Aeromod nissan leaf improved aerodynamics increased range

GetOffYourGas said:

When the vehicle is coasting, it has some kinetic energy that has already been put into the system via the motor. It will slowly lose that energy to rolling resistance and to aero drag..

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The goal is to measure the energy consumption while just moving at various speeds, and not the initial
energy to obtain each speed. That more effectively determines the energy efficiency of the aerodynamic mods.

GetOffYourGas said:

The rolling resistance is constant (independent of speed) and the drag is related to speed by a well known equation.

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The energy consumed by a vehicle's rolling resistance is:

Energy = K m V, where K is a constant & wheels related, m is the weight of the vehicle, V is the velocity of the vehicle


The energy consumed by a vehicle's drag resistance as it moves thru the air is:

Energy = K A V^2, where K is the coefficient of drag, A is the frontal area of the vehicle, V is the velocity (it's squared)
of the vehicle.

As can be noted from above, the vehicle's speed does affect both the rolling resistance energy loss and the drag
energy loss.

lorenfb said:

The goal is to measure the energy consumption while just moving at various speeds, and not the initial
energy to obtain each speed. That more effectively determines the energy efficiency of the aerodynamic mods.

Click to expand...

That's your goal. My goals are less strict and I put my ideas into practice. I encourage you to do the tests yourself. You can make a grill block out of a piece of cardboard, there is no excuse not to try it.

VitaminJ said:

lorenfb said:

The goal is to measure the energy consumption while just moving at various speeds, and not the initial
energy to obtain each speed. That more effectively determines the energy efficiency of the aerodynamic mods.

Click to expand...

That's your goal. My goals are less strict and I put my ideas into practice. I encourage you to do the tests yourself. You can make a grill block out of a piece of cardboard, there is no excuse not to try it.

Click to expand...

I commend you for your perseverance!

lorenfb said:

GetOffYourGas said:

When the vehicle is coasting, it has some kinetic energy that has already been put into the system via the motor. It will slowly lose that energy to rolling resistance and to aero drag..

Click to expand...

The goal is to measure the energy consumption while just moving at various speeds, and not the initial
energy to obtain each speed. That more effectively determines the energy efficiency of the aerodynamic mods.

GetOffYourGas said:

The rolling resistance is constant (independent of speed) and the drag is related to speed by a well known equation.

Click to expand...

The energy consumed by a vehicle's rolling resistance is:

Energy = K m V, where K is a constant & wheels related, m is the weight of the vehicle, V is the velocity of the vehicle


The energy consumed by a vehicle's drag resistance as it moves thru the air is:

Energy = K A V^2, where K is the coefficient of drag, A is the frontal area of the vehicle, V is the velocity (it's squared)
of the vehicle.

As can be noted from above, the vehicle's speed does affect both the rolling resistance energy loss and the drag
energy loss.

Click to expand...

Yes. We are both correct. You are talking about energy loss and I am talking about force. The amount of energy consumed by rolling resistance is proportional to the velocity of the vehicle. But then again, so is the distance traveled. Consider two vehicles: A and B. A is traveling twice as fast as B, but they go the same distance. Vehicle A loses energy to rolling resistance at twice the rate of vehicle B, but for half the time. In the end, they both lost the same amount of energy for the trip.

My point still stands. Rolling resistance is independent of speed. And you just supported that claim.

VitaminJ said:

lorenfb said:

The goal is to measure the energy consumption while just moving at various speeds, and not the initial
energy to obtain each speed. That more effectively determines the energy efficiency of the aerodynamic mods.

Click to expand...

That's your goal. My goals are less strict and I put my ideas into practice. I encourage you to do the tests yourself. You can make a grill block out of a piece of cardboard, there is no excuse not to try it.

Click to expand...

And it's an overly restrictive goal. It is not the only way to measure the effect of wind resistance. I'm not sure why lorenfb is requiring it to be - physics certainly doesn't.

It seems to me that the discussion about windtunnels vs observed improvements in daily driving range is similar to medical journals which divide data into POEMs and DOEs.
DOE is Disease Oriented Evidence - if I take this pill, my blood pressure will go down about that much. If I take a different pill, the results of my cholesterol lab tests will show a change in the good cholesterol and bad cholesterol concentrations or an ultrasound of my carotid artery will show less thickening.
POEM is Patient Oriented Evidence That Matters. Review of numerous patients shows that those taking some pills live longer with fewer heart attacks than those that don't.
Patients are more interested in POEMs. Researchers tend to study DOEs.
Some interesting results occur from contrasting results. Zetia was looking really good when DOE results showed lowered concentrations of bad cholesterol & less thickening of carotid arteries. Unfortunately, with more experience, the POEM showed no reduction in heart attacks or improvement in longevity. It turned out the medications (statins) effective in the DOE and POEM research were having an improvement in oxidation of cholesterol, which had been missed in early DOE research.
In this case, the information most interesting to me is - having purchased a 2011 Leaf & missed the battery lottery by 2 months - will pizza pans, beer-cooler Styrofoam, pilfered political posters & some Zip ties allow me to continue to commute to and from work without having to stop & charge my car on the way home? An extra five miles of range per charge, whether from driving more carefully, decreased wind resistance, or invisible unicorns pushing the car will save me a bunch of hassle.

