The Stovebolt Site Forums The Shop Area General Truck Talk Gas Milage

Poll for gas milage, as prices rise at the pump what are you doing to increase milage, I have a t5 with .63 OD and a 3.73 ring & pinion and get between 16 and 18 mpg, any suggestion on what to do next to increase milage. 66C10 w/250 ci.

Well 66Step, I'd say you're doing pretty darn good with that mileage. I get about 11-12 on my '65 with 292/T5(also a .63 OD)/4.57 rear/long tube headers/4 bbl/HEI. I've tuned and dialed everything in to the best of my ability and can't get anywhere near even 13mpg. I'd be ecstatic if I were gettin' 16 mpg.
-David

Muggsy did your milage improve when you went with the 4 barrel carb and headers, I also have HEI and keep motor tuned, at 70mph I am turning about 1900 rpm which is on the low side of the power band for my 250

I cant get more than 15 out of my 70 stepside. I am going to replace the Carter (Edelbrock) carb with a Q-jet.

16 MPG w/230/3spd/3.73, toilet bowl Rochester. HEI only thing changed. Brian

I never checked my mileage when I had the 1 bbl and stock intake/exhaust. But if I had to guess, I'd say it's a little worse with 4 bbl. The performance improvement however, is well worth it. I hated that craptacular Rochester 1 bbl.
-David

Computer controlled fuel injection would help but the cost of it would take a long time to pay for itself,
Scott

i wonder if putting a 6.2 diesel in would help?
lot's of torque.

About 16 on my '72 C-10 w/350 4-bbl and 3-speed manual trans.

My gas guage has never worked so I use a yard stick. I think I get about 21 miles to the inch.

That's awesome haha

I turned the idle screw down a little, I got better immediately.

I don't ever hurry and I keep my truck in pritty good shape. Mine is mostly origional including the one barrol carb. I get about 19 miles to the gallon.

I get 21 to 22 mpg with my 62' i/2 ton chevy truck with 235 ci six. The addition of a 3 speed overdrive to my truck helped a lot. I have a 390 rear end and keep the truck tuned up . A lot has to do with the way you drive and staying within the speed limit!

Did anyone suggest taller, narrower tires? You might even try synthetic oil to see if that has any impact.

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Norse
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OldTruckNetwork

Synthetic oil? Is that something you heard or you personally have used it and got better mileage?
-David

synthetics

I have been using synthetics for a few years. Typically, when I purchase a vehicle I change the oil and use synthetic. But I don't really keep a -close- eye on my mileage.

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Norse
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OldTruckNetwork

1955 2nd series.Built 350,700R4 tranny,3.90 rear-20MPG

I get between 12 and 14 with the two trucks I drive regularly.

My commute is 100 miles/week. If you figure 10 mpg I'm burning 10 gallons a week and at $2.50/gallon that's just $25.00/week.

A 10% improvement in mileage gains me only $120/year. If I could double my mileage I'd only save about $600/year on my commute. That’s real money but it isn’t enough to purchase, license and insure a car I don’t want anyway.

With gas prices going up I’m hoping to score a 4x4 dually someone is dumping cheap because they can’t add.

I've never checked the mileage in the '51, and won't from the standpoint of trying to increase it. I am curious what I'm getting, but whatever it is, it is.

Along the lines of Steve's post, Car Talk had an interesting puzzler earlier this year.

From http://www.cartalk.com/content/puzzler/transcripts/200505/index.html

You drive a gas-guzzling SUV that gets a whopping 10 miles per gallon. Your sleek and efficient spouse drives a sleek and efficient hybrid that gets 100 miles per gallon.

Now, let's assume that both of you drive the same distance each year. Your spouse sees an ad for a new, super-duper hybrid that gets 200 miles per gallon. She is lobbying to trade in her old, wasteful 100-mile per gallon hybrid for the new 200-mpg model; her thinking being that getting this new hybrid to replace the old one will really improve the average miles per gallon of your household.

On the horns of a dilemma, you seek out the one person you trust with questions automotive: your mechanic, Crusty!

"What can I do," you ask, "to improve our household's miles per gallon without buying this new hybrid?"

Crusty says, "Well, if we tune up your old SUV, and inflate the tires correctly, and remove that four inches of accumulated bird poop on the roof, I'm pretty sure we can get you all the way up to 11 miles per gallon." Your heart sinks.

What should you do? That's the question. Under which scenario would your household see the biggest improvement in miles per gallon: by getting the new hybrid, or by tuning up the old SUV?

For the answer go to http://www.cartalk.com/content/puzzler/transcripts/200505/answer.html

I love it! The guy with the right answer is from the little town where I grew up and went to high school!

There are 2 things that always work on any pick up -- remove the tail gate or put on a taonneau bed cover.

Actually, that tailgate tip is not true, according to some engineers. It goes against intuition, but leaving the tailgate on and up on a pickup is better. See here for an explanation on the Car Talk site. According to Ray, aerodynamics is a very complicated science, and air doesn't always move in predictable ways.

Anybody ever see any research on the effect of tonneau covers, or truck caps?

Well, based on the second guy's explanation, it would seem that the tonneau cover would do the same thing as the "bubble" of air and would probably not have an effect either way. Just my opinion :p

<font color=red>Bonus!</font> How many GALLONS of fuel were used in the manufacture of the catalytic converter on the -one- new hybrid?

Concerning the tonneau cover -- theories aside -- on my 95 Dakota, 5.2L, 3.55 my average increased from 18 to 20 -- only difference -- tonneau.

I get 21 on a 235 with dual Offy/Holly Weber/Howard M4F cam setup.

