Increase Your Gas Mileage by 41%.

I drive a '92 Honda Accord with manual transmission. It has driven over 221,000 miles and it is extremely reliable. I recently broke my gas mileage record by averaging 36 mpg for a tank of gas. Not bad for a car that originally only got 26 mpg highway 19 mpg city.  Assuming a starting economy of 25.5 mpg, that is more than a 41% fuel economy increase.  Still, I think I can do better. 

Someday I will commute to work in an all electric car that will get 100% of its propulsion energy from the sun via my solar panels. Until that time, I at least want to make my gas vehicle cheaper to drive. 

My 19.3 mile commute consists of 2½ miles of residential and city streets, 13 miles of 55mph highway and 4 miles of interstate.
I have gotten so familiar with the traffic lights and flow that I can almost drive the whole route without using my brakes.

Secrets to Increased Gas Mileage the oil companies don't want you to know about. OK, so maybe these are not secrets but they really will help you save a ton of money on your gasoline bill. You won't have to buy my book for $29.95 either.

Over-sized Exhaust: A few years ago I had to replace the entire exhaust system on my Honda from the manifold to the tail pipe. I have always wondered what would happen to the gas mileage if my car had a larger exhaust system. Trying to breath through a straw is difficult. I figured a tiny tail pipe is no different. Installing a bigger catalytic converter and muffler and going from a 1¼” diameter to a 2¼ ” diameter tubing increased my gas mileage 4 mpg.  Well, that was easy!  Why don't the car manufactures design cars with larger exhaust pipes?  It's a relatively easy thing to do with a quick return on investment. 

Fill oil to the low side of the hash marks on the dipstick.  A motor-head buddy of mine told me he fills his oil up to the low side of the dipstick to get more performance out of his race cars. The theory is there will still be sufficient oil for cooling and lubrication but the crankshaft won't be sloshing through the oil in the pan as much. He even went as far as sharpening the edges of the crankshaft so it would knife edge through the oil. Hmmm, interesting.

Slightly higher tire pressure (40psi instead of 36)  Increasing the tire pressure will decrease the rolling resistance of a vehicle's tires.  Quantifying a measurement like this is difficult without driving the exact same way for an entire tank first then increase the pressure and drive the same way for another whole tank. Outside temperature and weather will also effect the measurement.

Keep the engine RPM under 2500  If the engine RPM is low, the engine will not work as hard, nor burn as much gas. Lower RPM → less fuel intake strokes → Higher gas economy. You will use a lot less gas by accelerating slowly.  But be courteous and aware of others around you though. Accelerating too slowly might make the 42 drivers stacking up behind you angry. Keep out of the passing lane so others who have not read this blog can pass you.

Minimize Air Resistance. Drive slower  Who do you think you are?  Marty McFly?  Not driving 88 miles per hour will ensure you don't accidentally go back in time and also save you a lot of gas (and potential speeding tickets). The faster you drive, the more wind pressure will push against your vehicle. Around 40 mph this force becomes significant. Above 55mph, it becomes the dominant force and your engine has to work harder and burn more fuel to overcome it. You might as well be dragging a boat anchor behind you everywhere you drive.

The fuel economy approaches zero the faster you drive. 

Lighten up  A 3200 lb vehicle carrying a 180 lb driver is only using 5% of its gasoline to move just the occupant from point A to point B. The other 95% is being burnt to move the weight of the vehicle. When a vehicle is lighter, the efficiency of a vehicle will inherently be higher. Only carry in your vehicle what is absolutely necessary for your commute and for your safety.  It was for another reason but I removed all the upholstery and trim from my trunk. It's ugly but who rides in the trunk anyway?

Anticipate traffic lights and coast as much as possible  The less you brake, the less gas you just wasted getting you up to speed.  Every time you have to use the brakes, you are essentially wasting fuel.  Look farther ahead while driving so you can anticipate earlier when to let off the gas. 

Plan Ahead  Driving slower will add a few minutes to your commute time. Plan for the extra time and arrive to work/home refreshed and happy. I used to get caught up in the passing lane traffic. It really is a rat race. There will always be a bonehead going too slow or a psychopath going too fast. And there is never a cop when you need one.
One day I realized an important fact of driving. This is really important!!!  Once you read this, it will change who you are and how you think forever.  
The dirty, unshaven guy with the nasty mullet, sporting a wife beater tee-shirt, driving a spray painted 1987 rusted out Ford pickup with the 2' lift kit, swerving through traffic and tailgating me with his high-beams on isn't a jerk!
Nope! He is not a bad person. He just has really, really bad diarrhea. Poor guy, here I am taking my sweet time changing lanes and he's just trying to get to where he is going so he can take care of his really, really bad diarrhea.
This is more urgent than a firetruck with its lights on speeding to a puppy fire. This is a top priority emergency situation and this guy really needs me to move over so he can take care of the pain and anguish and embarrassment that he is going through.  It's probably running down his pant leg. Ew! 
Or maybe he doesn't have diarrhea. He could be just trying to get to the barber shop so they can work on that mullet of his. Diarrhea or Emergency Mullet-ectomy.  Either way, I'll just move over and let him pass. I will save gasoline no matter what, and that's what this article is about.