Jet Fuel and Automobiles

[InkBlot]

So, does anyone know what would happen if one attempted to fuel a car using jet fuel, or a mixture of said fuel with normal automotive fuel? I’m not thinking of attempting it, but someone pointed out to me that Jet Fuel is a much higher octane than normal automotive stuff, and burns much cleaner. Makes me wonder what other differences there are, and just how clean a car really could burn gas.

InkBlot

[Ethilrist]

Burns much hotter, too, and more explosively. Chances are all the various parts of your car that are built to take the heat and pressure of a gas-air mix exploding without falling apart wouldn’t be able to take it.

[Padeye]

Uh guys, jet fuel is equivalent to diesel fuel and is far less volatile than gasoline. You probably won’t get it to run in a gasoline engine at all. Yes, it is higher octane which is resistance to detonation. That’s why diesel engines have a compression ratio typically more than twice that of a gasline engine.

[Johnny_L.A]

Burns much hotter, too, and more explosively. Chances are all the various parts of your car that are built to take the heat and pressure of a gas-air mix exploding without falling apart wouldn’t be able to take it.

Erm… No.

Jet fuel such as Jet-A or JP-4 is basically kerosene. As such, I think it’s about 50 octane. Jet fuel is much less volatile than automotive gasoline (or “mogas”).

Since Jet-A is pretty much kerosene, it’s much cheaper than regular aviation gasoline. Good thing too, since turbines are thirsty.

Can you run car gas in a jet? Sure – but you have to be careful. Since mogas is more volatile and burns hotter, you may damage a jet engine by burning automotive fuel in it.

[Sofa_King]

My grandfather once told me a story about a crazy uncle of his who used kerosene in his Model A, because he felt it gave him a smoother ride. Jet fuel is usually very closely related chemically to kerosene, which has a low octane-equivalent rating. According to this site:

Jet engines have absolutely no use for high octane fuel, since their combustion process is totally different from that of gasoline engines. Putting jet fuel in an internal combustion engine is a sure way to destroy it immediately - not because the jet fuel is “too hot”, but because it has no knock-suppressing capability.

You may be thinking of aviation fuel, used for piston-engined aircraft, which is of fairly high octane, often in the 100-115 range. That’s a no-no as well, because it’s packed with tetraethyl lead. From the same site above:

Despite the fact that the pump is labeled “100 Octane LL (low lead)” it still has more lead in it than the worst 1960’s automotive gas. Running this through a car with an oxygen sensor or catalytic converter is sure death for those parts.

However, I once heard that the U.S. armed forces had a long-term plan to make all of its vehicles, from a Humvee to an F-15, capable of running on the exact same fuel. That way the logistical problems of supplying any branch of the armed forces would be greatly simplified–if you see a gas can, you can pour it in whatever you’re driving or piloting.

Unfortunately, I don’t know if this plan is still in place. Perhaps someone else knows.

[Ethilrist]

My bad. A local gas station sells high-octane gas (about 120?) and calls it jet fuel.

[Padeye]

thanks for correction on the octane.

FWIW JP-5 as used on carriers is so un-volatile that it’s difficult to get a puddle lit with a match or lighter.

[Johnny_L.A]

FWIW JP-5 as used on carriers is so un-volatile that it’s difficult to get a puddle lit with a match or lighter.

According to The Bluejacket’s Manual, this is not a recommended activity aboard ship.

[Padeye]

I don’t think I have to tell you we did a lot of things not reccommended in The Bluejacket’s Manual.

[Johnny_L.A]

Heh. Don’t tell me the BJM really does say “it’s difficult to get a puddle lit with a match or lighter.”! :eek:

[catmandu42]

*Originally posted by Sofa King *
**However, I once heard that the U.S. armed forces had a long-term plan to make all of its vehicles, from a Humvee to an F-15, capable of running on the exact same fuel. That way the logistical problems of supplying any branch of the armed forces would be greatly simplified–if you see a gas can, you can pour it in whatever you’re driving or piloting.

Unfortunately, I don’t know if this plan is still in place. Perhaps someone else knows. **

Oh, they did that quite a while ago. While I was in the Army, quite a few of our larger vehicles (deuce-and-a-half on up) Had what was called a “multifuel” engine. There was a big metal plate on the block that listed all the different fuels you could run through the thing. There were about 8 different ones, ranging from gasoline to diesel to kerosene. It also listed a couple of the JP fuels, 5 being one of them. There was a switch you had to flip in order to run some of them, although I never got the chance to flip it, so I have no idea what it did. I also never had to run anything but diesel in it, so I can’t report on it’s performance, either.

Actually, this appears to be an old concept, because one time for kicks, we did a trace on the truck’s serial number, and found out it had been made during the Vietnam war.

[InkBlot]

Thanks for all the replies, especially Sofa King with the great site. I feel less ignorant already!
inkblot

[Nametag]

Ethilrist sez:

My bad. A local gas station sells high-octane gas (about 120?) and calls it jet fuel.

Yeah, they’ll do that. Two little lies and one big one here:

1. Most very high octane numbers are RON-only. The Research Octane Number is the higher of two numbers that are averaged to get the Pump Octane Number (MON, or Motor Octane Number, is the other). The RON can’t be compared directly to the “92 octane” on the premium gas pump.

2. That stuff is probably leaded, and is illegal to put in your car.

3. The big lie, of course, is that it’s jet fuel. It’s almost certainly racing gasoline, which is often rated at 120 octane.