How to Get the Most Fuel Economy

Messages
1,420
Location
Sarasota, Florida
After many decades of experiments the answer is obvious yet it is not what people talk about. The test cars:

Heavy SUVs as the extended versions of the Expedition and Navigator, 6 - 7,000 lbs.
Heavy sedans as a Maybach 57, Flying Spur Speed, a Ghost, 5,500 - 7,000 lbs.
Sporty cars as an Enzo, Murcielago, 2,500 - 3,500 lbs.

Improving fuel economy is particularly important in these cars that may otherwise "suck it up."

Let's go over some of the factors involved. Typical use as an example is the Ford Expedition EL weighing in at about 7,000 lbs. The EPA figures on my last one were 16 and 20 if I remember correctly. Incidently, over the years the EPA numbers improved for the vehicle mostly because they have increased the number of gears in the transmission. My first Expedition had 4 gears and the EPA was something as 11 and 14 MPG. Over the years the SUV moved to 6, 8 and now 10 speed transmissions. With each increase was better EPA milage. Anyway, in no particular order:

Tire Pressure
This is so often overlooked yet plays a major role, easily 1 - 2 MPG. Let’s say the recommended amount is 35 PSI. I always pressurize at least 5 PSI over that which is spec’d. I check monthly and more often when the weather is cooling. My tires never got down to 35 PSI during the interval. Most people set it to 35 PSI and let it get down 5 or even 10 PSI before bringing it back to 35. Tire failures are often related to under inflated tires. I have NEVER seen the “dreaded” central wear pattern of the “over inflated” tire. Not once. Except for the one time when my wheel alignment in the rear was off, all tires have worn evenly.

Proper Wheel Alignment
I have no data on this. For the most part, my tires have worn evenly therefore they were set appropriately for the way I drive. But certainly there would be a penalty with increasing mis-alignment. I cannot give you an estimate but common sense should prevail. In the same department would be proper suspension operation and wheel balancing. Sometimes we recheck this when the tires are about half worn as both my wife and I can feel small differences.

Motor Oil Viscosity
I cannot say that I have noticed a difference going from a 5-30 to a 0-20 grade oil. But maybe as much as a 0.5 MPG increase from using a 40 grade in one step down to a 20 grade oil. Viscosity does make a difference but small. Maybe we should change the oil more often as long term oxidative thickening occurs with motor oils.
I do prefer using thinner oils most of the time. I feel more comfortable revving the engine up sooner running them. And there is definitely more get-up-and-go feeling as the oil is less honey like even at summer Florida temperatures. Who would not like a sportier feeling car? But using thinner oils is not giving me meaningful better fuel economy.

# ONE, Driving Habits
I normally get around 20-21 MPG (around town) the way I drive the SUV. My wife gets a mile or 2 less as she drives as most others. If I try to get the best MPG, I can get as high as 28 - 29 MPG around town. The trouble is that this type of driving annoys the people behind me, you must be careful these days. How is this achieved?
My definition of a good driver is one who rarely uses the brakes. This is done by constantly looking as far ahead as you can, in some cases a mile or so. In areas where you know the pattern of red lights and traffic patterns you can improve on fuel economy by 5 or 10 MPG assuming all else is correct with your vehicle. You anticipate what will happen in front of you. You will maybe slow down a little as you approach a traffic light but rarely stop. Take turns a little faster. Coast as much as possible.
Some cars are limited because they automatically down shift or use regenerative braking when you lift your foot off the gas pedal. If you are the type of driver who does not look ahead and anticipate then maybe this works for you. But if your car coasts well and you can predict what will happen ahead of time coasting is the key. If you brake you are turning kinetic energy into heat, a waste of energy. You have put energy into your car to get it going then you waste it by braking.
Also, though soft starts are of benefit they are not nearly as important as not using the brakes. If you start up faster you get to speed faster then use less gas to maintain your speed sooner. Most of the energy you put in goes to getting you up to speed. But braking is a total waste of energy.

The EPA should concentrate on teaching people how to drive conservatively and take proper care of their vehicles. Here’s another tip. Instead of trying to get to a destination sooner by weaving in and out of traffic, leave earlier!

AEHaas

PS: Next Topic - Coal Burning Cars
 

jurko

Site Donor 2021
Messages
607
Location
Carson City
When I employ the things you mentioned which I do all the time my aver. MPG is 45-46 in my Golf.
One time I decided for the duration of entire tank of gas to drive like a maniac to see what would happen and the aver. MPG was 32.
When I took my car couple weeks ago ( car has over 50K miles) for tire rotation the guy asked me. Do you ever use breaks? I told him the way I drive ( you mentioned some of it) I seldom do and if I have to it is very lightly. He says. No wonder. The brake pads thickness looks like they are new.
 
