Getting More MPGs Out of a Used Car

With all the fancy new Hybrids coming out, you make think your used car is wasting too much gas.  Believe it or not though, some used cars actually get better gas mileage then their newer hybrid decedents.

Image via http://www.flickr.com/photos/59574125@N05/5488043592/in/photolist-9mXEaf-7HsaHL-eE6GPP-b6rBMv-8R5PqH-8BuCBK-9vkpJq-89afaR-9cxvVg-b6rFMX-cUPVSj-7J9B8B-9cb1U3-aT7mnD-eE6GA8-e1yQAd/lightbox/In the mid-1990s, cars really started to gain bulk.  First air bags, then more air bags, then lots of plastic, computers and more airbags.  The result?  Cars started getting much worse gas mileage.  Gas mileage is pretty simple to understand, when you push your pedal to the floor, it’s how much fuel is burned to produce the energy to get you where you are going.

The energy required is a factor of wind resistance, weight, efficiency and power.  A very aerodynamic, lightweight, efficiently operating car will get the best gas mileage.  These are the things you need to optimize in your old used car to maximize the MPGs.

  1. Tire Pressure – Tires are the only part of your car that is contacting the ground, and as such, tire pressure makes a surprisingly large difference in gas mileage.  The more air pressure, the less contact surface and vice-versa.  Nothing annoys me more then when a tire shop or mechanic inflates all the tires to some random number like 35.  Look at your manual and do exactly the pressure your manufacturer recommends.  This will need to be adjusted each season or when the temperature changes.
  2. Air Filter, Clean Fuel Injectors and Oil Change – These relate to the efficiency of the car.  By maximizing the air intake and ensuring your parts are moving cleanly, your engine will burn fuel more efficiently.
  3. Aerodynamics – How can you affect this you might ask?  While your car was originally designed to be mostly aerodynamic, it’s possible previous owners have done things to make it less so.  Racks on top of cars make a huge difference.  But did you know having your windows open on the highway can make you much less aerodynamic?  While you may know that running the A/C can lower gas mileage, it’s actually better to run it at high speeds then keeping the windows open (which increases drag).
  4. A/C – Well, to the point above, anything else your car needs to divert energy to that is not going to the wheels will reduce your gas mileage.  Yes, technically even having your headlights on affects gas mileage, but it’s by such a fraction that you are better off keeping them on for safety reasons.  Try to minimize any feature usage you don’t need though.
  5. Driving Habits – Your car is fighting a constant battle against physics, and you are actually one of the biggest factors in affecting gas mileage.  Use cruise control as often as possible.  Avoid frequent starts and stops.  Go easy on the throttle, if you floor it all the time or drive 80, you’ll get as much as 50% less gas mileage as someone more judicious.

Hope these tips make a difference at the pump, I’ve gotten my old 90s Honda Civic’s to get as high as 45mpg with these tips, which is almost identical to the modern Civic hybrid.