Is torque steer normal during a Ludicrous Launch?

[DCEV]

Are the tire pressures correct?
When it torques, does it always pull the same direction?

It's not one side per se. It's more of a "slippery" feeling where I'm making minute adjustments to keep the car straight. I need to do some more testing though. Perhaps this just has to do with me holding the steering wheel firm and steady a certain way.

Good point about checking the tire pressure.

Are both of your front tires similar amount of wear as well as identical brand and size?

Brand new Michelin Pilot Sport A/S 3+ tires. Barely 1,000 miles on them and they were installed on brand new 19" wheels at the Tesla SC two months ago.

 

[Danc0926]

Could anyone who has experience with a P100DL share your thoughts about what you have observed with torque steer?

I've yet to do a full Ludicrous launch for more than 2-3 seconds, as I stay around the posted speed limit but I've noticed torque steer during these launches and wanted to see if this is normal.

One of the first times I tried a Ludicrous launch, I sprained one of my fingers(!) based on how I was holding the steering wheel in my effort to hold the car steady. Since then, I make sure to have a form grip on the steering wheel

Does anyone know the actual horsepower generated at peak acceleration? I've seen widely different numbers online.

The car's alignment was checked when I swapped the wheels to 19" whens so the wheels and tires (Michelin Pilot Sport A/S 3 PLUS) have barely 1,000 miles.

I'm also learning the best way to speed up to the speed of traffic, as quickly as possible, after turning from another street... If anyone has any tips or suggestions for Ludicrous launches or turning onto a street (90 degrees) with maximum acceleration in a safe way, please share them.

As I get to know the car, I want to handle the power as safely as possible.

Took mine in for service for
This problem complete alignment was done however I was told to expect this torque steer behavior and that it would be more prevalent in sport steer mode. Bottom line expect to hold some control of the steering wheel

 

[sorka]

Took mine in for service for
This problem complete alignment was done however I was told to expect this torque steer behavior and that it would be more prevalent in sport steer mode. Bottom line expect to hold some control of the steering wheel

You were told wrong. It is absolutely not normal and since my post earlier in this thread, I've test driven a brand new P100D at the Sunnyvale store and it did not exhibit any torque steer at all. You could mash the throttle from a stop with nothing but a pinky finger holding the wheel.

 

[Danc0926]

You were told wrong. It is absolutely not normal and since my post earlier in this thread, I've test driven a brand new P100D at the Sunnyvale store and it did not exhibit any torque steer at all. You could mash the throttle from a stop with nothing but a pinky finger holding the wheel.

I will try the pinky finger test. I know it requires some resistance on the wheel I wouldn’t describe it as a lot however no resistance results in a left
Turn

 

[sorka]

I will try the pinky finger test. I know it requires some resistance on the wheel I wouldn’t describe it as a lot however no resistance results in a left
Turn

The important thing is that on a smooth flat road that doesn't crown where you don't lose traction, the steering wheel shouldn't try and pull left or right while accelerating at WOT.

And let's be clear. I'm not telling you to go drive with a pinky. I'm saying I can do that and my car won't pull left or right under those conditions. I can't advise you do anything other than drive with both hands on the wheel firmly...of course.

 

[Danc0926]

The important thing is that on a smooth flat road that doesn't crown where you don't lose traction, the steering wheel shouldn't try and pull left or right while accelerating at WOT.

And let's be clear. I'm not telling you to go drive with a pinky. I'm saying I can do that and my car won't pull left or right under those conditions. I can't advise you do anything other than drive with both hands on the wheel firmly...of course.

Lol experienced race car driver here we adjust to make race cars do these sort of things I just didn’t think it was normal for this car to do it. I am kinda not believing the service center that it’s normal. The pinky will overcome the turn but I’m with you I don’t think it should be doing it.

