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MPG for 3.7L Transit Wagon or Van

121K views 128 replies 61 participants last post by  Sparky8535 
#1 ·
It would be helpful if owners of either Vans or Wagons with the 3.7L.

For now let's include all lengths and roof heights, using the Transit's computer MPG and/or hand-calculated figures. Running totals for the life of the vehicle, and for various discreet trips will be helpful, for those so inclined, in my opinion.

It will be very helpful if you can update your signature (via the User CP at the top right) to include all pertinent information, so that it is not necessary for others to ask about the details of your Transit.

Borrowed wording and idea from PeterR.

Thanks
 
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#4 ·
Ok maiden voyage MPG with 3.7

All the details
3.7 L
4:10 Rear
High roof
Long WB ext.
T 350 SRW
Loaded with approximately 1500 lbs of shelving /product.
Clear weather 10-15 wind from the west
70 -75 ave highway speed
Concord NH to Worcester ma SW in direction - approx 90 miles
of up and down highway use 16.2 mpg.
Concord to worcester to waltham to concord round trip
3/4 highway 1/4 in town stop and go 14.6 all according to
our onboard computer.
I thought we'd actually do better but this a large van with everything
against it. will repost after a concord to bangor trip next week
 
#5 ·
All the details
3.7 L
4:10 Rear
High roof
Long WB ext.
T 350 SRW
Loaded with approximately 1500 lbs of shelving /product.
Clear weather 10-15 wind from the west
70 -75 ave highway speed
Concord NH to Worcester ma SW in direction - approx 90 miles
of up and down highway use 16.2 mpg.
Concord to worcester to waltham to concord round trip
3/4 highway 1/4 in town stop and go 14.6 all according to
our onboard computer.
I thought we'd actually do better but this a large van with everything
against it. will repost after a concord to bangor trip next week
Look forward to your next report. With the 4.10 rear end and high roof, your posted MPG seems OK. FWIW my old Econoline Club Wagon E-350 with a similar rear end (4.09?) had much worse MPG. . .
 
#7 ·
11.26mpg First fill up 17gal at costco $2.24/gal (Orange Co. CA) 191.5 on the trip meter set leaving dealer . This number may be way off because the dealer filled the tank and I'm not sure if they topped it off completely.

250, lwb, mr

30mi. freeway driving 65-70mph the rest stop and go SoCal driving. (more stop then go :( )
 
#8 ·
t350 hr ext 4:10 3.7 L
I did not do the bangor trip this week cause of our blizzard that occurred today
instead went over the franconia notch
Tilton NH to Gorham NH 2000 ft elevation gain and loss 140 mile round trip
10 F no real wind 13.9 overall 80/20 hywy city
next week will be a real long distance hywy test
 
#9 ·
Ok got a trip from portland maine to concord NH
99 miles
13.9 mpg ave
75-80 cruise control assisted 90 highway miles
9 secondary highway miles.
5 degrees pretty strong winds from the side and head on .
fairly empty 1500 pounds maybe
I just think between the wind and the cold weather it is lower than I expected
 
#10 ·
Great data; thanks for posting. I think we can all agree that moving a large van at high speeds takes a toll on fuel economy.

It's also very interesting that your 13.9 MPG at 75 to 80 MPH is comparable to Longboard's 12 MPG at 80 MPH for a similar van but with 3.5L EB and 3.31 gears.

Obviously it's impossible to conclude much of anything from limited data, particularly when there is overlap in results that can't be explained with one or two known variables.

At least this report confirms for me that Ford's similar MPG ratings for EB and 3.7L vans must have some valid basis. Not that I doubted it.
 
#11 ·
Hubcappizza,

What would really be telling is if you made the same trip again, but keeping it at around 65.

Semper Fi
 
#13 ·
65mph



It would be hard for me time is $- but I imagine it makes 1-2 MPG difference
I think the big thing is the high roof,and ANY wind --
The over 20 EB mileage posts got me down a bit
but then these are low roof models.
I'll continue to monitor it though
 
#12 ·
Pushing the high roof through the air at 75-80 on cruise control is the killer to MPG IMO, especially if you were going up and down hills, without relying on the driver to coast on the down hills, and drop speed on the climbs as a hill is crested.
 
#14 ·
Another trip

Hey all 3.7 owners I did another trip
Concord NH to Worcester MA to Natick MA and back
it was 20 degrees no wind to speak of clear
relatively flat to rolling terrain 80% highway
20% mixed highway with some stop and go heavy traffic and
in and out of car dealer lots
idled 10-15 minutes ( it was cold)
full load 1200 lbs hardly anything for this High roof 350 though
205 miles 14.7 MPG
i was pleasantly surprised really would like to see 15 though
maybe soon -- :)
 
#16 ·
I kept the computer off and didn't look at it the whole trip
I don't push it real hard- slow starts and try to moderate stops
and assist the cruise in hill climbs.. Still I was happy with it also!
My benefit is the light load, since I bought out of dealer stock, I got
what I got i believe I would have preferred different rear end and eco
but if i can get to 15 that be ok
 
#25 ·
Chance,
You're right, my bad, I typed in the wrong info, hubcappizza has a 4.10.

