This is old article but gets one thinking...

Could a larger flexible black rubber air dam - maybe mounted 'down and under' to be nearly invisible help to dsome degree? Rather than smack in the face job they used in the link.

Car and Driver magazine ecomods a car: MPG up +25% - Ecomodder.com Fuel Economy Forum

 

Ford recently made a larger airdam for the Job #2 Super Dutys in an effort to increase MPG.

I'm sure doing something similar would work for our Excursions...on the highway.

 

I also thought the trick with the grill was interesting.


That ecomodder.com site has pages on aerodynamic and other modifications that are fascinating. Some guys are making their own clear grill covers. Underbelly mods and reducing rear turbulence reading is very interesting too. Pics of an experimental Volvo where they are experimenting with using some sort of cool little extendible wing/spoiler from under the rear bumper. Makes me wonder if a tiny-wrap-under-receiver-mount-spoiler might work on excursions. :-)

 

Will they fit older Excursions?

I've thought about extending mine down a couple more inches with a strip of heavy black rubber. Or is that too simplistic?

I'd still like to find someone that has smoothed out the Excursion's underbelly a bit. eg All those running board brackets alone must create some nasty drag. Even the rear bumper/receiver hitch seem like major problem areas - (but very easily smoothed if so).

 

I've been thinking more about this - visited that ecomodder site and GasSavers.org and looked at their aerodynamics postings - some very interesting stuff. Unfortunately they are working to push the envelope on most of their cars whereas some minor practical stuff for trucks and SUVs might not garner 70 mpg but might save a whole lot more fuel.

Anyway, someone mentioned on another recent post just how dramatically wind resistance rises as speed increases above 50 mph. So, my thinking is that if you improve an Ex's aerodynamics and you should get: better gas mileage - but also - one I've never heard mentioned :

:-) faster high speed acceleration and passing speeds!!!!

Right?

 

found it... (see below)

Now my Saab is really slippery and it apparently out accelerates some Ferarri from 50 - 100 mph or something according to the old propaganda that came with it. Even though it was classed as a large car, it's 4 cyl turbo allows it to top out at 150 mph. Its aerodynamics have to help. Looking under it - it's amazing compared to the Excursion.


https://www.ford-trucks.com/forums/7...t-4-mpg-2.html

"04-30-2008, 08:44 PM
JiminCA

The engineering reality is that air drag goes up as the square of the speed.

Double the speed, quadruple the air resistance.

There are other things that absorb power as you roll down the highway, but at higher speeds air resistance is the main absorber of power, and hence fuel.

Trying to linearize or generalize by saying "x mpg per 10 mph" is journalistic oversimplification."

 

Every time I crawl under my truck I wonder how much gain I would get if I fabbed up a full underbody "cover". But I'm not that skilled.

 

I don't even think that's necessary - it may be simply about directing the air under some of the big obstacles the same way the air dam works (it also forces more air up over the top). It may be one of those 80 - 20 rules where some small improvements create 80% of the benefit.

I'm guessing that the air dam provides some benefit for some distance back and then turbulence builds. Possibly another airdam (skid pan style or strip of rubber across the body or some sort of smoothing (coroplast or aluminum or something) would create a benefit and cut drag.

And along the sides the the running board brackets look like they'd create a horrible amount of drag - as does is the receiver bar area... (both prime areas for easy fixes)


Follow-Up Test: 2008 Chevrolet Tahoe Hybrid

It says the new Tahoe's air dam cut the aerodynamic drag Cd from 0.39 to 0.34 Cd - that's huge improvement from what I've read.


mpg Research • View topic - Aero mods and MPG on "Conventional Vehicles"

Interesting comments at this link that Lexus is apparently using them to improved handling and to reduce noise and comment about an increase of 2.5 mpg.

Also interesting is the the 7 mpg increase on a '94 Toyota Tacoma.


It would be great if someone knowlegable about aerodynamics could suggest something or if anything could be done at all.

 

Another link (video )
Better Aerodynamics Boost Fuel Economy - Video

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"the cooling flows for the radiators create a huge amount of drag – at about one-third of the total,..."