[MF4]

Hi, I wanted to ask if anyone managed to remove the speed limiter on Mini Cooper SE. 😛

As I wrote on another forum, I am working on it but so far I have only managed to change end scale of the instrumentation and the cruise control limit; I've successfully coded the DSC and Kombi ecus, it remains only the EDME ecu but unfortunately I haven't specific programs to access at the speed limiter parameter. 😟

In gasoline engines, the engine mapping programs also allow to remove the speed limiter, but I have no idea if they can read a control unit for electric motor (EDME).

 

[MF4]

However, here some pictures about the new Cruise Control limit.

 

[Vfv]

Did you already find a way to remove the limiter?

 

[SameGuy]

Every time I run across this thread's title -- and it's not incorrect -- I think of the limiter function on the cruise control, and wonder why anyone would want to eliminate it. 😄 But I too am wondering about the speed governor at the top end. The controller rolls off speed well below the car's capability; it should easily be able to keep pulling until maximum motor speed (and perhaps when aero drag starts slowing acceleration). I'm quite certain BMW chose to roll it off and limit speed to 150 km/h to prevent us from killing the battery.

 

[Blue al]

I'm quite certain BMW chose to roll it off and limit speed to 150 km/h to prevent us from killing the battery.

Spend some time in a BMW i4 X-Drive M50
and you’ll soon have a different opinion…

 

[RockCrusher]

Every time I run across this thread's title -- and it's not incorrect -- I think of the limiter function on the cruise control, and wonder why anyone would want to eliminate it. 😄 But I too am wondering about the speed governor at the top end. The controller rolls off speed well below the car's capability; it should easily be able to keep pulling until maximum motor speed (and perhaps when aero drag starts slowing acceleration). I'm quite certain BMW chose to roll it off and limit speed to 150 km/h to prevent us from killing the battery.

There are a number of reasons to limit a vehicle's top speed. Tire speed rating and aerodynamics of the vehicle come first to mind and the vehicle's market.

EV tires are intended to provide low rolling resistance. While I believe tires intended for EVs could be made to a higher speed rating where's the demand? To fit these tires adds cost and EV makers are fighting EV costs already.

Sure one could fit tires with a higher speed rating but that owner would be an extreme outlier compared to other EV owners.

There is also aerodynamics. As speed increases air flow over/around and even through the car (to cool the ICE engine and running gear) becomes ever more critical. As car top speed goes up cars take on a more aerodynamically friendly shape. This means less cabin space and harder ingress and egress.

Was a pretty easy activity to get into and out of my VW Golf TDi limited to 115mph. Not so easy to get into and out of my Porsche 996 Turbo drag/power limited to a top speed of 189mph.

Allowing the EV motor to spin faster generates more heat. From the increased amount of current flow and from friction. Now one has to provide a way to keep the temperature under control. More cost.

The vast majority of EVs are used for short commutes at relatively low speeds. Why burden every car with the cost to support a higher top speed when that is not what the EV market wants?

And the effect on the EV battery has to be considered. What effect would driving at max V have on the battery besides just draining it faster.

Saw a video of a Tesla 3 being used at Pike's Peak. The car was very quick. But it was noted that despite a full charge after the run there was a noticeable drop off in performance. Just calling on the battery to deliver the electrical power during the run up the mountain had a negative effect on the battery.

 

[cooper_se]

No idea about coding but doubt it could do more than 165km/h

The i3 motor, 168bhp at a maximum of 11400rpm had a 150km/h limited top speed.
I calculated max speed based on 11400rpm, 9.665 gear ratio and 0.3498m wheel radius to 155.54 km/h

For the i3s BMW used the same motor (same part no.) but raised rpm limit to 12000rpm and limited top speed to 160km/h
Doing the same calculation as above I get 163.73 km/h

I have seen "performance tuning" packages for the i3 & i3s to 156/157 km/h & 165 km/h respectively which would correlate with the above.

Remember EV has only 1 gear and rated power is for the i3 is listed in the datasheet @ 4800rpm, these are NOT built for top speed runs (even before considering the draw on battery/overheating).

What is surprising is the 223km range in the photo above, 123km is closer to what I get. That must be pootling around town mileage.

 

[SameGuy]

The question becomes: if it is capable of 165 km/h, why is it limited to 150 (and roll-off starts around 135)? My SE was delivered with Eagle F1 Asym 3 at a W (270 km/h) rating. That ain’t it.

 

[SameGuy]

these are NOT built for top speed runs

Most cars are not built for top speed runs, and nor are the vast majority of drivers adept enough to do top speed runs. And yet all of those cars sold to all of those drivers are capable of continuing all the way to red line; some of them have an artificial speed limiter that is easily defeated, and the car is capable of going faster, even though it is “NOT built for” it. My question isn’t whether or not it’s good for the battery or the car to allow it to go all the way to its maximum speed.

 

[cooper_se]

165km/h is for the i3s which is on 19s so even lower top speed for the mini (mine is on 16s) combined with the smaller battery 32 vs. 42 kWh you can see why they set the limiter on 160 & 150km/h respectively.

You are gear limited which is why you can’t go quicker, ICE with same power will do 235 km/h but has 5/6/7/8/etc. gears, and yes the drivetrain is built for top speed meaning it is geared for 280+ but will happily sit at 235 (where it’s power limited) without overheating in a couple of minutes.

You have a 135kW motor in the mini combined with a 32kWhpower source which is designed for acceleration NOT top speed. If it was geared for top speed acceleration would be lower, and you would need a beefier motor/bearings/cables/thermal management system/etc.

A Tesla geared for top speed will have for example a 100kWh battery with a motor that spins at 18000 rpm, taycan has a 2 speed gearbox (different approach)

Travelling at high speed in an EV is very inefficient, same for high loads such as towing which is why the cars are designed for the specific range we mention, removing the limiter in eDME won’t magically bring your top speed to 235km/h, need to change gearing or overspeed the motor to go above 160ish

 

[cooper_se]

The roll off you mention is just the typical torque curve of EV that drops off a cliff when you need it the most (drag at high speed)

https://www.press.bmwgroup.com/global/article/attachment/T0284828EN/415571

If the link works check the before to last page, you have 270Nm from 0rpm to 4500rpm, already down to 185Nm at peak power (7000 rpm) and under 100Nm at 12000rpm which is your top speed.
Previous graph shows 168bhp motor maxing out at 11400rpm

 

[RockCrusher]

The question becomes: if it is capable of 165 km/h, why is it limited to 150 (and roll-off starts around 135)? My SE was delivered with Eagle F1 Asym 3 at a W (270 km/h) rating. That ain’t it.

Probably for the same reason some brands (BMW, Audi, M-B come to mind) that have agreed to limit ICE vehicle top speed to 155mph. (There are high performance models that may be free of this limit though.) Even though some models limited to 155mph are capable of higher speeds and come fitted with suitable tires.

This was done as a nod to the ECO crowd.

Something similar may be the case for EVs. That last thing car companies want to do is appear to be engaging in some kind of top speed battle for vehicles that are all about being green.

Also I seem to recall some EVs come with a battery warranty. No EV maker wants to have to bear the expense of replacing mega expensive EV battery packs because of EV owners blasting hither and yon at V-max and killing those mega expensive battery packs...

 

[SameGuy]

Yes, battery protection was mentioned in my first post in this thread. I think we’re going in circles here. I’m pretty sure everybody responding to me hasn’t read my first post in this thread.