Testing Leaf's Acceleration

[RedLeader]

I wish there was a motorsports forum or something dealing w/ performance and/or tuning since this thread would be more appropriate in that location.

I had an opportunity this morning to test the acceleration of my Leaf on a flat straight section of road. This is the first of a few tests I'm planning on doing, a base-line for upcoming plans. The road was still damp from rain the night before. It may be a little while before road conditions will dry enough locally to allow for a good base-line test. Tested 0-60mph runs are about 9 sec. The Leaf seems to give up it's pull around 45 mph from my experience which is why the 0-60 times seem to be what they are. My goal is to test the acceleration of the Leaf from 0-40mph which should be an area where it is strongest. For telemetry I used the aLap Recorder HD on a Samsung Galaxy S2. From my experience it is at least as accurate (or more) than a 2 year old MaxQ data logger. Both record at 10Hz and can reference as many as 21 satellites. I had a clear view of the sky and took notice that 15 satellites were being detected before my 1st run. All runs started within 10 ft of the same location and ended around 48-50mph on the speedometer. I did a total of 6 runs running in both directions to negate environmental advantages of one direction, but the last one failed to yield usable data. Each run was taken by just simply flooring the throttle and keeping it depressed until the 48-50mph was seen.

2011 Leaf SL: stock
Ambient Temp: 41F as indicated on instrument panel
Road conditions: damp
TCS: on
Cabin Heat: on
Charge Level: 8 bars


Run # / Direction / Distance (ft) / Time (sec) / Speed (mph)
1 / Southbound / 60 / 1.873 / 20.3
1 / Southbound / 330 / 6.044 / 46.9

2 / Northbound / 60 / 3.655 / 21.4
2 / Northbound / 330 / 8.235 / 41.4

3 / Southbound / 60 / 3.487 / 13.3
3 / Southbound / 330 / 7.547 / 41.2

4 / Northbound / 60 / 3.003 / 13.9
4 / Northbound / 330 / 7.365 / 40.9

5 / Southbound / 60 / 1.790 / 24.0
5 / Southbound / 330 / 5.146 / 44.6


Run #1

Run #2

Run #3

Run #4

Run #5

Impressions:
It goes w/o saying that due to the damp conditions and cold temps, there was A LOT of wheel spin, TCS kicked in on every run. My best guess is that I was loosing nearly a second on TCS interference alone. From what I've been hearing and reading the OEM tires are very poor in the category of performance and grip I would have to agree. Best 60 ft time was 1.790 @ 24.0mph which considering the conditions was not bad. Best 330ft time was 5.146 @ 44.6, again, not bad. I chose to run w/ cabin heat on since it should not make any difference. I will be looking to repeat this test once conditions dry out and warm up attempting it w/o the TCS.

 

[nader]

Nice writeup. I am having a hard time believing the 1.79 second 60' time though. We used to run those times with much lighter and more powerful cars with slicks. . I bet it's closer to a 2.3-2.5 60'.

 

[lspooz]

...a hard time believing the 1.79 second 60' time though.

Uhh, based on what? Your instinct?!? His objective measurements seem rather well supported, and seem reasonable given the rapid torque...

We used to run those times with much lighter and more powerful cars with slicks. I bet it's closer to a 2.3-2.5 60'.

Very cool - but how was this measured?
Just wonderin'

 

[Herm]

Redleader, dont forget to record the battery temperature when you do runs.. the temp affects the horsepower available from the battery. The hotter it is the more power it can produce.

 

[TomT]

Unless it is REALLY hot (up in the red bands of the temp guage) and power has thus then been reduced to protect the battery, it will make no difference.

Redleader, dont forget to record the battery temperature when you do runs.. the temp affects the horsepower available from the battery. The hotter it is the more power it can produce.

 

[nader]

...a hard time believing the 1.79 second 60' time though.

Uhh, based on what? Your instinct?!? His objective measurements seem rather well supported, and seem reasonable given the rapid torque...

We used to run those times with much lighter and more powerful cars with slicks. I bet it's closer to a 2.3-2.5 60'.

Very cool - but how was this measured?
Just wonderin'

[/quote][/quote]

Measured at the drag strip. The leaf's torque is instant but full power doesn't come on until over 20mph. Put it this way. A 1.8 60' will put you in your seat and is borderline violent. Fact is that the Leaf just isn't that powerful.

Has anyone ran their car at the drag strip?

 

[RedLeader]

Nice writeup. I am having a hard time believing the 1.79 second 60' time though. We used to run those times with much lighter and more powerful cars with slicks. . I bet it's closer to a 2.3-2.5 60'.

Yes, you are correct. It is too good to be true if you go by the standard scenario while staged infront of lights. I failed to mention that w/ the aLap Recorder HD, it begins timing as soon as you start moving which means 0 R/T. Also there is a .1 second degree of error (since it logs at 10Hz) and quite possibly more at very low speeds. low 2's is probably correct. Really I should throw out the best and worst values and/or average them.

When I average them I get:

60ft : 2.762
330ft : 6.867

I checked the weather forecast for my area and it looks like nothing but rain, showers and overcast skies for at least a week out, daytime highs in the upper 40's. It may be sometime before I can attempt this in the dry.

