Bug Out Vehicles: Diesel or Gas?

By on September 10, 2014

Bug Out Vehicles: Diesel or Gas?



We recently wrote an article on 8 Bug Out Vehicle Considerations.  Many of you may have noticed, and a few of you pointed out, there was something missing, and rightly so.  The consideration of diesel versus gas was omitted from the article, and for good reason, it was getting its own article.  Other than electric power (which was mentioned in the first article) the biggest decision a person faces when choosing a bug out vehicle is the type of fuel that will propel it.  This is another age old argument in prepping articles and forums, which should you choose, diesel or gas?

The first road to understanding is to look at the differences between the two fuels.  To start, both fuels are derived from crude oil.  In a very basic explanation of the refining process, the crude is heated.  Different fuels have different vaporization points, heat the fuel to a certain temperature and gasoline can be separated, heat it even more, and diesel comes out.  In the end you end up with everything from heavy gear oils to naphtha from the base crude.  In the end, for our discussion, you end up with two very different fuels.  Gasoline is a relatively “clean” and light by product of the refining process versus diesel which is “heavier” and less “clean”.  It is in that statement that lays diesels only advantage over gasoline as a fuel, it’s heavier.  Being heavier it contains more energy per gallon, that’s it!  A gallon of gas contains roughly 114,000 BTU’s, a gallon of Diesel has 130,000BTU’s.  The reason folks choose diesel over gas is primarily economy,but there is more to this story.

Gasoline, due to being lighter, vaporizes the instant it hits the combustion chamber of an engine.  All that is needed is a spark to ignite it, and that is exactly what happens, a spark ignites it.  Being more volatile than diesel, a very rapid conflagration occurs in the combustion chamber.  Diesel is stubborn, it won’t light under these conditions.  It must first be compressed and then, whalla, it ignites on it’s own.  Diesel gets an advantage and a disadvantage here.  Because the engine must withstand higher cylinder pressures, the motor itself must be much stronger.  Either stronger materials or beefier castings must be utilized, leading to a more robust motor, overall.  It is this extra heft that leads to a diesel having greater longevity than it’s gasoline cousin.  Whereas modern gasoline motors sign off after a quarter million miles, a diesel can last half a million or more, assuming proper maintenance and a little luck.  The disadvantage of diesel is also due to the very high ignition point, in the winter the fuel may flatly refuse to light at all.  This is a major SHTF consideration if you live in northern climates.  Today, we simply plug in an engine block heater.  With engine block heaters requiring a thousand watts or more of power, all but the most robust alternative energy systems would be tapped out rather quickly.

Courtesy of dieselpowermag.com

Since a diesel motor is physically more robust it can also withstand the rigors of turbocharging.  Turbocharging captures some of the heat energy that is normally wasted out the exhaust pipe and is used to pump air back into the motor.  The more air you can get into a cylinder of a given size, the more fuel you can burn, the more fuel you can burn, the more power you can make.  I thought we were talking about efficiency just a second ago, who wants to burn more fuel?  The answer is, you don’t.  Turbocharging allows a smaller displacement motor to generate gobs of power when it is needed, i.e., you put your foot in it.  During normal driving, cruising or steady state running down the road, the turbo doesn’t provide boost and you get the economical benefits of a smaller engine.  Modern gasoline motors will convert about 30% of a gallon of gas into motive force, a modern turbo diesel can approach 50%.  Yes, gasoline motors can be turbocharged in the same fashion, for the same reasons, but you are still handicapped by a gallon of gasoline containing less energy.

Biodiesel is all of the hype in the prepper community, but in my opinion it is overly hyped.  If your plan is to create your own fuel in SHTF, you’d better start now.  It isn’t a simple process, as noted here, and it isn’t for everyone.  I’m sure some enterprising individual will make a fortune making it if we experience TEOTWAWKI, but I think folks would be better off with electric cars if self generation of fuel is going to happen.  We noted this in the first article.  As I alluded in the first article, in any major event, an event that would cause a nationwide bug out (or in), fuel would disappear in the first few days.

Other than the cold starting woes of a diesel, it sounds like gasoline loses in just about every category, and you’d be right…mostly.  the truth comes down to economics.  The price of a gallon of diesel is roughly on par with a gallon of gasoline.  All things equal, this gives diesel an economic advantage.  Since diesel has more energy per gallon to begin with, add turbocharging on top of that, it is also much more efficient for your wallet.  If the parity of prices per gallon were to drastically change, with diesel being priced above gasoline, diesel would be far less attractive.

Speaking of costs, all that beef and technology comes at a price.  Price is one of reasons you don’t see diesel vehicles all over American roads.  Diesels are typically far more expensive than their gasoline counterparts; adding the 6.7L diesel to a brand new Ford F-350 is an $8500 option.  These prices carry over to used vehicles as well.  Most of us, including myself, have to reach back to some really old vehicles to afford them.

Lastly, diesels drive differently than their gasoline counterparts and they can offend the olfactory nerves while they are at it.  They feel more utilitarian, but isn’t that we are considering in a SHTF vehicle?  The problem is, most of us can’t afford a dedicated bug out vehicle.  Some might be put off by the smells of a diesel.  Some of us like the overall performance of a gas powered vehicle.  The issue with the most impact, at least on the North American market, is the availability of diesel vehicles.  If every vehicle was offered with a diesel option the choice would be easier.  We could choose a vehicle that best suits our needs, and if it had a diesel option we could then make that choice, but this isn’t the case.  We are currently limited to large trucks, a few cars, and a smattering of SUV’s, usually from upscale brands. Here is an article that shows all of the new diesel powered vehicles being offered in the US.

In the end, if you had one gallon of fuel, a turbodiesel is going to do far more work than his gasoline powered cousin.  It is generally going to last longer and have more power.  If you don’t mind the smell, don’t live in a very cold environment (SHTF consideration), and have the cash, a diesel might be the right choice for your bug out vehicle.  Yet, for most of us, we have to choose a vehicle that best suites our needs and wallets.  At this particular time we have very limited diesel choices.  Four wheel drive diesel minivan, anyone?

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