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4x4 Fuel Saving Tips - Save Fuel Now!

Posted in How To: Engine on September 1, 2007
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Photographers: 4WOR Staff

We're all screwed. We're running out of petroleum and that's going to change life as we know it. You've already seen the effects. We're paying more than double what we used to for gas and diesel-and this isn't the end of it, folks. Not to scare you, but the faster we run out of fuel, the faster we're going to have to switch from our big-blocks to four-banger 4x4s. Eventually we won't even be running on internal combustion engines as we know them today. It's only a matter of time.

We don't know about you, but we want to keep driving our big-block K5s, our FJs on 39s, and our Super Duty diesels for as long as we can. These are things that make us tick. There's nothing like it for us. It's like giving a Twinkie to a fat kid. Like giving every disgruntled postman a gun, and Paris Hilton a drive-thru liquor store. We want-no, need-to drive our off-road toys, so we figured out some fuel-saving tips to make sure that we conserve fuel to sustain our depraved four-wheeling ways for as long as we can. If we can make our fossil burners get better mileage, then we can play with our toys longer (and those deranged hippies might just get off our backs).

Remember this important lesson: Increasing vehicle efficiency improves fuel economy. You increase efficiency by burning less fuel to do the same amount of work. How? Read on.

You burn less fuel when you increase your engine efficiency. By having a more complete burn, you are not only getting more work out of your consumed fuel, but you're also putting out fewer emissions. This is good for you, good for your neighbor, and good for the environment.

Programmers & Chips
A programmer like this Superchips unit ( will net you some increased fuel savings and juice your engine a little bit as well. Not only can it add horsepower and increase your mileage, it'll also change your shift points and make your vehicle all-around more fun to drive. You can buy a programmer (or at least a chip) for almost every computer-controlled 4x4 made. In fact, there's a good chance that your OEM will have its own factory performance ECU that you could swap right in if you're worried about plugging something foreign into your electrical system.

New O2 Sensor
By plugging a new O2 sensor into your exhaust system, you'll get better readings and your engine's ECU will not think your emissions are so dang dirty. Soot and particulates build up on oxygen sensors over time, and that can make your ECU think your engine is running more poorly than it is. When the ECU thinks the engine is running cleanly, it will allow the engine to run more efficiently.

Air Intake Systems
The benefits of an air intake system have been pounded into your head by every aftermarket air intake ad. On many vehicles it does actually help a bit, but be wary: You should expect about half or less of what some manufacturers claim on the outside of their boxes. Also, be aware that we really have not found an air-filtering element that does a better job of filtering the air than the factory equipment does. All that said, we'd still recommend one in an effort to increase your engine's efficiency.

Machining Work
Engine work like porting and polishing your heads or intake manifold can greatly improve the flow of air and fuel to and from the combustion chamber. This in turn allows your engine to work more easily, therefore increasing your power output per unit of energy consumed. Doing things like balancing and blueprinting your engine will net you a much better-running engine that will last longer, run stronger, and consume less fuel.

Throttle Bodies
Replacing or modifying the throttle body on your fuel-injected 4x4 will often increase the cubic feet per minute (cfm) of airflow into your engine. By smoothing corners and edges, companies like F&B Throttle Bodies ( can net you a few horsepower on all types of fuel-injected engines. Why aren't your stock throttle bodies built to be so free flowing? Cost, baby!

By replacing ignition parts with equipment like this distributor and wire package from Performance Distributors (, you can enlarge the spark in your engine or change the time at which the spark plug ignites the fuel in your cylinders. By doing so, you can manipulate and increase the energy output of the burn, therefore netting more energy (and more power) out of every drop of fuel.

Improving Exhaust
A good exhaust system expels your engine's hot air more efficiently than many cumbersome factory exhaust systems. In the last few years, OEMs have actually made it quite a challenge for your favorite muffler company to net you any power gains or fuel savings since the factory stuff has improved so much. But on older vehicles, you can get rid of some pretty restrictive stuff and make your engine do more work without having to use so much energy to expel the exhaust.

