I have a technical question I was wondering if anyone had the answer to. It is regarding the brake steer and lack of a limited slip differential.

I understand how the bs can work on the way into a corner, braking the inside rear wheel a touch to assist turn in is logical enough. What is less clear is on the way out when you are accelerating, my understanding is the process is used on the way out also ( as confirmed by mcl London just now ) its seems counterproductive to use brakes to aid acceleration but I can let that slide.

The confusion is , now that you can turn traction control etc completely off, when you have turned everything off is the brake steer still doing the job of a limited slip differential on the way out or are you in effect now driving a car with an open differential? Mcl London is looking into it for me, I thought it may be interesting to you all and someone may actually have the answer.

One more thing I presume there is a form of torque vectoring working in combination to the active roll bars and brake steer, can anyone confirm this?

Are owners getting excessive brake wear from these systems?

 

Chris Harris is surely the person to ask about this? Seeing as he's the only person I've seen successfully hang it (well, him and Chris Goodwin)

 

Because you race car.

 

I got the reply from mclaren . Everything can now be turned off , brake steer stays on only to prevent under steer not as a stability control measure .
Interesting no one here is interested or knows about their cars at the limit ...

 

Most Americans arent adventurous! LOL

 

Cannot be everywhere all the time!
As you now know the more dedicated sites usually can help,but there has been very little track time so-far and owners are still finding answers themselves

 

Understood
The amazing thing is they go so far out of the way to answer a question , mclaren truly offer fantastic service . Remember I'm not even an owner .

 

I know what you mean,the factory have been talking to me for over 3 years now,i thought this would be just untill the dealerships were chosen and up and running.But i still get rung by the factory to see how things are going,they do make you feel like you are part of the process.

 

For the record....

Brake steer is used to control the open diff and reduce under-steer. It is indeed working with ESC off. If it wasnt then the inside wheel would spin on exit and you would have no acceleration out of the turns, no fun slides and too much understeer. Yes, I know from experience.

From the manual.

Brake-steer
Brake steer offers the benefits of a torque
vectoring differential, but is integrated into the
braking system reducing weight and providing
excellent speed of response.
If the system detects that the car is starting to
understeer through a corner, the inside rear
brake is gently applied. This helps to increase
the yaw rate of the car, making the car feel
more resistant to understeer. The lateral ‘g’
force is also increased giving better handling
characteristics.
If the driver uses too much throttle exiting a
corner, the inside rear wheel increases speed,
which without brake steer could cause the car
to become unstable. In this situation, brake
steer will again gently apply the brake on the
inside rear wheel, thereby restoring traction
and stability.