Nice Efficiency Improvement

[bobkart]

I had replaced two of the steel wheels on my 2016 S with much lighter versions last September (Enkei RPF1s), but didn't really see an efficiency improvement then. I put it down to new tires having more rolling resistance than old tires, and the weather cooling off.

In March of this year I replaced the other two wheels. They're around 7.5 pounds lighter per wheel than stock. Partway through April I noticed my efficiency numbers headed towards the upper 4.x m/kWh range (I reset all those counter at the end of each month).

Admittedly I'm driving less now, and more of it is 'elective' as opposed to necessary (no more commute). The elective nature means I can be in less of a hurry. For April I averaged 4.9 m/kWh, over 234.4 miles. My previous best had been last May at 4.7 m/kWh.

Keep in mind that I've done a bunch of other weight-reduction efforts. Not going into full detail on that here, but (for example) one of the larger items on that list is the 12V battery tray, which because I reduced my battery size/weight down (via LiFePO4 battery), I replaced an over-four-pound set of parts with a ~170g setup, a weight reduction of over 10x.

I went for a short trip today (under six miles), with the counters starting at zero (first day of the month), and was able to get 5.3 m/kWh. I've never seen 5.x before today. This trip had hills even. And this is a round trip (started and ended at home). I was intentionally trying to get a good number, so my more normal driving style wouldn't do as well.

Feel free to contribute your numbers here!

 

[Anonymous]

Nice suggestion - wonder if they'd do well with Tesla-style aerodynamic caps.

 

[powersurge]

Most people don't know that the factory 16" steel wheels on the S are 5lbs lighter each than the alloy wheels.

 

[DougWantsALeaf]

That's like taking 80 pounds off of the car. Most of us believe that the 16" vs 17" wheels is the main driver of the efficiency difference between the S and SV/SL Leaf's in the 2019/2020 model year for the Plus.

 

[bobkart]

In case anyone wonders what they look like on the car.
(It was a bit on the dark side today so contrast is lacking.)

 

[Dala]

Looks good, now just 3d-print an aeromod front https://github.com/dalathegreat/Nissan-Leaf-Aeromod-Grille/

 

[bobkart]

I'm definitely considering something like that (but have no printer).

Is there any data on how much of an improvement that makes?

Thanks for the link.

 

[bobkart]

I'm wondering if anyone has done anything to blank out those empty foglight receptacles.

 

[LeftieBiker]

I'm wondering if anyone has done anything to blank out those empty foglight receptacles.

??? My 2013 had flush covers over them.

 

[bobkart]

Mine look like this (as do others I have seen of the same trim level and similar year):

I have some white Racer's Tape and have been tempted to try to cover that opening up with it.

But it would probably suffer appearance-wise.

 

[LeftieBiker]

So the reference was to covers for the fog light 'wells'?

 

[bobkart]

Sure . . . 'empty foglight receptacles' is what I used, 'fog light wells' seems okay too. Don't know the actual term for those.

 

[LeftieBiker]

I think the correct term may be "recesses."

 

[bobkart]

Cool.

Wish I could cover them up better. Wondering if removing that backing piece at the back would help (letting air flow through instead of having to go around).

 

[Anonymous]

which because I reduced my battery size/weight down (via LiFePO4 battery), I replaced an over-four-pound set of parts with a ~170g setup, a weight reduction of over 10x.

Hate to say this, but saving 3 or even 30 pounds on a 3500 pound road car is not going to be remotely measurable in terms of efficiency.

 

[bobkart]

Hate to say this, but saving 3 or even 30 pounds on a 3500 pound road car is not going to be remotely measurable in terms of efficiency.

I'm well past twice that 30 pound savings (the battery alone was 15 pounds). In terms of
power/weight ratio, every 1% drop in weight equates to an 'effective' 1% increase in power.
Also, 30 pounds of that weight reduction being rotating, is typically counted as at least double.
So my ~77 pounds of weight reduction (so far, more to go) comes to more than a 2% reduction,
then doubling the rotating weight part of that gives me ~107 pounds, or right at 3%. Increasing
the power (107hp) by that gives you 110.3hp 'effective'.

I agree that efficiency improvements of that magnitude won't show up on the dash meter (not enough precision there). Nor does it affect the cost to operate to any significant degree (it's already just 2-3 cents per mile). But having 'effectively' 3% more power could be noticeable. Running a zero-to-sixty calculator using curb weight (3256) and the above weight savings yields nearly a quarter second improvement (9.787 seconds to 9.545). Adding in the driver's weight doesn't change that improvement by much (0.242 to 0.239).

Of course every vehicle owner has different priorities as to what about their car is important. So I get that not everyone cares about a quarter-second better zero-to-60 time. And keep in mind that's just one benefit of weight reduction. For sure, lighter wheels/tires help with handling (unsprung mass reduction).

Thanks for your feedback.

 

[Anonymous]

The wheel weight reduction, to be clear, is a substantial improvement in efficiency

 

[HerdingElectrons]

Just adding a bit of info concerning the OEM wheel weight of the 2018 SL 17" wheel. The stock wheel weighs 25.2 pounds.

 

[frontrangeleaf]

Yep, I found the same number for the 2019 SL+ wheels. Bought aftermarket wheels at 20#, but not aero in any way. Saw effectively no change in net efficiency in town (suburban driving 35-55 mph, not too many stops).

 

[DougWantsALeaf]

I saw a Facebook poster reporting the 17" alloy wheels as weighing 41 Lbs, and online the part lists as 37 lbs.

Ev01 wheels arrive soon, reported to be 17.5 lbs. Will post pictures once tires are mounted on the S+.