Weight, AUW plays a massive role in this too. I'm a weight **** and giving my specs listed in my sig, - so far I'm guessing about 18mpg. Although I actually need to do a real test still. (and I'm just saying something to subscribe to this thread)

So far I've pulled out over 150lbs from a stock 79 4x4 setup.
- deleted smog pump, 02, cats, catback system
- no jack, no spare tire, etc (a can of Fix0Flat is light!!!)
- no horn
- switched from the steel wheels to aluminum
- scrapped off so much junk in the undercarriage..
- removed the useless center speaker

I also only fill her up to half a tank and never a full tank. My weirdness tells me that 8 gallons of liquid is heavy and therefor.. less performance. breaking, excel, millage, corners.

I "think" I have 4:11 gears.. I need to check and I want to be in the 3:55/3:75 range.
And/or find a 5th gear...

Thanks for this info, as a DD and 4x4 I want to max out the mpg.

 

I understand removing stuff to dump some weight. But seriously the horn? That's a safety item. That's something I wouldn't remove. If you want to save weight swap out the intake and exhaust manifolds for an aluminum intake and some headers.

Removing the horn kind of reminds me of a guy my dad use to work with. He gutted his geo metro to get better mileage. That included pulling the wipers, bumper covers, the entire interior except for the basic dash. That included the seats and seat belts. He drove 40+ miles twice a day sitting on a plastic milk crate! That is until a state trooper stopped him one day and made him park it!


My 78 F150 4x4 came with 3.50 gears.

 

haha. Yeah comes from racing days.
well, just like the harley, the exhaust is much more attention gett'r

 

Gas mileage update... 20+ mpg


4/07/15 221.2 miles 19.81 mpg town [50-75F]
4/18/15 264.1 miles 20.27 mpg town [50-80F]
4/20/15 164.3 miles 21.04 mpg hwy/loaded [55-70 mph]
4/28/15 220.1 miles 19.22 mpg town [45-75F]
5/08/15 241.3 miles 20.69 mpg town [50-85F]
5/15/15 201.4 miles 20.17 mpg town [55-85F]
5/21/15 218.1 miles 20.79 mpg town [55-85F]

 

Excellent! You are beating my new truck's MPG.

 

Yes, but I do not have conditioned seats, lane center correcting, self parking, cruise control, 4 wheel drive, special differentials, auto shut off, H-O-R-S-E-P-O-W-E-R, etc.

 

Haven't needed the air-conditioned seats yet, but would have used the heated part had we taken the truck to the airport this morn. As for the lane-keeping, the nudge it gives you to get back in the lane has been turned off. Just don't like it. But, I certainly like the horsepower!

 

Do you have a crystal ball?

 

[QUOTE=Gary Lewis;14725341]Excellent! I'll hazard a guess that next summer, when the temp warms back up, you'll see right at 20 MPG on your normal weekly runs. That's really good MPG. And, you still don't have pinging at any point? If that is the case then you may still have MPG being "left on the table". But, it is probably minimal.

And an even earlier prediction by you, Gary...

 

Dad always said "'Tis better to be lucky than good."

 

5/26/15 205.4 miles 19.96 mpg town [60-80F]
6/10/15 202.7 miles 19.96 mpg town [65-85F]
6/18/15 215.1 miles 19.37 mpg town [70-95F] landscaping & road construction.
6/27/15 225.2 miles 19.27 mpg town [75-95F] road construction /alt. route
7/08/15 229.4 miles 19.14 mpg town [70-92F] alt. route
7/18/15 254.3 miles 19.98 mpg town [75-99F] alt. route
7/29/15 227.8 miles 19.17 mpg town [72-99F] alt. route
8/08/15 218.3 miles 19.80 mpg town [72-98F] normal route
8/19/15 237.0 miles 20.03 mpg town [72-92F]


Good Lord willing, I plan to drive to OK in October. I will report back again with much cooler temperatures and highway driving.

 

Man, talk about consistency!

So, what can we do to increase the MPG a bit while here for the GTG? You already have the itty bitty chin spoiler - right? What would you think about going with the larger one from a 90's truck? Had one of those trucks in the shop yesterday and noticed the spoiler is a lot bigger. Dunno if it'll fit, but I'll bet it would - with some help.

What about synthetic lubes? Like the tranny and diff? And maybe engine oil if you don't already use it. I've seen a 1 or 2 MPG increase on some vehicles by changing the lubes to synthetic, but those vehicles had little engines and were already getting 30ish MPG and had lots of wind drag work done by the factory. So in their case the internal drag was significant. In your case the aerodynamics are pretty poor so the internal drag isn't as significant, percentage wise.

But, there's still another degree or two of ignition timing we could dial in if you don't have any pinging. Do you? I've forgotten.

 

I would not be opposed to using a later/larger chin spoiler.

The transmission has synthetic lube, but not the differential.

The timing is the same as set in OK [14 BTDC]. As you recall, it was close to 18 BTDC when I visited and it would sometimes drag upon starting. For the following 3-4 weeks after the OK tune-up, the vacuum advance was tweaked 2 full turns with each weekly fill-up and mileage changes recorded. Mileage improved with each adjustment with no ping [perhaps just the very slightest hint under light throttle on a very hot day], but the canister "bottomed out" after the 6 full turns.

Perhaps the initial timing could stand 1 degree (?) more, but most likely, the greatest benefit would come from additional curving of the distributor. However one might say, "if it doesn't smoke, don't fool with it"!

After the return trip from OK in 2014, the mileage was the same as before, but the engine was more free to rev [Ha! Ha! - you know my driving style. ] The final vacuum adjustments were made after the highway trip, so perhaps mileage will be different on the highway, now. No highway trips since last year.

For this year's trip, I thought about making a cover for the bed and if I could find a pair of the small sedan style door mirrors which some trucks had [I believe they use the same spacing for the screws to mount on top], I would try this as an "aero package".

 

IIRC, and, according to Mythbusters, the mesh tailgate was the most efficient. They compared it against a tonneau, the tail gate up, and the tail gate down. Would be a good time to test out the mesh! I think it was somewhat significant difference too, but I could be wrong.

 

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