How to Improve Gas Mileage on a Dodge Hemi

by David Houssein
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The Dodge Hemi is a 5.7L V-8 engine used in Ram trucks. Introduced in 2003, the Hemi engine produces 390 bhp and delivers 14 mpg in the city and 20 mpg on highways. The less popular 4.7L V-8 version produces 310 bhp and offers similar mpg to the 5.7 version. While the gas mileage is not the highest for its vehicle class, it's still a 4 percent improvement on previous models. Gas mileage can be improved further still by following these simple steps:

Step 1

Install a cold air intake. A cold air intake improves gas mileage because cold air is denser and contains more oxygen than hot air, and is therefore more efficient in a combustion engine.

Step 2

Use your experience to anticipate traffic. Accelerating toward traffic and slamming your brakes on is a waste of gas. It's more efficient to take your foot off the gas and roll toward the traffic, which uses almost no gas at all.

Step 3

Keep your car clean and maintained under the bonnet. Dirty oil causes a buildup of residue, while old air filters do not let enough oxygen into the engine. Both of these factors reduce the engine's ability to burn gas efficiently.

Step 4

Stick to the speed limit and do not drive too fast. While it may be tempting to enjoy the power which the Hemi offers, driving above 60 mph uses significantly more gas than sticking to 60 mph.

Step 5

Don't carry unnecessary weight. While it may be inconvenient to unload your tools into the garage when you don't need them, it costs you money to drag them around in the back of the truck. Extra weight equates to extra resistance, thus requiring more gas to move the same distance. For every additional 250 lbs you carry, you will lose 1 mpg. This represents approximately a 3 to 5 percent increase in fuel costs on a Hemi.

Step 6

Keep your tires correctly inflated. Flat tires have a wider surfer area, which increases drag. Look in the handbook for the optimal pressure and check the pressure weekly.

Step 7

Install a performance chip. A performance chip reconfigures the car's computer, which will adjust the mix of air and gas in the combustion mix. This will improve gas mileage as it will configure the engine to take more air and less gas.

Step 8

Close your windows at high speed. Open windows cause drag and will have a negative effect on your gas mileage. At high speeds it is more efficient to use air conditioning, and at low speeds it is more efficient to open your window.

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