50 mpg at 80 mph (project 2013 Golf TDI aero mods)

[cfd_guy]

This is going to be my project thread. My goal is to average 50mpg at 80mph in my TDI Golf. I am currently averaging 47mpg at 70mph. This project will strictly be aerodynamic widgets to achieve this goal.

I will initially be starting with the current car in CAD. Running a cfd analysis on it and comparing to analytical data found on the car.

My goal will be to have all the aero widgets under the car so they cannot be seen

CAD: Solidworks 2013
CFD: OpenFOAM

Current CAD Model:


The CAD model still needs wheels modeled and such but it is close. I have access to a 3d scanner and a 3d printer. All widgets will be 3d printed and tested before actual parts will be made

[renault_megane_dci]

mighty impressive !

[user removed]

Check out member Vekke's work with his VW. 50 at 80 is a tall order but good luck trying!

regards
Mech

[basjoos]

If you are willing to add an aero widget that can be seen (a boattail), you could raise your goal even higher. The Aerocivic gets lower 60's mpg at 80mph.

[MetroMPG]

50 at 80 is a tall order when restricted to "hidden" aero mods, but should be fun trying for it.

Originally Posted by cfd_guy

I have access to a 3d scanner and a 3d printer. All widgets will be 3d printed and tested before actual parts will be made

I've been waiting for someone to take this approach. This will be the best route to sharing mods in the future.

Watching with interest!

[bryn]

i know you are only talking aero at this point, but i would love to see 80mpg at 50 mph. i wonder which you would get to first?

[renault_megane_dci]

Did anyone fancy evaluating this statement with the appropriate tool ?
I threw some numbers at it and found out the following is required to hit 50mpg @ 80 mph
Vehicle weight [1]: 1200 Kg
Crr - Coefficient of rolling resistance [2]: .008
Cd - Coefficient of drag [3]: 0.30
A - frontal area [4]: 2 sq meters
CdA 0.60 m2 / 6.46 ft2
Fuel energy density (Wh/US gal.) [5]: - or -
Engine efficiency [6]: 0.35
Drivetrain efficiency: 0.95

One should try with the actual frontal area of the Golf.

What's the required Cd bump ?

[euromodder]

AFAIK the European 1.6 L TDi version will do close to that target ...

[HypermilerAX]

Do modern engines have that high efficiencies at medium load ?

[aerohead]

Originally Posted by cfd_guy

This is going to be my project thread. My goal is to average 50mpg at 80mph in my TDI Golf. I am currently averaging 47mpg at 70mph. This project will strictly be aerodynamic widgets to achieve this goal.

I will initially be starting with the current car in CAD. Running a cfd analysis on it and comparing to analytical data found on the car.

My goal will be to have all the aero widgets under the car so they cannot be seen

CAD: Solidworks 2013
CFD: OpenFOAM

Current CAD Model:


The CAD model still needs wheels modeled and such but it is close. I have access to a 3d scanner and a 3d printer. All widgets will be 3d printed and tested before actual parts will be made

VW has already optimized everything you see on the Golf.I'm pretty certain that the car's visible ' look' will have to change in order to achieve your goal.