Spoilers increase mileage?

I read a few threads down about improving consumption, one idea was to add a spoiler...

I have a 98Jetta with no wing. I have the stock GLX wing at home- Would that improve my mileage? I though it would make it less-

Can anyone shed some light and experiences with me?

I've been wondering the same for my 2001 Golf. I've heard the OEM spoiler on a Beetle is actually functional...haven't heard anything about the effects on your Jetta or my Golf. My second thought is which spoiler is better for the Golf, the OEM GTI 25th anniversary or the R32 design? One thing is for certain, drag can be a drag. Driving back and forth from Vegas, can get really gusty.

It all depends, but in some cases a spoiler will decrease drag. In some cases it will increase downforce instead, and finally, in some cases it does nothing but sit there and look pretty.
The reall hard part is figuring out which one will do what, and if you can use it.

What it all comes down to is the aerodynamics of the vehicle. Sometimes the spoiler will smooth out the airflow at the rear, sometimes it just disturbs it more. Hopefully someone here can find some of the testing info from VW?

honda adds a small lip spoiler to there accord and civic hybrids to increase their mileage

GetMore said:

(snip) in some cases it does nothing but sit there and look pretty. (snip)

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__. Yeah, if in the language from the planet you're on "pretty" is spelled D-O-R-K-Y!!
'

Spoiler placed in the right areas can reduce drag by preventing airflow seperation and increased drag. One of the forum members did a study on the New Beetle and found that strategic placement of what can be termed "Vortex Generators" increased his fuel economy and reduced the overall Cd value of the car.

On a side note these are not particularily attractive unless you look at it from an aerodynamacists stand point... so the marketing department at VW more than likely nixed the idea in favor of the more attractive to the public model currently on the show room floors.

DB

That spoiler would not suprise me if it was attached to a ricer. LOL Good one DB

Drivbiwire said:

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__. Ummm, speaking of other planets
'

USA Today Article on the car...
http://www.usatoday.com/money/autos/2005-09-15-fuel-efficiency-cover_x.htm

out18law18 said:

That spoiler would not suprise me if it was attached to a ricer. LOL Good one DB

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That fin increased fuel economy above 78mpg...No rice needed.

The car is owned by retired Aeronautical Engineer Ernie Rogers who got a documented 78mpg in that funky New Beetle.

The wing works with the air spilling over the car as well as the air passing along the sides and reduces the burble that develops behind and results in reduced drag and better fuel economy. No kidding.

Maybe he can chime in and be more specific since he designed it.

DB

http://stopglobalwarming.blogspot.com/

There is his blog

DB

HaHa those snow fences look like a P-38s tail.

Properly designed spoilers does reduce drag...it tends to be with lip spoilers, not spoilers mounted on posts (like the OEM MK3 Jetta spoiler).

The MK2 Toyota Soarer aka MK1 Lexus SC400 had an optional lip spoiler that dropped the Cd from 0.34 to 0.32

That Beetle looks like it has wings

That diesel can get 70mpg... and the "wings" actually act as a buffer by creating high and low air pressure zones to increase laminar flow of air over the vehicle while driving and to prevent vortices or air from forming, which is what increases your coefficient of drag. Ernie is on the cutting edge for VW NB's for improving the cd to maximize fuel mileage and mpg. Keep an eye on him, he's doing things and going places with TDI's that may benefit all of us at some time in the future.

Audi5000TDI said:

That diesel can get 70mpg... and the "wings" actually act as a buffer by creating high and low air pressure zones to increase laminar flow of air over the vehicle while driving and to prevent vortices or air from forming, which is what increases your coefficient of drag. Ernie is on the cutting edge for VW NB's for improving the cd to maximize fuel mileage and mpg. Keep an eye on him, he's doing things and going places with TDI's that may benefit all of us at some time in the future.

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I wonder what can be done for the wagons.

Here's Ernie's website: http://www.max-mpg.com

There's another guy here: http://www.maxmpg.org

And a lot of aerodynamic info from a retired NASA engineer here: http://autos.groups.yahoo.com/group/maxmpg/

Beauty is in the eye of the beholder, for sure. Kindred spirits, though, considering how many efficiency folks we have here on Fred's!

Andy

Audi5000TDI said:

(snip) Keep an eye on him, he's doing things and going places with TDI's that may benefit all of us at some time in the future.

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__. Yeah, his blog says "Present mileage is 58 mpg at 65 mph, or about 850 miles on a 14.5 gallon tank of fuel. " Wow, wonder what I could do to get up that high???? As I often sed, "I ain't cuttin' off two inches for anybody!" I like what he's doing -- in fact, that he's doing all this work is a great tribute to him and his scientific method, but the BS meter is showing fairly close to 0.8 already.

__. I got a good idea for his next aerodymanic trick -- how about putting a Jetta body on the NB?????
'

Thanks for the nice remarks. As far as I can tell, my wing lowers the Cd of the Beetle ( 0.38 before) to about the same as the Jetta with no wing (0.30). I agree with the remarks above about "lip" spoilers working by promoting flow separation. The Toyota Camry is an example of pretty good rear end design with a sharp edge built in all around the back-- its Cd is 0.28.

In order to get really good (low) drag, somebody has to make the effort to design a radically improved production car body. Toyota is making a good try on the Prius (Cd = 0.26?) but somebody can do much better.

So far, I don't see VW making any effort, but they are very secretive. The head design guy at the VW Design Center in California designed the Audi 3, a very low drag car sold in Europe. (Hope I remember that right.) I heard that BMW is selling a car in Europe rated at 100 mpg (?)