The less friction and resistance (F&R) there is in your vehicle, the better mileage you'll get out of a tank of fuel. F&R can come from a number of things, from dragging drivetrain parts or lugging out-of-round tires to pulling around too much weight. The less resistance to motion, the lighter your fuel bills.

Tire Pressure
Keeping good, equalized pressure in all four of your tires can really improve mileage. We've heard all sorts of amazing statistics about how many gallons are lost each day (if we told you, it'd make you sick) on the freeways around Southern California due to low tire pressure causing the tires to roll with more resistance to motion. By keeping all your tires inflated to optimum pressures on the road, you'll be using less of the earth's petroleum. Go take a look at your tires right now: If the outside tread of the tire is worn more than the middle, you're running underinflated, using more fuel to push around your ride. If the tread is worn more on the outside, the tires are likely overinflated, leading to premature tire wear.

Less Weight Equals a Lighter Load to Push
The less weight your engine has to push around, the easier it will be for the engine to accelerate your vehicle and keep it at speed. This isn't rocket science, just practical thinking. Think up ways you can lighten your load. Maybe you don't have to carry all your tools and camping equipment everywhere you go. We ditched the heavy steel front end of our K5 Blazer for some Glassworks fiberglass fenders ( and lost a considerable amount of weight.

Rid Yourself of Worn Parts
Keep up the maintenance on your rig, and you'll own a more efficient 4x4. Pieces like U-joints can wear out, making them resistant to movement and therefore taking more energy away from the power you put to the ground. If you're using more energy just to turn drivetrain parts, then you're using more fuel to get the same amount of work done.

Lighter Oils
Switching to lighter-weight oils in your drivetrain components (be careful when doing this) creates less drag and therefore lets the engine propel your 4x4 more easily. If you run 20W50 in your engine, try switching up to 10W30. Your engine might need the heavier, thicker oil, but if it doesn't, then you're just sucking power from your overall potential. This goes for gear lube and tranny fluid as well. The thicker the lube, the more drag as the gears try to turn.

Part Time Hubs
If your 4x4 has flanges instead of locking hubs, you're dragging around the front part of your drivetrain all the time. Do you really want that? Of course not. It wears out parts faster and is just more equipment resisting your forward motion. By adding locking hubs, you won't be using energy to spin those two front axleshafts and driveshaft.

Electric Fans
By replacing your mechanically driven fan on the front of your engine with an electric one, you'll be able to make it spin more easily, therefore gaining power and using less fuel. Electric fan kits like those from Flex-a-lite ( use electric motors to drive your radiator's cooling fan, and therefore only suck battery juice. And since the power needs of the electric motor is negligible, you're not making your alternator work harder to keep the battery charged, so don't try and debate that one.

Less-Aggressive Tires
Wow, are we actually endorsing this? We hate to say it, but less-aggressive tires are probably a good way to go with the truck you drive to work every day. By switching up to a more street-friendly tread design, there will be less friction between your tires and the road, and the whole package will just roll more smoothly down the road. To really make ourselves sick, we're also going to suggest that stepping down to a smaller tire size will also likely give you good results, as it means less weight to push around.

Get Another Gear
If you're not already using a transmission with an overdrive gear, then put one in. By getting yourself another gear, your overall ratio is lowered and you'll be spinning less rpm to go the same speed on the highway. As long as your engine has enough gusto to push you around in overdrive without being floored all the time, you'll get better fuel economy.

Change Your Axle Ratios
You can also change the gear ratio in your axles to lower the rpm of your engine at a fixed speed. By decreasing the rotations your drivetrain must do to push you a certain distance, you'll conserve fuel.

Better Shocks
You probably wouldn't think of shocks as fuel-saving devices, but if your ride is bouncing up and down instead of rolling smoothly along the highway, you're changing the force on your tires and the tires' force on the ground, therefore leading to more friction and resistance. By adding a new set of shocks, you'll smooth out your ride and make your 4x4 roll more effortlessly down the road.

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