az erik
Posts: 123
Joined: Fri Sep 06, 2013 10:25 am
Location: Phoenix, AZ

Re: PERFORMANCE TUNING ANYONE?

Fri Nov 08, 2013 11:01 am

I don't think it has an active traction control, more possibly passive (via the infamous rear Ford brakes) or just lack of a power band. reason being I can actually get the tire (yay 1!) to spin for about 1/2 second before it feels like the torque curve just craps out rather than an active traction control doing anything. My IS350 would pulse the power and ding like crazy when the traction control kicked in. The FFE feels to have just enough power to flub out after 1/2 second to make it seem like there is traction control.

Anyone drive the FFE in snow/ice want to chime in?

jmueller065
Posts: 2398
Joined: Tue Feb 12, 2013 4:36 am
Location: Southeastern MI
Contact: Website

Re: PERFORMANCE TUNING ANYONE?

Fri Nov 08, 2013 11:47 am

az erik wrote: before it feels like the torque curve just craps out rather than an active traction control doing anything.
I think that *IS* the traction control. It is an electric motor--there is no torque curve. The wheel speed sensors detect the front wheels starting to spin and the motor controller backs off on the current to the motor. That implementation is sooo much easier when everything is electronic--no need to back off a throttle, reduce gas flow, etc. just tell the motor controller to slow down...
I doubt that it would use the brakes to grab the wheels to slow it down (for one thing that isn't very efficient).
2018 Cajun Red Chevy Bolt
2016 Magnetic C-Max Energi (lease returned)
2014 Sunset Escape
2014 Thor Axis (V-10)
2013 Focus Electric (lease returned Jan 2016 for the C-Max above)
https://spareelectrons.wordpress.com/

az erik
Posts: 123
Joined: Fri Sep 06, 2013 10:25 am
Location: Phoenix, AZ

Re: PERFORMANCE TUNING ANYONE?

Fri Nov 08, 2013 12:06 pm

jmueller065 wrote: It is an electric motor--there is no torque curve.
Actually yes there is a torque curve. There has to be or "power" could not increase.
Image

Image
If this motor only had 1 RPM what you're saying would be true. But it's a variable speed, thus variable torque motor. Otherwise all speed and power would be handled through a CVT transmission and not a single gear transmission. It is what I would refer to as torque crap out. It's there, right off the line, all of it, but it is not a all off the torque all of the time as commonly referred to.

Image
The graph above shows a torque/speed curve of a typical D.C. motor. Note that torque is inversely proportioal to the speed of the output shaft. In other words, there is a tradeoff between how much torque a motor delivers, and how fast the output shaft spins. Motor characteristics are frequently given as two points on this graph:
The stall torque,[Ts], represents the point on the graph at which the torque is a maximum, but the shaft is not rotating.
The no load speed,[Wn], is the maximum output speed of the motor (when no torque is applied to the output shaft).
The linear model of a D.C. motor torque/speed curve is a very good approximation. The torque/speed curves shown below are actual curves for the green maxon motor (pictured at right) used by students in 2.007. One is a plot of empirical data, and the other was plotted mechanically using a device developed at MIT. Note that the characteristic torque/speed curve for this motor is quite linear.

This is generally true as long as the curve represents the direct output of the motor, or a simple gear reduced output. If the specifications are given as two points, it is safe to assume a linear curve.


Also note that the "100% torque available at any speed" can only be 100% available torque AT that speed. Note how fast the torque curve drops by RPM. I work on 4 pole brushless motors in my spare time. Torque to speed drop is about 60% torque loss per 10% rotational speed. What the motor lacks after 1000 rpm it makes up for in rotational speed at 6000 rpm.

jmueller065
Posts: 2398
Joined: Tue Feb 12, 2013 4:36 am
Location: Southeastern MI
Contact: Website

Re: PERFORMANCE TUNING ANYONE?

Fri Nov 08, 2013 2:34 pm

Actually I think the motor is an A/C synchronous motor...not DC. (Which is actually worse because those have a stall torque.)

Here is some pretty cut-away pictures of it:
http://www.engadget.com/2011/01/11/ford ... pery-guts/

If it was DC I'd expect the windings on the rotor not the stator.

It just makes so much more sense to me that it would be A/C synchronous:
- The speed is controlled by the frequency of the A/C (sort of: its the speed of the rotating magnetic field)
- No brushes
- Reversing the car is as simple as rotating the field the other way (reverse phase)
- Regen is also simple: the field rotates slower than the RPM of the motor
- Would use a constant voltage instead of varying the voltage for different speeds.
Last edited by jmueller065 on Fri Nov 08, 2013 3:20 pm, edited 1 time in total.
2018 Cajun Red Chevy Bolt
2016 Magnetic C-Max Energi (lease returned)
2014 Sunset Escape
2014 Thor Axis (V-10)
2013 Focus Electric (lease returned Jan 2016 for the C-Max above)
https://spareelectrons.wordpress.com/

az erik
Posts: 123
Joined: Fri Sep 06, 2013 10:25 am
Location: Phoenix, AZ

Re: PERFORMANCE TUNING ANYONE?

