Modified wheel-leading air deflectors

[thehelix112]

Hey guys,

I am interested in hearing if anyone has modified the wheel leading-edge air deflectors? I forgot to take pics this morning but will update the thread when I take some pics tonight, but they are some thin rubber strips that sit in front of the wheels (both front and rear). As a rotating wheel incurs a big (proportion to it's frontal area) drag coefficient hit, I assume this is done as a way to move as much of the air around the wheel as possible.

I was wondering if anyone has done any experimentation with extending these deflectors lower.
I am thinking of fabricating up some small extenders that mount to the body, then the stock deflectors mount to them. I'd try to keep the standard shape as much as possible. And given the nice miles/kWh metric the car comes with, over time I could perhaps get a reasonable indication of whether it's improved or not. Or coast-down tests, but I don't really have much space to do them in west LA.

Thoughts/comments/criticisms welcome,

Dave

 

[thehelix112]

Wow not much love here. Either way I'll likely proceed with this and report back any findings on range effect.

Dave

 

[Nubo]

My 2 cents is that the M/kWH readout of the car will not have enough accuracy or resolution to measure the effect. I think you'd need one of the CAN bus device solutions to give you a more accurate gauge.

 

[thehelix112]

Maybe. But if it's not significant to measure, that in itself is a piece of information about whether it's worthwhile or not

Dave

 

[DaveEV]

It's a good idea. I think that also increasing the size of the deflector in front of the rear tires would also be worthwhile.

I still think that getting some wheels that are more aerodynamic would provide the biggest bang. The cheapest way to do this would be to figure out how to mount some pizza pans to the wheels (I know some have used tapped zip-ties), but that might be difficult to ensure that wheel balance is retained. 2nd cheapest would be to figure out which 16" steel wheels can be found for cheap and mount some mooneye hubcaps on it.

I'm kind of suprised that Nissan didn't spend more effort here as aero drag from wheels is typically one of the largest sources of drag on a modern car. Look at what lengths BMW has gone to reducing this drag on the i3, for example, with the extra tall, skinny tires and very flat wheel face. The Honda Civic Hybrid is another good example of a good aerodynamic wheel.

 

[thew]

The LEAF is one of the most Areo Tested Cars on the Market today.. I would not make changes to the car that would affect its areo dynamics.. If Nissan Found that making those deflectors longer would have helped. I am sure they would have.. But have fun.. Let us all know what you find. P.S. I am surprised they ares still attached as mine already drag in most driveway approaches and Speed bumps.

 

[nater]

Forged wheels would make a bigger difference, reducing the rotational weight.

Chevy Volt has forged wheels, and there was a poster here who put some on his Leaf.

Nate

 

[Nubo]

I considered putting some Mooneyes on, but tapping holes in the rims was a bit over the line for a lease

 

[thehelix112]

Thanks for the input guys.

drees/nater, great points. Wheels are definitely an important point, both the shape and weight. It would make sense to me that improving the weight would help more when accelerating (including negatively), but that improving the aerodynamics would be more worthwhile if one drives on the freeway a lot.

Has anyone weighed the original '13 wheels? I'll rip off a '13 SL wheel this weekend and weigh it (with tyre) and report back here.

thew, no-one is arguing that the LEAF has a lot of aero work done to it. However I think OEMs are trying to juggle many attributes of the car, and sometimes the compromises they reach aren't what an individual owner would have chosen. That being said, it does mean that eye-balling it as an amateur is more fraught with danger, as we could actually make stuff worse rather than better if we don't understand all the individual pieces and how they cooperate. That being said, thankfully we have some semi-accurate measurement of efficiency in the LEAF, so we have a fighting chance.

Are you sure your deflectors are what is dragging and not the front underside? It seems unlikely given how close it is to the front axle versus the underside of the bumper leading edge.

Dave

 

[DaveEV]

thew, no-one is arguing that the LEAF has a lot of aero work done to it. However I think OEMs are trying to juggle many attributes of the car, and sometimes the compromises they reach aren't what an individual owner would have chosen.

Exactly. There's a lot of things Nissan could have done to improve aerodynamics out of the box, but they didn't do so because of other compromises:

1. Aero wheels: Looks
2. Lower ride height: ground clearance
3. Lower roof line: head room
4. More tapered roof line (think Prius): rear seat head room, visibility
5. Flush door handles (Look at the handles they have on the GT-R or Model S): cost, usability
6. Smaller side mirrors: Visibility
7. Larger wheel air deflectors: Looks, cost

 

[thehelix112]

Great point there. http://en.wikipedia.org/wiki/Automobile_drag_coefficient" onclick="window.open(this.href);return false; has a bunch more suggestions for reducing drag, a lot of which it looks like Nissan has already addressed.
Also is anyone here a member at ecomodder? I found a couple of links there, http://www.autospeed.com/cms/article.html?&A=2456" onclick="window.open(this.href);return false;, and this book: https://www.createspace.com/4201918" onclick="window.open(this.href);return false;

Might be worth a look.

Dave