Bestop is killing my MPG!!!

So I have had my truck about 14K miles and I have routinely gotten 13-15mpg out of it. I just assumed it was because it was lifted, supercharged, and bigger tires. But now I am starting to think that I am getting such shitty milage because of my bestop soft top.

My truck has always been weird and I have gotten better milage in town (20+mpg) than on the freeway (14mpg). Well yesterday I took my bestop off jsut for shits and giggles, the rails are still there, just unclipped everything and put it in my storage unit. I did a little driving around town yesterday and didnt notice anything differant. Then this morning I fill up the truck and head from Tucson to Phoenix, roughly 120 miles each way.

Well to my utter suprise I averaged 21.7 mpg going from Tucson to Phoenix, 20.4mpg going from Phoenix to Tucson, and 18.9 mpg around town in Phoenix. And thats doing 70-75 mph on the freeway both ways. I couldnt believe it. I had always noticed that my Bestop flopped around a little in the wind (it was all tight and on the tightest latch) and at freeway speeds the sides sucked in which I could tell wasnt very aero dynamic but I didnt think it was causing that much drag and reducing my mpg that much.

I did not realize that thing was turning into a giant wind anchor, I mean I felt it when I would get hit by a good crosswind from the monsoons but thats to be expected.

Has anyone else had this happen with there soft top? I might just have to leave it off until I need it or just keep it rolled up against the cab all the time now.

 

Not sure if its my Bestop or not but a few weeks ago when I went to the Rim I got roughly 10.5MPG pulling a 5x8 trailer with a quad on it. Around town I will get no better then 15MPG. I will take it off as you did and see if my mileage improves.

 

thats interesting

i really wouldnt expect that

 

I get between 15 and 18 mpg around town and 20+ on the hwy {70 or less mph}. I lost 1-2 mpg with my supertop.

 

Driving mine like this for almost 6 months:



M/Ts at 32 PSI and a 2.5" lift all around. I'm pulling close to 19mpg on-road and 21mpg highway. Put mine on at about 31k and closing in on 40k miles soon. Pretty much a personally-owned work truck that sees all terrains through-out the week. Never put the windows on.

I've figured the Bestop kills just shy of 1/2 a mpg per tank in just about any situation. Wind direction pending, of course.

Might be the blower, or your foot. How do you have your's configured? With or without windows? Shouldn't make a difference, but just curious.

 

Its not my blower or foot. I have had the bestop on for 14k since I got the truck. I didnt make any driving differances other than the removal of the bestop. I am going to leave it off for another week or two and then put it back on to see if it re-confirms my findings.

 

Yeah mine kills mpg too. Good thing I can remove it easily.

 

Saw you have a scan gauge in your sig, is this what you're basing it off of? Just curious.

I dumped my SG2 because of it's inaccuracies a while back. Well, in terms of monitoring my gas mileage. I calibrated the shit out of that thing, and it never got accurate enough to provide a difference in tire sizes, lift or even with the Bestop on there. Not new to SG, though. Been working with them since they used to suck. Some things never change.

 

I base mine off multiple sources, scan gauge, GPS with milage info (my GPS and scan guage are dead on identicle), my milage travled (I reset it every time I fill up. Milage is based off of distance the truck thinks x tire size differance). All of my calculations come out to pretty close the same and I have been tracking my milage since about the 1000 mile mark.

The only dramatic change I saw was an increase in milage around the 10,000 mile mark with no other explination than the engine loosened up and increased milage like most peoples do.

 

Tops in general make a vacuum behind your truck... Definitely no good for your mileage

 

Huh, this might be a bit of a clincher for whether I get a soft top or trailer.

Good thing you posted this.

 

x2. The ones with a more sloped back are better for MPG because it disrupts the vacuum. The best aerodynamics you could get for a truck is a slanted shell that's a straight line from the top of the cab to the top of the tailgate (it'd look horrible but would theoretically get you the best MPG's).

 

Those things look like an aerodynamic nightmare, but I didn't realize it would be such a huge difference. Ouch.

Not sure what the difference is between that and a hard tonneau cover, but the MPG alone would make spending extra on the tonneau worth it

 

It can range from a couple hundred difference to double the price between Bestop/Softtopper and a hard tonneau but you lose a lot of versitility with a hard tonneau. You can usually pick up a used fiberglass shell for about the price of a Bestop new, if you can find one in the right color and close enough to you.

 

*shrug* I love my undercover, because I can ride around with it off 99% of the time, and throw it on for road trips or whatever.

(And the reason I prefer this to a hard topper is that it comes off so much more easily.)

 

That's the hard foldable cover right? Those things are nice! A hard shell is one of those things, you either need it and use it or you don't and it's a pain in the rear. I got by with a tonneau for a long time but the shell is very nice for traveling, keeps everything out of the cab.

 

Nah, it isn't foldable. I looked at those, but I was afraid of leaks. The undercover is the 40lb flat piece of ABS plastic. I love it for road trips, but I only fill the bed up to where I can't use the cover if I'm moving or something. There's plenty of room for my regular luggage (or camping gear) for the trips I take.

Yeah, there have been a couple of occasions where it'd have been nice to have a hard top (mainly moving large furniture when it was raining) but I like being able to yank a 40lb piece of plastic off the truck real easily.

Edit: About the only thing I'd like the top for is dog transport... she's lucky enough to get to sit on a platform behind the seats.

 

going to have to check my MPG since I put mine on, but I haven't taken any really major road trips.

 

I had to find this thread while waiting for mine to show up at the house... oh well. Hard to imagine it robbing me of any more mpgz than the RTT that has spent the summer on the truck... I hope

 

It has seemed that since being in Arizona my bestop has become less aerodynamic due to the heat it has stretched and become "loose and floppy."
Although looking back I got bad gas milage in Washington as well but I just attributed it to the hilly environment and the engine still being new and not broken in.