second question then, would a spoiler on the front to deflect the air from under the van help?
Possibly... you would be calculating the difference between reducing the air going under the van against increasing the frontal area.
This is why manufacturers spend mucho-$ in wind tunnel testing... and why 99.9% of aftermarket "body kits" are not worth their weight in plastic as a real performance upgrade.
What kind of mileage are you getting now? I was getting 17mpg on the highway, about 13 in town, and 14 to 16 with mixed driving in a '92 E150 with a 351..... We get 16 to 18 out of our '04 E150 with a 4.6.... 350wagon, what engine do you have? Is it a 351, or a 460? If it's a 460 and you are getting 10mpg then that's about right...
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1992 E150, 351, 1 ton E4OD (RIP)
Courtesy of my WIFE: "Why do they call it 'scruff' when it's more like mini-daggers?"
Pfogle, I have a 93 350 club wagon it has a 1 ton floating rear axle with373 gear the engine is a 351w with the automatic trans , I checked the milage this morning I got 13 miles to the gal. and that is city and hyway mixed, I once got 15 on a long trip, but thats been awhile, This van is well maintained from oil change to tune ups ,I change the trans oil about once a year unless I have done some heavy pulling of my tag along camper in which case I get around 9 maybe 10 miles to the gal. I have experimented with the exhaust and the emissions, and a few other mods, but I am always trying to sqeeze more milage out of it. maybe I need to stop complaining and just be happy with what I got!
I'm going to assume that it's not an extended van, and that is right about what I got in my '82 15pass E350 with a 351.... BUt 13 is just about as good as it gets unfortunately, you could try hotter spark plugs.
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1992 E150, 351, 1 ton E4OD (RIP)
Courtesy of my WIFE: "Why do they call it 'scruff' when it's more like mini-daggers?"
My 1994 E150 with 351, E4OD and 3.55 gets 10 mpg combined hwy city. Doesn't matter if it's winter or summer or anything else. It drops to about 9mpg when towing my 28' Avion travel trailer. On one occasion it got 16mpg while crossing a few states that had strictly enforced 65mph speed limits. I just recently replaced virtually every sensor, filter and the typical tune up stuff and guess what...10 mpg.
Bear in mind that I am not using the diesel owners formulas and methods for figuring my mileage. That's where you drive no more than 2000 rpm down hill for 300 miles, figure your mileage and then multiply the results by 1.33 and claim that this is what they get everyday. Mine is a real world figure, sad to say.
I've said it before and I will say it again. Change all the gears and tires sizes you want, they really don't affect your mileage one bit! Physics, it is pure physics that determine what your gas mileage is going to be and the number one cause for MPG being what it is is weight! Gears and tire size can affect the power or torque that the vehicle has. But when it all boils down, changing them ain't going to change your MPG. Don't throws the darts yet! Let me duck first. You can make things more effecient because you do have effeciency losses in the engines and transmissions and the axles and differential and such, but when you have two otherwise identical vehicles side by side, changing the gears and tires size won't affect the mileage.
When one guys says his 4.30 gets 15 MPG, he's doing 55 MPH on flat roadway. When another says his 3.55 get 10 MPG, he's doing 85 miles up and down hills. Switch the situation around and you'll find they are getting the same MPG on otherwise identical vehicles.
When hauling a trailer in the flats of MI, I get 15 MPG. Empty in the hills of PA, 10.
I've said it before and I will say it again. Change all the gears and tires sizes you want, they really don't affect your mileage one bit! Physics, it is pure physics that determine what your gas mileage is going to be and the number one cause for MPG being what it is is weight! Gears and tire size can affect the power or torque that the vehicle has. But when it all boils down, changing them ain't going to change your MPG. Don't throws the darts yet! Let me duck first. You can make things more effecient because you do have effeciency losses in the engines and transmissions and the axles and differential and such, but when you have two otherwise identical vehicles side by side, changing the gears and tires size won't affect the mileage.
When one guys says his 4.30 gets 15 MPG, he's doing 55 MPH on flat roadway. When another says his 3.55 get 10 MPG, he's doing 85 miles up and down hills. Switch the situation around and you'll find they are getting the same MPG on otherwise identical vehicles.
When hauling a trailer in the flats of MI, I get 15 MPG. Empty in the hills of PA, 10.
You make a valid point about the two vehicles, however I dissagree. Imagine you have a pair of 1" tires on your truck (just pretend that it is possable and that they even touch the ground instead of just scraping your differential) How fast is your engine going to be revving to go say 85mph?? Pretty fast huh? So you're gona tell me that since i have small tires and my engine is constantly at the point of blowing 8 cylinders through my hood that my fuel economy has not changed since it is easier to turn those hotwheels tires?? It requires more energy to rev the engine than to let it idle, thats why it doesn't race until you touch the pedal.
