Maximizing MPGs at high speed

[dogboye]

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.

I had not noticed those on our F150PB. I actually had to go out and look. Awesome!
Looked at my Tacoma (a 2015). It has a similar attachment in front of the front tires, but nothing in front of the rear. NOW I want to go find some rear spats for my Tacoma!

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[RuggedGoods]

I had not noticed those on our F150PB. I actually had to go out and look. Awesome!
Looked at my Tacoma (a 2015). It has a similar attachment in front of the front tires, but nothing in front of the rear. NOW I want to go find some rear spats for my Tacoma!

You can probably just make some. sheet of abs plastic, screw it into the lip of the rear fender, etc.

 

[SteveP150]

Above 75 air resistance pretty much trumps everything else by far. Adjusting tire pressure, transmission, boost, etc will only provide very marginal gains. My understanding is that it's unclear if a tonneau cover actually helps. I thought I remember a test where the best result was by replacing the tailgate with a cargo net. If you're lifted, undo that.
Beyond that, as other have pointed out, drafting a semi can make a big difference, but you have to be willing to do that, and find one going pretty fast for a long part of your trip.

If you really want to address this, I will soon be marketing the Prius Fairing. This is a full carbon fiber monocoque fairing designed to bolt on to your existing Powerboost and give it the aerodynamics of Prius. As an added bonus, you also get the look of a Prius, and guys with modified diesels will want to roll coal on you ;-).

 

[Samson16]

The Powerboost full hybrid is never ICE only. It’s electric only for short spurts and both ICE/Traction the rest of the time. I absolutely averaged right at 20mpg staying above 80mph unless traffic or weather forced me to slow down. Did this from Orlando to Ocean Springs, MS and back. It’s not magic, just amazing!

edit* I apologize for the lack of cleanliness in the close-up. I took that pic before turning the truck off after arriving home from the trip lol

 

[fordhouston]

tailgating 18 wheelers will result in maximized fuel economy!

 

[HammaMan]

tailgating 18 wheelers will result in maximized fuel economy!

Especially towing a trailer. They really hate that though. Just snuggle on up there and let em pull you along. When the self-driving becomes more ubiquitous they'll be a few feet from each other if not able to have some type of 'quick soft coupling'.

~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..

With 87 octane e10, 2" front lift my powerboost gets mid to upper 19s at 80mph.

 

[STM]

This is a great thread.. There have been many threads where people talk about getting well over 25 mpg on a regular basis and I used to wonder if something is wrong with my PB.. because after 20k plus miles, my average is 18.9 mpg!

But 90% of my driving is on freeways in and around Austin where the speeds are 75 to 85 mph..

This thread tells me my mileage is not an outlier and is pretty much on par for my driving patterns!

 

[Calson]

If you truly care about fuel economy you would drive slower. When I am towing a boat I get behind a tractor trailer rig and draft it and am usually going at 55 to 65 mph.

Do the math and determine exactly how much time you save by traveling at 90 mph to work versus driving at 70 mph. In my case I would save at most 5 minutes on my commute to work. Saving 5 minutes is not savings at all if I am going to have to make more stops to buy gas for the truck.

Usually it is ego that is involved. I often have someone speed past me and then go back into my lane to exit the freeway. Their brain is turned off to be doing this. My father used to wait until the last possible moment to take his foot of the accelerator pedal and start to brake when approaching a red light. Not fun for the passengers.

 

[Samson16]

If you truly care about fuel economy you would drive slower. When I am towing a boat I get behind a tractor trailer rig and draft it and am usually going at 55 to 65 mph.

Do the math and determine exactly how much time you save by traveling at 90 mph to work versus driving at 70 mph. In my case I would save at most 5 minutes on my commute to work. Saving 5 minutes is not savings at all if I am going to have to make more stops to buy gas for the truck.

Usually it is ego that is involved. I often have someone speed past me and then go back into my lane to exit the freeway. Their brain is turned off to be doing this. My father used to wait until the last possible moment to take his foot of the accelerator pedal and start to brake when approaching a red light. Not fun for the passengers.

Now that I'm older, I wake up early, take my time getting to work and am still the first one there.

But...

Out on the road when I'm not towing, the PB does 80mph so easily with the flow on an interstate it just feels smooth and natural, not fast at all. Mileage suffers a bit as a result but the PB is so opposite world I claw back some mpg driving through towns or if there is some traffic slow down lol.

 

[nitrobass24]

So here is some admittedly non-scientific data from my Dallas-Austin-Dallas trip last week.

Dallas->Austin
had a half tank of 87e10, drove without CC, attempted to keep RPMs right at 2k. Of course sometimes more sometimes less but the goal to was keep it steady.
2kRPMs = 80mph and 19.7mpg for the trip.

Austin-> Waco
Was completely empty, got 4 gallons of e85 and 26 gallons of 93e10.
Kept RPMS right at 2k, same as before.
2kRPMs - 83mph, and 22.9mpg for the trip.

Waco-> Dallas
Put on CC @ 90mph.
2.2k RPMs and 18.1MPG.

A few thoughts here.
1. I have no idea what impact the wind may or may not have had, but dont recall it being significant.
2. There is a significant efficiency cliff somewhere between 83-90mph.
3. Im pretty surprised at the variances here. Im now curious what is having a greater impact: CC or Speed.

I still have about half a tank of the e85/93 blend. Im going back to Austin next Tuesday and will try with and without CC again but at similar speeds to see how much of an impact CC is having.

 

[Shane150]

Drove from Toronto to Massachusetts(480miles). 4 people in the truck and 200lbs of load in the bed. Managed to get 22.5mpg. Quickly learned Bluecruise was not helping so took it off that and kept the speed between 60-70. This might suffer as I am leveling the truck soon and installing full Talon Garage plates.

 

[gb7FRz26]

My main trick is to put the radar cruise control in one-car-length mode and find an 18 wheeler that is going as fast as I want to go, then just draft them.
If it's hilly I will lock out 10th gear. Usually see 23 mpg instead of 17 or 18 then.
My second main trick is to change my mentality on driving. Getting there eventually is fine. Why rush? My wife hates it.

 

[Rockman5159]

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.

When I do intersate driving,I get better MPGS in Sport Mode.

 

[Rockman5159]

My main trick is to put the radar cruise control in one-car-length mode and find an 18 wheeler that is going as fast as I want to go, then just draft them.
If it's hilly I will lock out 10th gear. Usually see 23 mpg instead of 17 or 18 then.
My second main trick is to change my mentality on driving. Getting there eventually is fine. Why rush? My wife hates it.

lol I used to draft behind 18 wheels but after 3 windshields, mulitple rock chips I backed off

 

[powerboatr]

tailgating 18 wheelers will result in maximized fuel economy!

i watch the antennae do the wiggle then smooth out and then the boost gauge drops to zero . as the draft scoops me up.. then the adaptive cruise backs me off

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