 

[DaveinOlyWA]

nice write up. if you are getting wheel spin, reduce tire pressure to 30 PSI.

i would definitely do several repeat runs during Summer as well when pavement is very dry.

 

[Ingineer]

The Leaf has an acceleration ramp that brings on power over about the first 3 seconds. In other words, you don't get full power until after that ramp.

Here's a graph from Sparky where he plotted the acceleration from the CAN bus, which is likely more accurate than GPS due to lag and the low sample rate:

I have a design for a device that will allow adjustment or elimination of this ramp, so the driver can control when/how much of the ~80kW is applied. It's on my list of things to do as soon as there is enough time.

-Phil

 

[Drivesolo]

Too bad about the weather being what it is. You got time though. If anything it'll get you more time to set things up (Tien suspension?) or finish up the Other car. For giggles we should try a run against each other but I might have the upper hand since I'm currently on winter tires which surprisingly are grippier than the OEMs. Yeah, the OEMs are that cr@ppy.

 

[DurkaDurka]

The Leaf has an acceleration ramp that brings on power over about the first 3 seconds. In other words, you don't get full power until after that ramp.

<SNIP>

I have a design for a device that will allow adjustment or elimination of this ramp, so the driver can control when/how much of the ~80kW is applied. It's on my list of things to do as soon as there is enough time.

-Phil

I WANT THIS.

 

[nader]

The Leaf has an acceleration ramp that brings on power over about the first 3 seconds. In other words, you don't get full power until after that ramp.

<SNIP>

I have a design for a device that will allow adjustment or elimination of this ramp, so the driver can control when/how much of the ~80kW is applied. It's on my list of things to do as soon as there is enough time.

-Phil

I WANT THIS.

Ditto! Anyway to beef up the regen?

 

[Deleted member 3147]

The Leaf has an acceleration ramp that brings on power over about the first 3 seconds. In other words, you don't get full power until after that ramp.

<SNIP>

I have a design for a device that will allow adjustment or elimination of this ramp, so the driver can control when/how much of the ~80kW is applied. It's on my list of things to do as soon as there is enough time.

-Phil

I WANT THIS.

Phil, you are such a tease

If it wasn't for the fact that I've seen what you can do at BayLeaf meetings, I wouldn't believe half of what you write!

 

[SanDust]

I have a design for a device that will allow adjustment or elimination of this ramp, so the driver can control when/how much of the ~80kW is applied. It's on my list of things to do as soon as there is enough time.

That would be a popular product but I wonder if the ramp up is there to protect the battery.

 

[Herm]

That would be a popular product but I wonder if the ramp up is there to protect the battery.

Probably to protect the motor shaft

 

[TomT]

And also likely to protect the gear box, CVs, and to reduce torque steer.

That would be a popular product but I wonder if the ramp up is there to protect the battery.

Probably to protect the motor shaft

 

[ElectricVehicle]

To protect ICE drivers from "Sudden Launch Syndrome"! In the electric, drop the pedal and GO! In the gasser, drop the pedal, wait for the engine to spinup all that rotating mass and get to an RPM level where it can produce Torque, say half a second and then GO!

In the EV1, I'm pretty sure they delayed the accelerator response so they wouldn't alarm people used to driving gas cars by the instantaneous full torque and immediate acceleration.

 

[aqn]

Here's a graph from Sparky where he plotted the acceleration from the CAN bus, which is likely more accurate than GPS due to lag and the low sample rate:

RedLeader sez "...at least as accurate (or more) than a 2 year old MaxQ data logger". If true, that's plenty useable.

How reliable is the speed information reported by the CAN bus? Is it the same speed as shown by the speed display? According to the service manual (TM-39, BR-24, BRC-43, etc.), "vehicle speed" signal and wheel sensors' signal are supposed to produce "almost the same reading as speedometer". If that's true, the speed/time information seen on the CAN bus is not any more accurate.

 

[sparky]

Here's a graph from Sparky where he plotted the acceleration from the CAN bus, which is likely more accurate than GPS due to lag and the low sample rate:

RedLeader sez "...at least as accurate (or more) than a 2 year old MaxQ data logger". If true, that's plenty useable.

How reliable is the speed information reported by the CAN bus? Is it the same speed as shown by the speed display? According to the service manual (TM-39, BR-24, BRC-43, etc.), "vehicle speed" signal and wheel sensors' signal are supposed to produce "almost the same reading as speedometer". If that's true, the speed/time information seen on the CAN bus is not any more accurate.

I calculated the speed from the RPM readings off the EV-CAN bus data. Since the LEAF is direct drive it should be very consistent if not pretty accurate. I like the high rate of the CAN-bus readings as well. Also, it's easier to see when I hit the accel pedal and the accompanying lag of about 0.3 sec. It seems this is harder to do with a GPS unit. It would be good to have a direct comparison with your measurement technique sometime.

 

[fotajoye]

I know this car weights a lot; but, with 200ft/lbs it should have more snap; with a variable ramp setting and improved suspension, this car could be fun rolling out of corners.