Aeromod nissan leaf improved aerodynamics increased range

[minispeed]

Ah, that makes a lot more sense now. I feel that driving like that in New York would be very dangerous. Or maybe I'm just not dedicated enough? Here the speed limit is 65MPH, and people typically drive 75-80. Letting your speed drop to 48MPH would be a bad idea.

I should take a close look at my tires. I keep underestimating the hit I am taking to efficiency by using cheapo tires. I had to replace the stock tires before my lease was up, so I went real cheap. But I since decided to buy out the lease, and could stand to get some good efficient ones.

I agree that the Leaf is too high. I typically like very low cars, since they handle much better and give you a better connection to the road. I have zero experience in this area - I'll have to dig into it a little more.

The only time I'll drop down to 48 mph is IF there is no one behind me and it will cause me to crest a hill without adding power then I add power on the top of the hill. For the big hills (climbing the Niagara escarpment) or when I see people behind me I'll keep speed higher. Most of those are also highway ramps with a turn so the speeds are lower already and the recommended turn speeds are 50 mph.

Here there is a pretty good flow of traffic at 115 (72) and above, usually the left 2 lanes are 110 plus. I use to drive my whole way to work at 140 (88) when I had my 91 GTR. Also my speeds are pretty accurate with my larger tires. If you're on stock 16s you're going about 4-5% slower than your speedo reads. Since almost everyone else will have the over reading speedos (all cars are designed to over read for various reasons) my holding a few under the speed limit will actually have them thinking I am going the speed limit.

Speeds at and just under the speed limit are not dangerous, they frustrate other drivers at times but if someone is going to rear end you cause you're going 48 and they weren't looking for long enough to see you and slow down or move they would probably still rear end you if you were going 58. I try very hard to ensure that I don't lower my speed when there's no passing opportunity for others, there almost always is for my drive so I guess I'm lucky.

How did you lower your car?

Tein H-Tech springs from nengun in japan.

I keep hoping to discover a less-expensive way to lower the car a bit.

You can always cut them but the ride is usually terrible.

 

[GetOffYourGas]

The only time I'll drop down to 48 mph is IF there is no one behind me and it will cause me to crest a hill without adding power then I add power on the top of the hill.

Yeah, such conditions never exist here unless it's the dead of the night (and often times not even then). I do agree that going at or slightly under the speed limit is not unsafe, provided there is a passing lane. I typically drive about 60MPH on the highway, where the speed limit is 65MPH. Although others are going much faster, I have never felt it any less safe than keeping up with traffic. In fact, this gives me far more time to react to something unexpected.

 

[lorenfb]

To evaluate the effectiveness of any mods to reduce drag, one might consider using LeafSpy to monitor
the power being used (kW) or the regen (-kW) at various speeds. Both of these numbers should be reduced
if the drag mods are effective. This method should be more meaningful than to try and use the miles/kWh
displayed by the Leaf which includes coasting resulting in an error of actual energy used or regened.

 

[minispeed]

To evaluate the effectiveness of any mods to reduce drag, one might consider using LeafSpy to monitor
the power being used (kW) or the regen (-kW) at various speeds. Both of these numbers should be reduced
if the drag mods are effective. This method should be more meaningful than to try and use the miles/kWh
displayed by the Leaf which includes coasting resulting in an error of actual energy used or regened.

That would only work if doing A-B-A testing. With other things such as weather and wind it would be hard to get accurate numbers. That's why I like to compare numbers over multiple drives, a weeks drive for me is 450 miles over 10 drives that gives a lot of balance to things like traffic and weather (as long as there aren't spikes+- with temp during one of the weeks).

The best test is to actually use a coast down test since it eliminates as many factors as possible. Tire rolling resistance is the other big factor but it's pretty easy to make sure you have the same psi, temp and wind direction/speed for each test. Unless you live in some place really windy. Only thing is you need a good long straight downhill section with no traffic.

 

[lorenfb]

With other things such as weather and wind it would be hard to get accurate numbers.

That's always a problem no matter what methodology/data gathering is used!

That's why I like to compare numbers over multiple drives, a weeks drive for me is 450 miles over 10 drives that gives a lot of balance to things like traffic and weather (as long as there aren't spikes+- with temp during one of the weeks).

