Gas Mileage

[Redneckmoparman]

So i have yet to see a thread anywhere that talks about gas mileage and what anybody has done to improve it. So lets start a discussion about it and what numbers have been acheived what vehicle modifications have been done for it and ideas to improve it. Now obviously later MPFI models are going to be better than earlier carbeurated models and 2wd over 4wd but let's not exclude anybody or bash because of numbers acheived this is to help all of us better our vehicles and wallets, not to have a pissing contest. lets start with some EPA ratings for the platform (i searched the dodge just because thats what i have) being 2wd 5 speed is 17/22 http://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&path=1&year1=1990&year2=1990&make=Dodge&model=Ram%2050%20Pickup%202WD&srchtyp=ymm
and 4wd automatic v6 is 15/18 http://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&path=1&year1=1990&year2=1990&make=Dodge&model=Power%20Ram%2050%204WD&srchtyp=ymm giving both ends of the spectrum according to the epa so what do you guys get for numbers?

[minimotos95]

if i remember right the one time i calculated mine it was around 25mpg mixed driving, my father claimed to get 30mpg on the highway, i'm not sure i believe him on that, considering he got 8mpg in a nissan titan...
that's for a 2wd 5 speed 4g64.
how to improve gas mileage:
i try to keep it under 60mph except when getting momentum before a hill

lift off the throttle early and coast to stops

accelerate slowly and once you hit cruising speed make sure you're in 5th

tires: LRR tires are the best but in general the skinnier the better, taller if you want to lower your cruising RPM

aerodynamics, i'm not smart enough to know what would help these trucks but i bet one of those chin spoilers like on the coor's race trucks would help

don't put unnecessary load on the engine, like AC

i have always found the EPA numbers way off, usually over 25% low

[lush90]

I have two 4x4's, both with 3.0 V6's. One is the stock truck engine and it consistently gets 17 to 19 around town for my landscape business. It doesn't seem to matter much if it's empty or has a ton of stone in the bed. I drove over to Spokane on the interstate at 75 and got about 14 mpg but came back on a two lane highway doing 60 and got nearly 21. The other truck has the higher compression version of the 6G72, a low mileage Japanese import from a Diamonte, and I have gotten as high as 24 mpg doing 70 on a road trip. This was coming back from Pullman, which is a pretty flat drive with altitude loss, which I am sure helped.

[Fordubishi]

Lets see 28 year old carb that runs rich (worn out), 300+hp 302, 2400 lbs D-50 gets 16-18mpg in the city opening the 4bbls a lot on the weekends. Highway at 70-75mph getting 24-26mpg......... :P

[Andy 2]

My '89 4x4 5 speed gets between 20 and 24 mpg. My commute is at around 55 mph on the secondary highways,fairly flat drive. It goes down in the colder months as the choke stays on longer. I run fuel system cleaner through it once in a while which I think helps. Definitely not too good around town. Too many starts and stops, I would estimate 18 mpg in town. I've heard water injection can help but never tried it. With the new Dodge rams boasting 32 mpg there has to be a way for our lighter smaller trucks to match it.

[noahwins]

Lightening the flywheel and driveshaft might help. Greasing the wheel bearings with synthetic grease is another cheap thing to do. Fresh transmission and diff fluid. Cleaning up the dirty aero, like the huge mirrors and lower valance if you have one of those bumpers. Maybe making an underbody cover out of sheetmetal. Lower the truck a few inches.

Tonneau cover would be huge. An open bed is the worst for dirty aero.

[camoit]

Lightening the flywheel Makes it rev up faster and is harder on the trans. The mass of the flywheel is there to absorb the shock of the pistons firing and to give enough innershia to keep the engine spinning smoothly.

[noahwins]

Yes, but it would reduce the load on the engine right? At the expense of the transmission's lifespan.

[BradMph]

H2O injection has many good points and not only increases mpg, it also keeps internal engine parts pretty darn clean too.

In internal combustion engines, water injection, also known as anti-detonant injection, is spraying water into the incoming air or fuel-air mixture, or directly into the cylinder, in order to cool them. It has been used historically mainly to increase the power output of military aviation engines for short durations such as dogfights or takeoff, however it has also been used notably in drag racing. In Otto cycle engines the cooling effects of water injection also allow for greater compression ratios by reducing the problem of engine knocking (detonation). Alternately this reduction in engine knocking in Otto cycle engines means that in some applications significant performance gains can be obtained when water injection is used in conjunction with a supercharger, turbocharger and/or other modifications such as a more aggressive ignition timing. Depending on the engine, improvements in power and fuel efficiency can also be obtained solely by injecting water. Water injection may also be used to reduce NOx or carbon monoxide emissions.

