an open diff because the car is going to be less sensitive in yaw at large throttle opening (especially sudden ones that tend to be used by drivers who think the accelerator pedal is a switch.....)
cerb4.5lee said:
I'm a very big fan of a LSD for the improved grip and the added fun factor, yet Lotus/Porsche/Mercedes don't seem to fit them as standard.
Also you only get a LSD on Bmw's full fat M cars, but I think the M140i/M240i would benefit from one, is it purely cost why manufacturers don't bother with them? Or the fact the most drivers maybe wouldn't even notice if one was fitted.
Think it depends on the car. Mid engine and less grunty are arguably less in need of an LSD. Anythink Yank and performance oriented tends to have an LSD as standard still. Also you only get a LSD on Bmw's full fat M cars, but I think the M140i/M240i would benefit from one, is it purely cost why manufacturers don't bother with them? Or the fact the most drivers maybe wouldn't even notice if one was fitted.
liner33 said:
Bill said:
AIUI Lotus prefer the feel of their cars without.
As does Jaguar, a lsd makes a car less manoeuvrable so the Jag system keeps it open and only locks it when really needed http://goodtobebad.kinja.com/how-jaguars-active-di...
rockin said:
LSD by definition makes it harder for the driven wheels to rotate at different speeds, which is what they need to do to help you get round a corner. In other words, an LSD tends to promote understeer by pushing the car in a straight line when the driver's trying to make it turn.
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