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Discussion Starter #1
Has anyone tried putting metal or plastic panels under their transit to improve fuel mileage?

Looking at all the cross-framing on the underside says there is a lot of drag created! Most new passenger vehicles employ panels to reduce drag.

If anyone has done this what were the results?

Thoughts...............Ideas?????????
 

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Most things you can do other than driving 45mph on the highway would probably only cumulatively give you 10% better mpg; or 1-2mpg at best. And modifications such as air dams to reduce the drag are only effective at higher speeds, they would be useless around town.

If this is a financial decision, is the cost of the additions and parts worth the 10% fuel savings over your span of ownership? For example, if you spend $2500 on modifications, how long until you "break even" on the cost of fuel savings? 10% of $3 is 30 cents. That's about 8300 gallons or about 125,000 miles at average Transit mpg to reach $2500 savings. So, you'd start saving money after you drive 125k miles. Obviously the less you spend on modifications to get that 10% more miles per tank the sooner you start saving.

Like Mike said, the best way to use less fuel is to stay under 70 (or 65) on the highway. And avoid fast acceleration, and predict red/green lights so you don't have to apply the brakes and waste all the gas you used to get up to speed in the first place.
 

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I assume panels would help, but would be a lot of work maybe. Under inflated tires will contribute to lower mpg, and air is cheap. I know some people have suggested lower pressure for a softer ride, but it does lower your mpgs.
 

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Discussion Starter #7
I assume panels would help, but would be a lot of work maybe. Under inflated tires will contribute to lower mpg, and air is cheap. I know some people have suggested lower pressure for a softer ride, but it does lower your mpgs.
I'll run the tires at whatever pressure gives me an even wear.
 

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Here is a thread from the past I remember: Vortex Generators.

 

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......cut.....

Thoughts...............Ideas?????????
I think it would be very difficult to build, and wouldn’t be that effective anyway.

Streamlining the bottom of the van would require working around the driveshaft and the exhaust system. It’s not practical or desirable to cover them up. And if you did a good job of smoothing the bottom it would likely reduce necessary air flow to keep differential and brakes cool when they were working hard. In my opinion it’s a bad idea and not worth any minor improvements you may get.

The steps that are normally recommended would be more effective. Keep weight down by removing unused items, drive like a retired person with time to kill (or leave early so not driving in a hurry), install lower rolling resistance tires if available for van weight, etc.

On the highway driving slower is easy and yields great results, particularly if engine is right size for needed load. An oversized gasoline engine doesn’t gain as much as would be possible because it becomes more inefficient at low speeds and therefore low load. Still, your MPG will increase by slowing down as long as you’re going over 45~50 MPH.

With my V10, I gain about 1 MPG for every 5 MPH I slow down. If my engine was about half the size, improvement as a percent should be even better. On average I get the following:

80 MPH = 13 MPG
75 ~ 14
70 ~ 15
65 ~ 16
60 ~ 17

I’m certain if I had a 3.5L or smaller modern engine I could do better than 20 MPG at a steady 60 MPH.
 

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P.S. — To maximize MPG, it would also help to leave van roof area intact. No roof A/C, vents, solar, cargo racks, awning, etc. But you’d have to ask yourself how important is fuel economy if van doesn’t meet your needs?

Not saying you can’t have a van without these features because I do, but I left roof alone for other reasons, not to save gas.
 

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What pressure have you found is the best for even tire wear?
You can scale the vehicle then look for the recommended psi found on any tire manufacturers chart using the scale weights.

You can improve mpg by adjusting toe at the front to anywhere from .020 to .030 per side in. I prefer .020. The range oem uses is pretty wide, they can't do it on the assembly line and be exact so they get close. I've seen wide variations and usually expect 1-2mpg improvement, less wear on tires and parts. Rear toe can be pretty bad, I've seen .25" in but you can't adjust it on the solid axles unless you get the heating torch out.

I lately bought a truck off a ford diesel mechanic who'd bought it around 2004-5, it was a 2001 F350. I put it on the alignment machine and it was .40"ish in on both sides. He couldn't believe it but he rarely drove it. That $100 or whatever you do to check front end alignment is gonna pay for itself more than about anything else and prob drive better.
 

