Maximizing MPGs at high speed

[nitrobass24]

If you want mpg at speed, you need to focus on aerodynamics. I took a 2003 Jetta TDI from 46 mpg to 56 mpg hwy (70-75 mph cruising) with some extensive aero-modding.

Do you have a tall antenna flapping in the wind? Go shorty.

Is your bed covered with a tonneau cover?

Tow mirrow or regular mirrors? Do you reeeeallly need that passenger side mirror?

Adding more front air dam, wheel spats, seal front gaps, partial radiator block off, full underbody panels, rear diffuser under the spare tire, partial wheel-well covers. And more.

LRR (low rolling resistance) tires at 50 psi. Michelin defenders are excellent.
Lightweight wheels can help around town, less effect on the highway.

Antenna is just removed
I have a Tonnaua Cover
Regular Mirrors...supposed I can fold them in while cruising.

Wheel Spat? I dont know what this is.
Been looking at the Talons Garage skid plates, but not sure if that is really a full underpanels. Do you know if someone makes something like this that is a bolt on?
When you say wheel well covers, do mean the liners or something else?

LRR tires, Im about due to replace my factory tires. Ill keep this in mind.

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[RuggedGoods]

Not certain "spats" is really the right word, just seen them called that before. It's a small panel (typically black plastic) placed in front of any wheel/tire to direct air away from it. Rotating wheels and tires create a lot of air turbulence. So the more you steer incoming airflow away from them, typically the lower your drag is.

F150s now come with them in front of the rear wheels. If you look around on the road, you'll see that almost every new car has these front and rear:

The front air dam usually accomplishes this in full up front. But I was thinking about expanding my coverage with a couple more small panels.

 

[KBKEITH]

The best advice has already been given. Reduce your speeds and stay out of the boost.

 

[RuggedGoods]

For the underbody panels, the OEM stuff is pretty aerodynamic already. In the front and under the transmission, anyway. Aftermarket skid plates might hang down further, and actually create more drag.

Behind the transmission, it looks to me like it wouldn't be that hard to buy a 4x4' sheet of aluminum and span flat across between the big frame rails. Then you are kind screwed with the rear axle and big rear diff hanging down no matter what. Behind the rear axle, a diffuser panel that hangs below the spare tire and smoothly guides the airflow back up and out behind the truck might help a LOT. But fabricating one seems tricky. I want to make one for my truck, but who knows when I'll have time to waste on such a project.

 

[Davexxxx]

Does a short radio antenna really make a difference?

Enough to pay for itself?

 

[Samson16]

Does a short radio antenna really make a difference?

Enough to pay for itself?

It looks good regardless

 

[amschind]

Texas 130 toll road. I have a construction services business in Austin so I am driving all the time between job sites and this is the fastest way to go north/south. Quite remarkable to be going 90 and get your doors blown off.

I had a Lamborghini pass me on 6 near B/CS a decade ago.....I was going 75 and it appeared for an instant that I was moving in reverse.

 

[MJ Heat]

This may get a rise out of some of you. I travel a 100 mile stretch of very rural & mostly flat interstate, back & forth on a regular once a week basis. I have found that drafting gets me about 25 - 26mpg on that run at about 70mph. That is to say that I will intentionally follow a larger vehicle going along at my desired speed at a respectable distance (that is at the median set point back on adaptive cruise).

 

[nitrobass24]

This may get a rise out of some of you. I travel a 100 mile stretch of very rural & mostly flat interstate, back & forth on a regular once a week basis. I have found that drafting gets me about 25 - 26mpg on that run at about 70mph. That is to say that I will intentionally follow a larger vehicle going along at my desired speed at a respectable distance (that is at the median set point back on adaptive cruise).

You can get 28 @ 65 behind a Semi-trailer. I've done that a few times when im driving to Dallas on I35, bluecruise right behind it.

 

[JerseyGlock]

If you want mpg at speed, you need to focus on aerodynamics. I took a 2003 Jetta TDI from 46 mpg to 56 mpg hwy (70-75 mph cruising) with some extensive aero-modding.

Do you have a tall antenna flapping in the wind? Go shorty.

Is your bed covered with a tonneau cover?

Tow mirrow or regular mirrors? Do you reeeeallly need that passenger side mirror?

Adding more front air dam, wheel spats, seal front gaps, partial radiator block off, full underbody panels, rear diffuser under the spare tire, partial wheel-well covers. And more.

LRR (low rolling resistance) tires at 50 psi. Michelin defenders are excellent.
Lightweight wheels can help around town, less effect on the highway.

You don't want partial block off radiator, that's what grill shutter designed for.

 

[RickBullotta]

Tuck in NASCAR style behind another fast moving vehicle. No bump drafting though. That'll end badly.

 

[HammaMan]

Get rid of any unnecessary weight. Install Tonneau cover, fold in side mirrors on straight sections (if you are ok with that). Air tires to 40. AEM air filter(dry flow).

It's not mass, it's aerodynamics. Bed drag is less than you think. Even in lightnings with closer observation of energy, they don't yield anything. Factors that do affect mileage is wheel design as well as tires -- 15-20% savings there. Air filter is moot at speed.

 

[Samson16]

I love summer time. We are actually having a fairly serious conversation about improving fuel efficiency in a half ton pickup doing 90mph. ?

 

[RuggedGoods]

You don't want partial block off radiator, that's what grill shutter designed for.

Nahh. See, thats sorta what i first thought also. But the active shutters are not particularly well sealed to the entire front grill assembly, so their aerodynamic benefit is sorta limited. a fully smoothed front end is surely more aerodynamic.

I’m sure that was part of Fords design goal, but i think the primary function is more to regulate the radiator temps (faster warmup and keep warm in winter, etc).
every time i look at my grille shutters, they are just tilted down at a 45 degree angle or so. I cant see how that helps anything. Perhaps they do close fully at highway speeds? Ooh, is there a PID i can monitor with my sct bdx tuner?

 

[bgalakazam]

~17.4 MPG according to the computer, flat, no wind, speed limit cruise at 80mph (91 octane E10). Even with 3.31, anything above 60mph increases RPMs, gets more wind resistance, and kills mpg.. Only gets worse with lower gearing. Unless the hybrid can do some magic, but I don't know how much electric you can get at these speeds.

When I took the truck to England on a holiday, speed limit there is 60mph on country roads and 70mph on the freeways. There are speed cameras everywhere so limit is enforced. I hit 24mpg those 2 weeks there.

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