Prerunner Tech

Prerunner Fuel Efficiency

Fuel Efficiency and Prerunners seems a little contradictory. With the price of gas the way it is, and since most of us drive our prerunners on a daily basis we decided to see if we could find some way to get a few more MPGs out of our Desert 4×4 Project Ford Ranger.

One of the biggest problems with fuel efficiency and prerunners is their inherent lack of aerodynamics. Let’s face it with 6” bulge fiberglass fenders and no factory bumper our Project Ranger is about as aerodynamic as a barn. I had no idea this was going to be such a big deal when driving on the highway. To give you an example of how “anti-aerodynamic” our Ranger is, when we were headed to Ontario for the SoCal Dirt & Sand Expo, we were heading into the wind. We had to stop in Victorville and fill up. This means we were getting about 8-10 mpg. That is horrible for a V6. On the way home with the wind behind us we used a little over ½ of a tank.

So you ask yourself, should I really put ‘glass fenders on my prerunner? Our answer is yes. Along with the obvious clearance they offer you, they are also lighter than the factory steel fenders. Weight savings equals more MPGs. It is said that for every 100 pounds you shed off the vehicle, you can gain 1 mpg. OK so how else can we save a little weight?

Well another way is to leave your heavy spare tire at home when you are just doing a little city driving. We are running a 33” BFG Mud Terrain mounted on 16×8 Mickey Thompson Classic Locks. Having this out of the bed can save a ton of weight (well not literally).

Putting your prerunner on a diet is not the only way you can increase your mpg. When building a prerunner one of the first things people do is put taller (and heavier) tires on. Aside from the added weight they also raise the gearing of the vehicle. If you have the 4.0 V6 in your Ranger you might not notice too much of a difference except on long inclines, but if you bought your Ranger with the 3.slow V6 in it, you might find yourself cutting a hole in the floorboard so you can mash the throttle further. Most people say you get worse gas mileage when you re-gear your prerunner, but that only happens with the crawler group because they increase their gearing to increase their crawl ratio. Properly selecting your gearing after taller tires are installed will get you back to what you were used to before the new tire install. Without the lower gears you have to mash down on the gas pedal to get going, and in heavy traffic you might be able to see your gas gauge’s needle move.

Now your prerunner is a little lighter, it is geared properly to overcome the extra height of your prerunner’s new “shoes”, so what’s left? What else can we do to stop having to make so many stops at the pump? Since we are talking about fuel efficiency how about we look at how to make your current engine more efficient? It seems like the logical next step.

With the current CARB laws requiring automakers to make their vehicles more efficient it seems hard to beat what the factory is already doing. Well that is not entirely true. Along with meeting those mpg requirements they also have to meet a budget for building the vehicle. Certain things might have to be shaved in the name of money.

The best way to make your engine more efficient is to be able to move the air in and out as quickly and as easily as possible. How do we do this? First I would start with a new high efficiency air filter. I am not much of a fan of the new trend in replacing the entire intake. Most are made with shiny metal tubes. Metal conducts more heat than plastic. The more heat you have the less dense the intake charge is, again lowering efficiency. When the Fuelie Mustangs came on the seen in the late 80’s, drag racers used to put a bag of ice in their airbox to make the intake charge as cold as possible for the run. This is the same concept. Now that you are getting the air in more efficiently we have to find a way to get it out, and that is done with a high flow exhaust. If you have the money headers are a great way to “get the air out”. The design of most modern day headers helps to scavenge the exhaust out of the motor. Yes they can be pricey with all the special aircraft coatings on them, but it is worth it. There is nothing worse than rust holes in your headers.

Along with headers get a high flow cat-back exhaust system. Most of them are aluminized which will shave a few pounds (not many) from your factory exhaust, and they flow a lot better. Today’s flow though muffler designs are very efficient.

Last on the list of efficiency is a new computer program either by a reflashed chip or a programmer. We bought the SuperChips Power Programmer to fix the speedo on our Ranger and a by-product of the new program was a little better gas mileage. There are performance programs available with our Power Programmer, but we save that for when we go hit the trails.

Another simple way to get better gas mileage is by making sure your tires are properly inflated. You might lower your tire pressure if you are playing in the dunes, and driving on the highway with that lower pressure adds resistance and lowers fuel economy, so bring an air source with you and air up before going home.

I know most of us would not trade our bulgey fiberglass fenders just to save a mile or two per gallon, but we here at Prerunner Maniac would rather put that extra money into making our prerunner perform better. If we can shave a few dollar here and there by making our Ranger more efficient, then hey why not.

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