Hello, I would like to improve the MPG with aerodynamics on my Box van. I have been looking for different things that would improve flow and reduce drag. But to be honest there's no straight answers that I could find online. This van is 16' high and 11' tall, there's a few things that I have interest in using like; -Over the cab wind deflector (usually in fiberglass) -Under the front bumper skirt -Air foils at the back like airtabs -Rear wheel covers, does this work? Any suggestions on companies that sell these products that would help improve MPG by aerodynamics would be greatly appreciated. Thanks! LM
Welcome to CleanMPG! Before digging too deep into aero mods, read the article Beating the EPA. Major changes in the body shape won't pay off unless you are driving well over 50mph most of the time. Large box vans usually benefit from changes in driving style that minimize stopping and idling. Optimized tire pressure, thinner engine oil, and a very light foot on the accelerator and fast upshifting will do more good than fiberglass domes glued onto the body. If you want to experiment, be aware that most home-n-hobby aero mods generate serious lift. At higher speeds, anything that's not securely fastened to the body may be torn away. Aerodynamic drag increases exponentially with speed. Trucks, with their squarish body shells and low-range gearing, benefit more from reduced speed than just about any other factor. Depending on existing gearing, you may find that serious aero enhancements don't pay off much if the engine is spinning around 3000rpm at interstate speeds. Beyond air drag, tire rolling resistance and driveline friction are other target areas for reducing overall energy losses involved in moving the truck down the road.
The over the cab wind deflector is your best bet, probably giving measurable improvement. The other project to consider would be some sort of boattail. (http://people.clarkson.edu/~kvisser/research/drag/truck/index.html , or search "trailer boattail" ). Drag is huge on box like that, making other mods insignificant. I haven't seen consistent research on the airtabs- and EPA doesn't list any "vortex generator" technology as smartway approved. It seems they improve stability more than mpgs. Reduced speed always trumps aero mods. Keith
Looking at your truck there are four Aerodynamic mods you could do to improve fuel efficiency above 45 mph. Front air dam Air deflector on top between the cab and box Side skirts under the box section rear semi boat tail. Examples of factory side skirts rear boat tail on a semi trailer. Going with MaxxMPG's advice of reading up on Beating the EPA will generate a lot more fuel savings than just the aero mods. If the truck is spending a majority of it's time on the highway then the aero mods will help a lot but so does slowing down to 50-55 mph. If this truck is being used for local delivery then the aero mods will cost you far more than the fuel savings they will generate.
I would go with an over the cab deflector, and maybe side skirt extensions along with rear wheel skirt covers...where I work we have Sprinter box vans that have 11'6'' boxes on the back, and after about three months, all of the Sprinter box vans in our fleet were outfitted with these options to help maximize their MPG, and it does show an improvement. If you google image search Frito Lay Sprinter, you can find pictures of our sprinter box vans with the Aero kits installed. Best of Luck, Chris
Wow great suggestions, thank you guys. Yeah we are not about going fast just being as efficient as possible. We have over inflated our tires, changed gearing, the trans shift sooner. We just got a over head wind deflector today, so we are installing this. The goal is to work every area to get this van to burn less fuel. We know the future will how higher gas prices and now is the time to be ready for whats to come. Thank you again for all the excellent feedback. Chris
More truck aero ideas: http://green.autoblog.com/2011/02/1...-reduce-fuel-consumption-of-semi-trucks-by-7/