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Adding to the tire pressure hijack of this thread;
I bought a take-off set of Contis that had 5k on them. Two of them had 3x as much wear on the outer edges as the other two but the same wear in the center. My educated guess is that the previous owner had them inflated to the recommended specs, either on purpose or just ran them as inflated from the dealer. The ones with the edge wear, a sign of underinflation, were most likely the front. I run 60 front 65 rear right now to avoid adding to the edge wear on the front tires. Sure the ride is rougher than if they were 50psi or whatever the spec is, but it's a VAN, it's not supposed to have a luxury car ride. I don't typically have a lot of weight in the back, but if I know I'm going to haul over 1500lbs of stuff I'll pump up the rears a bit.
 

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OH SH!T A COP
95
90
85
80 MPH = 13 MPG

Do you have mpg readings for higher speeds? 12, 11, 10 as you go up by 5?
 

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OH SH!T A COP
95
90
85
80 MPH = 13 MPG

Do you have mpg readings for higher speeds? 12, 11, 10 as you go up by 5?

No. We actually have 80 MPH speed limits, so not a cop issue.

It’s not theoretically linear as my estimates suggest, but over many years and many tanks of gasoline, that 60 to 80 MPH speed range can be approximated. There are always variations due to weather, road surface, etc., but on the highway I’ve never measured under 13 or over 17 MPG.

I usually drive 70 or 75 MPH on Interstate road trips, and get +/- 15 or 14 MPG respectively on average. The thing is that if my van can do 13 MPG at 80 MPH, IN THEORY it should exceed 20 MPG at 60 MPH if the engine could remain at same BSFC, but it doesn’t. It’s too large. That’s why new Transits have 3.5L V6 instead of 6.8L V10. I looked at option to replace engine years ago with 4.6L V8 but would never get the cost back in fuel savings.
 

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What ever you do dont add a ladder rack to the top!

Sent from my SM-A102U using Tapatalk
Unless you have to have one like myself. I didn't notice any decrease in mileage from my rack but I never drive to save gas so I really don't pay too much attention to MPG. Used as a cargo van squeezing a mile per gallon is the least of my concerns.
 

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I've had short sections where I get 7mpg or 23mpg, such as going up a steep hill or getting behind a semi with the wind at my back on the highway, but these are not long lived. My Torque apps max's out at 255mpg, and I could take a pic of me getting 255mpg as I coast down a hill, but it's not indicative of overall mpg. Claims of hypermiling are illegitimate unless they encompass the entire tankfull between fill ups.

People saying they get "24mpg with my ecoboost", well, I have you beat because I often get 255mpg with my 3.7
 

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No. We actually have 80 MPH speed limits, so not a cop issue.
Top line was intended to reflect 100 MPH (watch out for cop humor), then 95, 90, 85.... But I am genuinely curious about MPG at 85 and 90, since I routinely drive at 85-87 in my SUV, and have been seen full sized Transits following me or doing similar speeds. Speed limit near El Paso is 80 too, and I usually do 5-7 over any limit. I always tell myself I'll drive slower, but by the end of a 10 hour drive I'm back almost always 5-10 over.
 

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I’ve caught myself a few times going well over 90 MPH, particularly on smooth roads and with a little tail wind. I think it happens mostly due to it being a little quieter and it’s easy to lose track of speed. I always slow down immediately but more for our own safety, not due to law enforcement.

I’ve never driven long enough to get an idea on fuel economy, but expect it would be even more than the 1 MPG per 5 MPH. Above 80 MPH my engine doesn’t get much more efficient, yet drag force increases exponentially. At 90 MPH I’d expect around 10 MPG, but that’s just an educated (engineering) guess. My personal interests are more in the 60 to 75 MPH range where I burn most of my fuel.
 

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Discussion Starter #20
Top line was intended to reflect 100 MPH (watch out for cop humor), then 95, 90, 85.... But I am genuinely curious about MPG at 85 and 90, since I routinely drive at 85-87 in my SUV, and have been seen full sized Transits following me or doing similar speeds. Speed limit near El Paso is 80 too, and I usually do 5-7 over any limit. I always tell myself I'll drive slower, but by the end of a 10 hour drive I'm back almost always 5-10 over.
A saying from a trooper friend of mine many years ago was, "8 is great, but 9 you're mine". It holds true in most states to this day. Had a young trooper pull me over last year in Illinois when I was running 12 over and he let me off with a warning. Once he said warning I asked him about the 8 vs 9 and he replaied, "I cannot confirm or deny that is still true"!
 
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