12 Valve Fuel Economy - Diesel Bombers

12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

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Old 10-14-2008, 10:30 PM
Woody35's Avatar
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Default 12 Valve Fuel Economy

Im looking into getting a 12 Valve. it will have stock suspension and will be 4 wheel drive

say i get a regular cab, regular bed, manuel tranny, strait pipe exuast(thinkin 4 or 5 Inch),

BHAF, aftermarket intake manifold, maybe say 40HP injectors because i hear they are more

efficent than stockers and maybe a fuel plate one step down from the stocker. if i get a

truck just like this what fuel economy should i expect.i dont really want to lower the axle

ratio but if they makes a huge difference might think about. any other suggestions on a way to get better feel economy is always appreciated.
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Old 10-14-2008, 10:37 PM
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Location: Mason City, Iowa
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I've got a 94, 5 speed, 3.73 rear, 4"exhaust, big filter. I get 22-24mpg at hwy speed of 55-60. On the interstate at 70-75, it gets19.
Oh ya, it's for sale too
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Old 10-14-2008, 11:27 PM
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with all my mods and 35" tires with a 4" lift im at 21-23mpg hyway and 19-21 city, winter sucks becasue of warm up time here so im down to about 13-16 with all the idle time
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Old 10-14-2008, 11:50 PM
Join Date: Jun 2007
Location: Fayetteville AR
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If my star wheel is cranked and im playing hard ill get 15-16 mpg Just running around random driving 17-18 mpg and highway at 70 mph ill get around 20 mpg.

My 97 on the way i home i got 25 mpg. I never got that again. but i would regularly get 21-22 on the highway with it.

Mild injectors should help you and if its an auto a nice converter will help alot as well.
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Old 10-16-2008, 09:16 PM
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i have 265 tires, 5-speed, fuel plate #10, replacement filter. I get 18-20 in town and 25ish in the high way.
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Old 10-17-2008, 11:00 AM
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With the 35's, I get about 16 around town, 20-22 on the highway, and thats a 4x4 with a Ranch Hand bumper. Just got 23.2 round trip going to Syracuse and back, I was real happy. I also have a clutch fan, which helps a lot, I only turn it on if I'm idling for a while or if I'm in bad traffic.
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Old 10-17-2008, 01:13 PM
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I get 20-22 sometimes if I can keep my foot out of it I get 22-24
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Old 10-18-2008, 04:07 AM
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With what i've done to my truck i get around 17/19 city,and around 22/24 on the highway unless i'm really romping on the go fast pedal.Another thing you can do if you get the truck is put some fuel conditioner in the tank every other fillup.I've noticed that also helps my fuel economy.
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Old 10-19-2008, 06:34 PM
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thanks guys. i just need the money and i will hopefully be the owner of a new truck
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Old 09-12-2010, 12:11 AM
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Smile 12v in 97 Ford F-350

I have a 1997 Cummins 12v in a 1997 Ford F-350 4x4 with a 6 speed manual transmission. I went from getting 9-12 MPG with the 460 V-8 to getting 20-24 MPG with the 12v.

I pull a custom made 5th wheel (48' Long... 24' with bunks for a boat and 24' up front with a custom made Lance Camper to fit the style of the trailer). I can pull the fifth wheel fully loaded (about 10,000 pounds gross) 65-70 MPH and get about 19-20 MPG.

Before with the 460 I got 6 MPG and Could not even pull the dang thing.

Cummins All The Way!

Ford 460 =
Cummins 12v =
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