Some modifications to improve mpg

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Jul 1, 2007 | 02:09 PM

luckster

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Some modifications to improve mpg

No longer using my 69 F100 for work so gonna change a couple things to try and get 20+ mpg. Low/no dollar mods

My plans:
Go to small tire, 225/60-15 for light weight and less height of vehicle for less drag. I have the tires already

Change axle gears from stock 3.70 to 3.2 or 3.0. Available to me no cost, labor only. Basically making 4th gear about 20% higher, like overdrive would.

Truck has 240 straight six with slightly larger cam, T-18 trans, rocker arms from chevy six, stock one barrel carb, 2.5" exhaust w/flowmaster, pertronix electronic ignition, aluminum cab height canopy.

Your suggestions?

Jul 1, 2007 | 05:38 PM

Kalashtar

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I'm getting 20mpg in a stock 69 f100 long bed no canopy.
300, T18, points, motorcraft 1101 1bbl, 3.50 gears and LT235/75/15's rear P235/75/15s front.

Jul 2, 2007 | 10:42 PM

Chevy_Eater

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Taller tires are better for mileage, but if you're going to stick 3.0s in the rear then you probably won't want too tall anyway.

Jul 3, 2007 | 04:16 PM

390fe

Fleet Mechanic

Joined: Jul 1999

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From: Iowa

Keep a clean air filter, fresh plugs, and a good tune on it. Keep your tires properly inflated. What really got my mileage up was playing with the tune-up. These trucks will run under a wide range of conditions, so experiment.

Jul 4, 2007 | 02:06 PM

"Beemer Nut"

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From: "Islander"

Draft behind a 18 wheeler, drive at 45 mph and less.
Geared too tall can cause lower mpg than being under geared
seeing you only have a 240 and aerodynamics of a brick.
Go MPI.

Jul 4, 2007 | 04:01 PM

R Rocks

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From: Porterville Utah

I like this Beemer Nut.

Jul 4, 2007 | 04:08 PM

galaxie641

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From: SE Wyoming

Slap some dual Electric fans on, you'll gain power and mileage.

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Jul 24, 2007 | 06:52 PM

Danger_Dave

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From: UPSTATE NY

i've heard sometimes a bigger carb can offer better gas mileage if you keep your foot off it. i went from a 2barrel to a 4, but my right shoe seems to be defective and rather heavy so i wouldnt know for sure.

Jul 24, 2007 | 10:24 PM

#10

"Beemer Nut"

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From: "Islander"

15%? add spinners and you'll gain another 20% provided they are pitched in the right direction to pull ya thru the air.

Jul 24, 2007 | 11:42 PM

#11

repower

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From: Marquette Mi.

I like the electric fans, but what's an MPI ?

Tom

Jul 25, 2007 | 08:32 PM

#12

mattri

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Multi Port Injection

Jul 26, 2007 | 10:30 AM

#13

repower

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From: Marquette Mi.

Thanks mattri . fairly obvious , just outside of my intersts . With the exception of a brief romance with a 302 in my 65 F250 , I've always driven inline 6 , 4 speeds . I drove a couple injected versions that friends owned and thought that they stole the soul of that motor when they injected it .Seems like a lot of revs and clutch slip required to start in 2nd gear . The situation may be different with an automatic ,but thats not my cup of tea . What kind of mileage gain does the MPI give ?

Tom

Jul 26, 2007 | 12:17 PM

#14

"Beemer Nut"

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From: "Islander"

Cover up the bottom of the truck with sheet aluminum for cleaner aerodynamics, this should gain you some mileage.
Shave the front roof rail as it's an air dam.
Strip it down removing all the weight you can including adding a fiberglass front end. MPI gives the motor a wider rpm torque range pulling vs a carb that it ideal at only one given rpm but does good thru it's range.