Gasoline ratios
Serious damage to gas engines can occur if you attempt
to run a high compression ratio with a low octane type
of fuel.  Detonation is the ignition of the fuel due
to the high temperature caused by a high compression
ratio that is developed by design.  The fuel is
ignited prior to the spark of the plugs that result
in a rapid, yet uncontrolled burning.

Diesel ratios
Keep in mind, the diesel is a heat engine, using heat
developed from the compression of air.  High compression
ratios are possible since the air is compressed.  The
hot compressed air is sufficient to ignite the diesel
fuel when it’s finally injected near the top of the
compression stroke.

Diesel engines
Fuel and air in the design of diesel engines are not
premixed outside of the cylinder.  Air is taken into
the cylinder through the intake valve and then
compressed to make heat.  The diesel fuel is injected
near the top of the piston’s stroke in an amount or
ratio that corresponds to the load on the engine.

Heavy duty
The higher compression ratio causes engineers to
design, and test the block, heads, head bolts,
crackshaft, connecting rods, rod bolts, pistons,
piston pins, etc., with a greater range of structural
capacity.  To put it in other terms, diesels are
heavier than gasoline engines.

Gasoline
Deciding on gas and diesel can be tough, although
there are several reasons why you should use diesel.
 1.  Diesel engines produce twice the power
per gallon of fuel than gasoline.
 2.  A gallon of diesel is normally cheaper
than a gallon of gas.
 3.  Diesel fuel doesn’t blow up. The fact
is, its hard to get diesel to burn at all.
 4.  Diesel engines will last four times
longer than gasoline engines.
 5.  Diesel fuel that is untreated will last
longer in storage than untreated gasoline.
 6.  Treated diesel fuel will last longer in
storage than treated gasoline.
 7.  Diesel fuel treatment will cost less
than gas treatment.
 8.  Spoiled diesel can be reconditioned to
refinery specifications, as spoiled gas can’t.
 9.  Unmodified diesel engines can be ran on
vegetable oil.

Diesel engines that are naturally aspirated are far
more massive than gasoline engines of the same power
for two reasons.  First, it takes a larger capacity
diesel engine than a gas engine to produce the same
amount of power.  Essentially, this is because the
diesel can’t operate as quickly.  The rev limit is
slower, because getting the correct fuel to air ratio
into a diesel engine fast enough is more difficult
than a gas engine. The second reason is due to the
fact that a diesel engine needs to be stronger to
withstand the higher combustion pressure needed for
ignition.

Diesel engines also produce very little carbon
monoxide as they burn the fuel in excess air except
at full loading capacity, where a full quantity of
fuel is injected per cycle.  They can however,
produce a black soot from the exhaust, which consists
of unburned carbon compounds. 

Often times, this is caused by worn injectors, which
don’t atomize the fuel sufficiently enough, or a
faulty management system that allows more fuel to be
injected that can then be burned with the available
air. 

For commercial use that requires towing, diesel
engines tend to have more desirable torque.  Diesel
engines tend to have their torque peak quite low
in their speed range which provides smoother control
over heavy loads when starting from rest, crucially
allowing the engine to be given higher loads at low
speeds than a gas engine.

The lack of an electrical ignition system in diesel
engines improves the reliability.  The high durability
of diesel engines is also due to the overbuilt
nature as well as the combustion cycle, which will
create a less violent change in pressure when
compared to a gasoline type spark ignition engine.
Diesel fuel is also a better lubricant than gasoline,
so it is less harmful to the oil film on piston
rings and cylinder bores – making it routine for
diesel engines to go 250,000 miles or more without
having to be rebuilt.

For several reasons, diesel proves to be better than
spark engine ignition.  Diesel engines last a lot
longer, they offer more torque, and they are also
more reliable.  They are also more expensive as well,
although you get what you pay for.  If you have
never owned a diesel vehicle, you owe it to yourself
to see everything they offer you – and you’ll find
yourself a very satisfied customer.