Water injection is also used in some jet turbine engines and in some shaft turbine engines, normally when a momentary high-thrust setting is needed to increase power and fuel efficiency.


Theory:
For any fuel to burn most efficiently it must be combined with a specific amount of air. This specific air/fuel ratio is called the stoichiometric ratio. For gasoline in a piston engine, the ratio is 14.7 parts air for each part fuel, by weight. At this ratio all the fuel is combined with all the available oxygen in the air to get the most energy from the fuel. Unfortunately if most engines are run at this "ideal" ratio of 14.7:1 they will quickly overheat, knock, and soon seize.

For the engine to survive it must be run on a richer air/fuel ratio than economically optimal, say from 10.5:1 to 12:1, thus allowing the excess (i.e., unburned) fuel to cool the cylinder. (The catalytic converter eventually burns the excess fuel before it leaves the tail pipe, but the energy content of the fuel is still wasted.)

Since water is cheaper and more abundant than gasoline, LPG or diesel, it can be injected into the cylinder to serve the purpose (i.e., cylinder and/or charge cooling) of the excess fuel. In a gasoline engine the air/fuel mixture can then be leaned out to the 14.7:1 stoichiometric ratio while still providing the same power as the richer mixture. In addition water has both a higher density and specific heat capacity than most hydrocarbon fuels, so smaller volumes are required for the same cooling effect.

National Fire Protection Association's code states that over 25% methanol in water is deemed a flammable substance.

Some points about fluids

* Distilled water, because of mineral deposits or hard substance contamination are the enemy of water injection users, distilled water is preferred over tap water. The fluid being used should come from a sealed container. Distilled water is low cost and easily obtainable.
* Washer fluid, typically contains about 35% methanol this is the simplest solution to get methanol into you're WI system..more often then not 35% methanol is an ideal mixture for most users.
* Methanol, added to either washer fluid or distilled water. This can be purchased straight up from race shops or garages that sell fuel to racers.

[Redneckmoparman]

thats about where i thought these trucks should be at and ill report on what mine gets once i get it running good

[amcervantes]

86 MM 2wd gets 22 mpg consecutively. cruise to work, stop and go traffic on the way home

[Andy 2]

I seem to recall some years ago there was a product being marketed as a fuel saver that used platinum and rhodium to maximize the burn in the combustion chamber. The ad was in all the papers and called something like 1-800 less gas. For around $300 you got the kit, which was basically a plastic bottle with some vacuum line and fittings, and the solution to put in it. You would hook the vacuum line up to your manifold or carb somewhere and it would draw air through the solution and pick up the platinum particles. Platinum is what is in a catalytic converter that burns off the un-burnt fuel in the exhaust. After installing it they said your carb would have to be adjusted and the idle speed lowered as it would idle higher with the system. Supposedly you would not have to depress the accelerator as far to drive, thereby using less fuel. They claimed that fuel economy would improve by 20% or something and would last for over a year. After that you had to buy another bottle of their solution for around $175. I remember calling the number and getting all the info but gas was not so expensive back then so didn't bother trying it. It was just as economical to spend the money on the fuel as it was the kit. I don't think it would matter how much we improve our gas mileage. If we could get 100 miles to the gallon, the price of gas would be $20 a gallon. The oil companies need the revenue to keep people working,(oil industry employs millions) and the government needs the taxes so they have enough money to mismanage. I thought gas was over priced here..... take a look at European prices. They are up around $8 a gallon.

[Redneckmoparman]

Well so far i got 22.5 mpg and 300 miles to the tank its not the advertised 18gal i should have with the macro cab unless it says empty with over 3 gal left in the tank.... I think i need to run it dry and find out

[Andy 2]

before you run your tank dry and suck any residue into your fuel lines there is another way to achieve the same goal. Reset you trip odometer when you fill up. When the trip odometer reads 200 miles for example, fill up again and record how many gallons it takes. Do this a few times resetting the trip meter each time you fill up. You can calculate your mpg each time using simple division, and you can find your average mpg over a period of time by keeping a record of how many gallons you use. 5 recordings of gallons used would equal 1000 miles of driving. This way you can keep lots of gas in the tank without sucking the dregs into your fuel line and you won't run out of gas.

