Why the JCW Factory MINI will not get LSD.
Over the past months there has been quite a low level rumble from MINI enthusiasts about the lack of availability of LSD (Limited Slip Differential) on the new factory JCW MINI. The engineers have opted, instead, for an EDLC (Electronic Differential Lock Control). The reason for the EDLC over the LSD is due to the fact that with a mechanical LSD, the high amount of torque in the JCW MINI causes the LSD to engage too quickly causing what’s been referred to as “anti-torque steer”. Torque steer is something that usually causes the steering to pull to one side under hard acceleration.
What they found with LSD on the JCW MINI was that it caused the car to want to pull the steering back to center and go straight under hard acceleration – not a desirable, or safe, effect in a lot of situations. This is a simplistic, easy to understand explanation and I’m sure a dissertation could be written on the technical aspects of force and intertia involved but hopefully this will help answer the question as to why no LSD. In the end, both options were tested and the EDLC gave the JCW the best handling.
We’ll be discussing this further after we get a chance to spend more time in the new JCW MINI. Currently our plans are to drive the new JCW MINI and a GP back to back next month. The JCW MINI will officially hit the streets in the US starting July 14, 2008.
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Limited Slip Unavailable on Factory JCW MINI / MotoringFile
From what you had to say about the car on the auto x course I was interested to hear your feedback. I will almost always choose mechanical systems but have to say the weight Mini saves by not adding it is a bonus. Will be interesting to get some seat time on the track and see how it behaves.
Odd then that Mazda fits a mechanical LSD to its MS3 which has a great deal more torque and yet doesn’t get much torque steer. Sounds like MINI cheaped out when a product that costs 6 grand less can offer it.
Cost was not a factor at all. If cost was a factor it would have been offered as an option like it is on other R56s. The LSD is only a $500 option on the R56 so the idea that MINI “cheaped out” on the JCW is not a conclusion I think anyone can jump to.
So the way I read this, they decided against LSD for safety not performance. I think most people “rumbling” about the lack of LSD have been coming from the performance perspective. So the rumbling will continue.
“What they found with LSD on the JCW MINI was that it caused the car to want to pull the steering back to center and go straight under hard acceleration – not a desirable, or safe, effect in a lot of situations.”
Wow, amazing finding! Seriously, substituting “a FWD car” for “the JCW MINI” above would be just as accurate. Even in a RWD car, LSD is an anti-safety feature and requires more driver skill to control under acceleration when cornering, but driven well, you WILL come out of the corner faster.
<blockquote>So the way I read this, they decided against LSD for safety not performance.</blockquote>
I am sure that safety was a consideration but I believe handling is the main reason why this decision was made. One has to remember that MINIs are street cars and not built to be dedicated track cars save the Challenge car. They are designed to be driven daily on public streets by many different type of drivers. A balance of safety and handling has to be a consideration in any production vehicle. You are fooling yourself if you believe otherwise.
Be it for safety or for performance reasons – it seems to work pretty well – personally, I can’t wait to give it a try!
Are there different engagement modes of the ELSD, like track mode, street mode, slippery roads mode?
Sounds like they made the best with what they had to work with. They used an easy for them electronic solution to the more difficult solution of re-engineering the suspension and steering geometries to get rid of the torque steer, something that may not be practical at any cost with the current platform. Hopefully they can design the next generation to be a bit better in that area but with electronics getting better and space more valuable I imagine it could be a difficult choice.
I’m all for weight savings – lighter wheels, no sunroof, the redesigned rear suspension using aluminum, etc. – these are all good things.
Anyone know the weight of a mechanical LSD? Can’t imagine it can be all that much, and the performance gain from the potential added traction should outweigh (pun intended?) having a few extra pounds over the front axle.
Maybe the ELSD is a dumbed down version of the ELSD found on F1 cars? If so there must be some way to eventually tweak in the future…with your bluetooth enabled PDA/phone..:)
Very interesting insight into MINI’s reasoning on not making a mechanical LSD available for the JCW. Eagerly awaiting the video that was promised, any idea when we can expect it lads?
Look for the video with a follow up later this week.
@ SteveS re: Mazdaspeed 3
What Mazda does do, though, is reduce power to the engine on release in 1st and 2nd gear in order to counter this. MINI employing the ELSD eliminates the need to reduce engine power to counter torque steer issues.
If the ELSD works well, the only downside is brake wear – we won’t know about that till the car’s been out for a year or more …
Hmmm – the proof will be in the driving.
I find it a little odd though that while my car (Stage 1 JCW kit R56 S) drives fine with a mechanical diff, a car with less than 4% more torque than mine requires an ELSD.
By the way, there are a number if other FWD cars with significantly more torque than the MINI and a mechanical LSD that do just fine – The Renault Megane R26 for example.
This whole thing makes me wonder if, like the on board computer everyone will have it and with the correct payment it can be turned on with a mouse click.
Happy Motoring,
Jack
Some comments…..
We will see more of these systems over time, not less. All the parts are already on the car, just waiting for good enough software package to control them. The ABS/DSC system had all the pumps and the like for automatic torque distribution systems. Just throw some dev costs into making it work and bingo! More code, but no more parts.
As far as going straight with a limited slip, it does happen if you overpower the turn exit. Same thing happens to me with a Quaiffe on my R53.
I’m thinkin that this will play out just like the ATC/DSC stuff. The concepts are fine, but it will remain to be seen if the software nails the functional demands of enthusiasts.
Time will tell….
Matt
I waited by the MC JCW before deciding to buy the MCS.
As a matter of price, I eventually decided by the MCS.
I want to buy the MCS with the mechanical differential (LSD) optional, with ESP (DSC) – despite having traction control (ASC + T) of origin – and sport suspension, but with the OEM (16″) rims (195/55 R16 tyres) – because of the comfort and to prevent the steering torque in excess.
But now I’m confused about the best handling that I can get with the optional mechanical differential (LSD).
My thought was that the EDLC is more an upgrade of traction control than a real difference, because:
1º It provides no more torque to the wheels that need it most, only lock the wheel whose torque is excessive.
2º Switched on only when the DSC is switched off.
Therefore, I have concluded that I can have more fun for less money with the MCS with LSD than with MC JCW (with the same security with the choice of optional DSC – but unfortunately without the DTC program).
I am wrong?
Best regards from Portugal!