The best test is to actually use a coast down test since it eliminates as many factors as possible. Tire rolling resistance is the other big factor but it's pretty easy to make sure you have the same psi, temp and wind direction/speed for each test. Unless you live in some place really windy. Only thing is you need a good long straight downhill section with no traffic.

And what data/parameters are you going to use for comparative evaluation, hopefully not the values the
Leaf displays?

Anyway, have fun. We all need to find something to keep busy during the day.

 

[minispeed]

With other things such as weather and wind it would be hard to get accurate numbers.

That's always a problem no matter what methodology/data gathering is used!

That's why I like to compare numbers over multiple drives, a weeks drive for me is 450 miles over 10 drives that gives a lot of balance to things like traffic and weather (as long as there aren't spikes+- with temp during one of the weeks).

The best test is to actually use a coast down test since it eliminates as many factors as possible. Tire rolling resistance is the other big factor but it's pretty easy to make sure you have the same psi, temp and wind direction/speed for each test. Unless you live in some place really windy. Only thing is you need a good long straight downhill section with no traffic.

And what data/parameters are you going to use for comparative evaluation, hopefully not the values the
Leaf displays?

Anyway, have fun. We all need to find something to keep busy during the day.

In a coast down test the data is how far the car went.

Better than leaf spy or the dash. And even though the dash might not be as accurate for mile/kWh since it gets the numbers from the same place as leaf spy it will be just as consistent run after run.

 

[Wennfred]

Well guys, guess what... It works! Saw 4.2 from 3.8 wirh just the front on, installed them yesterday and took my normal trip to work last night, GIDs were 203 at start and normally arrive with 128 GIDs, this time I ended with 140 GIDs, average KWh was 4.1, again that's up from 3.8 kWh.

I haven't covered the front Grill next, that will be my Project today when I get home.

Install was easy and fast, didn't have to drill a screw on the side but the Bolt on the bottom and 2 screws into the black plastic wheel well, I will put a nice thin sheet of 3M clear tape over it to prevent any hard wind on the edge of the mud flap, with the bolt underneath its holding pretty tight.

Tires are Nokian eTyres normally at 50 PSI, I'm sure they were lower PSI last night, will check it later and run the test tonight with the Grill covered.


4.2 from 3.8, will post results on the way home later.




Fred

 

[lorenfb]

4.2 from 3.8, will post results on the way home later.

One data measurement hardly qualifies for a conclusion.

 

[NeilBlanchard]

It will take more data to confirm the quantity of improvement from the aero improvements - but lower drag does have significant benefits. I have done a lot of aero mods to my previous car, a Scion xA, and I have lots of data showing the improvement. Here is a graph of the fuel log for 7 years, that shows the increase over the first ~2 years, when I added more aero mods:

Overall, I beat the EPA Combined rating of 30MPG by more than 50% with a lifetime year round average of 46 MPG.

http://ecomodder.com/forum/em-fuel-log.php?vehicleid=550

Here is the build thread for all the aero mods:

http://ecomodder.com/forum/showthread.php/scion-xa-aero-mods-2969.html

I did a coastdown test and I estimate I lowered the stock Cd of 0.31 down to ~0.26-0.27.

 

[Wennfred]

4.2 from 3.8, will post results on the way home later.

One data measurement hardly qualifies for a conclusion.

Got way better results on the way home, 4.7 from 3.8 also I normal arrive home with 49 - 50 GIDs, this time I arrived with 74 gids! How much proof do you need, that's awesome stats and enough data for me as I know my daily data. Will post a picture in a sec of results.

Fred

 

[Wennfred]

Well there you have it, average 49 - 50 GIDS at 3.8 kWh daily on my return home, as you can see in this picture parked in the garage, 4.7 kWh at 73 GIDs, proof is in the picture.


Fred

 

[lorenfb]

Well there you have it, average 49 - 50 GIDS at 3.8 kWh daily on my return home, as you can see in this picture parked in the garage, 4.7 kWh at 73 GIDs, proof is in the picture.


Fred

That result is very easy to achieve by just driving at a slower speed, e.g. heavier traffic. You have hardly gathered any reliable data.
As mentioned before, use the power (kW/HP) being consumed at various constant speeds above 50 MPH where there's a minimum
of traffic to distort each data "run" with and without the mod. Using the "Energy Economy" calculated by the Leaf which includes
coasting is unreliable, i.e. it's generally not repeatable/reliable data.

