Tonneau cover MPG gains

They did what normal people don't do... they actually used scientific method to the best of their ability and tackled everyday questions.
Were they always right? No, and that's what's cool about testing... sometimes you don't get the obvious result. I have been testing for 30 years and I know that surprises happen.

 

Shouldn't that work out be 22 MPG X .018 instead?

 

Already posted a mea culpa on this. I screwed up.
Results in a whopping 0.4 MPG increase.

 

Sorry, l just caught up to that Post.

 

When I drive with the back window open more than half way and the in car air circulation off (outside air flowing through the car) I always gain 2-4 mpg.

also second the summertime mpg being much better


Saw that your back window was open in the pic

 

I haven't tested it scientifically but Ive tried it in the winter too...back window open seems to increase MPG

 

This is my first vehicle with any windows that roll down behind the front two. A rear slider was a must for me. I can't tell you how much nicer it is to have rear door windows that roll down, let alone a rear slider. And that's just from an airflow standpoint. The engine definitely doesn't work as hard when your parachute has holes in it. 85° with the windows down? No problem! In my old vehicles? Not a chance.

 

Winter gas is only part of the reason we get worse fuel economy in winter.

https://www.fueleconomy.gov/feg/coldweather.shtml

 

You’re increasing drag and reducing fuel economy with the windows down, Krazy.

 

Yes,its been proven many times not make any extra gas mpg savings.

 

If you also want 50 more horse power from your motor,put a hood scoop your truck,lol

 

You are thinking about the TRD Pro 4x4 stickers on the Pre-runner... hood scoop is only good for 45HP.

 

Had the factory do it for me, so my extra 50 is documented

 

Day 4 and I can honestly say I have gained at least 2 mpg since adding the cover.

Used to be at 23mpg, now I'm at 25.

Have not changed my driving habits, this is merely anecdotal info for anyone reading.

 

No, no you didn't.

 

Are you relying on what the truck's computer tells you or are you calculating from fill-up to fill-up?
I'd trust the latter before I'd believe the truck's computer.

 

My truck's computer is dead on accurate with my hand calculations.

 

Same, my truck will finish plus or minus .1 or .2 when l hand calculate.