BeanAnimal,

I'm not here to argue. I get almost 20 mpg driving 55 (highway), and about 15-16 driving 70 (also highway). Wind resistance is a funny animal--It's not a linear increase the faster you go--it's logarithmic. Just simple physics--the faster you go, the more horsepower you need to push the air out of the way, so the less gas mileage you'll get.

Yup Hovy, less people will die too if you go 55, but cars nowadays are much safer at higher speeds than they were 10 years ago, so the Feds dropped the national 55mph limit because less people were getting killed.

I'm not trying to "stir the pot." Just trying to add a different angle to all these high dollar quests for improved gas mileage, when a low dollar improvement is right under your right foot. :-)

---Oh, and I'm not a "tree-hugger." I've got three wood stoves in my house!

I did a lot of testing on the highway when I first got the F150. There's a thread on this forum that shows that research in depth. I'll see if I can find it.... Here it is:

https://www.ford-trucks.com/forums/s...8&page=2&pp=25

BeanAnimal, I totally understand your point about gearing, and I agree that vehicles are geared to maximize horsepower at a particular speed/rpm, but when you compare your own vehicle at different speeds on the highway, the gearing doesn't change (in my tests the terrain was also flat, but the prevailing wind was in one direction which clearly adversely affected the mpg in one direction while improving it in the other), so any difference in mileage can't be the result of gearing. As long as you're comparing the same truck in the same gear, gearing cancels itself out as a factor.

 

You have a great point here. I am picking up my truck tomorrow (04 heritage xlt) and have no idea what kind of mileage I am going to get. I was speaking from experience with our Honda accords and other passenger cars. Different gearing and different aerodynamics all together.

I still stand by the fact the the 55 mph lies...were just that....lies. The lives saved are due to the safety of the vehicles more than the lower speeds. In reality, many studies have shown that the lower speeds have caused more accidents simply becuase they are artificialy low.... and people become impatient.

Have a nice evening,
Bean

 

You bring up a good point here too. I believe (but I've got to do some real digging to prove it) the national 55 mph limit was originally imposed right after the 1976 energy crisis to save gasoline, not to save lives. It's very possible that I could be mistaken, so I'll have to see if I can find any literature on the subject. In fact, the 55mph limit was imposed long before air bags were invented, so at least the auto makers didn't use the 55mph speed limit as an excuse not to need to make vehicles any safer.

Good point!

 

You are 100% correct. The peanut picker was the one who forced the 55 MPH rhetoric on us "to save energy". The joke was that all of the cars built up until (and after) that time were not made to run optimally at 55 MPH. The horsepower curves and gear ratios were not even close. Most of the time the horsepower and gearing choices were made to make the cars "feel" quicker or more responsive. Shortly after, the "55 to stay alive" crap began, as an added push for keeping and promoting the lower speed limites. The police departments loved it, the public has been duped by the weenies and they get to write exponentially more tickets.

With mileage now a common concern among buyers, where would you think the average vehicle gets the best mileage? Do most people drive at or abive the speed limit? Do most people buy a car because it is responsive or sluggish? The answers are pretty obvious.

I apologize for partially hijacking this thread.

Bean

 

k+n about +3\4mpg
tonneuo cover +1.5
under drive pulleys +.5
started at 15.5 ish mpg now at 18+ if i keep the air off and my foot off floor always in a hurry.
pulleys made noticable change in accel, i like it
01 5.4 4x4 scab lariat love this truck
went on vacation four people in truck loaded to max with camping gear bikes on back doing 80-85 most of way still got 16.7mpg
just got predator still exparimenting, this thing is cool

 

I just drive my wife's Altima if I want better gas mileage. As far as the truck though, I'm averaging 15 mpg ( or so the info center says ).

 

How can you enjoy your vehicle without putting it to the wood?????

 

I'm glad to see that all the calculations we did in engineering school were not a complete waste of time. We had to calculate the HP (due to air resistance) to push a car down the road at 50 mph and 70 mph. If I remember correctly, it took about twice the HP at 70 than at 50.....