Gas mileage improvements..

[skunked]

Yes this kind a thread has been around before..but who has good ideas or mods to boast our mileage?

[drlocke]

Drop your keys down the well.

[88GWSteve]

Get one of these.... http://www.krakar.co.uk/rrs/tw_bike.jpg
Or if you wanna do keep it, just do basic maintenence, keep it tuned, TFI install, rebuild carb if needed, etc.

[Spectre]

Yes this kind a thread has been around before..but who has good ideas or mods to boast our mileage?

In terms of effective modifications to increase mileage (regardless of price):

1. Overdrive transmission.
2. Multipoint Electronic Fuel Injection.
3. Convert to a diesel engine, which, surprise, can come with an overdrive transmission.

Other than that and keeping your boot out of it, there's not much you can do.

[Don S]

..
skunked;

Boosting Fuel Mileage
... It takes X amount of power to move gasoline engine vehicles from point to point. The engine converts gasoline to heat as the power source. Much more than fifty percent of the heat is wasted unused and is dissipated though the radiator and exhaust system. Large cubic displacement engines normally consume more fuel than smaller engines but this is not a ‘hard’ fact.
FOOD for THOUGHT. Why are four cylinder engines capable of better fuel mileage than six or eight cylinder engines of the same size and at the same RPM? This is due to the longer duration of the combustion stoke allowed by fewer cylinders. The longer duration for the burning process in a four cylinder is double that of an eight cylinder. The eight is more wasteful in theory than the four or six cylinder engines. More cylinders shorten the time that combustion has to finish the job of totally burning all the fuel especially at max power out put. One of the fuel saving technologies of the day is reducing the of fuel using ‘cubic inches’ of the engine when full power is not required.
... Here is a list of a few of the mechanical things that can effect fuel mileage.
Cam and ignition timing, cam lift, duration and valve size. Leaky fuel delivery systems with vented vapor losses, restricted air induction systems i.e. dirty filters. Intake air can also be too hot or cold. Restricted exhaust scavenging systems. Operating temperatures of fuel and engine. Carburetors with bad power valves, accelerator pumps and fouled choke systems. Carbon fouled injectors, sparkplugs, and piston rings. Type of transmission, automatics without lock-up converters and over-drives, gear ratios. The type of tires, tire size, the tire pressures and the wheel alignment. Example; Just think, is it possible that larger wider tires require less ‘toe in’ that could reduce drag and get better fuel mileage? But the larger wider tires cause increased air flow resistance.The vehicle speed, the load, the wind speed and direction. The list can continue on including the type and additive mix of the gasoline. Gasoline blends are changed continually by local area, altitude and season. These are changes in the volatility of the gasoline. Winter Gasoline will evaporate much faster in the summer temperatures and less octane is required at high altitudes.
The driver knowledge and ability is the big factor for achieving the best fuel mileage if the vehicle is in proper condition.
Make sure the odometer in the vehicle is showing correct mileage. Increasing the diameter of the tires will reduce the amount of miles shown on the odometer. Keep a record of all fuel amounts, the mileage and the Miles Per Gallon between each gas-up. The record can be helpful in spotting problems with the engine when there is a sudden drop in mileage.
An example of the simple formula is 200 miles divided by 10 gallons = 20 MPG
Full tank amounts will vary due to air trapped in the tank but the MPG will average out in the long run.
Here are a few thoughts about saving fuel.
First thing a driver will notice when they start to conserve fuel is it will agitate other drivers around his vehicle. Please be considerate of other drivers who have no concept of your economy driving. The other drivers want to race to the next stoplight and remember, if they don’t get there quick enough they won’t get to stop!
1. Think about driving as an art while doing so. Stop rubber-necking, turn off the music, turn off the cell and drive.
2. Install a dash-mounted vacuum gauge and use it. As the fuel mileage drops the vacuum needle drops. Try to prevent the needle from dropping below five inches. Readings will change with altitude changes.
3. Drive as if you had a fresh egg taped on the accelerator AND brake pedals.
4. Apply accelerator and brake petals smoothly.
5. Reduce speed as much and as soon as possible. Speeds above 50 MPH eat into the pocketbook!
6. Scan far ahead of your vehicle for traffic control signals and things that will allow you to ‘get off the gas’ sooner so you don’t have to ‘hit’ the brakes as hard – later. The over use of brakes means fuel has been wasted.
7. Drive as if your afraid your brakes are in poor condition and you are trying to save them.
8. Purchase your fuel in the morning when it’s cool and keep the tank full.
9. Air you tires up when they are cold and on the plus side of the recommended pressure and check them often especially on cold days.
10. Small amounts of high quality low ash synthetic Out Board 2cycle oil in the fuel (less than ¼ Oz per gallon) will clean and lubricate and reduce friction. The low ash oil will help the following items for better fuel mileage and life; electric gyrator fuel pumps, carburetor/injector parts, spark plugs, valve stems, compression rings and EGR systems. One sticky fuel injector can drop fuel mileage by up to one third.
11. Air dams can enhance cooling and reduce aerodynamic drag. Reduce the amount of air getting under the truck because the underside of vehicles create much air turbulence and drag at highway speeds. Bug shields, sun visors, wind deflectors, roof top racks and large outside mirrors can reduce fuel mileage.
12. The effect of heavy loads is detrimental to fuel mileage and brake life.
13. Modifying a vehicle with lifts and large wide tires is detrimental to fuel mileage and brake life.
14. Cruise control may save fuel in ‘flatlands’ but may not be economical in hilly country.
15. In hilly country do not allow the down hill run to cause engine ‘braking’ i.e. slowing down the vehicle unnecessarily. Run your fastest speed at the bottom of a hill and the slowest at the top. ... Only use engine braking when the vehicle is going to gain excessive and unsafe speed that would have required a fair amount of regular brakes. Excessive downhill braking can cause many heat related problems. Among these are warped rotors, brake fade, boiling brake fluid, wearing out pads, over heating seals, bearings and lubricants.
... Down hill engine braking and downshifting for increased engine braking is not going to consume very much fuel because the throttle will be closed. Long downhill runs of five or more percent grades are a good time for downshift engine braking. Two miles of seven-percent grades with curves should be mandatory.
So in hilly country it's a case of the having to use more throttle to regain the speed you lost by allowing short periods of unnecessary engine braking.
16. Allow the engine to warm up and/or drive gently till it does. Cold engines get poor fuel mileage.
17. Put the transmission in neutral or stop the engine when long waits in traffic are encountered i.e. train crossings and long red traffic lights.
18. Reduce the Air Conditioning and the electrical demands on the alternator. Alternators draw much horsepower and extra fuel so fancy lights and sound systems burn extra gasoline and bother other peoples eyes and ears.
19. If the automatic transmission is equipped with overdrive and/or lock-up torque converter learn at what speeds it changes gears/locks. Often one can get the transmission into overdrive and lock the converter sooner by backing off the accelerator pedal a little at the right time.
20. The use of WOT (Wide Open Throttle) to gain speed is wasting fuel.
21. Some people are claiming fuel mileage gains by adding small amounts of acetone to their fuel. There is an Acetone article in the Fuel Tech Section.
22. Hey!.. wake-up!! We are sorry we put you to sleep… do you have any other ideas?