GetOffYourGas said:

lorenfb said:

GetOffYourGas said:

When the vehicle is coasting, it has some kinetic energy that has already been put into the system via the motor. It will slowly lose that energy to rolling resistance and to aero drag..

Click to expand...

The goal is to measure the energy consumption while just moving at various speeds, and not the initial
energy to obtain each speed. That more effectively determines the energy efficiency of the aerodynamic mods.

GetOffYourGas said:

The rolling resistance is constant (independent of speed) and the drag is related to speed by a well known equation.

Click to expand...

The energy consumed by a vehicle's rolling resistance is:

Energy = K m V, where K is a constant & wheels related, m is the weight of the vehicle, V is the velocity of the vehicle


The energy consumed by a vehicle's drag resistance as it moves thru the air is:

Energy = K A V^2, where K is the coefficient of drag, A is the frontal area of the vehicle, V is the velocity (it's squared)
of the vehicle.

As can be noted from above, the vehicle's speed does affect both the rolling resistance energy loss and the drag
energy loss.

Click to expand...

Click to expand...

Read it again! There're two factors affecting energy loss while the vehicle is moving:

1. the rolling resistance energy loss - not affected by any aero mods & contributes the most below 45 - 50 MPH, increasing tire pressure beyond normal has minimal effect
2. the drag energy loss - has the most effect at highway speeds greater than 50 MPH, without major body
re-designs and when driving at speed limits, aero mods have little to no REAL effects.

Without any real data, e.g. using a scientific methodology, the results provided in this thread are no better than conjecture!

lorenfb said:

Read it again! There're two factors affecting energy loss while the vehicle is moving:

1. the rolling resistance energy loss - not affected by any aero mods & contributes the most below 45 - 50 MPH, increasing tire pressure beyond normal has minimal effect
2. the drag energy loss - has the most effect at highway speeds greater than 50 MPH, without major body
re-designs and when driving at speed limits, aero mods have little to no REAL effects.

Without any real data, e.g. using a scientific methodology, the results provided in this thread are no better than conjecture!

Click to expand...

10/10 brilliant trolling sir.

lorenfb said:

Read it again! There're two factors affecting energy loss while the vehicle is moving:

1. the rolling resistance energy loss - not affected by any aero mods & contributes the most below 45 - 50 MPH, increasing tire pressure beyond normal has minimal effect
2. the drag energy loss - has the most effect at highway speeds greater than 50 MPH, without major body
re-designs and when driving at speed limits, aero mods have little to no REAL effects.

Without any real data, e.g. using a scientific methodology, the results provided in this thread are no better than conjecture!

Click to expand...

Yes, and might I suggest you read my comment again?

Your assertion that "aero mods have little to no REAL effects" is what is pure conjecture.

Almost exactly 2 years ago lorenfb had different ideas about the validity of the aero mods we're doing:

lorenfb said:

TomT said:

Ford published statistics on the fuel efficiency improvement that came about from the shutterstats that they incorporated in to some of their vehicles... When they were completely closed, blocking off the grill entirely, the efficiency improvement was approximately 5%...

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That sounds about what one might expect.

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5% isn't real. It's FAKE efficiency!

I do the exact same drive to and from work every day: 9 miles out, 10 miles back. For almost 3 years I've been measuring my energy consumption on the drive. The average at this point is somewhere about 4.0mi/kWh, but depending upon conditions I've seen it as a low as 2.9 mi/kWh and as high as 6.2 mi/kWh. In fact, it was the day *after* I first attempted to install the PedalLogic dongle that I got the 6.2. If I hadn't failed on that first attempted install, I might have come to the mistaken conclusion that the 6.2 was because of the PedalLogic dongle (rather than that day the ambient temp was 68F, or that I accidentally drafted behind a big truck, or that I was stuck behind that person doing 30MPH in the 50MPH stretch).

By seeing such a variable in my own repeated drives, I just think there are too many factors at play in day-to-day driving to base the result on a perceived notion of the current efficiency. Perhaps I'm just a sloppy driver and everyone doing these mods is far better at controlling the way they drive and the conditions they drive in.