Messages
1,195
Location
The IL
While, yes, there are habits that you can form that can have your vehicle running more efficiently. When you buy a loaded Expedition, you aren't very concerned about fuel efficiency.

If efficiency is what drives you (no pun intended), the market has dozens of great choices you can make.

Some worry about this stuff, some don't.
 
Messages
9,745
Location
Ontario, Canada
Coasting in neutral with a manual has saves gas down the hills you don't need engine braking, or when coming up to a stop. Cars don't cut fuel much at all when coasting in gear to avoid lean burning and to keep the cat nice and hot. On the scan gauge you can watch the timing be retarded to flush fuel through the motor into the cat when you let off the gas in gear... Also on moderate hills, if you can keep the pedal steady and bleed off some speed to reach the top, this saves quite a bit compared to maintaining your speed exactly.
 
Messages
13,090
Location
North Carolina
I agree with above, and i've done some of that for fun, coasting letting off early etc. But I'm careful not to do it with other cars behind me, I a line of traffic, and idiot trying to hypermile can cause problems and really hold up traffic.

I've seen fools go so easy on the gas that they are the only one getting through the traffic light before it turns yellow again. Now the rest of us are burning fuel at a red light so 1 car can pussyfoot it through the intersection.
 

gathermewool

Site Donor
Messages
8,927
Location
New England
Completely incorrect. Coasting in neutral is using gas to keep it idle. Coasting in gear does not uses gas.
Coasting in neutral with a manual has saves gas down the hills you don't need engine braking, or when coming up to a stop.

I read this as: use your brain. If engine-braking will stop you short of your destination on a slide grade, coasting in N makes more sense. Coming to a stop, engine-brake until you're at risk of stalling.
 
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17,214
Location
...
I agree with everything AEHass has said. The tire inflation is often overlooked, especially nowadays with TPMS.

Accelerate smoothly, coasting up to stops and red lights, and just sensible driving in general add up not only for better fuel economy but a longer life for the vehicle and less maintenance.
 
Messages
515
Location
KY, USA
I use the same techniques as the OP and since lots of my driving is on secondary roads with a lot of deer most of my driving is in the 40-50 MPH range. The EPA estimates on my '16 Nissan Versa are 31 city 39 highway and 34 combined. Since I bought the Versa in Feb. 2019 my worst tank was the first one I ran through it in cold wet weather at 42.345 MPG. I also use 10w40 conventional motor oil. I've been driving for over 45 years and don't think I've ever had a car that I couldn't beat EPA combined estimates by several percent in normal everyday driving. This includes when I was younger and didn't really try very hard to save gas.
 
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gathermewool

Site Donor
Messages
8,927
Location
New England
I agree with everything AEHass has said. The tire inflation is often overlooked, especially nowadays with TPMS.

Accelerate smoothly, coasting up to stops and red lights, and just sensible driving in general add up not only for better fuel economy but a longer life for the vehicle and less maintenance.

There are some of us who run winter tires without TPMS. Visually checking the tires every day and checking the actual pressure weekly isn't very hard and likely standard practice for those I've mentioned.
 

jurko

Site Donor 2021
Messages
607
Location
Carson City
Absolutely clueless this man is
Come on man.
Have some control over your trigger happy fingers which causes you to come up with lame, condescending and useless reply.

If you don't have anything of substance to add or expand on OP experience it's better to just be spectator and hopefully learn.
The BITOG will be better for it.
 
Messages
1,665
Location
California
All very good reminders, thanks.

The EPA should concentrate on teaching people how to drive conservatively and take proper care of their vehicles.
Just like the DMV should concentrate on awarding licenses only to safe drivers. We all know that is definitely not happening.

Here’s another tip. Instead of trying to get to a destination sooner by weaving in and out of traffic, leave earlier!
Amen, brother. However, keep in mind that people can't even keep their infant children safe. So, how is anyone supposed to spare a few minutes to arrive alive and on time? Most people nowadays care about nothing except what they want, and of course their destination is more important than everyone else's. The character and intelligence of the average person has been on a steady decline for decades, and it's only going to get worse until and unless something huge happens around the world. A great start would be enforcing our existing laws. We all know that is definitely not happening.
 

JC1

Messages
6,057
Location
Oshawa, Ontario Canada
Back in the early 90s when I first started working after college, I quickly figured out that if you drive the speed limit on the hwy and don't gun it could go 5 days of commuting without having to fill up on Thursday. My job was about 35 miles one way and i was driving a 4 speed Toyota Tercel at the time.

Told this to one of my coworkers at the time he had a Volvo 240 and he started doing the same thing. Not many people can drive this speed and keep their sanity.
 
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