How To Improve Gas Mileage On 6.4 Hemi

In our modern world, technology rules our lives like no other. We use our cars for almost everything we do on a day-to-day basis. A vehicle serves the purpose correctly as long as we take good care of it. However, some car engines don’t provide the results we look for. There can be several reasons for this. Fixing those issues can improve the efficiency of the engine and make it last longer. 

The 6.4 Hemi engines are one of the most popular machines that powers a lot of vehicles. 

What is a 6.4 Hemi?

The word ‘hemi’ stands for the hemisphere. The American motor company Chrysler first started to make these engine models in 1951. The first models were called ‘firepower engine’ for their power and performance output. It is a V8 gasoline engine with two or more hemispherical combustion chambers, hence the name hemi. The 6.4litre engine churns out 525 hp and is fitted into high-powered, high-performance cars and trucks. The model became available in 2007.

Initially, the Hemi stood for the engine’s configuration, but later in 2003, it came out more as a marketing term. Other companies took the design and made their versions of Hemi engines. 

Efficiency and mileage 

 The company made those engines to power high-intensity, heavy-duty vehicles such as trucks. For that, the mileage they provide is not quite satisfactory. Moreover, the mileage they provide fluctuates even when you use them for the same series of tasks. On average, the engine delivers 10 miles per gallon of fuel, sometimes even less than that. This makes the engine a poor performer in terms of fuel efficiency. The engine ends up consuming more fuel, and the ratio increases with time. 

Fortunately, maintaining your engine regularly can help avoid the main problem with Hemi engines. A few tweaks here and there will increase the gas mileage and help the engine function better in the long run. 

Tips to improve gas mileage on a Hemi 

You can always take your hemi to an auto shop for detailed, professional treatment. But before that, here are some things you can check.

A lot of factors add up to the overall efficiency and performance of the engine. Do not treat any of them as less important as everything has its significant contribution to increase and decrease the mileage. 

Engine oil

The engine oil is a significant element that can significantly manipulate the performance of the engine. This directly impacts mileage. In other words, if you want better mileage, change the engine oil regularly. 

The engine oil acts as a buffer between the internal components and reduces friction. For this, the engine works less and saves fuel. Otherwise, it will not provide the mileage you want and damage the engine after a few years. 

Change the oil of the RAM every 3000 miles (4800 kms) for the best result. It is also better to use high-quality engine oil for your engine. Look for the manufacturer’s recommendations or ask an expert. 

Drive your vehicle

It is crucial to drive your car regularly and test it in a variety of road conditions. A fair share of highway runs and off-roading will condition your engine accordingly and help it become more fuel-efficient. 

If you let your vehicle sit in the garage for long, the parts can become rusty and significantly decrease your mileage. It is a given that any engine will not function properly if left idle. So, take your vehicle out as much as you can. It will only leave a positive impression. 

Tune-up the engine

Checking the engine at regular intervals is another vital step for the improvement of gas mileage. This process includes testing different components of the engine. Also, change the spark plugs while tuning up the engine. This will result in improved power delivery, hence less stress on the engine. 

Most people don’t tune up the engine, which creates a number of problems in the future. Decreased mileage is one of them. The point of tuning the engine is to make the engine run effortlessly. Otherwise, the engine will end up consuming a lot of gas. In addition to that, the engine will get damaged. It is recommended that you tune up your Hemi engine after an oil change. 


You have to check your tires before going out with your vehicle. If your tires are corroded, the engine will create more drag. To create more drag, it will burn more fuel. Also, if your tires have lower air pressure than recommended, your engine will consume more gas. As this can result in low mileage, it can be a significant safety issue on the road, too. 

You can use the simple Lincoln penny method to check if your tires are alright. Keeping the tire pressure at the optimum level as too low or high pressure can complicate other factors.


It is a given that if your vehicle weighs too much, it will burn more fuel. More weight on the wheels creates more friction, hence more drag. As a result, your engine will burn more fuel.

Keep your vehicle as light as possible to get the benefits of improved fuel efficiency. 

Air filter:

The air filter supplies clean air to the engine so it can run smoothly. Otherwise, dust particles can enter and slowly damage the engine. It also can make the engine work harder, decreasing fuel economy. 

To check the filter, place it near a light and look if you can see through. If not, it’s time to change the filter.

Efficient driving

You can save a lot of fuel if you drive responsibly. An efficient driving includes no hard acceleration and braking, staying within the speed limit, etc. turn off your engine when idle. All this will leave you with better mileage. 

Use high-quality gasoline or the fuel recommended by the manufacturer for less fuel consumption. If you follow these tips, your Hemi engine will run like a brand-new while improving mileage in no time.

Liam Dare

As CEO of, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.