Picture this: you’re driving on a highway,
and suddenly see something you’ve failed to notice earlier: your gas tank is almost
empty! You drive to the closest gas station, only
to find they have no other gas but 87. Should you pump it inside your car or not? What’s the difference between those numbers? Let’s find out! First of all, gasoline can actually be different,
and it’s not one type fits all. In the US, the most typical numbers you’ll
see are 87, 89, and 92. In other parts of the world, the numbers can
vary, but most common ones are 91, 95, and 98. The higher the number value, the higher the
cost of the fuel, so it might seem natural to choose the cheapest one and go with it,
but it’s not as simple as it sounds. In fact, these numbers indicate the fuel’s
octane rating. It’s the measure of how well the gas resists
“knocking” at the time of combustion — I’ll get back to this a little bit later. First, I should explain how higher or lower-octane
fuel works with different engines. It’s a surprising thing to say, but if you
have an older car, you’re lucky. That’s because you generally don’t have
to care about which type of gas to pump inside your vehicle. Higher octane rating tells you how well the
gas would perform with your engine, but in reality, if your car’s user manual says
you can use any fuel, including the 87, the practical difference will be minuscule. That means very small. Yeah, I know you already knew that. Under normal conditions, 87 and 92 are basically
the same. By pumping the 92, you can slightly reduce
your carbon emissions and may notice that your car consumes a little bit less fuel,
but that’s about it. It all changes, however, when your car’s
manufacturer expressly states that your vehicle should only drive on 89 or 92. You see, the 87 is a basic type of gas that
fits most older cars. 89 is a midgrade octane rating that’s suitable
for newer vehicles; and 92 is the premium gasoline that’s mostly required to drive
elite and sports cars, but sometimes even new middle-segment automobiles can demand
the 92 and nothing below that. Like I said earlier, if the user’s manual
states you can use any of the three, then the choice is absolutely yours. You and your car will feel no difference whatsoever. But if the octane rating is important for
your vehicle, then you should take note of that and not use any fuel that has a lower
rating than required. And here’s where we get to the issue I promised
to explain a while back — the “knocking.” The term itself was coined thanks to the sound
a car makes when its tank is filled with the fuel with a lower-than-necessary octane rating. It gives off an audible “knock” or “ping,”
and can even not start from the first attempt. That’s because the fuel mixes with air in
the engine, and if the octane number is too low, this mixture can combust too early and
damage the engine. Have you ever heard this sound while starting
your car? Let me know down in the comments — now you’ve
learned the reason behind it! Anyway, manufacturers may require a higher
octane fuel because their engines receive more air thanks to supercharging or turbocharging. The reason can also be in a higher compression
ratio, which increases pressure in the cylinders. The engine becomes more efficient with these
features, but a higher octane rating is necessary for them to work correctly. More air in the engine means faster ignition,
and that can lead to early detonating of the mix. With high-octane fuel, this is usually out
of the question, which can’t be said about the low-octane type. So if you pump the 87 into a car with a supercharged
engine that requires at least 89, you’ll most likely hear that dreaded “knocking”
sound as soon as you turn the ignition key. The damage caused by wrong fuel is not immediate,
though. You’ll probably be able to drive for weeks
before encountering any trouble. On top of that, most modern cars have a protection
system that softens the “knocking” effect and doesn’t let the vehicle take too much
damage from the lower-octane fuel. So answering the very first question of this
video, yes, if you’re stuck on a highway with no other fuel than the 87, you can safely
pump it into your tank. But I’d still not recommend abusing this
practice. In the long run, the cost of repairing the
engine will outweigh the fuel economy by far. In addition, the higher the octane rating,
the “cleaner” the gas, so it will both help keep your car in a good condition and
reduce your emissions. Now if I could just reduce my emissions.. So now you may ask why higher octane fuel
costs more, especially since it makes no difference in cars that can run on the 87. The reason, though, is quite banal: money,
as always. Higher octane rating is achieved by adding
components that boost it, and those are expensive. The more they add, the higher the cost (which
is pure logic). So buying an expensive car is just the first
step in a long road paved with service and maintenance bills. Some time ago, however, a new type of gas
appeared on the market, and it has a separate label: E10 or E15. The letter E stands for ethanol, while the
number indicates its percentage in the fuel — 10 or 15%, respectively. Most gas sold in the US contains up to 10%
of ethanol, and car manufacturers approve of its use in their vehicles. With E15, the situation is a little bit more
complicated, but still many automakers design their cars to fit this type as well. And finally, there’s also E85, or flex fuel. This type contains anywhere from 51 to 83%
of ethanol, and only several car manufacturers allow its use in their vehicles. Ethanol is basically one of the most efficient
additives in gasoline. It has a high octane rating by itself (about
109), it’s much safer for the environment, it’s renewable, and it reduces dependence
on oil. Ethanol is made from plants, such as sugar
cane or corn, and the easiness of its production helps keep its cost pretty low. So why don’t we just switch to ethanol-based
cars then? Well, if only it could be that simple. First of all, ethanol is one-third less efficient
than pure gasoline. It means that if you can drive for 3 hours
on 100% gasoline, you’ll only have enough 100% ethanol for 2 hours’ ride. Now make it days, and you’ll see how drastic
the difference is. Secondly, only the newest cars allow for E85
to be used, so it’ll take a lot of time for all manufacturers to adopt this type of
fuel. And thirdly, there are precious few stations
that have ethanol-based fuel at their disposal yet. And let’s not forget about other types of
vehicles, such as electric-powered cars, that are more efficient in terms of pollution than
ethanol-driven ones. Electric cars just might drive both gas and
ethanol from the market and replace them completely. Alright, we’ve covered the topics of octane
rating and ethanol-based fuel, but I can’t get rid of the feeling that we forgot something… Ah, yes! The diesel engines! What’s wrong with these guys? Nothing, in fact. They’re just absolutely different from gas
engines in the way they work. So what could happen if you accidentally (or
on purpose, although I’ve no idea why you’d do that) pump diesel into your gas-powered
car? At first, you’ll drive as if nothing’s
wrong. That’s because the engine will use up the
remains of gasoline in the tank. But as soon as those last few drops are expended,
your car will just stop. It happens because diesel and gas have different
ways of combustion, and what works for gas is useless with diesel, and vice versa. You won’t be able drive any further with
diesel in your gas tank, so you’ll need to tow your car to the service station cand
drain it. Don’t worry, though: since the engine doesn’t
work, no damage is usually done to the internals of your car. But if draining doesn’t help, you should
prepare yourself to shell out a hefty sum for disassembling the engine and putting it
back together again, dry. If the opposite happens, however, and you
fill your diesel tank with gasoline, things get much worse. You see, diesel isn’t just fuel; it’s
also a lubricant — a quality which gasoline lacks. And if gas-powered engines can’t combust
diesel fuel, diesel ones are actually able to fire up gas. But it doesn’t really help the situation. Gas will detonate too early upon combustion,
creating that same “knocking” I told you about before and damaging the car from inside. It will also leave the fuel-injector pump
without lubrication, which can lead to its rapid failure. All in all, if you make such a mistake, be
prepared to replace some parts of your car. So remember: when choosing fuel for your vehicle,
and you’re given a choice of several grades, you can proudly decide at the pump, and say:
Diesel work just fine, fill ‘er up! Hey, if you learned something new today, then
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