Click for Coverage
  • JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler
Subscribe to the Free

Tips & Tricks To Better Fuel Economy

Posted in How To: Engine on December 1, 2006
Share this

If the sting of high fuel prices hasn't affected your pocketbook, you're probably either filthy rich or leeching off the fat of some corporation with sinful expense budgets. In either case, you're not like the rest of us who, by the nature of the beast, are forced to tolerate ever-increasing pump prices and accept the fact that our vehicles are now more expensive to operate than ever before. Wait-is that really the bottom line? Or is there some fuel-economy loophole that the government isn't telling us about? We got curious about the topic and did some investigating. What we discovered was that there actually are some feasible options to increasing fuel efficiency. We're not talking about the standard intake, exhaust, and chip upgrades everyone already knows about, either. Check it out.

Approximate Gains: Limitless
Works on: Diesel-powered vehicles
What is it: We'd like to think of this as the permanent answer to our diesel fuel woes. Unfortunately, it's not. However, it is a step in the right direction. We're talking about converting a diesel-powered vehicle to run on recycled cooking oil, just the way Rudolf Diesel invented the diesel engine to run more than 100 years ago. We've tested this idea and will confirm it works great. However, this solution is not without its drawbacks. We had a vegetable oil conversion system installed on or resident Project Dodge Ram (aka Baja Bomber). We got it from Veg Powered Systems of Ojai, California. The kit worked great, but we found ourselves dumpster-diving behind fast-food restaurants in search of usable fuel-oil. This scavenger hunt approach didn't exactly jibe with our fast-paced lifestyles. So we decided to hold off testing until we could afford and house the solution to our problem: Purchasing brand-new oil in bulk. In larger quantities, vegetable oil can run between $.30 to $1.25 less per gallon than regular Number 2 diesel. Keep in mind that this savings is restricted by one's ability to store and transport large quantities of it. We've seen many others do this but haven't yet had the opportunity to try it for ourselves. We plan to cover the conversion process soon in a future issue.
Pros: Works on most diesel-powered vehicles; the technology is proven; performance losses are minimal; engines run smoother due to increased lubricity; short payback period; veggie oil is everywhere-check with your local burger joint.
Cons: In all cases your warranty is toast; doesn't work well in cold climates; with more and more people doing it, the availability of usable oil drops; the kit physically robs vehicle space; additional maintenance may be required on some vehicles; noticeable change in exhaust odor may increase appetite for fried food.

Approximate Gains: Limitless
Works on: Diesel-powered vehicles
What is it: Biodiesel is diesel fuel made through a chemical process calledtransesterification, whereby glycerin is separated from fat or vegetable oil. The process leaves behind two products: methyl esters (the chemical name for biodiesel) and glycerin (a byproduct usually used in soap production). Today, tons of home-brew do-it-yourself systems exist for those who want to make biodiesel at home. We like this idea in theory because it helps create additional markets for our nation's farmers, and it lowers our dependency on foreign oil. But brewing biodiesel requires more time and resources to set up, manage, and quality-control than most folks can summon on their own. It also requires the handling of dangerous chemicals (such as methanol), the disposal of waste materials (glycerin), and if brewed improperly, it can damage your vehicle's engine. If home-brewing, you may even be required to register with the EPA as a "refiner," which will require you to adhere to the new Tier 2 ultra-low-sulfur diesel rules (and all the paperwork that comes with it) that take effect next year. Bottom line: This is a job best left to the experts. Fortunately, commercial biodiesel sources are becoming more plentiful each year, and OE manufacturers such as DaimlerChrysler are already moving to incorporate the use of biodiesel in their diesel truck engines (in DC's case, B-10 biodiesel has been approved for new Dodge Ram diesels). Check out the National Biodiesel Board at for more information.

In our own testing of B-100 (100 percent) biodiesel in our '05 Liberty CRD, the engine ran poorly and even stalled on occasion. We suggest not running a richer blend than B-10 (10 percent biodiesel, 90 percent diesel) unless manufacturer specifications suggest otherwise.

