[JANNETTYRACING]

From what I am learning, the computer applies torque to the opposite axle of the direction your turning to help you go around the corner.

Mine is applying all the torque to the right clutch or the left clutch is not responding to the command and that is what is driving my car left causing what I call torque steer.

Ted.

[ninetres]

Originally Posted by JANNETTYRACING

Update, back to the dealer yesterday afternoon, Tech hooked up a the MDI, and Service manager brought out some tech bulletins.

They wanted to verify the Steering sensor calibration as someone mentioned above, and it was fine, they did a calibration anyway.

NOTE to guys complaining about the Trammelling as GM calls it, or Wiggle on acceleration, there is a reprogramming update released March of 2018 to address this.

They applied this update to my RDCCM, Rear Differential Clutch Control Module.

They also found a code for a Clutch control command permanently failed.
I may have worded this incorrectly but that is how I remember it.

So They are trying to get an OK to order a new Differential.

Waiting

Anyone have the TSB number?

[travislambert]

Originally Posted by JANNETTYRACING

Not a recall it is a bulletin, so they only apply the reprogram if someone complains of this wiggle thing.

I suspect is applies more even torque to the right and left clutches with a wider window of Steering angle.

Just my Opinion no facts.

Ted.

The eLSD works with a single clutch on the passenger side of the diff.

I'm wondering how a software update could even work to prevent wiggle unless it simply relaxes the clutch a little to allow more slip.

This is an interesting problem, and I'm very much looking forward to the solution.

Thanks for keeping us in the loop!

[travislambert]

Originally Posted by JANNETTYRACING

From what I am learning, the computer applies torque to the opposite axle of the direction your turning to help you go around the corner.

Mine is applying all the torque to the right clutch or the left clutch is not responding to the command and that is what is driving my car left causing what I call torque steer.

Ted.

The eLSD doesn't vector torque. It's simply an electronically controlled limited-slip differential... just like regular limited slip differentials of the past, but with a software controlled clutch. All of the magic happens in the software which attempts to choose the perfect amount of slip for a given condition.

[JANNETTYRACING]

Originally Posted by ninetres

Anyone have the TSB number?

No sir.

[Mr. Wyndham]

Originally Posted by travislambert

The eLSD doesn't vector torque. It's simply an electronically controlled limited-slip differential... just like regular limited slip differentials of the past, but with a software controlled clutch. All of the magic happens in the software which attempts to choose the perfect amount of slip for a given condition.

In a way, it will vector, though...when going through a turn, most of the torque will be applied to one side of the car or another (depending on how the direction you're turning), like an open diff. I believe it remains open, or mostly open most of the time, to achieve very low pre-load.....not sure of that, though.

So, by specifying the percentage of clutch engagement, at a specific time in the turn & throttle input, they can change the torque bias from the "natural" wheel to the opposite wheel (which just so happens to be turning at a different rate, and has more mechanical advantage at that moment).

I would LOVE to see the computational models of the physics and acceleration vectors behind the system in different situations.

[2SSRS@Gen5diy]

Ted not trying to step on your thread, but i hope this helps, its what i found on SI and added it to help.

The software is for the Rear Differential Clutch Control Module (RDCCM) as far as we can find the new updated Version 2, was Released November 20, 2017 and on
March 01, 2018 – was Added to Corvette model.

[Mr. Wyndham]

Originally Posted by 2SSRS@Gen5diy

Ted not trying to step on your thread, but i hope this helps, its what i found on SI and added it to help.

The software is for the Rear Differential Clutch Control Module (RDCCM) as far as we can find the new updated Version 2, was Released November 20, 2017 and on
March 01, 2018 – was Added to Corvette model.

[travislambert]

Originally Posted by Mr. Wyndham

In a way, it will vector, though...when going through a turn, most of the torque will be applied to one side of the car or another (depending on how the direction you're turning), like an open diff. I believe it remains open, or mostly open most of the time, to achieve very low pre-load.....not sure of that, though.

So, by specifying the percentage of clutch engagement, at a specific time in the turn & throttle input, they can change the torque bias from the "natural" wheel to the opposite wheel (which just so happens to be turning at a different rate, and has more mechanical advantage at that moment).

I would LOVE to see the computational models of the physics and acceleration vectors behind the system in different situations.

I certainly see your point about the vectoring, but I was mainly trying to help explain that there are not multiple clutches actively vectoring torque to the wheel of the eLSD computer's choosing. The clutch can work to equalize the torque from the natural wheel to the opposite wheel, but I don't believe the eLSD alone could ever force more than 50% of the torque to the unnatural wheel (i.e, without activating the rear brakes).

The part I'm struggling with is under what scenario could any level of eLSD clutch engagement cause the car to pull to one side while the driver is trying to go straight? I just can't wrap my head around how that could happen.

[Mr. Wyndham]

Originally Posted by travislambert

I certainly see your point about the vectoring, but I was mainly trying to help explain that there are not multiple clutches actively vectoring torque to the wheel of the eLSD computer's choosing. The clutches can work to equalize the torque from the natural wheel to the opposite wheel, but I don't believe the eLSD alone could ever force more than 50% of the torque to the unnatural wheel (i.e, without activating the rear brakes).

The part I'm struggling with is under what scenario could any level of eLSD clutch engagement cause the car to pull to one side while the driver is trying to go straight? I just can't wrap my head around how that could happen.

Right. Luckily!! BMW's version of this system uses an open diff with brake modulation, and I hear it roasts the rear brakes during track use.

Anyways....since the conditions appear to be WOT, and it turns to the left...my guess is that when sudden throttle is applied, the clutch doesn't engage quickly, or strongly enough to keep the wheels equal, and the left wheel loses traction first before coming back under control. That would cause the right wheel to stick and "push" the car to the left. Just a guess.

[JANNETTYRACING]

Originally Posted by 2SSRS@Gen5diy

Ted not trying to step on your thread, but i hope this helps, its what i found on SI and added it to help.

The software is for the Rear Differential Clutch Control Module (RDCCM) as far as we can find the new updated Version 2, was Released November 20, 2017 and on
March 01, 2018 – was Added to Corvette model.

I appreciate you chiming in I did not read the bulletin the manager just showed me the date on it and told me what it was to address, called Trammelling (spelling)

[JANNETTYRACING]

Originally Posted by Mr. Wyndham

Right. Luckily!! BMW's version of this system uses an open diff with brake modulation, and I hear it roasts the rear brakes during track use.

Anyways....since the conditions appear to be WOT, and it turns to the left...my guess is that when sudden throttle is applied, the clutch doesn't engage quickly, or strongly enough to keep the wheels equal, and the left wheel loses traction first before coming back under control. That would cause the right wheel to stick and "push" the car to the left. Just a guess.

it is not Just WOT it is any application of power pushes the car left like a car with a spool and a broken left axle.

[Mr. Wyndham]

Originally Posted by JANNETTYRACING

it is not Just WOT it is any application of power pushes the car left like a car with a spool and a broken left axle.

holy crap...didn't realize that.

Did the recalibration fix it?

[JANNETTYRACING]

Originally Posted by Mr. Wyndham

holy crap...didn't realize that.

Did the recalibration fix it?

NO change what so ever.

They called today they want my car at the dealer so GM Tech support can link in to my car and look things over.

Personally I don't think it is computer/electrical related, I think it is mechanical and I need a new diff.

I don't think the diff is responding to commands.