I have my tires at 42psi. That's an easy change to make and it probably does increase the range. I'd install a grill block and put on backwards facing mud flaps if they were as easy to do as increasing the tire pressure. Since it's a lot more effort, I'd love to be able to see some numbers that can be easily, clearly, and repeatedly measured showing that these changes make a noticeable difference. I really suspect something like a grill block does make a difference -- but does it increase efficiency by .01mi/kWh or .5mi/kWh?

As you say, your car's lifetime efficiency average is 4.0mi/kwh. If you increase the efficiency of the vehicle, it will report an increase in the lifetime efficiency of the vehicle while you, the driver, have not changed anything in how you operate the car. End of story.

Taking a razor blade to a piece of cardboard and sticking it to your grill takes the same time and effort as filling your tires to a certain PSI. Ford says it's worth 5% in a combined city/highway cycle. That's enough to get me off the couch.

My numbers aren't (cumulative) lifetime efficiency -- they are per-trip, reset every time I get in the car.

jlv said:

My numbers aren't (cumulative) lifetime efficiency -- they are per-trip, reset every time I get in the car.

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If you have Carvings then you can look it up. My point remains true whether you were accurate about your lifetime efficiency or not.

Hopefully this satisfies some people because it was a pain in the butt to do!

[youtube]http://www.youtube.com/watch?v=w5OVB4peSIA[/youtube]

lorenfb said:

Read it again! There're two factors affecting energy loss while the vehicle is moving:

1. the rolling resistance energy loss - not affected by any aero mods & contributes the most below 45 - 50 MPH, increasing tire pressure beyond normal has minimal effect
2. the drag energy loss - has the most effect at highway speeds greater than 50 MPH, without major body
re-designs and when driving at speed limits, aero mods have little to no REAL effects.

Without any real data, e.g. using a scientific methodology, the results provided in this thread are no better than conjecture!

Click to expand...

Um, not really.

The drivetrain efficiency is the most important factor to efficiency to moving the car. This is why EV's are so much better than ICE vehicles.

The second most important factor is aerodynamic drag. For typical cars HALF the load on the drivetrain occurs at 28-30MPH. And it increases rapidly - aero drag goes up by the square of the speed.

Rolling resistance is third, and it increases linearly, so it dominates below 28-30MPH.

Weight is next - and weight can be partially regained, through coasting and regen.

Here's my blog post on this, based on the data from the Automotive X-Prize:

http://neilblanchard.blogspot.com/2010/09/x-prize-knockout-round-cont.html

NeilBlanchard said:

lorenfb said:

Read it again! There're two factors affecting energy loss while the vehicle is moving:

1. the rolling resistance energy loss - not affected by any aero mods & contributes the most below 45 - 50 MPH, increasing tire pressure beyond normal has minimal effect
2. the drag energy loss - has the most effect at highway speeds greater than 50 MPH, without major body
re-designs and when driving at speed limits, aero mods have little to no REAL effects.

Without any real data, e.g. using a scientific methodology, the results provided in this thread are no better than conjecture!

Click to expand...

Um, not really.

The drivetrain efficiency is the most important factor to efficiency to moving the car. This is why EV's are so much better than ICE vehicles.

The second most important factor is aerodynamic drag. For typical cars HALF the load on the drivetrain occurs at 28-30MPH. And it increases rapidly - aero drag goes up by the square of the speed.

Rolling resistance is third, and it increases linearly, so it dominates below 28-30MPH.

Weight is next - and weight can be partially regained, through coasting and regen.

Here's my blog post on this, based on the data from the Automotive X-Prize:

http://neilblanchard.blogspot.com/2010/09/x-prize-knockout-round-cont.html

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It appears that you have failed to fully read this thread and understand the points being made,
i.e. by those making the mods. Try re-reading this thread again, i.e. THE ISSUES BEING DISCUSSED
ARE EXCLUSIVE OF THE DRIVETRAIN LOSSES!. You obviously have overlooked where VitaminJ has
focused his efforts.

lorenfb, do you have any opinions on the video I posted above showing the car with and without mods at 65mph?

VitaminJ said:

lorenfb, do you have any opinions on the video I posted above showing the car with and without mods at 65mph?

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That was a good test, but please post the actual data without having the viewer remember the comparative
results from each run. It would be interesting to repeat the tests at 45 MPH for those of us not always
driving at freeway speeds. Thanks.

lorenfb said:

That was a good test, but please post the actual data without having the viewer remember the comparative
results from each run. It would be interesting to repeat the tests at 45 MPH for those of us not always
driving at freeway speeds. Thanks.

Click to expand...

Wow I thought I made that really easy by putting a popup that says "Skip to 10:12 for results." Here it is nice and easy for you:




After over a year and 20 pages of this thread, which you have been a part of from the very beginning expressing skepticism...after all that you can't even be arsed to watch the test video of the test you asked for. What a great sport you are! Instead of talking about the results of my 65mph test you ask "oh gee someone should do it at 45mph instead." People like that...