Cah Tawk

This week’s feature presentation is one of my favorites for saving energy: automobiles.  Let’s take this recent post from Fuel Fix and dive right in.

The first one I read is “make sure your gas cap is broken or missing.”  That’s right.  You can save 3 cents per gallon if it is broken or missing.  I think they need some proofreading.  I suggest using a well-oiled and fully functional gas cap.  Where they get the 3 cents per gallon savings, I have no idea.  That’s like saying a 20 minute power walk will reduce the energy content of a milkshake by 50 calories per dollar.  Think about that a while.

Drive the speed limit.  I have trouble with this one.  Let’s say I’m traveling for “business”, meaning I simply need to get from A to B on a freeway.  There is nothing I want to get out of the way faster than such a drive.  A week ago today I had to drive from Wisconsin to the southeast shores of Lake Michigan.  After 45 minutes of stop and go approaching downtown Chicago Saturday afternoon, I was in no mood for the 55 mph signs in northern Indiana.  The fastest dudes doing 85-90 mph were my best friends.  I still clocked 33-34 mpg – the upper range for my car.

The other case is driving around home in Western Wisconsin, the greatest place to drive on the planet with baby-butt-smooth roads and lots of curves.  For example, on last week’s trip, we were rolling down our street as we pulled away from our house and my wife is fidgeting around placing this and that in the car and I said, “What in the world are you doing?”  I just throw my stuff in and go.  She was strapping stuff down because I like cornering.  No food or drink allowed!  Driving the posted speed limits around curves is just wrong, like a two hour wedding.

Stay off the brakes.  Tell you what – I’m going to dedicate an entire rant to this one.  Next.

Turn your car off.  Duh.  Millions of people should actually pay attention to this one.  The worst offender here is starting your car in the winter to let it warm up in the driveway or garage.  My parents always used to do this for comfort reasons I guess.  I just don’t get it.  Run out in the freezing cold, start the car and let it run for 15 minutes.  The engine probably pukes out more pollutants in 15 minutes of cold idling than while burning an entire tank going down the highway.  Why?  Combustion in a cold cylinder is not complete, resulting in hydrocarbons.  Pollution control devices catalytic converters (oxidizers) don’t work because they are too cold.  It does NOT damage an engine to take off from a cold start – and it pollutes less when you get it up to temperature fast.  Tip: for anyone without covered/indoor overnight parking and frost-covered cars in the morning, use Rain-X.   Use it anyway.  It greatly improves vision in rain, and bug guts, road slime/salt and goo roll right off.  It also makes physical ice-scraping much easier.

Tire pressure.  These guys say over inflating tires does no good.  Get this: rolling resistance due to tire flexion is one of the biggest losses of energy while driving down the road – probably more than the drag (wind resistance), starting, stopping and hauling freight.  Why do you say that Jeff?  First, because I get close to 20% better mileage in the summer compared to winter when tires are stiffer.  How do I know it’s the tires?  Because I drive big hills to and from work and in the winter, my car slows down going down the big hill and barely stays steady if I totally coast (take it out of gear).  In the summer, it speeds up while engine braking and when out of gear – zoom, like hot wheels down the track (millenials – look it up).

Here is another thing to consider: My car weighs about 3000 lbs with some gasoline and me in it.  I get about 35 mpg, or about 52.5 ton-miles per gallon.  Freight trains can move almost TEN TIMES as much freight/distance per gallon, not even counting the weight of the train cars and locomotives.  What’s the diff?  Rubber on concrete versus steel on steel.  Trains have virtually zero rolling resistance.  Tires are huge energy wasters.

The auto mechanic always puts my tires at 33 psi, presumably for a “smooth” ride.  Bullshit.  I pump them to just a few psi below the maximum as stated on the sidewall.  You can do what you want.

Keep your air filter clean.  Yah, sure.  A dirty filter makes it more difficult for your car to breathe but if you really want to save energy in this vain, remove your exhaust just downstream of the exhaust manifold like a race car.  Mufflers and all that pollution control crap in your exhaust system wastes energy.  That’s a fact, Jack.  You can do what you want.

They say keep the windows closed and run the air conditioner because the reduced drag saves more than it costs to run the air conditioner.  This is splitting hairs.  I’ve done both and I see no discernible difference.  As mentioned previously, I get better mileage driving fast in the summer with the air conditioner running than driving 55 in winter with no AC consumption, and the windows up of course.

Even though your kids may like to hang out the window or stand up through the sunroof for that free and easy feeling while you race them to daycare, I would discourage this activity as it increases drag and degrades mileage.  Send them down a steep hill on their bike if they clamor for the easy rider feeling.

To be continued.