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3400 mile roadtrip, change gears for MPG?

garlicbreath

garlicbreath

1/2 ton status
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I am planning a trip to colorado from western NY in October, 1800 miles one way in my 71 blazer. I have a 400hp 350, auto, 1 tons, 37's, and 4.56's

Since the 14FF has a bolt in pinion, could I setup a set of highway gears, pop them in for the trip, swap back to the 4.56's for the wheeling, and go back to highway gears for the trip home?

I wouldn't even bother normally but it is more than half way across the country, and ALOT of miles.

At 3.00 a gallon, and a somewhat reasonable but optimistic 13mpg it would be 831.00 in gas. Even saving 150.00 would be worth it.

My family lives in Denver so I have access to garages and tools.
 
If you plan on this, I would do no less than 4.10 becasue I dont think the 350 will be quite as torquey with higher gears, and you will end up using more gas.
 
neverendingproject said:
If you plan on this, I would do no less than 4.10 becasue I dont think the 350 will be quite as torquey with higher gears, and you will end up using more gas.
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Or, 31's, 3.07's, and throw the 37's in the bed?? Should get 15-16 I'd say if running right, maybe better? Probably worth it.
 
I drove from NorthEast Illinois to San Diego in my truck and got 12.5 MPG avg for the whole trip.

1987 1 Ton K-10 Longbed.
SM465, NP208, 4.56 gears and 35 BFG MT's
 
To me its a lose lose situation. The amount of money you spend buying tires/gears/magical fuel mileage thingys will hardly make a difference, you'd be lucky to get an extra 5-10% in fuel savings over the whole trip which would be around $40-80.
 
Not gonna fly or rent a car, the whole point of the trip is for wheeling and camping for a week.

Trans is a th350.
 
garlicbreath said:
Not gonna fly or rent a car, the whole point of the trip is for wheeling and camping for a week.

Trans is a th350.
Click to expand...

You might be able to get your truck and yourself on a train to get you some of the way there. Again, would probably save money.

Cost of 31's: Free, borrow or every respectable CK5er has parts trucks,
3.07's (did they even come that tall 1-ton?) used??? Why not if it's for the sole fact of driving there. Couldn't cost that much. You'd look funny going down the road with 8" of lift and on 31's. :wink1:
 
hawkeye649 said:
You might be able to get your truck and yourself on a train to get you some of the way there. Again, would probably save money.

Cost of 31's: Free, borrow or every respectable CK5er has parts trucks,
3.07's (did they even come that tall 1-ton?) used??? Why not if it's for the sole fact of driving there. Couldn't cost that much. You'd look funny going down the road with 8" of lift and on 31's. :wink1:
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I look funny anyways!:haha::haha:
Don't think the 31's could hurt much.

I have a set of 265's in the basement on 8 lug wheels already, but wouldn't going to smaller tires AND the gear swap be counter productive?
I have thought about the wear on my swampers though.

Too bad I ain't redneck enough to weld a steering quickener from a race car onto my rear output! Redneck overdrive, for a while.

I would put a 700r4 in, I have been thinking about it for a few years, but the last time I swapped one in a car, I never could get the TV cable right and burned it up. Gears are one thing, a tranny rebuild or swap 1800 miles away from MY tools is another.

I have even wondered about machining some adapters to run the 22.5 rims and tires from a big rig. I am a machinist so it wouldn't be a big deal. Anyone know what the OD is on those tires?

As for the train idea, that one is new to me. How would one go about getting a lifted blazer on a train?

So far the best idea I had was to design a hydraulic ram with a grapple hook on the front of the truck. That way I could catch a trucker headed the right way, extend my mechanical hook, latch onto his trailer, and coast!
 
We just got home from vacation last week where we traveled 3529 miles and spent Gas $539.70 on gas.... But we didn't drive eather of my Blazers but my mothers Mini Van.....
 
garlicbreath said:
I have even wondered about machining some adapters to run the 22.5 rims and tires from a big rig. I am a machinist so it wouldn't be a big deal. Anyone know what the OD is on those tires?
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The OD will range from 36" to 42" depending on what size you run. The problem is weight. One bare 22.5 steel wheel will weigh the same as a 37 on a steel wheel. The tires are very thick and weigh a lot also. A tire and wheel can weigh about 200 pounds. Then you have more rotational mass, and it takes more energy (fuel) to keep more mass rotating. That's why a shorter/lighter tire with a gear change will get better milage.

What other vehicles do you have? Maybe you could put some stock tires on the K5 and flat tow it with a more fuel efficient vehicle?



.
 
Id like to see a K5 with 10:00 24" tires!

I think it would look COOL to have semi-truck tires on a K5!--but impractical,for the reasons Divorced listed...

We had a 68 GMC 4x4 with 20" bus tires and rims at the junkyard--we cut the centers out of the 20" rims and welded the 15" rims inside them!:D ..it was a flatbed we used to tow stuff around the yard with..not roadworthy,but man it looked MEAN!....the front fenders didn't like the 20" tires though--they got torn off the first day!...:wink1: we had to use low range too--too high geared with those big tires in 4Hi !..

Some folks here are trying to save fuel in their older gashogs by "disabling" cylinders on their V8's,much like the new 2007 cars are doing..(remember the 4-6-8 Caddy motors?--their baaaack!)....

One guy I know "shut off" 4 of the opposing cylinders of his 350 by using custom pushrods he made, with springs that are weaker than the valve springs in the center of them,where he chopped out a section,so the pushrods wont open the valves on those cylinders..he claims it gets 20+ mpg,but I'm skeptical..and no oil can flow to the rockers anymore,so that probably wont last long!..I told him backing off on the rocker arm adjustment would have been better..:crazy:
 
Honestly, Forget about doing anything that messes up a good setup. 4.56 isnt that much more than 4.10's at that gearing. Plus, since your going out there, your pedal's going into the metal for some of those passes without the high gearing.

I'd keep it as is- I'd however, consider finding a set of rim/tires just so you dont wear out your trail tires. a set of H2 rims and tires are perfect for you.

As for gas- Yes, over the distance it will cost you more, but I dont think its going to be dramatic-

Lets say you drive easy, and get 13mpg, its all highway.

3000/13=230 gallons.

Lets assume you had a stock k5 with 31" tires and 3.73 gears- I used to get about 15-16mpg on flat level ground.

3000/15=200 gallons
2000/16=187.5 gallons

The difference will be about 30-40 gallons, which is one to two tank fulls.

Average 35 gallons, 3.50 a gallon, you get $122.50 as your overall difference between your mpg, and the best possible mpg you could have ever gotten.

Honestly, you'd get better fuel economy savings by fabricating a skirt under the height of the truck. That skirt saves some serious fuel economy on all the big rigs. Also, driving at 50/55 will save TONS more gas.

The final option of course, is to go diesel. :bow: Then you could get 18-20mpg, run on waste oil, and call it a day.
 
hawkeye649 said:
3.07's (did they even come that tall 1-ton?) used???
Click to expand...

Not on the 14bFF... 3.21 and 3.42 exist though. 3.07 could be had in Dana axles ;)

Rather than gears.... how about a pair of 40"+ tires for the back? :crazy:
 
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