If you're going to post results, please post reliable results that other forum members can rely on.

 

[DaveEV]

That result is very easy to achieve by just driving at a slower speed, e.g. heavier traffic. You have hardly gathered any reliable data.

Unfortunately, I agree. I know that my firsthand experience doing this kind of ad-hoc testing usually results in a short term boost, mainly provided by sub-consciously or consciously driving more efficiently than normal.

I disagree that the efficiency as reported by the LEAF is not reliable - it is reliable as long as you understand it's limitations.

That said, for an aero mod efficiency test, I'd recommend one of two tests which I'll describe - and I also recommend A-B-A testing to rule out errors in measurements or environmental changes affecting results.

1. Coast down test - Find a slight downhill slope where you can coast in neutral without excessively exceeding the speed limit. Coast from the top of the hill to a prescribed location further down the road and note your speed at the prescribed location. This could be a 60 second test.
2. Efficiency test - find a stretch of road without traffic that may affect results. It should be at least a couple miles long at a fixed speed. Rest the efficiency meter the beginning of the test area at a prescribed speed and note the efficiency at the end.

With both of these tests, you should alternate between stock and modified configurations at least twice. And if you can run both tests to confirm results even better.

 

[Wennfred]

Have been reading 3.8 with these tires for months, nothing has changed but this new Mod in the front, so to finally see 4.2 - 4.7 each way is pretty cool.

Drees, let's look for a hill to coast from, we pretty much have the same car to compare notes.

 

[ishiyakazuo]

There is a tendency to want whatever you do to work, so your driving habits may subtly change because psychologically, you know that something needs to show a difference. Going from 3.8 to 4.7 does seem to indicate that something rather sizeable happened, but whether that's all mod-related could be dubious.
Honestly, if you're happy with the changes, that's what's really important. It's not all about impressing people on the Internet

 

[lorenfb]

2. Efficiency test - find a stretch of road without traffic that may affect results. It should be at least a couple miles long at a fixed speed.

Right, the higher the speed the better. Remember, Cd (drag factor) has a greater effect the higher the speed
(Power Loss = k X Cd X V^2) which will better differentiate the delta.

Drees was going to do his own test awhile back (see up-thread).

The results here seem too good to believe, but easy to try so I whipped up a quick chloroplast grill block using an old yard sign and some zip ties. Probably not quite as effective as Brenthasty's because I left the grill block flush with the mesh grill and it doesn't quite cover as much grill (the gaps are more even than the pic looks as I didn't take the pic head on - my license plate is already mounted like his in front the grill), but I should be able to tell if there's a noticeable difference after a few days of driving. If not, I'll make my grill flush with the bumper and check again.

 

[jlv]

It would be incredible if a simple mod like this could substantially improve efficiency. I'd certainly do it. However, there's been nothing in this thread yet that shows this really works. Please do the type of tests suggested above (preferably A-B-A).

I can vary from 3.8 to 5.5 mi/kWh simply by not accelerating heavily (I really do love quietly peeling out when the light goes green) and driving more sedately. My wife likes to chide me because she regularly gets .5 mi/kWh more than me.

 

[DaveEV]

Drees was going to do his own test awhile back (see up-thread).

Yes, and I found no noticeable difference in my daily commute that I couldn't attribute to driving more carefully. Certainly nothing like getting different tires did to efficiency where the change was drastic.

 

[AutoHaulersinc]

I am sooo glad I found this thread, primarily because I thought the mudflaps ruined the lines of the vehicle and just looked like an after thought. It was great to see how easily they are removed and I put all the factory screws back in so there are no holes. I removed the rear bolt clips, and filled the holes with black plastic plugs. I know not many of you are concerned with the look of the vehicle, but I tend to be because of my auto restoration background ( I own a company that builds mobile auto detail systems/trailers)

Im going to use 3m tape to protect the area where the flap was. Now here is a weird thought/question. I shaved all the emblems off the car, looks much cleaner, I wonder if I gained any aero advantage from mot having the "zero emission" emblems on the side?? ....probably not.

 

[DaveEV]

I wonder if I gained any aero advantage from mot having the "zero emission" emblems on the side?? ....probably not.

I highly doubt that it makes any noticeable difference. But if you like the way it looks better, then all good!

By 3M tape, are you talking about the clear protective film?