Why does Robert Llewellyn's Leaf have faster acceleration?

Howdy,

A while back on his "FullyChargedShow" show, Robert Llewellyn did a 0-60 test on a Nissan Leaf. You can see it at the start of this episode:

[youtube]http://www.youtube.com/watch?v=6m_iIbX0gmA[/youtube]

He manages 0-60 in about 7.5 seconds.

I remember reading that the 0-60 was closer to 10 seconds and I decided to try it for myself. Whether I have traction control on or off I get about 10.5 seconds. Just in case he was on kilometers (I thought this was unlikely but figured I would check) I tested my 0-38 which came in at around 5.5 seconds.

So what is going on here? Does he have a fast Leaf? Do I have a slow one? I've always felt that there was a little delay right off the line when the car starts - could that be an artificial delay that isn't there on the UK version of the Leaf?

I think you must have a slow one. 8-9 seconds should be easily achievable by even a novice driver.

He may have been attempting a little too hard to prove a point and not really divulging all the situational factors. Primarily, he may have been going down a slight incline.

Try a neutral drop. You can have the motor at 80kW at start, rather than the slower ramp up.

Hmm that was interesting..I wonder if he realizes how puzzled we all are at his 0-60 ,7.5 video..Im starting to wonder if he really did 0-60 in 7.5 seconds

rainnw said:

Try a neutral drop. You can have the motor at 80kW at start, rather than the slower ramp up.

Click to expand...

You're being facetious, right? That only works in an ICE. When you put the LEAF in neutral, the motor will not spin whether you push the accelerator or not.

LEAFfan said:

rainnw said:

Try a neutral drop. You can have the motor at 80kW at start, rather than the slower ramp up.

Click to expand...

You're being facetious, right? That only works in an ICE. When you put the LEAF in neutral, the motor will not spin whether you push the accelerator or not.

Click to expand...

The way I understand it, pressing the accelerator makes the software ramp up inverter output. Inverter output is disabled when the car is in neutral. So by flooring it while in neutral, the inverter output ramps up but doesn't get to the motor... putting it in "D" then enabled the inverter output putting full power to the motor right away without the "soft start."

The theory is sound and there's a whole thread about people trying it successfully.
=Smidge=

Smidge204 said:

The theory is sound and there's a whole thread about people trying it successfully.
=Smidge=

Click to expand...

I've never seen anyone say that they did that, not to say they didn't, I just haven't read it. If they did do that, they would peel rubber half way down the street, traction control or not. I've managed to squeal the tires off the line with traction control on. I can't think of anyplace here where I could test the 0-60 timing. I would love to do it though.

I think he used a prototype Leaf, and they had different software calibrations.. there have some other reports like that in the early tests.

LEAFfan said:

I've never seen anyone say that they did that, not to say they didn't, I just haven't read it. If they did do that, they would peel rubber half way down the street, traction control or not.

Click to expand...

http://www.mynissanleaf.com/viewtopic.php?f=27&t=2789&start=20

=Smidge=

rainnw said:

Try a neutral drop. You can have the motor at 80kW at start, rather than the slower ramp up.

Click to expand...

I went ahead and tried this, but I did not really see any difference. I did have someone else doing the timing (I was using the stopwatch feature of my watch, which requires hitting one button for start, and a different for stop), and we were able to get times around 9.5 seconds. However, we got those times whether we did this trick or not. I only did a couple of runs and it was extremely non-scientific. The one thing I do know is that I'm certainly not getting anywhere near the 7.5 that Mr. Llewellyn got.

Herm said:

I think he used a prototype Leaf, and they had different software calibrations.

Click to expand...

This is what I suspect. If the Leaf does have this potential to accelerate faster it makes me wonder if someone will end up hacking the car and "fixing" this.

I think Liewellyn's numbers are simply bogus. With an 80Kw motor in a car the weight of the Leaf, and an 8:1 gearing, you can not mathematically get below 9 seconds.

JasonT said:

If the Leaf does have this potential to accelerate faster it makes me wonder if someone will end up hacking the car and "fixing" this.

Click to expand...

The timer thing he puts in the video might be a second off but otherwise you can clearly see the speedometer and count yourself. Not sure how bogus it could be unless the video was sped up slightly...

If the Leaf + Robert + Gear is 1600kg (wiki says 1521 kg for the car alone) and we go 0 to 60MPH (26.8 m/s) we can do that math. We start with zero kinetic energy and accelerate a mass (m) to some final speed (V) and kinetic energy (E). It's a problem straight out of a high school physics textbook!

E = 0.5 * m * V^2 = 0.5 * 1600 * (26.8^2) = 574,592 Joules

The Leaf motor is 80kW, or 80,000 Joules per second. 574,592 / 80,000 = 7.1824 seconds.

7.5 "ish" is possible - unlikely since there is increasing resistance with speed but whatever. Since I think the counter is off by about a second let's make it 8.5 seconds. Plausible by high school physics at least.


Edit: Going by the video alone, counting frames, the time is clearly under 8 seconds. However I know his videos have some problems sometimes (audio sync, which means either the video or audio is running too fast or too slow) so watch your sodium intake on this.
=Smidge=