High speed braking instability - ABS/ESP bug?

[22522]

If you can get them to make whale tail, or even dolphin tail, just for you, please share.

I don't know if they would look at tire pressure as a function of velocity to see if it were installed?

Don't know if they have sensors on the suspension or can infer from the ultrasonics or camera

 

[OPRCE]

finally got the rights to post this on a German Tesla Forum
Instabilität beim Bremsen aus >200kmh, ESP/ABS Problem? • TFF Forum - Tesla Fahrer & Freunde

General consensus over at TFF after 19 responses to @electrifier’s post seems to be that M3 gets distinctly light in the tail at speed ~200kph (effect independent of surface but possibly worse in cold weather and/or with hot tires), with one further report of unsettling “stamping” of ABS/ESP as weight distributes to front under moderate to heavy braking in curve from 235kph.

Maybe ~150kg of ballast in the trunk, equivalent to the downforce a large spoiler, would be a hot-fix?

 

[22522]

General consensus over at TFF after 19 responses to @electrifier’s post seems to be that M3 gets distinctly light in the tail at speed ~200kph (effect independent of surface but possibly worse in cold weather and/or with hot tires), with one further report of unsettling “stamping” of ABS/ESP as weight distributes to front under moderate to heavy braking in curve from 235kph.

Maybe ~150kg of ballast in the trunk, equivalent to the downforce a large spoiler, would be a hot-fix?

In the US, if a pick up truck, it would have been a couple of bails of hay, but they don't bail hay any more - they roll it.

Seems like a good way to use that deep hole in the trunk. There is enough space that you wouldn't even notice.

 

[OPRCE]

In the US, if a pick up truck, it would have been a couple of bails of hay, but they don't bail hay any more - they roll it.

Seems like a good way to use that deep hole in the trunk. There is enough space that you wouldn't even notice.

Yep, I'm thinking about 6x 25kg sacks of gravel could disappear in there nicely and the wife would never be none the wiser!

 

[paranoidroid]

General consensus over at TFF after 19 responses to @electrifier’s post seems to be that M3 gets distinctly light in the tail at speed ~200kph (effect independent of surface but possibly worse in cold weather and/or with hot tires), with one further report of unsettling “stamping” of ABS/ESP as weight distributes to front under moderate to heavy braking in curve from 235kph.

Maybe ~150kg of ballast in the trunk, equivalent to the downforce a large spoiler, would be a hot-fix?

This was what my guess of the issue is. The car does get a bit light at high speed. Maybe the spoiler from the performance car would help (or aftermarket).

Unplugged Performance recently tested the factory spoiler:

Independent Aerodynamic Study of Tesla Model 3 by Unplugged Performance

"Overview: The optional factory Tesla rear spoiler provides sleek looks with optimized airflow characteristics to enhance efficiency as well as high speed stability.

Result: As expected, this product is not just for looks, it indeed performs improvements in high-speed stability and drag reduction. The vehicle’s total drag was reduced by 2.3% and the rear downforce was increased over baseline by 34.7%. This reduced the total drag coefficient (Cd) by 0.005."

 

[Dangerous Fish]

Hold on, what is making some of you think the Model 3 gets light at speed?

Aero on F1 and Indy cars is one thing, but it rarely makes a big enough difference on an 1800Kg road car to be perceptible. There would have to be a very big imbalance in the first place and let's not forget the COG of a Tesla is very low in the first place.

Adding weight into the trunk could actually make the problem worse as you are then altering the weight distribution and putting extra load on the rear tyres.

Let's see what Tesla says about this (if anything) before anyone does anything drastic to change the existing setup.

Or just get Elon to start making a batch of RHD cars so can I get mine and I'll happily try and reproduce the problem!

 

[golfpilot]

I am not in Germany where I can legally let the car go, but there are a couple roads on an occasional commute where my car can get to (accidentally?) to 120-130 mph followed by a turn that requires braking. Braking is poor at best. I believe this is due to the fact the brakes aren't very big compared to the weight of our cars. I have considered upgrading the brakes but because I have aero rims the options are rather slim. The stock brakes are probably not designed for braking at higher speeds. I wouldn't recommend stock brakes for anyone driving over 80mph on a regular basis. I can't speak for the performance model brakes, but I do know that Mountain Pass Performance makes a big brake kit that works with sport wheels but not aeros. Those would be a really good idea for the autobahn

 

[Dangerous Fish]

I am not in Germany where I can legally let the car go, but there are a couple roads on an occasional commute where my car can get to (accidentally?) to 120-130 mph followed by a turn that requires braking. Braking is poor at best. I believe this is due to the fact the brakes aren't very big compared to the weight of our cars. I have considered upgrading the brakes but because I have aero rims the options are rather slim. The stock brakes are probably not designed for braking at higher speeds. I wouldn't recommend stock brakes for anyone driving over 80mph on a regular basis. I can't speak for the performance model brakes, but I do know that Mountain Pass Performance makes a big brake kit that works with sport wheels but not aeros. Those would be a really good idea for the autobahn

I drove a LR RWD for 3 days in the U.S. down canyon roads and at speed on the freeways and I never felt the brakes were inadequate.