You will experience an efficiency loss because the engine and transmission create heat through friction and heat is a waste product (loss of MPG). But, if your engine is turning 10,000 RPM, the amount of fuel being consumed is based upon the amount of force it needs to exert. Since you have tiny little wheels, the amount of torque necessary to do 85 MPH is small, hence a small amount of fuel per RPM. With great big tires and turning only 1,000 RPM, the amount of torque necessary to do 85 MPH is large, hence a large amount of fuel per RPM. When you multiple Fuel Per RPM x the RPM, the fuel consumption is pretty much the same. There are, sweet spots were the engine / transmission will operated at it's most efficient. With most drivers, they do a wide range of speeds, RPMs, terrains, so it all averages out. It's not like your going to get 15 MPG with 225s and 10 MPG with 245s. I recently changed my rears from 245's to 225's to fit a DRW conversion. No change in fuel mileage, the speedometer didn't get all crazy either. The diameter change of 1.2" (vehicle height change of .6") didn't make the vehicle fly up in the air because of wind resistance or anything else folks mentioned in previous posting.
In fact, Ford sells the E-350 and DRW E-350's with 225 tires. The 245s are the options for the wagons and they don't adjust the computer, ring gears, speedometer pickup or anything like that. .6" is a little bigger than 15/32". 15/32" is the tread depth of my Load Range E tires. I wear them down to 2/32" before replacing. So I really don't think going from 225's to 245's is going to do a thing because the net effect is just like wearing down your tire normally. In fact, I know it won’t do a thing.
Then explain the decrease in performance and mpg when we put 215/70R15s on my '92 It specifies 235/75R15. I saw a noticible decrease in performance, and mpg.
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1992 E150, 351, 1 ton E4OD (RIP)
Courtesy of my WIFE: "Why do they call it 'scruff' when it's more like mini-daggers?"
215/70s are a smaller tire than the 235/75s. You will see an increase in power (more torque) but when cruising around you will see no difference in MPG if only the height of the tire is changing. Did you also change a different tread configuration (HT to a AT) and a lower pressure tire (80 PSI to 55 PSI) by any chance? Did you swap from a LT to a P tire also? Those come into play, but merely changing tire size (height) won't.
BMW did a study on gas milage a few years ago and came to the conclusion that best milage comes at the lowest engine RPM the vehicle will run at. I have seen this study referenced a couple of times in magazine articles but I can't remember where. It would be interesting to find out what parameters they looked at.
BMW did a study on gas milage a few years ago and came to the conclusion that best milage comes at the lowest engine RPM the vehicle will run at. I have seen this study referenced a couple of times in magazine articles but I can't remember where. It would be interesting to find out what parameters they looked at.
It is only common sense that the lower the RPM the better fuel economy. If you have one gearing ratio that will move a vehicle X mph at 2000RPM and another ratio that will move it X mph at 4000 RPM, well obviously it will burn up more fuel at the 4000 RPM over the 2000. For all you who don't believe me, well then drive with your car/truck with it in Drive and not Overdrive for a week and then tell me that your getting better fuel economy. And if you still don't believe me leave it in 1st the whole week and let me know what that does for ya, sure you'll have all the power in the world just before you shoot yer pistons through the roof, and anyone with common sence will say, that it is not being driven very efficiently. When you rev it higher to move your vehicle the same speed, you are causing more heat due to internal friction, which means you need to give it more fuel just to turn the engine that much faster, not to mention everything else, seals, bearings, etc. will wear down that much faster.
I believe that my 93 bronco with 270,000 miles is still running strong since it does 65mph at only 2,000 rpm and 40mph at 1400rpm.
I know that this is the van area but I have to reply to adventure's comment that tire size has nothing to do with gas milage. My truck was getting 14 mpg with the stock 33" tires. I put on 36" tires with the same tread width and my mileage dropped to 12 mpg. I was running the same route as I normally take. If tire size does not affect gas mileage what caused my drop in mileage? nothing else was changed and when I went back to the stock size I started getting 14 mpg again.
My 1994 E150 with 351, E4OD and 3.55 gets 10 mpg combined hwy city. Doesn't matter if it's winter or summer or anything else. It drops to about 9mpg when towing my 28' Avion travel trailer. On one occasion it got 16mpg while crossing a few states that had strictly enforced 65mph speed limits. I just recently replaced virtually every sensor, filter and the typical tune up stuff and guess what...10 mpg.
Bear in mind that I am not using the diesel owners formulas and methods for figuring my mileage. That's where you drive no more than 2000 rpm down hill for 300 miles, figure your mileage and then multiply the results by 1.33 and claim that this is what they get everyday. Mine is a real world figure, sad to say.
Gene
That's exactly what I used to get in my 91 E-150 5.8l work van. Granted I did carry a fair amount of weight but the 351W is a serious gas guzzler in these vans. I just don't get these higher mileage quotes on these vehicles. Unless they're empty or it's completely highway(no mix at all which is unusual because you have to actually get to the highway) these vehicles with the 5.8l aren't capable of these figures.
I wish people would be more specific about what they're putting in these vans. They're "cargo" vans. Work vans get heavy, conversion vans get heavy, extended vans obviously weigh more. I would consider an empty or almost empty van to be the exception for most usage. The modular V-8's are certainly a different animal and capable of some more respectable MPG's
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