My speed vs mpg experiement

[sjwelds]

I'm the same way. I really don't care too much about the fuel mileage, and I know it wouldn't be all that great anyway. It's just too much fun at 10psi, plus I use my truck mainly for short trips. 15-20 miles one way is probably the longest I ever run it. I've got the front tank removed, so don't have a whole lot of range to speak of anyway.

 

[jayro88]

What he said

Double your cruise speed and it takes more than double the horsepower. This means more fuel to cover the same distance if all other factors are the same.

Yep. When speeds start getting higher it takes A LOT more power/fuel to increase. I know a couple of people who do land speed racing. They spend as much time/$$ trying to reduce drag as they do on more power.

Wish there was an easy way to increase the Areo of the van slightly. I built a front air dam, but have yet to be able to test it well.

 

[sjwelds]

Had a guy tell me once that the old cab-over style big rigs were actually the most fuel efficient out there? He claimed that you just broke wind, so to speak, just once, as opposed to first the hood, then the fenders, then the cab on a traditional style rig. Less turbulent air and so forth.

I personally think he was full of it.

 

[jayro88]

I always say Im going to calculate my mpg, but I never do. I just figure its gonna be,whats it gonna be. I bought the truck to haul loads, so I need the load hauled regardless of the mpg.

I would like to at least know it, so I can have a base. That way if I ever do any upgrades I can tell if it made my MPG worse or better.

maybe one day

Depending on your loads, distance and frequency of hauling you maybe able to do a few things that could add up to a decent savings. Most of my driving is unloaded so it is a little easier to see an increase. With the amount of miles I am currently driving a few mpg more can give me more money to play.

All of this is probably just my inability to leave stuff alone and the fact that I saw a number of individuals with my vehicle that were in the high teens to low 20's. Made me have to try and figure out why there is the difference.

 

[Greg5OH]

Had a guy tell me once that the old cab-over style big rigs were actually the most fuel efficient out there? He claimed that you just broke wind, so to speak, just once, as opposed to first the hood, then the fenders, then the cab on a traditional style rig. Less turbulent air and so forth.

I personally think he was full of it.

yup, total frontal area as "viewed" by the wind is where the front resistance comes from. Newer long nose, round fenders bulbous cabs are way more aerodynamic than a flat 8x10 brick in the front.

 

[OLDBULL8]

A friend of mine owns a large trucking company. He recently bought all new Volvo tractors (25). The savings from 2+ more MPG netted him over a couple of Million dollars a year in cost of fuel savings.

 

[Greg5OH]

millions... wow

 

[asmith]

yup, total frontal area as "viewed" by the wind is where the front resistance comes from. Newer long nose, round fenders bulbous cabs are way more aerodynamic than a flat 8x10 brick in the front.

I am not sure about that. all the newest styles that is purely for milage are cabover.

this is the current model with the best mpg

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Here are some in the works.

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[sjwelds]

Huh. Interesting.

 

[david85]

Kinda hard to compare highway rigs based entirely on appearance since engine technology also changes. I know Iveco has been offering a turbo-compound engine (That's "turbo compound", not "Compound turbo"). Not sure if others are offering it now, but as the evolutionary conclusion to turbocharging, I have no doubt more will start using turbo-compounds since it offers power and efficiency gains across the board by recovering waste exhaust heat.

 

[sjwelds]

a turbo-compound engine (That's "turbo compound", not "Compound turbo").

Care to elaborate on this technology?
Thanks

 

[asmith]

Kinda hard to compare highway rigs based entirely on appearance since engine technology also changes. I know Iveco has been offering a turbo-compound engine (That's "turbo compound", not "Compound turbo"). Not sure if others are offering it now, but as the evolutionary conclusion to turbocharging, I have no doubt more will start using turbo-compounds since it offers power and efficiency gains across the board by recovering waste exhaust heat.

I don't know much about big rig tech. I do know as oldbull pointed out, that the slightest increase in mpg for them nets huge savings. I believe it is UPS that plans its routes with the fewest left turns as possible, because it saves them idling time. Anyway obviously the manufacturers are working ******* the engines and their efficiency, but as stated earlier aerodynamics play a massive part too. In Ca. you are required to have the side skirts on your trailer now because it cuts down on turbulence and improves mpgs. All part of their plan to save us from global warming. There is a reason the new trucks coming out look like the ones I posted. Because the companies have spent millions of dollars figuring out what designs are most efficient as a whole package, engines and aerodynamics.

 

[92F350CC]

Yep, the bigger the scale, the larger the savings.

For many of us, the savings won't be that big. I learned with my last car to stop caring about mpg, because there wasn't much I could do about it. It was a 92 Lexus that got worse city MPG than my gasser F350 does. Doing 80 mph northbound on I-15 through utah will get me about 16 mpg. I wonder what it would be if I had an IDI under the hood, or if I just slowed down to 75 or 70. I'll never know I guess. Never bothered checking the MPG when I had my 6.9

 

[Greg5OH]

^sorry to derail but my 00 lexus gets 25-26 mpg on the freeway doing 75 cruise on. Love that thing. Does about 18-20 in town.

 

[greenskeeper]

53mpg @ 65mph....oh wait that's driving the TDI

truck is around 20mpg @ 65mph