Repeated stops from 130 mph with heat soak in the pads and rotors might be different, but the OP here doesn't indicate anything other than the brakes being at normal temperature when they experienced the issue. The pads and rotors on the RWD are actually quite large compared to other cars of that size, so I'm sure they've taken the extra weight of the car into consideration when speccing them.

No, I don't believe there is anything fundamentally wrong with the brakes on the sport or non-sport Model 3 for normal road use, including use in Europe. It is very unusual to have to repeatedly brake hard from high speeds on European roads, including Autobahns. If a driver is doing that, they are driving like an idiot or are just a really bad driver, incapable of looking and planning ahead. Particularly as they have regen to help slow the car.

 

[22522]

Was looking at the trunk. They are greeting as much of a spoiler out or the single sheet of steel as I can recall.

 

[golfpilot]

I drove a LR RWD for 3 days in the U.S. down canyon roads and at speed on the freeways and I never felt the brakes were inadequate.

Repeated stops from 130 mph with heat soak in the pads and rotors might be different, but the OP here doesn't indicate anything other than the brakes being at normal temperature when they experienced the issue. The pads and rotors on the RWD are actually quite large compared to other cars of that size, so I'm sure they've taken the extra weight of the car into consideration when speccing them.

No, I don't believe there is anything fundamentally wrong with the brakes on the sport or non-sport Model 3 for normal road use, including use in Europe. It is very unusual to have to repeatedly brake hard from high speeds on European roads, including Autobahns. If a driver is doing that, they are driving like an idiot or are just a really bad driver, incapable of looking and planning ahead. Particularly as they have regen to help slow the car.

Your right. Normally people aren't going to need the bigger brakes, especially with the way regen works. What is on there is adequate. There is nothing wrong with the OEM brakes. But bigger rotors and upgrades brake pads would be welcomed on windy roads with occasional high speed sections or just anywhere you want better braking power. At high speeds the car acts just like the OP described.

My recommendation to upgrade the brakes comes from 19k miles with my Dual Motor 3. There is a reason the Performance Model has better brakes and I think the Dual Motor Variant would benefit from a similar upgrade as there is very little difference between the two cars at higher speeds. The OPs braking situation sounds normal to me for the stock setup. The RWD version doesn't have any regen up front when braking, the driving experience with the RWD version is different than the AWD (good or bad is at the drivers discretion) but you can't make hardware evaluations for the Dual Motor off of experience with the RWD variant.

 

[Dangerous Fish]

The RWD version doesn't have any regen up front when braking, the driving experience with the RWD version is different than the AWD (good or bad is at the drivers discretion) but you can't make hardware evaluations for the Dual Motor off of experience with the RWD variant.

Good point. It would be interesting to hear from any drivers who used a non-performance 3 at one of the Tesla Corsa events to see if they had any braking issues.

 

[golfpilot]

Good point. It would be interesting to hear from any drivers who used a non-performance 3 at one of the Tesla Corsa events to see if they had any braking issues.

Mountain Pass Performance literally makes their parts to fix the issues the OP is having. They take the car to the track to test. They have even found the Performance brakes to be inadequate for this type of driving.

 

[Dangerous Fish]

Mountain Pass Performance literally makes their parts to fix the issues the OP is having. They take the car to the track to test. They have even found the Performance brakes to be inadequate for this type of driving.

Yes, I know about the MPP and Unplugged upgrades, but watch Randy Probst in a stock Model 3 hustling it around the track. Never complained the brakes were bad.

 

[paranoidroid]

Stock brakes are fine for street. Stopping power is not brake limited but tire limited. You are only brake limited when the brakes get too hot from heat soak from repeated high speed braking over and over again. This generally only occurs on the track.

 

[TSLA Pilot]

Hold on, what is making some of you think the Model 3 gets light at speed?

Aero on F1 and Indy cars is one thing, but it rarely makes a big enough difference on an 1800Kg road car to be perceptible. There would have to be a very big imbalance in the first place and let's not forget the COG of a Tesla is very low in the first place.

Adding weight into the trunk could actually make the problem worse as you are then altering the weight distribution and putting extra load on the rear tyres.

Let's see what Tesla says about this (if anything) before anyone does anything drastic to change the existing setup.

Or just get Elon to start making a batch of RHD cars so can I get mine and I'll happily try and reproduce the problem!

At Autobahn speeds aerodynamic forces are extremely significant and can induce a variety of problems. This is why any very high speed issues are likely to have been unnoticed until sale of the first Model 3's in Germany . . . .

