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4.9L MPG [recent trip]

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1986F150six
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4.9L MPG [recent trip]

Post #1 by 1986F150six » Tue Nov 06, 2012 9:00 am

1986 F150 with 4.9L [160,900 miles], 4 speed manual O.D. transmission, 3.08 rear gears and 215/75 X 15 tires.

Duraspark conversion with Carter YF from a 1970 F350; stock exhaust with original catalytic converters, but no EGR. The distributor has been recurved.

I drive very conservatively.

This past Saturday, my son and I decided to visit the Corvette Museum in Bowling Green, KY. I live in northwest AL, so the trip is a pleasant ~190 miles of hilly country. It starts off @ 55 mph and then changes to 65-70 mph on I-65. When we began, the temperature was in the mid 40s and had warmed to the mid 70s for the return trip.

While on the Interstate, I decided to check my odometer against the mileage markers posted on the roadside. After 20 miles, my odometer indicated 19.65 miles, so it is "slow".

I checked the mileage both ways and filled up at the same gas station.

Tank #1 covered 196.8 miles and required 10.211 gallons = 19.27 mpg [uncorrected].

Tank #2 covered 196.9 miles and required 9.732 gallons = 20.23 mpg [uncorrected].

:D :D :D

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Re: 4.9L MPG [recent trip]

Post #2 by Harte3 » Tue Nov 06, 2012 9:03 am

:thumbup: :beer:
'83 F150 300, 0.030 over, Offy DP, Holley 4160/1848-1 465 cfm, Comp Cam 260H. P/P head, EFI exhaust manifolds, Walker Y Pipe, Super Cat, Turbo muffler, Recurved DSII, Mallory HyFire 6a, ACCEL Super Stock Coil, Taylor 8mm Wires, EFI plugs.

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THE FRENCHTOWN FLYER
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Re: 4.9L MPG [recent trip]

Post #3 by THE FRENCHTOWN FLYER » Tue Nov 06, 2012 9:33 am

YUP. When I drove my '86 van conservatively, with similar drivetrain (except EGR functional and initial advance tweaked a few degrees) I used to get 19.5.

Intrestingly, with my non EEC controlled '81 van I used to top 20 regularly.
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clintonvillian
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Re: 4.9L MPG [recent trip]

Post #4 by clintonvillian » Tue Nov 06, 2012 10:25 am

sounds very promising for my build

1986F150six
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Re: 4.9L MPG [recent trip]

Post #5 by 1986F150six » Tue Nov 06, 2012 10:36 am

I have had this truck for almost 5 years and have recorded every tank and figured the mileage. I am the 2nd owner and the 1st tank returned 8 mpg. I knew I had my work cut out for me!!!

One can still get 20-22+ mpg on the highway, but it is more difficult with gasohol. I would estimate a ~1 mpg decrease since 10% gasohol became the norm.

Mr. FTF, my son's 1984 F150, with all emmission systems still functioning, has seen as high as 26 mpg @ 60 mph. This was years ago, when the truck was mine. At that time, it had the 2.47 rear gears and was a "dog" regarding acceleration, but a champ regarding mileage. It now has 3.55 rear gears, is much more fun to drive and gets 20-22 mpg highway with 201,000 miles.

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Re: 4.9L MPG [recent trip]

Post #6 by Harte3 » Tue Nov 06, 2012 10:44 am

"Intrestingly, with my non EEC controlled '81 van I used to top 20 regularly."

I suspect with an EEC controlling things, they run more in an eco-friendly stoich AFR and less in a more mpg-friendly leaner burn?
'83 F150 300, 0.030 over, Offy DP, Holley 4160/1848-1 465 cfm, Comp Cam 260H. P/P head, EFI exhaust manifolds, Walker Y Pipe, Super Cat, Turbo muffler, Recurved DSII, Mallory HyFire 6a, ACCEL Super Stock Coil, Taylor 8mm Wires, EFI plugs.

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80broncoman
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Re: 4.9L MPG [recent trip]

Post #7 by 80broncoman » Tue Nov 06, 2012 7:33 pm

Harte3 wrote:"Intrestingly, with my non EEC controlled '81 van I used to top 20 regularly."

I suspect with an EEC controlling things, they run more in an eco-friendly stoich AFR and less in a more mpg-friendly leaner burn?


I that is correct as long EVERYTHING in that EEC system is working right. THe second something takes a dump, it goes to fixed timing and thus the single digit MPG.
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THE FRENCHTOWN FLYER
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Re: 4.9L MPG [recent trip]

Post #8 by THE FRENCHTOWN FLYER » Wed Nov 07, 2012 11:33 am

Harte3 wrote:"Intrestingly, with my non EEC controlled '81 van I used to top 20 regularly."

I suspect with an EEC controlling things, they run more in an eco-friendly stoich AFR and less in a more mpg-friendly leaner burn?



I suspect you are exactly correct.
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Re: 4.9L MPG [recent trip]

Post #9 by StrangeRanger » Wed Nov 07, 2012 3:50 pm

My 96 with 3.08 gears and an E4OD pulled 19.5 from Knoxville TN to Akron OH via the WV Turnpike and some mountainous stretches of I-81. It would probably have done better with an M5OD and would certainly have done better with a tonneau. So maybe EEC doesn't hamper mileage all that much.

With the 3.73 gears in it now....let's not discuss mileage. :lol:
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
2013 Hyundai Elantra Coupe (daily driver)

1986F150six
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Re: 4.9L MPG [recent trip]

Post #10 by 1986F150six » Wed Nov 07, 2012 4:27 pm

Mr. StrangeRanger,

Your mileage and mine are very similar. You described the mountainous terrain... what speed(s) were you driving?

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Re: 4.9L MPG [recent trip]

Post #11 by tom954x4 » Wed Nov 07, 2012 6:22 pm

My highway numbers in my current truck ('95 4x4) are similar to 86F150six under similar conditions, 55-65 mph, on 10 percent ethanol. My '91 F150 2WD M5OD with no shell also did similar on the highway with pure gas.

I rented a 2012 Ford Taurus last week. 19.8 mpg overall/mixed driving. My '95 F-150 4x4 with 171,000 miles: 17 mpg overall. I am not complaining. Taurus owners should be. :bang:
1995 F-150 XL, 300-6, 4x4, ex-cab, sb, 3.08 5-speed, 2 1/2 in. exhaust w/flowmaster 50, MSDignition failed with no warning, now out, canopy, 179,000 + miles. Gone but not forgotten 1965 F-100 240 3spd lwb "the green hornet"; 1960 F-250 4x4, 223 six, 4sp with wrap-around rear window, two-tone paint, overhead camper.
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Re: 4.9L MPG [recent trip]

Post #12 by Harte3 » Wed Nov 07, 2012 6:56 pm

It's not hard to get 26 mpg with our 2004 Taurus...done many times between KC, MO and Spokane, WA.
'83 F150 300, 0.030 over, Offy DP, Holley 4160/1848-1 465 cfm, Comp Cam 260H. P/P head, EFI exhaust manifolds, Walker Y Pipe, Super Cat, Turbo muffler, Recurved DSII, Mallory HyFire 6a, ACCEL Super Stock Coil, Taylor 8mm Wires, EFI plugs.

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Re: 4.9L MPG [recent trip]

Post #13 by StrangeRanger » Wed Nov 07, 2012 7:18 pm

1986F150six wrote:Mr. StrangeRanger,

Your mileage and mine are very similar. You described the mountainous terrain... what speed(s) were you driving?


Speed limit +5 on cruise control
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
2013 Hyundai Elantra Coupe (daily driver)

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