The info from his post(s) was that he was not happy with his mileage on a particular run traveling at high speed. He was asked to maybe do it again at 65 or less. He did and had much better milage.

Semper Fi
 
#26 ·
Trip Mileage, Part Deux

So a follow-up on MPG with my T-250 LWB Medium Roof, 3.73 limited slip. Around christmas I did a 2,400 mile loop down the Oregon and California coast to San Francisco. Got 17.6 on the trip computer and 18 by my math. Weigh station said my GVWR was 6,500 or thereabouts and average speed overall was pretty slow. Probably 45-50mph.

A couple weeks ago I did a work trip to San Francisco, but this time on I-5 both directions. There were 4 big guys and about 1,500 lbs of luggage and gear, so GWVR was upwards of 7,500 lbs. A little mellower going southbound probably averaging somewhere around 65mph. Got 17mpg southbound. Heading back north we pushed through and did it in one day so we went a bit quicker—5-7mph over the speed limit at all times and pushing it through the mountains. Average speed was upwards of 70mph overall and we were doing 75mph regularly in the faster sections. It brought the overall average down to 16.5mpg for the whole 1,900 mile round trip.

Around town I regularly get 12-13mpg. I live in a small town that is all hills, shorts trips, lots of stop and go, no highways.
 
#28 ·
The general trend as reported seems to me to be that on the highway the most important factor is speed, followed by air temperature. Both affect drag. Load or GVW isn't quite as important on highway. Differences between 3.7 and 3.5 EB and or axle ratios are hard to detect by comparison; short of doing statistical analysis.

Above excludes towing, which changes everything. For me the bottom line is that since they are all very similar, I'm not going to select/equip a $40,000 vehicle to perhaps save or spend an extra $100 in gasoline. I'll get what I want and live with the consequences.
 
#29 ·
Mileage computer tells me I'm getting 14.8 - 14.9 mpg. And it's the same whether I'm driving at 60, 65, 70 or sitting perfectly still, idling in traffic! Not a lot of confidence there.

Last weekend we took the iron tent camping in the desert of So. Cal. Roughly 180 miles round trip, including slow, winding back roads and 65-70 mph highway. Filled up before and afterwards and got 14.6 mpg.

Go figure. Apparently the system is clairvoyant.
 
#30 ·
When you are in the MPG screen, are you resetting the MPG to zero it out for each trip segment and/or fill up? There are separate tallies for Trip 1 and Trip 2, and MPG and Trip Mileage screens, each of which must be manually reset if you want correct data (not just cumulative reports).
 
#32 ·
Transit 350 passenger wagon with 12 seats

First fill up since purchase exactly 10 gallons for 179 miles traveled. That is 17.9 miles per gallon of regular fuel.
95% highway at 60 - 65 mph with full air conditioner running at fan speed 2

3.7L TIVCT V6 engine,
6-SPD Auto Select Shift TR,
235/65R16 BSW All-Season Tires,
3.73 Limited Slip Axle X7L
 
#36 ·
Thanks Richard, I am curious whether you have also tallied actual gallons pumped for each tank, as my dash MPG is regularly more than 1 MPG higher than the actual data.
 
#38 ·
I almost never use cruise control on California's two-lane roads - too many idiots out there. It was not used at all during that period.
Good to know (both facts :eek:) On trips where it's safe to use the cruise computer, I find the manual pedal uses more fuel, even when holding a steady speed, which I can't actually do as well as the machine.
 
#42 ·
"I think the 3.31 axle is not even available with NA 3.7L engine. And for good reason."

Most of my driving is long haul highway miles so I assumed the 3.31 would achieve better mpg efficiency over the 3.73 rear end. You seem to know what you are talking about and it sounds as if you would disagree with my assumption, so would you explain why the 3.31 would not (or may not) achieve better mileage?
I did not feel I needed the extra power of the Ecoboost nor the acceleration of the larger rear ends, so I was contemplating mating the 3.7 with the 3.31. It appears Ford and you may have determined this is not the optimum and I would appreciate the explanation and a better understanding of how the rear ends relate to the engines and fuel economy. I thank you now for the best explanation you can provide to a novice.
 
#46 ·
Actually, I think it's possible that under some conditions a Transit van with the 3.7L naturally-aspirated engine may get higher MPGs with 3.31 axle in lieu of 3.73 axle. It depends on a lot of factors, which Ford apparently didn't think occurred often enough to justify that tall a gearing with the lower-torque engine. For many it would work just fine but that same van could end up driven by someone else whose driving conditions and style made the van downshift too often. And we know from reports here that most people don't like downshifts at highway speeds even if gearing is selected that tall to save fuel.

