REMOVE SPEED LIMITER

[lotusman]

Anybody offering a solution for this? The car seems to have the power to go past the 85 mark, 100 would be a lot more usable.

People routinely drive 80-85 on the highway, and it is a safety issue not being able to pass anyone.

Any ECU tuners out there have a solution?

[paw160]

Electric motors experience a severe drop in torque near 100% speed. I would assume that Ford arranged the 1 speed gearbox so that the motor stays within the nice portion of the motors torque curve.

I would assume that if you want to go faster than 85 you would need to modify the gearbox. There are ways to have the motor controller spin the motor past 100% rated speed but you will lose torque which you want for passing.

How about not driving so fast? Not sure where you are but around here 75-80mph puts you faster than most people on the road.

[Astrand1]

This topic seems to creep up every now and again. I for one used to be a heavy foot fast lane driver going 80-85 all the time. Of course out here in LA everybody goes 80 if there is not a traffic jam. But now that I am electric I have calmed down and I find just staying to the right lanes I have no problem. There are a few times when I get up near the speed limiter when I need to make a move but there is such a range hit that I do my best not too. My 2 cents is that I'm fine with it the way it is.

[michael]

I'm also thinking that the limit may relate to maximum allowable speeds for the motor or other components. I don't know what speed the motor is spinning at 84 MPH in the FFE, but I'm told the Tesla motor runs up to 16,000 RPM. I'd be concerned with overstressing components and impairing their life.

Ford could have used a different drive ratio and allowed higher speed, but at the cost of reduced low-end acceleration.

And bear in mind also the greatly reduced range at higher speeds.

I'm with Astrand1....I'm also in LA and I used to drive my BMW like a low-flying jet. Now I find it more fun to tuck in behind a truck going 60 and try to achieve lower energy consumption.

[jeffand]

This causes more stress on the battery when driving at high speeds. Increasing your speed from 60 mph to 80 mph will about double the current draw on the battery. The only reason a Tesla can go so fast is because its battery is more than 3 times the size of the Focus battery. This is one of the reasons the Tesla also has a speed limiter on it. A sustained high load on the battery can damage it by over taxing the cooling system.

[rabar10]

Jack it up and put bigger tires on it

[EVA]

The range hit at 84 MPH is horrible, almost worse than running the heater. I think Jeffand has the right idea, the limit has more to do with battery stress.

You know there could also be a safety issue with the suspension. We've discussed towing the car on this forum. The owner's manual says to never tow the car with the rear wheels on the ground. The most logical conclusion I saw from that discussion was the increased weight of the battery (or whole car) and the weight shifted to the rear suspension not being safe. There may be some kind of limit that the car can't hit that high speed.

[v_traveller]

The only reason a Tesla can go so fast is because its battery is more than 3 times the size of the Focus battery.

I'm thinking that another reason is that the Tesla has a motor that is three times as powerful as the FFE motor. If it had the same or similar motor as the FFE, it would probably be programmed with a lower top speed, closer to the FFE... Perhaps its top speed would be even lower than the FFE, since the Model S is even more of a pig than the FFE - almost 5000 pounds!

In my opinion, the absurdly low limit on the FFE's top speed is probably very conservative - I'm guessing that the drive system is capable of more, at least 100mph. Here's why:

1) The Leaf, with a programmed max of 92-93 mph, has a similarly-sized battery (24kWh) and similarly-capable motor (Leaf is 80kW, FFE is 100kW... the Tesla, 310 kW!) This is about 8mph more than the FFE, and the Leaf doesn't even have a thermal management system for its battery. So I'm guessing that the FFE, with its thermal management, should be able to overcome any heat issues at a sustained speed of 93mph or higher.

2) The Volt has a top speed of 101mph, and there's a youtube of a guy doing it in Needles, CA in pure electric mode. The Volt also has a similarly capable motor (111kW), but has a much smaller, thermally managed 16kWh battery. I would think based on jeffand's theory of bigger battery means higher top speed, that the FFE should then be capable of over 101mph if not for its annoying speed limiter.

So maybe that low limit might be related more to what paw160 mentioned - that perhaps the way the FFE is geared, at 85mph the motor is near where the torque really starts dropping off. But then I've hit that 85mph numerous times just to merge into the HOV lane, and it sure doesn't feel like the torque is ready to drop off... the FFE pulls and pulls right up to its limit.

Wish there was more info out there. Without published documentation from the manufacturer it's all just conjecture by a bunch of hacks like me.

[jmueller065]

Also note that the motor is liquid cooled as well. In the cutaway pictures of the motor you can see a water jacket, and if you remove the big piece of foam from under the hood you can see where the coolant hoses go in/out.
Sure EVs don't generate as much heat as an ICE but there is heat there.

[WattsUp]

Also note that the motor is liquid cooled as well. In the cutaway pictures of the motor you can see a water jacket, and if you remove the big piece of foam from under the hood you can see where the coolant hoses go in/out.
Sure EVs don't generate as much heat as an ICE but there is heat there.

I hope they at least cycle the heat from the motor to heat the battery (when needed). It would be cool if they could use any excess heat to warm the cabin too.