Have a good one and http://content.worldgroups.com/GRP002/GrpPhotos/F/FSJ_TECH_202/060414/002959000.GIF CUL.. Don S..

[66rustbucket]

I've started running amsoil in my motor and that helped a bit. They say if you replace all fluids from front to back you can expect a 5 to 10% increase in gas mileage. Just a thought...I'm getting 14 mpg in my 66 Gladiator with a buick 350!

[drlocke]

Seriously on this topic:
1) Do a complete engine analysis and assess compression from cylinder to cylinder and then do a followup leakdown test every cylinder. If compression readings are extremely variable from cylinder to cylinder then analyse leakdown findings to determine if air injected into the cylinders via sparkplug hole is leaking past exhaust or intake valve, or head gasket or rings. You may find yourself doing a complete engine overhaul, or you may find that you only need to pull the heads and clean out carbon deposits.

Assess condition of the valve train, including sprocket and chain assembly for slop, and cam for lobe conformation.

Overall the engine needs to be operating within proper tolerances for all working surfaces.


2) After the engine mechanical has been covered then do a complete tuneup, including checking the distributor advance curve and make sure the distributor components--such as flyweight springs and the like--are still up to snuff, and that the drive gear for the distributor isn't unduly worn. Make sure points or pickups are in good shape, and make sure that all plugs are gapped properly.

3) Overhaul carburetor to ensure that it is operating in all aspects--including such as jetting, idle fuel metering and automatic choke, etc--to its utmost efficiency by design--which isn't saying much as far as fuel economy is concerned in most cases. Better to try TBI or MPFI if you can manage.

4) Check transmission and driveline to make sure they are at 100%.

5) Check chassis geometry and wheel alignment for optimum adherence to spec.

6) Check brakes to make sure they are stopping the vehicle when you want to stop, and not trying to when you don't.

7) Check tire condition and pressure often.

