effect on MPG of flat roof racks
- Thread starter rc51kid
- Start date
I have a Baja rack on mine but I havent driven it enough to see any real difference. I'll be criss-crossing the state in the next month or so, but then of course, it will be loaded down with crap.
I usually remove mine when I'm not using it, though. That, and it won't fit in the garage with it on there...
I usually remove mine when I'm not using it, though. That, and it won't fit in the garage with it on there...
mhiscox
Expedition Leader
I know it's not the OP's actual question, but I gained about 1.5 miles per gallon taking the roof rack and its contents off the roof of my first Sprinter:
I mention this only in case anyone doubts that you can save fuel if you keep the roof clean. When you can't--and I couldn't during that phase of the van's use--expect to pay for the storage in fuel dollars.
I mention this only in case anyone doubts that you can save fuel if you keep the roof clean. When you can't--and I couldn't during that phase of the van's use--expect to pay for the storage in fuel dollars.
zimm
Expedition Leader
second. i have a flat rack with a removable rail. taking the rail off didnt do anything really noticeable. i think if you want to limit the pain, a wind deflector cut to the contour of the roof is more important. noise is turbulence, which is drag, which equates to mpg loss.
if all youre carrying is skis, and bikes and stuff, the oval cross bars are a better buy.
removing between trips is worth it, but i always have something in my 18ft lift bay that isnt running. i would NOT put one on for looks.
Rockhounder
Explorer
I put full solar panels (9 units) across the entire top of my 88 suburban, starting at about driver head position, going up over the factory roofrack bars, continuing across roof to about 3 feet from the back of the suburban at a height of about 3 inches off the roof itself, then last panels droop down to perfectly meet the factory "angle roof corner mini spoiler" on the back of those suburbans of that era, at an altitude of about 1.5 inches. fairly smooths out the roof, and that slightly humpback shape across the entire roof length now gave me a surprise of about 1 mpg increase, which from about 1 month ago, has been consistent. Really surprised me, was not expecting anything like that, and as I only used to get about 10mpg on average, was really happy to get a 10% increase in my mileage out of a gallon of gas..... Will try to take a picture of the setup tomorrow and post.
I really do think that possibly the turbulence started by the roof rack, somehow creates a bigger vortex vacuum on the back side of the suburban, and eliminating this helps a lot. If you put a 6 foot long closing cone at the back of the suburban (like those aerodynamic cars did from the 30's), who knows, but I'll bet you get huge mileage uptick..
I really do think that possibly the turbulence started by the roof rack, somehow creates a bigger vortex vacuum on the back side of the suburban, and eliminating this helps a lot. If you put a 6 foot long closing cone at the back of the suburban (like those aerodynamic cars did from the 30's), who knows, but I'll bet you get huge mileage uptick..
zimm
Expedition Leader
^^ same here.
Really no difference between rack and no rack.
Wind deflector really just cuts down on the noise . . . a little.
i notice your rack rails are perpendicular not longitudinal like mine. it would be interesting to see the difference in a wind tunnel.