Fri Nov 08, 2013 3:18 pm

jmueller065 wrote:Actually I think the motor is an A/C synchronous motor...not DC. (Which is actually worse because those have a stall torque.)

Here is some pretty cut-away pictures of it:
http://www.engadget.com/2011/01/11/ford ... pery-guts/

If it was DC I'd expect the windings on the rotor not the stator.
You're right it's a AC motor. Those actually do provide 100% torque at full speed. They deliver 100%+ from break torque and pull up torque, which makes the "100% torque" true. Which is better than 300% torque off the line.

Image

Reason I got all wrapped up in DC is the EMW and a few others conversion kits I've been looking at use DC/DC. Makes me wonder just how much AC voltage is coming out of this battery. I thought I saw the battery at 480 volts or so.

jeffand
Posts: 441
Joined: Thu Jan 31, 2013 3:26 pm
Location: WI

Re: PERFORMANCE TUNING ANYONE?

Mon Nov 11, 2013 2:47 pm

Stickier tires should give a slight improvement in acceration, but at the cost of higher rolling resistance.
This will reduce the vehicle driving range. Taking weight out of the trunk will help. A good place to start is the cargo organizer.
2013 FFE, Ingot Silver
Delivered September 2012

davideos
Posts: 409
Joined: Mon Jan 21, 2013 8:58 pm
Location: So Cal

Re: PERFORMANCE TUNING ANYONE?

Mon Nov 11, 2013 3:12 pm

I know there is a big bulky thing in the trunk that takes up a bunch of space...maybe take that out. ;)
Not sure the organizer is going to make much of a difference...but I have thought how much better if the FFE could be if it were 18" shorter as a 2 seater coupe and some of the battery weight over the front tires.

hcsharp
Posts: 108
Joined: Mon Aug 05, 2013 1:40 pm
Location: Vermont

Re: PERFORMANCE TUNING ANYONE?

Mon Nov 11, 2013 9:22 pm

lotusman wrote:I wouldn't consider it peppy, I guess its relative to what you're used to. V10 audi S6, highly tuned lotus v8 twin turbo, tuned mark 6 vw gti, these are the FFEs stable mates.

I appreciate the challenges and difficulties, I didn't know if there were torque limiters in place at lower speeds (for example to control wheel spin, I am putting stickier tires on, so have more traction to work with).
Hey lotusman, I understand where you're coming from. You need a Tesla Roadster. You can get it with an adjustable suspension (from Tesla or aftermarket) that allows you to make some significant handling improvements. You can also do more with the traction control, which is much better than the FFE to start with. It will probably out-accelerate your lotus 0-60 and definitely 0-40. And unlike your lotus and S6, it won't wake up your neighbors doing it LOL. Oh, and it will be vastly cheaper to operate than your stablemates.

When I first drove the FFE, my first reaction was "Why doesn't it have any power?"
When my wife drove it for the first time, she said "Wow, It has lots of power"
All depends on where you're coming from. The Ford salesman reminded me that it has more power than the gas Focus.

Torque limiting is not done the same way it's done on an ICE vehicle. Everything is extremely tightly integrated in the FFE and the inverter is one of the limiting components. The firmware is so complex that you would go insane trying to reverse engineer it. I'd love to see what happens with lower profile stickier tires (other than reducing your range, which they will). Let us know when you try it!

hcsharp
Posts: 108
Joined: Mon Aug 05, 2013 1:40 pm
Location: Vermont

Re: PERFORMANCE TUNING ANYONE?

Mon Nov 11, 2013 9:41 pm

A couple more ideas. Drive the car hard for a few minutes to make the battery as warm as possible. Then top it up on a 30A charging station so the battery doesn't have much chance to get cooled down again. A warm battery performs a little better. Always drive in L. It has exactly the same acceleration but more regen on the accelerator so it feels more responsive (and it is). And the last idea might be to let some air out of the tires. They're low rolling resistance and hard.

I have no plans to try any of these things. It's really the wrong car if you want a sports car.

jloucks
Posts: 61
Joined: Sat Oct 26, 2013 11:41 am

Re: PERFORMANCE TUNING ANYONE?

Thu Nov 14, 2013 7:26 am

Wow! Tons of good info in this thread. I learned a lot. Thanks!

...that's all I got... :D
2014 Chevrolet Corvette
2013 Ford Focus Electric
2009 Cadillac STS V8
2005 Ford Crown Victoria LE
2004 Dodge Ram 3500

Return to “Modifications & Accessories”