Understand overall that if you have made a vehicle with gear ratios and limited slip differential for off-road use then it will not be a good vehicle for the DD on the highway to work and back if fuel costs are a concern.

Also understand that if you have an FSJ my advice in my previous post is by and large the best measure in saving fuel. My own waggy is uncompromisingly boxy and non-aerodynamic, and to borrow and butcher a phrase from E.B. White in "Farewell My Lovely", a reminiscence about the model T Ford: ....uncompromisingly erect ...and the [8] cylinders push the [vehicle] through the atmosphere with a total disregard of physics...."

[drlocke]

As predicted by me as I was interrupted in writing my spiel, Don S to the rescue, with a much more comprehensive and better treatise than I could ever wish to give.

Way to go, Don S.! LOL :)

What he said..... :o

[FSJeeper]

Don S did a great job for what to do with a gas engine in a FSJ. No matter what you do though, mileage with a gas motor is not going to ever be outstanding with a gas engine. Aerodynamics of a FSJ are non-existent.

A diesel will improve your mileage dramatically. Non turbo mid 80's Blazers with the 6.2 were EPA rated at 29 mpg on the gallon. It is an easy swap.

[drlocke]

The E.B. White quote I excerpted from an article describing the model T Ford--that I miserably butchered before--actually reads.....

"Directly in front of the driver was the windshield - high, uncompromisingly erect. Nobody talked about air resistance, and the four cylinders pushed the car through the atmosphere with a simple disregard of physical law."

Sound somewhat familiar?

I will post this as a separate article soon. Look for it, as it is to my way of thinking worthwhile reading and such as most of us would enjoy.

[funwheeling]

These vehicles are not made for fuel economy. Look now at the commander 14/19.
The best way for you to get good milage out of your wag is to put stabilizer in your tank and drive a hybrid.
I doubt that anyone will be able to get any more then a lucky 15 mpg out of these ever without a lot of cutting chipping and ducktape.

Just my opinion.

I didn't buy mine to save dinosaurs.

Like trying to squeeze water out of rocks in the desert.

[rawdave]

www.eagle-research.com (http://www.eagle-research.com)

This guy provides low-cost DIY manuals on increasing fuel mileage up to 100%.

I have read the manuals and once my Jeep is completely tuned with the new MPFI, I intend to implement several of his suggestions.

[steven79]

Just tested mine last trip to keystone lake, 16.6 at 60 mph thats useing a gps to check mine, when i used the old speedo i get 11 mybe but i know it is way off. In town i very between 9 and 12 mpg. It is all in the tuneing and condition of the motor.;)

[will e]

Just tested mine last trip to keystone lake, 16.6 at 60 mph thats useing a gps to check mine, when i used the old speedo i get 11 mybe but i know it is way off. In town i very between 9 and 12 mpg. It is all in the tuneing and condition of the motor.;)

Unfortunatly you can't determine accurate gas milage on one trip or one tank of gas. It is almost impossible to get the tank exactly to the same fill point as the last. Temp can have a impact on this as well. It doesn't take much. A 1 gallon difference in a 10 gallon fillup throws off the results by 10%. That is, if you went 100 miles and you got 10 gallons in it is 10mpg. If you got 9 gallons you will think you got just over 11mpg. (Steven79 this isn't directed at you specifically).

[drlocke]

Just tested mine last trip to keystone lake, 16.6 at 60 mph thats useing a gps to check mine, when i used the old speedo i get 11 mybe but i know it is way off. In town i very between 9 and 12 mpg. It is all in the tuneing and condition of the motor.;)

I'm gonna get a gps installed in my Wag first thing tomorrow!

[Serious Johnson]

Following up on some points above:

The vacuum guage/egg thing works OK-ish for a big 'Murican boat with a V8 & slushbox, but who drives those anymore :) ? For a fuel-injected 4-cylinder car with a manual transmission, it's most efficient to get up to speed quickly, using large throttle openings (but not quite full-throttle, which imposes open-loop mode), and shifting at very low revs. Less pumping loss from an open throttle is more efficient. That's a diesel's main advantage. Get the heck out of those lower gears as soon as possible and, above all, waste no revs!

Warm-up can only hurt -- you're getting zero MPG during that time, and causing the motor to come up to temperature much more slowly. Just start it up and drive off immeiately but, as said, gently.

Aerodynamics & other drag are certainly important. I've noticed that, in flat country, I get about the same fuel mileage when towing an empty car hauler as when there's another 5,000 lb aboard. A Wag or narrow Cherokee are not all that horribly shaped, particularly with the small stock mirrors & no roof rack. Some modern SUVs are worse -- I'm thinking of that one named for a blow-job.

