anyone here do any hypermiling?

Some of the hypermiling techniques, like following a semi closely to take advantage of the 'vacuum' in its wake, are dangerous.

I've found two techniques work well to achieve a consistent 36 mpg in the city and 48 mpg on the highway.

In the city accelerate slowly and smoothly. Anticipate stops or slowdowns and get off the gas early and coast to the stop. Try to anticipate traffic lights and slow down early so as to have more green lights.

On the highway, cruise control is fantastic at gaining mpg's. I'm disappointed at anything below 45 mpg these days.

Of course there are other ideas to increase mileage. Keep the tires at or slightly above recommended pressure, keep the alignment good, don't carry unnecessary weight, and wash the car before a long trip. Look up 'parasite drag' for an explanation in the last point.

There has been great debate over the decades about whether it is better to roll down the windows or leave them up and use air conditioning. For me, AC is the better choice on the highway.

The Elantra is a fantastic car in terms of fuel efficiency. It has a low coefficient of drag and a drivetrain optimized for efficiency. With a little help you'll do well

2020elantrave said:

Thanks Randy. Do you have any particular ways you approach hills that you can see are coming up ahead of you? And have you by any chance compared a tank full of 87 octane to that of 91 to see if you get better mileage with premium?

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I've seen no scientific technique of handling hills for best gas mileage. My anecdotal approach, from 50+ years of driving, is to slightly increase speed before reaching the onset of the hill with the intent of maintaining momentum and delaying any transmission downshifting while on the upslope. Here, you need to balance traffic conditions, weather conditions and speed laws.

Growing up in Kansas, never got much of a chance to practice this, but when I lived in hilly Missouri I had many chances to play with maintaining momentum and keeping the lowest rpm possible. In Missouri, most hills are preceded by a decent. It is here where I will accelerate a little. Accelerating on the downslope requires less engine energy than on level ground, thus better fuel mileage. Generally, for simplicity, I would accelerate to about 10 mph more than my constant speed. Not perfect on every hill, but a good balance between increased fuel mileage and not getting a speeding ticket.

(With this said, today I use cruise control as much as possible. The computer is smarter and more efficient than I am.)

I've experimented with 87 versus 91 octane on long trips (Kansas City to Denver, for example) and have seen no appreciable difference in mileage. 87 octane can easily maintain cruising rpm. I certainly don't think any possible mileage difference will justify the additional cost.

More important is the type of fuel you use. If you can find a station that offers 100 percent gasoline you will find that it provides significantly better mpg than a 10 or 15 percent ethanol mix. Never use E85 (85 percent ethanol) as that will give you absolutely horrible gas mileage

A better idea I think is to keep your engine running at its best efficiency. Be diligent about keeping a clean air filter. I religiously use a tier one gasoline (with more cleaning additives). I'm currently running a tank of off-brand discount fuel and there is a hesitancy in acceleration, perhaps because it was poorly refined.

I also regularly throw a bottle of fuel cleaner into the tank. Hyundai recommends Chevron Techron, which has gotten a little pricey recently. I may switch to the cheaper STP fuel cleaner.

I regularly clean the air intake mechanism (the proper term eludes me now), too. You can find the procedure on YouTube.

There are tires specifically designed for higher fuel mileage. These have stiffer sidewalls to reduce rolling resistance. I get the same effect by increasing my tire pressure.

If you have noticed, the Elantra SE with 15 inch tires gets better gas mileage than higher trims with larger tires.

Another idea that I haven't tried since my four-on-the-floor days, is keeping the engine to the lowest possible rpm for the longest period. Using the sport shift mode on today's CVT transmission (that mimicks a stick shift), manually shift into a higher gear at the earliest moment. Conversely while decelerating, leave the transmission in gear until the engine begins to lug. That's how we used to do it in the old days when we had real manual transmissions.

A fun thing to explore is the possibility that a stick-on spoiler, like advertised on sites like sharkracing.com. This, theoretically, would increase the Kamm effect on your car (straightening out the airflow at the rear of your car, thus decreasing turbulence and increasing aerodynamic efficiency). Who knows, it works on Nascar racers).

Since I'm writing a monograph on fuel mileage, let's consider the aerodynamic efficiency of the car. The Elantra is good at 0.28 CD (coefficient of drag), but not as good as its corporate cousin, the Kia Forte, that has class leading CD of 0.26.

An even crazier idea -- vortex generators. In aviation, we install these small little wings (about the size of a fingernail) at critical places on the airplane to straighten turbulent airshow and decrease drag. Don't know if there are any aftermarket VGs for Hyundais, but they would be fun to play with if any existed

Have fun.