[amcervantes]

before you run your tank dry and suck any residue into your fuel lines there is another way to achieve the same goal. Reset you trip odometer when you fill up. When the trip odometer reads 200 miles for example, fill up again and record how many gallons it takes. Do this a few times resetting the trip meter each time you fill up. You can calculate your mpg each time using simple division, and you can find your average mpg over a period of time by keeping a record of how many gallons you use. 5 recordings of gallons used would equal 1000 miles of driving. This way you can keep lots of gas in the tank without sucking the dregs into your fuel line and you won't run out of gas.

that's exactly what I do, should also mention that I have a 2.0l with a re-manufactured mikuni carb. Going to put in a weber when my electric fuel pump comes in and compare the two. From what I read on here it seems people get better throttle response, power and better mpg.

[pennyman1]

On Geronimo 2.6,5spd, weber 32/36, pacesetter header into 2 1/4" pipe to free flow cat, a flowmaster to dual 2" outs I get 19-20 city and 25 on the highway with the speedo pegged at 85

[amcervantes]

nice, is that a stock final gear in the tranny or an extra tooth or two?

[Andy 2]

Are those mpg numbers you're quoting in imperial gallon or U.S. gallon Pennyman ? We Canadians have to buy our fuel in litres so I need to know for the conversion.

[pennyman1]

Miles per U.S. gallon - 3.91 final axle ratio, stock 5th gear ratio. - Also have a lightened stock flywheel.

[DroppedMitsu]

There's a nifty site that takes all the math out of figuring out your fuel mileage and all that and gives you a bunch of other info. You guys should check it out, it comes in pretty handy. http://www.fuelly.com

[Andy 2]

Well, if you're getting 25 miles to the U.S. gallon, that's almost 30 miles to the imperial gallon. The U.S. gallon contains 3.8 litres and the imperial contains 4.54 litres. The difference being around 18%. That's quite a lot when it comes to fuel economy. North of the border there is a system that gives fuel economy in litres/100 kilometers. In this system the lower the number the better. 25 miles to the U.S. gallon would be around 9.4 L /100 km. 25 miles to the imperial gallon would be around 11.3 L/ 100 km. That's 1/2 a U.S gallon difference over a distance of 62 miles, which is why I asked which gallon you are using.

[Redneckmoparman]

im not talking about running it dry to find mpg just how big the tank really is cause it was like 14.xxx us gal with the needle just about at the empty mark but i think i need to find a starion/conquest owner to trade diffs with so i can drop those rpms im not the biggest fan of the 3.91

[pennyman1]

the starquest gears only fit the front of a 4wd - get the gears from a 87 up MM / ram 50 with an automatic - they are 3.55 gears and fit the truck rear. I edited the mileage post to U.S. gallons.

[Andy 2]

My 1988 Ram 50 owners manual says the following for rear wheel drive trucks: 2.0 liter engine 52.0 liters (13.7 gals); that's U.S. gallons.
: 2.6 litre engine 52.0 or 69.0 liters
(13.7 or 18.2 gals)
those are the approximate fuel capacities for 1988.
The four wheel drives had either 15.7 or 19.8 gallon tanks. I will assume that the longer wheelbase trucks had the larger tanks as my 4x4 ext cab has the 19.8 gal tank and my 2wd ext cab has the 18.2 gal tank.

[amcervantes]

now is that final gear off the newer MM fit even the manual tranny or does it fit only the automatic?

[Andy 2]

If you go to a higher ratio in the diff can you swap the speedometer drive gear from the tranny so your speedometer will read true?

[pennyman1]

yes if you can find one that matches the ratio you put in - not sure if they can be bought a a dealer anymore.

[Redneckmoparman]

the final gear goes in the rear end the different trannys just were built with different sets and pennyman the gears fit all they just dont bolt in to the carrier you have to actually swap the ring and pinion and if i could find an auto mm in a jy i would do that instead and if i could find a lsd that would be icing on the cake to swap in lower gears and an lsd at the same time

[pennyman1]

I was referring to the speedo gears that go in the tailshaft of the tranny - they have to be changed when the rear gears change. Look for a 1st gen montero for an lsd that will drop right into the rear if you don't want to get a power grip lsd

[Andy 2]

I don't know if changing the gear ratio will make that much of a difference. The bottom end torque will be reduced and your engine will have to work harder to accelerate at the same rate you do now. Also will probably have to gear down more going up grades. My 4x4 5 speed will cruise up a fairly good hill in 5th gear at 55 mph just by giving a bit more gas. The 2wd automatic always drops out of overdrive to go up a grade unless cruising at 65 mph or so. 2800-3000 rpm seems to give me pretty good fuel economy with the 5 speed

[pennyman1]

you have to look at the height difference compared to the stock 26" tires - if the tires are taller it raises the effective axle ratio(numerically lower) which moves the power band and makes the truck have less pickup. Lowering the ratio in the axles (numerically higher) brings the motor rpms up faster into the motors power band, restoring original performance or improving it, at the cost of the top end speed. With the right gears, running tall tires can give almost stock economy and power, provided the weight difference isn't substantial

[drphils87]

How about an electric golf cart motor bolted engine block to the driver's side that connects to the harmonic balancer by belt or chain. That is, if you don't have anything there already. It would only make sense for in town driving while accelerating.