In certain cases, for instance, a stock wag with a slushbox tranny & 2.72 gears, slowing down below typical highway speed doesn't help. I've seen such a rig, in perfect condition, get slightly worse economy at 50 MPH than at 75. I blame poor low-rpm efficiency in the non-lockup torque converter.

My Wag, modified with a hotrod 360, fuel injection, manual tranny, 3.73 gears, dual limited-slips, 33" tires, & 4" lift gets about 20 MPG in the mountains if I drive like I have some sense. It could do only a little better than half that when it was stock.

S.J.

[janie]

Leave the tailgate down. Every lil bit helps.

[drlocke]

Leave the tailgate down. Every lil bit helps.

I have that tailgate delete option on my I-bird pickup. :D

[JeeperJay]

Adding an electric fan should help a little bit....right?

That is my next planned modification. Get rid of the giant mechanical fan and install an electric one. Oh yeah, and downsizing back to 31" tires. D'oh!

[pb]

Weight = crappy mileage for stop and go driving
Aerodynamics & drivetrain = crappy mileage on highway

The heavier the object, the harder it is to start moving from rest. That's why newer aerodynamic SUV's the same weight as ours get the similiar city mileage. Not going fast enough for aerodynamics to make a great impact on mileage in city driving or for overdrive to kick in.

Aredynamics and drivetrain are important at steady speeds. An object in motion tends to stay in motion until an outside force acts upon it (air resistance & gravity) SJ described this when talking about towing. It takes less energy to keep the mass in motion than it is in getting it to that speed, not getting into the momentum/weight aspects. The more efficient the drivetrain, less energy is expended in overcoming the outside forces and remaining in motion. This is why you can get better mileage with a diesel, efi and/or overdrive in a nonaerodymanic FSJ at highway speeds as compared to stock components.

As far as improving mileage, lighten the weight and increase the drivetrain efficiency as previously mentioned.

[IslanderOffRoad]

Luckily for me, my Jeep is a hybrid- it burns gasoline, oil, and just about any other fluid you can think of!

Now if only it could burn rubber.

[drlocke]

Luckily for me, my Jeep is a hybrid- it burns gasoline, oil, and just about any other fluid you can think of!

Now if only it could burn rubber.

Try placing a spark plug wire boot on the exhaust manifold. :D

[710 Burner]

I can't drive with my tailgate down. I'll choke on the fumes.

[Steelhead]

Janie-
I saw a Mythbusters that busted the tailgate thing for trucks. Turns out the tailgate up creates an air-cushion that actually decreases resistance and improves mileage over tailgate down.

[IslanderOffRoad]

Try placing a spark plug wire boot on the exhaust manifold. :D

flamethrowers are fun!

[Tonka J200]

Leave the tailgate down. Every lil bit helps.

Sorry, Janie, I used to think the same thing, but then I found this:

"Gas Mileage and Pickup Tailgates (http://horsepowersports.com/gas-mileage-and-pickup-tailgates/)

Tailgate up or down? The television show Mythbusters is sometimes interesting, sometimes silly but I caught one yesterday addressing this “what everyone knows” advice.
The often repeated premise is that an open pickup truck bed is bad for gas mileage because it catches the air and creates drag, so the easy, zero cost method for increasing mileage by reducing drag is to drive with the tailgate down thereby letting the air escape. Seems logical, right?
The two hosts drove two Ford F150s, as identical as possible, filled up with identical amounts of gas, one tailgate up, one down, until they ran out of gas. Driving one behind the other, you guessed it, tailgate down went dry first! The tailgate up truck went 30 miles further. Hmm …
Searching for an explanation they built a fluid flow simulation of a wind tunnel with a model truck. The answer lies in the fact that an open bed with a closed tailgate creates a rotating bubble of air in the bed that remains trapped there. Air coming over the top of the cab is kept out of the bed by this bubble and drops down behind the truck. Open the tailgate, the bubble disappears and air over the cab drops down faster, hitting the bed and creating drag. This explanation agrees with designers from the auto manufacturers who say the same thing. Who knew? They didn’t address the bed cover or no bed cover question which I presume will be coming up next season. "

[Russianwolf]

I just did a little research and now can say with certainty that for $10k you can have a Jeep that will never have to stop at a gas station again.

Convert the thing to EV.

One charge will get you about 70 miles. The motor is rated for vehicles up to a 5000lb GVW. If I had $10k I might try it to see how it works out.