As soon as it is produced, diesel fuel begins to
deteriorate.  Less than 30 days of refining, all
diesel fuel, regardless of the brand, goes through a
natural process called oxidation.  This process forms
varnishes and gums in the fuel by causing the
molecules of the fuel to lengthen and start bonding
together.

Now, these components will drop to the bottom of the
fuel tank and form diesel sludge.  The fuel will
begin to turn very dark in color, smell bad, and
cause the engine to smoke.  The engine starts to
smoke as some of these clusters are small enough to
pass through the engine filtration and on to the
combustion chamber.

As the clusters begin to increase in size, only a
small amount of the molecules will get burned, as
the rest will go out the exhaust as unburned fuel
and smoke. 

Its estimated that eight out of every ten diesel
engine failures are directly related to poor quality
and contaminated fuel.  The build up of contamination
in the fuel systems and storage tanks can clog
filters, thereby causing the engine to shut down,
and damage to the engine to occur.

The number one reason for bad fuel is due to the
increasing popularity of diesel power and the
accompanying increased demand for more diesel fuel.
Long ago, diesel fuel remained in the refinery
storage tanks long enough to naturally seperate and
begin to settle, allowing the clean fuel to be
drawn apart.  Now, with the demand getting higher
than ever, the fuel is never stationary long enough
to settle, and the suspended water and solids are
passed on to the person buying the fuel – you.

The changes in refinery techniques is also a
problem.  In order to get more products, diesel
fuel is being refined for more marginal portions of
the crude barrel.  This results in a lower grade
product that is thicker and also contains a lot
more contamination.

As time continues to pass and technology gets better
and better, one can only hope that the quality of
diesel fuel improves.  As it stands now, the quality
isn’t good at all.  If you run diesel fuel, all
you can basically hope for is that the fuel you
are getting isn’t contaminated.

Diesels have experienced a great history here in the
United States.  In 1980, General Motors modified
their 350ci gas V8 to run on diesel fuel.  The result
however, wasn’t that god.  These engines offered
better fuel economy but little else.  They were
very slow, and not very reliable.

Mercedes Benz on the other hand, had better luck
in the 1980s with an array of vehicles available
with diesel engines.  These great vehicles offered
amazing durability although they were rough, noisy,
and smoked quite a bit.  Volkswagon offered diesel
as well, although they had a habit for spewing
blue smoke from the tail pipe.

Throughout the 90s, Benz and Volkwagon offered
diesel vehicles in the United States, with each
generation becoming cleaner, smoother, and more
powerful than the last.  Overall, they were a
tough sell as they still lacked the horsepower
that many were seeking.

Today, Mercedes, BMW, Jaguar, Volkswagon, Ford,
and many other manufacturers are offering diesels
to many markets throughout the world.  To put it
simple, forget everything you know or think you
know about diesel engines in the United States.

These newer engines benefit from hundreds of
technical innovations.  There are several diesels
in Europe that offer better acceleration than
their gasoline counter parts.  BMW’s 120d has
163bhp, goes 0 – 60 in under 8 seconds, and
achieves 49.6 miles per gallon.

Benz offers the C320 CDI SE that has 224bhp, and
over 360 lb foot of torque.  This car gets just
under 48 mpg on the highway, with an acceleration
of 0 – 60 in under 7 seconds.  Throughout North
America, you won’t find a gasoline engine that
offers this unique blend of fuel economy and
excellent performance.

The reason why diesels haven’t caught on in
North America comes down to one word – sulfur.  We
have too much sulfur in the diesel here in the
United States.  This cheap grade of diesel fuel
will run havoc on the more sophisticated diesels
offered overseas and cause an increase in
emissions. 

There is hope however, as refiners will soon be
producing what is known as ultra low sulfur
diesel fuel.  This will help to reduce the sulfur
content from 500ppm to 15ppm.