Contrary to what is being reported here, these relatively small-displacement modern engines DO NOT have to operate at or below 2,000 RPMs, or at full throttle, to be in their so-called sweet spot. Ford technical data often shows that highest engine efficiency, or lowest specific fuel consumption, occurs in the 2,500 RPM range. And these engines can be as efficient at 3,000 RPMs as at 2,000 RPMs, depending on load.

Many people focus on engine RPMs, which is a function of gearing, and jump to conclusions about gearing that are simply wrong. Or misleading.

As I've stated before in other threads, just switching to 3.31 gears doesn't necessarily improve fuel economy. It's not that simple. If it were, why not 3.15 gears, or 2.73 gears with even more overdrive transmission ratios? Gearing that is too tall is not efficient even if engine can pull it.

The only way to estimate whether the change you are contemplating would help, and by how much, is to have a lot more data or to do reverse engineering to determine if going from 3.73 to 3.31 gears would work for "your" conditions.

Unless I was trying to drive very conservatively just to improve fuel economy (like hypermiling), I would leave it at 3.73. Even if 3.31 saved a few cents, you would probably not get back the cost of switching axle ratios. Not in a reasonable timeframe. Plus drivability would suffer.

Just my 2 cents. You can find specific data in a thread I started a while back on this subject.
 
#43 ·
Eureka,
BLUF: for a given power requirement, generally best BSFC occurs at the lowest engine RPM wide throttle openings can be maintained without stalling, in other words when engine manifold vacuum is greatest. Engineers choose vehicle gear ratios in an effort to keep a particular engine in its BSFC "sweet spot."

Compare the rated power outputs of the Transit's available engines:
3.7: 275bhp @ 6000rpm, 260 lb-ft @ 4000rpm (high rpm, lower torque)
3.5EB: 310bhp @ 5500rpm, 400 lb-ft @ 2250rpm (med rpm, torque monster)
3.2D: 185bhp @ 3000rpm, 350 lb-ft @ 1500rpm (very low rpm, torque fiend)

Now compare the RPM's of the 3.7 with different final ratios (and if you have any mpg data, please feel free to add it):
130, LR, 3.7 w/ 4.1
75mph = 2545rpm (tach reads ~2700rpm), 17mpg
70mph = 2375rpm (tach reads ~2500rpm), 18mpg
65mph = 2205rpm (tach reads ~2300rpm), 19.5mpg
60mph = 2036rpm (tach reads ~2100rpm), 20.5mpg
55mph = 1866rpm (tach reads ~1900rpm), 22mpg

130, LR, 3.7 w/ 3.73
75mph = 2315rpm (tach reads ~2500rpm), ? mpg
70mph = 2161rpm (tach reads ~2300rpm), ? mpg
65mph = 2006rpm (tach reads ~2100rpm), ? mpg
60mph = 1852rpm (tach reads ~1900rpm), ? mpg
55mph = 1698rpm (tach reads ~1750rpm), ? mpg

130, LR, 3.7 w/ 3.31 (if it were offered)
75mph = 2054rpm (tach reads ~2200rpm), ? mpg
70mph = 1917rpm (tach reads ~2000rpm), ? mpg
65mph = 1780rpm (tach reads ~1900rpm), ? mpg
60mph = 1643rpm (tach reads ~1700rpm), ? mpg
55mph = 1506rpm (tach reads ~1550rpm), ? mpg

Finally, compare the frontal area of the three configurations:
LR: 39.3ft^2
MR: 48.4ft^2 (23% more aero drag force than LR)
HR: 53.3ft^2 (36% more aero drag force than LR)
(aerodynamic drag varies directly with frontal area & the power requirement (fuel burn) varies with the cube of velocity)

A 3.7 pushing a heavy 148, HR would simply not have the juice at the given gear ratio provided by a 3.31 rear (which puts the engine well below its optimal BSFC power band <2000rpm) to overcome the enormous rr & aero drag. A heavy 148, HR motivated by a 3.7 & a 3.31 rear would essentially become a 4spd- as the 6spd auto's programming would have a hard time selecting 6th & even 5th gears to keep the engine in its optimal BSFC range. The 3.7 simply can't put out sufficient bhp/torque efficiently that low in its rpm range & the vehicle load requirements would be too high for this particular final drive configuration.

Hope this labored explanation helped a little.
 
#45 ·
Eureka,
BLUF: for a given power requirement, generally best BSFC occurs at the lowest engine RPM wide throttle openings can be maintained without stalling, in other words when engine manifold vacuum is greatest.
...
(aerodynamic drag varies directly with frontal area & the power requirement (fuel burn) varies with the cube of velocity)
...
An apparent typo and a clarification:
1. Low engine RPM, wide open throttle = 'lowest' engine manifold vacuum (highest manifold pressure)
2. While the fuel burn RATE (lb/hr) varies with the cube of velocity, your travel rate also varies, therefore fuel use PER MILE to overcome aerodynamic drag is relative to velocity squared.

Glad to have another member here who likes to look at the numbers and the reasons behind them :)
 
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