[Andy 2]

Welcome to the site drphills87.Im not sure I understand golf cart motor idea. Could you give us a bit more detail please.

[Law Dog]

Them gears are often used in a variety of trans, just take the old one to a dealer that has inventory for those type of trans.

[geezer101]

Golf...what? Putting load onto the crank via the harmonic balancer sounds like a recipe for disaster (and how do you disengage it?) I have been wrong before but...

[Andy 2]

Are you talking about using an electric motor as a power assist? What powers the electric motor? If you power it off the trucks alternator you will have to burn more fuel, just like running ac. You can't make electricity without an energy source. If you cover the truck in solar panels and charge batteries with them just for the golf cart motor you may be on to something. How would you regulate the power it required so that it actually assisted the motor instead of loading it down. Like geezer101 says though, loading the crank from the balancer might not be wise.

[Andy 2]

Gas is now $1.30 a liter up here. Almost $5 a U.S. Gal. Has anyone looked into propane conversion? It's only $0.69 a liter. I know it doesn't give the same power as gas but it burns a lot cleaner. No need to worry about emission tests, and you can use longer oil change intervals.

[Fordubishi]

You need to build the engine to run Propane. You need hardened seats,Stainless Steel Valves, compression 12:1-14:1, and replace the carb/efi to run the propane.Plus the tanks. Yes you can do duel fuel or the crappy conversion kits but you will be replacing heads every year or 2. The conversion kits are a pain in the butt as if the temp drops below -10C they are a pain to start.By the time you have done all the work you will have somewhere around $4000-$5000 into the conversion.

[Lem Forder]

I had an old Chevy V-8 pickup that was converted to dual fuel. It was fine for no/low load driving, but you could really feel the power loss on hills or with a load. We decided that the cost savings did not justify the down side lack of power and the loss of 1/2 of the bed to the tank. The story we heard when we bought it was that the conversion had originally been done by a rancher in Texas who lived so far outside of town that he basically ran out of gas by the time he got home with the stock set-up, knowing he had to get back to fill up again. So he converted to propane to give himself the range and put in a huge tank.

[Andy 2]

I knew propane didn't have the same bang for the buck as gas and with a 4 cyl. engine the power loss would probably be even more noticeable.I did some checking around and called a couple of places that do conversions. They told me that you need about 15% more propane to go the same distance. I guess the price of tanks has really gone up as well and I was given prices between $4000 and $5000 to do a conversion. So add that to the down side of that idea. You can buy a lot of gas for that kind of money.

[TohruRokuno]

I did some research and found the G63B was used in LP forklifts. If you could find a used one of those for a reasonable price you could buy it for the motor and scrap/sell the rest.

[geezer101]

You can get an improvement on power if you tune the engine to run on the stuff. You will also need to add an upper cylinder lubricant feed to the intake to prevent the issues of valve wear. The upside is LPG is cheaper than regular fuel but the downsides are the amount of space the LPG tanks take up and the extra fuel consumption. You will find that engine oil looks cleaner for longer when using LPG and the combustion chambers don't carbon up (but don't be a monkey and think you can get away with doing extended duration oil changes) - and if you run into issues you will need to take it to an experienced LPG technician. And yes, trying to start an engine running on LPG when it's really cold is a biatch. Messing with LPG is not an option for the DIY mechanic as a system leak could turn your truck into a rolling inferno...

[Brady H]

My 89' 4x4 standard cab mighty max gets about 19 around town and about 24-25 on the high way cruising in 5th gear usually. Its a 2.6 with the weber carb kit. And it seems to be very constant as far as I have monitored.

[Redneckmoparman]

Wow this took a left turn from my original post lmao but I love it and running a emoter off the crank could work I've seen other homemade set ups like it that use a motor to assist the engine to allow less throttle to accelerate but usually on a diesel and would likely have small returns on the inefficient 4g6x sohc 8v motors

[obsidian]

95 2.4 2wd. 24-25 usually no matter what I'm doing. Highest I got was 28 being grandpa moses on the interstate.

2 1/4" catback exhaust with no cat is the only thing done performance wise.

[Rahtid]

On my 90 and 94 i would get 24-27 mpg