 

[TSLA Pilot]

I am not in Germany where I can legally let the car go, but there are a couple roads on an occasional commute where my car can get to (accidentally?) to 120-130 mph followed by a turn that requires braking. Braking is poor at best. I believe this is due to the fact the brakes aren't very big compared to the weight of our cars. I have considered upgrading the brakes but because I have aero rims the options are rather slim. The stock brakes are probably not designed for braking at higher speeds. I wouldn't recommend stock brakes for anyone driving over 80mph on a regular basis. I can't speak for the performance model brakes, but I do know that Mountain Pass Performance makes a big brake kit that works with sport wheels but not aeros. Those would be a really good idea for the autobahn

Your issue has NOTHING to do with the Model 3's brakes. Nothing.

You have a major tire/wheel problem that is 100% self-induced: You are at driving at extremely high speeds on the base, 18" Aero wheels, and then trying to perform high-performance driving maneuvers at triple-digit speeds?

This is remarkably unwise, on so many levels. The Top 2 are:

1. The 18" base wheel contact patch, all-season tires and wheels are optimized for range/efficiency, not grip at triple-digit speeds.

2. Your current tires are not the Summer, Performance 19" or 20" tires and wheels that are required for such high speeds.

If you're still alive, you need to stop trying to join the Darwin Club, yesterday . . . .

 

[SammichLover]

In the US, if a pick up truck, it would have been a couple of bails of hay, but they don't bail hay any more - they roll it.

A having a full round bale is the back is not unheard of in northern prairies in the winter. A couple of square balls would only be about 45kg, not nearly enough plus they're prone to shifting. The round bale stays put....until you run into something, then it'll roll over the cab. But out on the prairies there's not much to run into, by far the highest vehicle risk is rolling over in a ditch, because you lost control, fell asleep, or were drunk. The bale helps with the first one at least.

Have seen 4 or so 20kg sacks of gravel used, with the bonus it could be used for traction if the need arose.

 

[SammichLover]

Your issue has NOTHING to do with the Model 3's brakes. Nothing.

You have a major tire/wheel problem that is 100% self-induced: You are at driving at extremely high speeds on the base, 18" Aero wheels, and then trying to perform high-performance driving maneuvers at triple-digit speeds?

This is remarkably unwise, on so many levels. The Top 2 are:

1. The 18" base wheel contact patch, all-season tires and wheels are optimized for range/efficiency, not grip at triple-digit speeds.

2. Your current tires are not the Summer, Performance 19" or 20" tires and wheels that are required for such high speeds.

If you're still alive, you need to stop trying to join the Darwin Club, yesterday . . . .

Yeah, the MXM4 are W rated so nominally good to 168mph, they aren't in anyway outright bad tires, but they're A/S and as you correctly point out Tesla's stock inflation regime is geared towards range efficiency, and the tires were in part selected for durability as they are 500 tread wear so not nearly as "sticky" as the Pilot Sport 4S that are used on the 20" wheels.

 

[Dangerous Fish]

At Autobahn speeds aerodynamic forces are extremely significant and can induce a variety of problems. This is why any very high speed issues are likely to have been unnoticed until sale of the first Model 3's in Germany . . . .

I'm not saying aerodynamics are not significant, I'm saying devices (spoilers) fitted to production cars rarely have a significant effect on downforce and I'm sceptical that the Model 3 in particular has an overall design issue which induces lift at speed. But I'm happy to be proved wrong if someone has some quantifiable data which proves otherwise.

I also still believe that the Model 3 has been tested at Vmax at a proving ground somewhere before being signed off. If it hasn't, that would be a concern for sure.

 

[Daniel in SD]

I'm not saying aerodynamics are not significant, I'm saying devices (spoilers) fitted to production cars rarely have a significant effect on downforce and I'm sceptical that the Model 3 in particular has an overall design issue which induces lift at speed. But I'm happy to be proved wrong if someone has some quantifiable data which proves otherwise.

I also still believe that the Model 3 has been tested at Vmax at a proving ground somewhere before being signed off. If it hasn't, that would be a concern for sure.

There was a problem with the first Audi TTs at speed above 112mph which resulted in a recall, retuning of ESC, and addition of a spoiler so it's not unheard of for production cars to have problems.
From wikipedia:

Early TT models received press coverage following a series of high-speed accidents and the related fatalities which occurred at speeds in excess of 112 mph (180 km/h) during abrupt lane changes or sharp turns. Both the coupé and roadster variants were recalled in late 1999/early 2000, to improve predictability of the car's handling at very high speeds.[14] Audi's Electronic Stability Programme (ESP) or Anti Slip Regulation (ASR) and rear spoiler were added, along with modifications to the suspension system. All changes were incorporated into subsequent production.