Approximate Gains: 2 to 4 mpg
Works on: Gas- and diesel-powered Dodge Ram and Ford Super Duty pickups
What is it: Dodge and Ford Free-Spin Hub Conversion Manual-locking hubs reduce wear and increase fuel economy by preventing parts from rotating constantly in two-wheel drive. Designed specifically to remove a weak link in popular Dodge Ram and Ford Super Duty 4x4 trucks, Dynatrac's Free-Spin heavy-duty hub conversion kits replace the factory unit bearings with fixed spindles for superior strength and improved fuel economy. The complete kit includes inexpensive, serviceable Timken bearings, chromoly spindles, cast nodular wheel hubs, Warn Premium manual locking hubs, and massive 1.50-inch-diameter, 35-spline outer stub shafts. We like these kits because they are made in the U.S.A. and reduce wear on frontend parts, while increasing economy at the same time. Trade off: you have to deal with locking hubs.

Approximate Gains: 5 to 45 percent (see above)
Works on: Gas- and diesel-powered vehicles
What is it: Walker Engineering Enterprises of San Fernando, California, basically leased the rights to the patented technology that Advanced Power Systems International developed for the Fitch Fuel Catalyst. In other words, the Walker Fuel Sep is the same as a Fitch unit. Walker just packages them differently and with an emphasis on marine applications.

The most significant thing you can do to improve fuel economy is drive smarter. Think of your gas pedal as a fuel flow valve. Cranking that valve wide open results in fast acceleration, but in many cases it doesn't propel the vehicle much faster than 31/44 throttle would. Try it yourself-you may find that your vehicle has a similar response. When we try to save gas, we act as if the gas pedal has little Peggy's lost Easter egg underneath it, driving at as low an rpm as we possibly can.

Approximate Gains: 5 to 45 percent, depending on vehicle
Works on: Gas- and diesel-powered vehicles
What is it: The Fitch Fuel Catalyst is a maintenance-free device that easily installs in the fuel line, much like a fuel filter. Think of the Fitch as a finish-polisher before fuel reaches the combustion chamber. We like the Fitch because it lets you run 87-octane gas on a vehicle designed for 92 octane. This saves you money immediately at the pump. On our '05 Jeep Liberty CRD, we found it increased economy by 1.2 mpg on average.

Approximate Gains: 3 to 30 percent, depending on gear ratios
Works on: Gas- and diesel-powered vehicles
What is it: Gear Vendors Overdrive units are basically a planetary gear cluster that bolt on behind the transmission. They are designed to be used in two-wheel drive and can be shifted under any throttle condition. We like them because they let you shift up or down just half a gear at a time. These units have traditionally been reserved for heavy-duty towing applications where power and economy go hand and hand. However, an auxiliary overdrive, or "gear splitter" as some call them, can actually shave a sizable chunk off your annual fuel bill unloaded. The reason: A gear splitter doubles your available gear ratios. For example, imagine your engine requires one gallon of fuel at 60 mph in overdrive to take you 15.5 miles. With a Gear Vendors Overdrive unit installed and with the double overdrive gear selected, you could theoretically go 20 miles on that same gallon of fuel. Simple gearing allows the engine to work less to cover the same distance.

Approximate Gains: 1.1 mpg
Works on: Gas- and diesel-powered vehicles
What is it: Electric Fan Conversion Everyone knows crank-driven fans rob engine power, and that's why Flex-a-lite offers several electric fan conversion kits for popular diesel-powered pickup trucks. The one shown here is for '01-'05 Chevy/GMC Duramax Diesels (PN 284). What this does is eliminate the power-robbing beltdriven fan and shroud, replacing them with an electric fan to improve mileage, horsepower, torque, and air-conditioning temperature.Independent dyno tests have shown a fuel savings of 1.1 mpg with a 27 hp and 34 lb-ft of torque increase at the wheels with this kit.

Approximate Gains: .5 to 1.5 mpg
Works on: Gas- and diesel-powered vehicles
What is it: The Turbo Air Guide (TAG) is a simple device invented by a company called Diesel Power Products of Pasco, Washington. Designed to be used in conjunction with any turbocharger, the TAG helps get more air smoothly into the compressor housing. The TAG straightens air out and directs it into the compressor of the turbo, resulting in more power, cleaner burning and better mileage. It is constructed of a stainless steel welded honeycomb material and is easily installed in the turbo inlet on most popular American diesel pickups. We tested a TAG on our own Baja Bomber project truck and noticed a very slight increase in economy in stock form.

