I have a rear wheel drive 2013 Mercedes-Benz A 45 AMG built to a PI of A661 and am trying to dial out the aggressive oversteer. I know how smooth I am on the accelerator is probably the biggest factor but if reducing the diff lock on acceleration helps, is there a trade off? Do I need to adjust anything else that reducing diff lock on acceleration affects?? I have reduced it to 40% which does help.

Thank you.

40% accel is quite low - usually RWD cars require around 70% or more accel. You probably losing speed while cornering which such low accel. What’s your decel?

Instead of lowering accel I would look into reducing bump or rear springs.


Look at it this way:

With a completely open differential, as soon as one driven wheel has less traction than the other, all the power goes directly to that wheel and you get a “one tire fire” and no power to accelerate with. With a completely locked differential, all of the power is going to both tires equally, so either both tires have traction or both tires are spinning.

Both extremes can cause handling issues.

A limited slip allows some difference in power distribution between tires, allowing you to balance power distribution and cornering grip while under power. How strong it needs to be depends on a lot of factors; tires, power, gearing, the track, your driving habits, etc. I usually start with a really low setting (Accel = 20) and increase it in increments of 5 until I can keep the inside tire from spinning on aggressive corner exit. You’ll have to drive your car for a bit and pay attention to how behaves under heavy throttle. If you’re spinning the inside tire on corner exit (turn on the tire grip telemetry and/or watch your replays), raise the Accel. If you’re suddenly breaking traction with both rear tires mid-corner, try reducing it some.

One more piece of advice: Try using a wet track to adjust your limited slip. I’ve found it makes the difference between “spin one wheel” and “spin both wheels” a lot easier to detect.

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Notice that a sports-diff is typically set to ca.50-55%. That is a wery good place to start. As soon as the diff-setting gets higher the car will tend to understeer.

You wont need 100% of the power while youre still in a turn, but this is where tirewith & tirequality (+forcedown) comes in to help us.