[Don S]

Sorry, Janie, I used to think the same thing, but then I found this:

"Gas Mileage and Pickup Tailgates (http://horsepowersports.com/gas-mileage-and-pickup-tailgates/)

Tailgate up or down? The television show Mythbusters is sometimes interesting, sometimes silly Driving one behind the other, you guessed it, tailgate down went dry first! The tailgate up truck went 30 miles further. Hmm …
Searching for an explanation they built a fluid flow simulation of a wind tunnel with a model truck. The answer lies in the fact that an open bed with a closed tailgate creates a rotating bubble of air in the bed that remains trapped there. Air coming over the top of the cab is kept out of the bed by this bubble and drops down behind the truck. Open the tailgate, the bubble disappears and air over the cab drops down faster, hitting the bed and creating drag. This explanation agrees with designers from the auto manufacturers who say the same thing. Who knew? They didn’t address the bed cover or no bed cover question which I presume will be coming up next season. "
..
Dear Mythbusters;

... No two vehicles are going to run (consume fuel) exactly alike.
... No two drivers are going to have the same style.
... Was more air trapped in the fuel tank of one?
... Was one vehicle benefiting from drafting?
... What kind of designers? I am a designer.:rolleyes:
hummmmmmmmm...
... In flow tests air compresses and decompresses as it flows around objects. Liquids are virtually uncompressible. Hot air from under the hood as well as hot exhaust gasses are expanding behind the real trucks will have a small effect on the air flow at the rear.
... NASCAR uses real wind tunnels to test rear spoilers for Drag (slows the vehicle and eats fuel) and down force.
I doubt the tailgate plays a large roll in fuel mileage. I have a camper shell on my Frontier and get above average fuel mileage.

Have a good one and http://content.worldgroups.com/GRP002/GrpPhotos/F/FSJ_TECH_202/060414/002959000.GIF CUL.. Don S..

[joe]

http://www.krakar.co.uk/rrs/tw_bike.jpg


Oh so sweet!

[JPSwapMohn]

IslanderOffroad, You should get really good gas milage after mounting your GW on a Samari frame! My wife got a real kick out your Avatar!

[drlocke]

IslanderOffroad, You should get really good gas milage after mounting your GW on a Samari frame! My wife got a real kick out your Avatar!

Looks like a cross between a Chero and a Morris Mini-Minor.... :confused: :rolleyes:

[kennyh]

My birthday was last week, and my Dad, who will be 72 next week, got me a dang Fuel Mizer, a fancy little magnet gizmo that you put on your fuel line and it magically lines up all the particles/molecules/atoms/whatever to increase fuel mileage! Wow! And the manufacturers never figured that out! It took a bonafide snake-oil salesman to do that. Well, the manufacturers know about the wonderful effectiveness of the Fuel Mizer, but a conspiracy by the oil companies forces them to deny any knowledge about it or install it on any vehicles.

I have half a mind to buy my Dad a worthless piece of junk that he may be able to use as a paperweight for HIS birthday. Jeez, at 72 you'd think he'd be a little sharper than that. I guess I'll go ahead and get him a Walmart gift card so at least there's a chance he'll buy something that works.

I hope he doesn't buy that little piece of sheet metal called the "Tornado" that you install in your intake tube or above your carb/throttle body, and it swirls the air, causing better atomization and not only greater fuel economy, but MORE POWER! It's so strange that the manufacturers, who have spent billions on engineering, have never found that a 5-cent piece of tin could do so much. And about that lake-front property in Florida...

[Boghog1]

www.eagle-research.com (http://www.eagle-research.com)

This guy provides low-cost DIY manuals on increasing fuel mileage up to 100%.

I have read the manuals and once my Jeep is completely tuned with the new MPFI, I intend to implement several of his suggestions.

I assume you have done the MPFI by now any updates on this?

[letank]

the only serious way..... shed the pounds..... aluminium sheetmetal..... could trim 1000 lbs, may do the trick.... run skinny tires at 50 psi....

removing the windshield.. and the tailgate glass could stream the airflow....

and airshocks: lowrider.... for the freeway.

Now you do the $$$$ total of transformation work..... probably not too much savings in the total invested for the benefits....

but as said earlier.... driving w one person or 5 w all their equipment for 1 month vacation... i could not see a change in mileage.....

[75J20]

About the fuel miser, I picked up one at Harbor Freight for cheap and figured it was worth a try and if it didn't work return it. I put one on a '73 F350 Super Camper Special with a 390 & C6 trans that was getting about 5-7 mpg tops. After I installed it I could actually feel that the motor was running smoother and my mileage went up to 9 mpg. I didn't think it would work but my results said otherwise. I plan on putting one on my J2000.