I think we should put pressure on VW to get serious. They could build a Jetta-sized car that gets 90 mpg TOMORROW if they put their minds to it.

Ernie Rogers

Aluminum Unibody frame combined with reinforced composite and plastic body panels, 2 cylinder 4 valve aluminum VWCDI engine, 6 speed DSG, External glass reinforced Polycarbonate laminate windows, 1liter style seats (Frames and suspended fabric with integrated heater wires in the mesh for winter), total weight 1,200# super low Cd. Fuel economy easily in excess of 100mpg @60mph and current TDI performance without Hybrid drives in a 4 seat sedan.

DB

Drivbiwire said:

Aluminum Unibody frame combined with reinforced composite and plastic body panels, 2 cylinder 4 valve aluminum VWCDI engine, 6 speed DSG, External glass reinforced Polycarbonate laminate windows, 1liter style seats (Frames and suspended fabric with integrated heater wires in the mesh for winter), total weight 1,200# super low Cd. Fuel economy easily in excess of 100mpg @60mph and current TDI performance without Hybrid drives in a 4 seat sedan.

DB

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Great! When will VW start selling those??

I don't think that would pass saftey tests in the US...

mrGutWrench said:

...but the BS meter is showing fairly close to 0.8 already.

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My BS meter is also in the red, I'm afraid. Basic aerodynamics is a fairly simple subject to understand, and basic airflow fairly simple to visualize.

Nitrowolf said:

I don't think that would pass saftey tests in the US...

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Nah, DBW mentioned materials used in Indy/F1 race car monocoques.

Ernie Rogers said:

Thanks for the nice remarks. As far as I can tell, my wing lowers the Cd of the Beetle ( 0.38 before) to about the same as the Jetta with no wing (0.30). I agree with the remarks above about "lip" spoilers working by promoting flow separation. The Toyota Camry is an example of pretty good rear end design with a sharp edge built in all around the back-- its Cd is 0.28.

In order to get really good (low) drag, somebody has to make the effort to design a radically improved production car body. Toyota is making a good try on the Prius (Cd = 0.26?) but somebody can do much better.

So far, I don't see VW making any effort, but they are very secretive. The head design guy at the VW Design Center in California designed the Audi 3, a very low drag car sold in Europe. (Hope I remember that right.) I heard that BMW is selling a car in Europe rated at 100 mpg (?)

I think we should put pressure on VW to get serious. They could build a Jetta-sized car that gets 90 mpg TOMORROW if they put their minds to it.

Ernie Rogers

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iirc, GM's EV1 (leased in CA...sold in Saturn dealerships)... had a Cd of 0.19

Ernie Rogers said:

Thanks for the nice remarks. As far as I can tell, my wing lowers the Cd of the Beetle ( 0.38 before) to about the same as the Jetta with no wing (0.30). I agree with the remarks above about "lip" spoilers working by promoting flow separation. The Toyota Camry is an example of pretty good rear end design with a sharp edge built in all around the back-- its Cd is 0.28.

In order to get really good (low) drag, somebody has to make the effort to design a radically improved production car body. Toyota is making a good try on the Prius (Cd = 0.26?) but somebody can do much better.

So far, I don't see VW making any effort, but they are very secretive. The head design guy at the VW Design Center in California designed the Audi 3, a very low drag car sold in Europe. (Hope I remember that right.) I heard that BMW is selling a car in Europe rated at 100 mpg (?)

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I read that the B4 Passat has an incredibly low Cd -- .25 or something. I may have the number wrong, but I remember being very surprised by it.

I wonder about the new A5 Jetta compared to the A4. I also wonder about the new Civic, which is very Prius-like.

Hey, great work on the Bug! I wonder if smoothed-over, Moon-style hubcaps would help much. Along with the wing it could be an interesting retro hotrod look. Remember the "Cal" style Bugs of the 60s and 70s?

I think we should put pressure on VW to get serious. They could build a Jetta-sized car that gets 90 mpg TOMORROW if they put their minds to it.

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I have no doubt about this.

My old Rabbit Diesel hit over 70 MPG several times, cruising at 45-50 MPH on the Interstate in a snowstorm. This was the early, German built one with a normal (not wide ratio) 5 speed, weighing about 2000 LB. (Most of the time I got 45-50 MPG.)

--

Bob_Fout said:

Nah, DBW mentioned materials used in Indy/F1 race car monocoques.

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The problem may not be the safety tests, but repairability and therefore insurability.

The B5/5.5 Passat has an 0.27 drag coefficient, and the B6 has an 0.28 drag coefficient, FWIW.

What I'm finding for the A5 Jetta is 0.31.

Bring back the EV1

Yes, those numbers look familiar. In order to fully appreciate the value of the drag coefficient, Cd, you should have the frontal area, A, also:

Drag = Cd A 1/2 rho V^2

The EV1: now, THAT was a car-- Cd = 0.19, or lower with a tail modification. GM, pleeeze bring back the EV1 (plus a small diesel engine?).

Maybe a little bigger, for four+ people.

Ernie Rogers

bhtooefr said:

The B5/5.5 Passat has an 0.27 drag coefficient, and the B6 has an 0.28 drag coefficient, FWIW.

What I'm finding for the A5 Jetta is 0.31.

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Heck, if they just hadn't crushed the things, a TDI conversion would be possible...

There's 100-200 left, depending on who you ask. And I don't think anyone's going to give theirs up.

If a replica EV1 for use with a diesel engine could be created, it wouldn't actually have to meet most US safety standards, IIRC - just kit car standards, which mainly deal with lighting.