 

[AWDtsla]

Took mine in for service for
This problem complete alignment was done however I was told to expect this torque steer behavior and that it would be more prevalent in sport steer mode. Bottom line expect to hold some control of the steering wheel

Lol experienced race car driver here we adjust to make race cars do these sort of things I just didn’t think it was normal for this car to do it. I am kinda not believing the service center that it’s normal. The pinky will overcome the turn but I’m with you I don’t think it should be doing it.

How exactly are you defining torque steer? You want to do hands free ludicrous launches on roads that are crowned?

 

[Danc0926]

How exactly are you defining torque steer? You want to do hands free ludicrous launches on roads that are crowned?

No not really wanting to do anything hands free except maybe autopilot.

The car steers left under heavy acceleration either from stopped or while driving at a constant speed and then acceleration heavy. It will do this on any surface unless resistance is applied to the wheel not much resistance is required to keep it in check. It is not a drift it turns the steering wheel.

 

[TIppy]

I tried this with my recently delivered p100dl raven and did get some mild torque steer. If I accelerate in a straight line there is no torque steer. However, if I'm merging from a holding lane, when I turn the wheel to the right to align my path with the lane I'm merging into, the car wants to continue turning to the right. I have to supply mild torque to straighten out the steering wheel. I can't see it causing any discomfort no matter how I was holding the wheel. I have done this merge many times in my previous p90dl and never noticed torque steer.

I am turning the wheel very slightly to align my path. Perhaps if you have just taken a right turn and accelerate before completely straightening the wheel, you would get more torque steer depending on how far off center the wheel was.

 

[TIppy]

Apparently, torque steer can be caused by friction in the differential and is compensated by placement of the cv joints relative to the steering axis. Part of the improvements listed for raven was improved gear shapes in the differential to make them more efficient. If they didn't adjust the steering geometry for the reduced friction, this may account for the new torque steer.

 

[AWDtsla]

Apparently, torque steer can be caused by friction in the differential and is compensated by placement of the cv joints relative to the steering axis. Part of the improvements listed for raven was improved gear shapes in the differential to make them more efficient. If they didn't adjust the steering geometry for the reduced friction, this may account for the new torque steer.

I don't see how this makes any sense at all. Friction in the diff doesn't matter. I haven't looked under my car yet, but usually the problem is that the halfshafts are different sizes. The difference in mass will cause more torque to go to one side. This can be fixed by attaching a weight to the shorter half shaft. Either this or your alignment is f***** and your caster angles are all wrong.

Thankfully this is one problem I'm not having in my raven...

 

[TIppy]

I don't see how this makes any sense at all. Friction in the diff doesn't matter. I haven't looked under my car yet, but usually the problem is that the halfshafts are different sizes. The difference in mass will cause more torque to go to one side. This can be fixed by attaching a weight to the shorter half shaft. Either this or your alignment is f***** and your caster angles are all wrong.

Thankfully this is one problem I'm not having in my raven...

From wikipedia

Ways to reduce the effect of torque steer
Equalise the torque better between the driveshafts by using a low friction differential. The torque difference is zero if the differential is frictionless, and limited slip differentials, intended to increase power transfer, actually make torque steer much worse. For this reason, limited slip differentials by automobile transmission manufacturers like Quaife, Torsen, TrueTrac, Gold Trac have not been much used until recently, and require other measures to be implemented, such as careful positioning of suspension pivot points and driveshaft CV joints, in order to keep the resultant torque steer to a manageable amount. Limited slip differentials do not improve cornering, or steering feel, however they will improve power transfer in situations where one wheel experiences limited adhesion, and so may improve overall performance.

 

[AWDtsla]

From wikipedia

Ways to reduce the effect of torque steer
Equalise the torque better between the driveshafts by using a low friction differential. The torque difference is zero if the differential is frictionless, and limited slip differentials, intended to increase power transfer, actually make torque steer much worse. For this reason, limited slip differentials by automobile transmission manufacturers like Quaife, Torsen, TrueTrac, Gold Trac have not been much used until recently, and require other measures to be implemented, such as careful positioning of suspension pivot points and driveshaft CV joints, in order to keep the resultant torque steer to a manageable amount. Limited slip differentials do not improve cornering, or steering feel, however they will improve power transfer in situations where one wheel experiences limited adhesion, and so may improve overall performance.