Typically, we tend to avoid chemicals that claim to improve fuel economy. We find it hard to believe anything you simply pour into an engine can significantly improve mileage. However, for this article we decided to test some additives to see if any of them actually worked. Now keep in mind, these results were obtained on an '05 Jeep Liberty CRD, and your results may vary, depending on driving style and other factors.

Approximate Gains: 1 to 2 mpg
What is it: Antifriction metal treatment (additive) We tested a quart of Maxi Lube antifriction metal treatment. Thanks to its secret synthetic formula, we noticed a 1.1mpg increase on our Liberty test mule. We like this product because it's environmentally safe and it actually works. Maxi Lube is not an oil additive as much as it's a metal treatment. We poured it into the transmission, transfer case, differentials, and crank case. Once treated, friction is virtually eliminated. Engines are said to run cooler, quieter, and cleaner with more power, reduced oil consumption, and in most cases, better mileage. Our test supported these claims.

Approximate Gains: 7 to 19 percent
What is it: Ethos Fuel Reformulator is a light-colored, multifunctional fuel reformulator. It's designed for use in all fuels to increase power and mileage, dissolve built-up gums and varnishes, lubricate upper cylinder components, and keep the entire fuel system clean and lubricated. It is recommended to use 1 fluid ounce per 10 gallons of fuel. This formula is a combination of non-toxic, specially designed esters that uses only the elements of carbon, hydrogen, and oxygen. This combination of low-molecular cleaning esters and the high-molecular lubricating esters reformulates any fuel, whether it's gasoline, diesel, methanol, ethanol, LNG, compressed natural gas, or biodiesel. We icked up an impressive 1.6 mpg in our '05 Jeep Liberty CRD test mule.

1. Avoid unnecessary idling. Turn off the engine if you anticipate a lengthy wait. No matter how efficient your vehicle is, unnecessary idling wastes fuel, costs you money, and pollutes our air.

2. Remove excess weight from the vehicle. Avoid carrying unneeded items such as multi-mount winches, tools, and spare tires. An extra 300 pounds can reduce any typical SUVs fuel economy by 1 to 2 percent.

3. Use cruise control if you have it. Using cruise control on highway trips can help you maintain a constant speed and, in most cases, reduce your fuel consumption.

4. Keep your tires properly inflated and aligned. By law, car manufacturers must place a label in the car stating the correct tire pressure. The label is usually on the edge of the door or door jamb. If the label lists a pressure range, use the higher number to maximize your fuel efficiency. Underinflated tires work great on the trail but can increase fuel consumption by up to 6 percent.

5. Keep your engine tuned. Studies have shown that a poorly tuned engine can increase fuel consumption by as much as 10 to 20 percent. Check air filters and change spark plugs and engine oil regularly. Follow the maintenance schedule in your owner's manual; you'll save fuel and your rig will perform better and last a lot longer.

6. Install proper gearing for your vehicle's use. If you drive a Jeep with 4.56:1 gearing to and from work each day, consider installing a lower low-range gear ratio in the transfer case for the trail, and running 3.73:1 gearing in the differentials for the street. You'll save a ton of fuel this way.

7. Run regular 87-octane gas. Most new vehicles will run perfectly fine on regular old 87-octane. Unless you've added some component(s) that require 92-octane, you'll be money ahead by sticking to regular unleaded. This will typically save over $10 per fillup on most late-model fullsize pickups.

8. Avoid bad traffic. It's been said that in city driving, nearly 50 percent of the energy needed to power your vehicle goes to acceleration. This is then scrubbed off by braking. The waste in stop-and-go traffic is ridiculous. We suggest leaving earlier or later to avoid "rush hour" traffic.

9. Buy a cheapo commuter car. If your lifestyle allows for it, get a second vehicle that's more fuel-efficient than your current rig. Sure, it won't get you to that remote fishing spot, but with the money you'll save in fuel expenses, you'll probably have that econo-box paid for within a year's time.

10. Consider fuel economy when buying your next vehicle. You may not be able to do much about your current vehicle's consumption, but everyone can think ahead and plan for the future when it comes to the next rig.


Fife, WA 98424
Gear Vendors
El Cajon, CA 92020
Diesel Power Products
Dynatrac Products
Huntington Beach, CA 92647
Walker Engineering Enterprises
Sun Valley, CA 91352
Veg Powered Systems
Advanced Power Systems International Inc.
Ethos Environmental Inc.

Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Browse Articles By Vehicle

See Results