Next month I go bolt in (our 41 Sedan) a OD and 1958 rearend. Hope that helps the milage.

Gas is verrrrry expensive over here in Germany. About $ 5,56 a Gallon low octan pump gas!! (1.15 Euro a liter)

You folks live in a cheap gas country ;-)

That`s why lot`s of guys over here experiment with super carbs, fuel heaters, PCV-Jars, Hydro Boosters and whatelse.

Some of this stuff works only on pre 1970 engines without electronic emission stuff and cheap single grade oil. Only fuel heating (wich is verry popular here) works for injection and saves 10-20%.

Frank

Compelling argument but I'd need to see that one with my own eyes. Put some leaves in the bed and watch that "slowly rotating air bubble" do some mighty funky things.
Maybe it's having the 50 lb tailgate off that's saving the gas...

I have a tonneau cover my 97 GMC and I do get a slight increase in milage with it. Maybe a 5 % increase on a tank of gas.

mine will get 20 plus on the hi-way and somewhat less in town,, but then I drive like an old man.Fred

With my 96 Chevy C/K 1500 4.3 Vortec 5 speed I get a consistant 21 mpg. But like Joker sez I drive like an old man I guess its because I am an old man. Doesn't matter if the topper is on or off mileage is the same. I have found if you keep your foot out of the carburetor (or is it the injectors?) and shift smoothly the mileage is the same. Now pulling a camper its a different story. Mileage drops to 14-16 because I can't get out of 4th gear because the rear end gearing is so high and the camper is quite heavy, My .02. Also when analyzing MPG always deduct at least 10% from what anyone tells you because you have to allow for the bull$h%t factor. Weeds

Andre,

The 6.2 diesel was something of a dog. I think the power rating in the 1988 chevy pick-ups was 143 hp and about 247 ft lb of torque. you could squeeze that out of a healthy six probably with similar gas mileage.

TWE I dont know how you get that kinda mileage from a 5.2, we have a 96 grand cherokee with that motor and it's 15-16 on the highway tops. This is with stupid AWD and 3.73s though.

I had a boss once who said a man will lie about 3 things, 1)his sex life, 2)how much money he makes, & 3)his gas mileage. Brian

let's see here, 137in. wheel base 1ton panel,went to the feed store and put her on the scales and weighed in at 4650,has a 4:10 3rd member(took out the 5:14 was getting 5mpg)she wears 7.50x17 12 ply tires, gets between 8 to 10 mpg. If you can't run with the big dogs, stay on the porch!
tony'n weatherford :p

All the wind tunnel tests and expert analysis apparently doesn't refer at all to my 52 Chevy going down the freeway....

Here are my actual real-world daily driver gas mileage experiences, which can easily be repeated to proof they are 100% correct.

Putting the tailgate down, hanging on the chains,
will give a clear measurable improvement in gas mileage, the longer the distance driven at high rpm/mph and high wind drag.
In fact, the faster you go and the longer the distance, the better the gas mileage.

Here are the numbers:
Once a month I do a business trip of about 200 miles of pure freeway driving at 2500-3000 rpm and 65-75 mph. I am using 91 octane gas (highest you can get in CA). See engine specs below...

With closed tailgate I get about 17 miles/gallon, but with open tailgate on the chains, I get a little over 20 miles/gallon.

That's a measurable increase of 20 % in gas mileage for prolonged freeway driving.

These numbers are with an unloaded bed.
But check this out - when I hauled a fully loaded bed up to the rear window with a two inch drop on the rear tires going the same route and distance, I also got 17 mpg just like driving unloaded with closed tailgate !!
So the engine works just as hard with a fully loaded truck as unloaded with tailgate up.
Unbelievable how huge the wind drag works against the engine on the freeway and high speed.

City driving has considerable less wind drag and the tailgate makes little to no difference if up or down.

Driving, maintaining and understanding old trucks is not rocket science, after all.
Wind tunnels are not the same as actually freeway driving with an engine creating the wind drag, rather than a giant wind machine...

I don't know how other trucks behave in this simple freeway test, but it doesn't cost anything or take any effort to let the tailgate down, next time you drive down the freeways at high speed.

One more note: I don't do this to my engine, but I imagine gas mileage goes down again, if you go past 3500 rpm for prolonged periods.

The cool thing about old trucks is you don't have to be an engineer or expert - these trucks and engines actually talk to us ... all you got to do is listen and have fun with them.

Road Again--

My experience is similar to your own--I drive 60 miles up to where my parents live. I've noted that the tail gate down seems to positively affect milage. I was surprised by the piece and suspect no wind tunnel tests were performed on old stovebolt trucks. An additional point I've noticed is that wind direction affects milage more than anything else--if ur fighting a headwind get your wallet out...

283 (.030 over)2 bbl Rochester, 3 speed trans and 3.90 rear = 11.6 mpg last summer round trip to CA. This is close to what I've gotten for the last 31 years no matter what. You guys hurt my feelings.

bznhafdzn,

You are so right - I live in a very high wind area (Mojave Desert/Sierras) with hundreds of windmills covering the mountain range.
I just moved out here recently and we are in the 'windy season' right now.
I bet I get even better milage during the hot dry and windless summer.

I am starting to think about adding some special shaped panels after and below the front bumper to prevent the air from kreeping inside the engine compartment from underneath.
Maybe some guys with more free time than I have, did some experimenting on that...

Bruce, have you thought about going to 202 heads? my dad used to run a stock 283, with a 3 speed, 2 barrel roch, along with 202 heads and headers, in a '68 3/4 ton, with 5.something rearend, and he got around 24...or so he says. lol

.later days.
.desperado.
.sam.

Remember the 10% rule. Weeds