That's so full of wrong it's painful. Tesla doesn't use LSD's, regardless. But let's say it did, and the front differential could lock up entirely - which is exactly the opposite of low friction, it is a friction coefficient of infinity - torque steer as a result of differential torque would be impossible. The car would only want to do one thing - go straight. Very straight.

 

[TIppy]

That's so full of wrong it's painful. Tesla doesn't use LSD's, regardless. But let's say it did, and the front differential could lock up entirely - which is exactly the opposite of low friction, it is a friction coefficient of infinity - torque steer as a result of differential torque would be impossible. The car would only want to do one thing - go straight. Very straight.

You are thinking of what happens with a rear ls or lock up differential. It causes a torque vector opposite to the turn, but it doesn't get transferred to the steering wheel through the rack.

I think what the wiki is talking about is torque around the steering axis (king pin) that causes a torque on the steering wheel and also turns the car. Normally the torques about the king pins cause forces that are equal and opposite on respective ends of the rack and cancel each other. If there is an imbalance, the rack gets pulled to one side causing torque on the steering wheel. If the differential is "perfect" it doesn't allow different torque on the left and right half shafts, so there can't be any torque steer passed on to the steering wheel. Any friction in the differential can allow a different torque on the left and right sides of the differential.

The steering wheel can certainly overcome the torque vector caused by a solid rear axle.

 

[TIppy]

@DCEV may have experienced what happened to me when I first got my p90dl. When you come out of a turn, you develop a feel for when and how much power you can bring in as you are straightening the wheel. But the speed comes up so quickly on these cars that you can go past straight ahead if the wheel is turned even a little. Your reaction is to jerk the wheel in the opposite direction. If you are in sport mode, this can take considerable force. It just takes a little time to re-calbrate for turns.

 

[DCEV]

@DCEV may have experienced what happened to me when I first got my p90dl. When you come out of a turn, you develop a feel for when and how much power you can bring in as you are straightening the wheel. But the speed comes up so quickly on these cars that you can go past straight ahead if the wheel is turned even a little. Your reaction is to jerk the wheel in the opposite direction. If you are in sport mode, this can take considerable force. It just takes a little time to re-calbrate for turns.

This is exactly it! I've had my car for about 2 weeks and wasn't ready for the intensity of power, soon after turning. My sprained finger took almost 2 months to heal!

I had turned right from a smaller street and I thought I had straightened the car before accelerating but any little deviation in steering angle makes a huge difference when you go Ludicrous. This particular spot is tricky because people drive 45+ mph and with heavy traffic so I like to accelerate as quickly as possible so I'm going the speed of traffic. Now after I turn right, I give it an extra second and make sure I'm going absolutely straight and steady before going anywhere near Ludicrous. Plus I hold the steering wheel properly.

Good thing, as a rule, I kept the car in Sport Mode for the entirety of the first week, as it takes some getting used to. In a good way...

 

[AWDtsla]

I've been trying to detect torque steer all week in my Raven. Many hands-free launches 0-40, 0-60, and full throttle from 50+mph. Can't find any.

 

[TIppy]

I just installed 2019.28.3.1, and I no longer have torque steer.

 

[Dithermaster]

I've been trying to detect torque steer all week in my Raven. Many hands-free launches 0-40, 0-60, and full throttle from 50+mph. Can't find any.

Similar with me; none detected (but not as many tests as you).

 

[SSonnentag]

Even the non-performance models have what you might be calling torque steering. The steering gets really stiff due to what I think is the car's attempt to keep the car headed straight. It's traction control fighting your steering input. My S 100D does this, so I'm sure the P models are worse. I wouldn't call it torque steer though, more like traction control keeping you on the road.

Side story: I turned off traction control in my Camaro SS once while driving in the rain. Oops! Things get out of hand really quickly.