Why You Really Shouldn't Run Jet Fuel In Your CarS

Most gearheads have probably heard stories about running jet fuel in cars for instant, magical speed increases. If you look online, the question comes up pretty often. The same goes for other exotic fuels, like aviation gasoline and Pegasus urine. So what's the truth here? Is jet fuel a magic speed-serum?

We received a tip from a nice somebody named 4X (maybe a friendly robot?) about this car seized in Dubai that was clocked going over 215 mph. The noisy, fast car and driver were eventually caught (after trespassing into a house to hide the car?), and when police inspected the car, they found

"...that it was fitted with a computer system, another engine and a jet fuel tank plus extra cylinders and other additions……its driver said he used jet fuel to increase its speed and admitted that the jet fuel and the additions were provided by a car maintenance shop."

This description is pretty confusing. Another engine? "Extra" cylinders? Jet fuel? Looking at the picture doesn't really help— it mostly looks like an engine with some shiny blue air intakes and a turbo (helpfully labeled with a marker as "turbo"), but any other engines or the baffling "extra cylinders" aren't shown. It doesn't really sound like the writer knows so much about cars, and the reference to "jet fuel" just confirms this.

Why You Really Shouldn't Run Jet Fuel In Your CarS

But the writer's not alone— the idea of "jet fuel" being used in cars to get additional performance comes up an awful lot, and, as crazy gonzo Car Hackers, I'm sure we've all fantasized about filling our Diahatsu Charades with jet fuel and leaving all the Zondas you see embarassed at stoplights. But there's lots of myths and confusion surrounding what jet fuel, aviation gas, and other non-car fuels really are, and what they can do. So what's up with the flying gas?

Let's start with jet fuel, which is the one most often referenced. In your head, when you think about putting jet fuel in your car, most people immediately think there'd be at best some kind of colossal burst of power and at worst a black, charred outline on the pavement where your car once was. We think that because jet engines are huge, powerful things the fuel must be this magic ichor of boom.

The truth is way, way more mundane. Jet fuel has more in common with home heating oil than, say premium gasoline. Jet fuel (there's variants, but a very common one is known as Jet A) is really close to regular old diesel fuel. And, for that matter, kerosene. You can even run it straight in your diesel car or truck, though it doesn't lubricate as well so if you do, you'd want to add some sort of lubrication additive.

The big point here is that you can't run Jet A in your gas-powered car, because it's basically like putting diesel in your gas car. If that happens, it won't destroy your engine (like the other way around could) but it will mean you'll have to drain the tank and clean fuel components and generally do a lot of things that are the exact opposite of going superfast.

Jet engines work fundamentally different than piston engines, so their fuel requirements are wildly different. Plus, hard-to-ignite diesel is a much better choice for busy airports, where you don't want puddles of highly flammable liquids all over the place.

Part of the jet fuel as super-car-fuel likely comes from the confusion of jet fuel with what's known as avgas, or aviation gasoline. Avgas is for aircraft with car-like piston or rotary engines. Most of these fuels are about like they were when they were formulated around WWII, where they were used primarily in powerful, supercharged piston engines. As such, they tend to have very high octane ratings, often around 100.

The high octane ratings are the allure of avgas— and some people have tried it as a substitute for racing gas, but it's not really a great idea. High octane is good in that it helps stop premature detonation (knock) but avgas is less dense, requires different carb or injector jettings, and is generally designed for very different environments than, say, racing gas.

The most common avgas is 100LL— the "LL" stands for "Low Lead" but it's important to note that does not mean "No Lead". There's lead in there, and as such will effectively murder sensitive and expensive emissions components in modern car engines, like catalytic converters.

Why You Really Shouldn't Run Jet Fuel In Your CarS

So while the idea of using aircraft fuel in your car sounds pretty cool, it's one of those things that just sounds better on paper, or to lie about to the Dubai cops who impounded your car. It's sort of like cheetah blood that way— you look super-cool pouring it into your gas tank, but don't expect it to do you any good.

Because, as everyone knows, for speed you need to rub cheetah blood on the intake manifold. Duh.