Is it really possible to "disable" a car with a banana?

Actually welding is cheap. Not a clamp in sight in the last few cars I have bought.

Shaddap!

J’ve seen both in real demonstrations: I think it is more a question of geometry: Flower petals are thin sheets that shatter easily, while a banana is a solid junk. Think of the the mechanical properties of a solid block of ice compared to a thin sheet of ice

Diesel trucks provide additional braking by blocking the exhaust path. This is what an exhaust brake looks like: Bestand:Exhaust brake governor.jpg - Wikipedia

The exhaust brake is also used to turn off the engine. If you just turn the key the engine will keep running, since there’s no electric ignition system in diesels. The exhaust brake is operated via a button on the floor with the heel of the left foot.

The notion that things (and especially parts of people) will shatter into fragments when frozen is something that happens in the movies a lot, but not nearly so much in real life. Things that were fragile in the first place (such as flower petals) are the exception.

This may have been true on older diesels with mechanical fuel injection, but modern diesels all have computer-controlled injection; turn the key off, and the computer stops injecting fuel.

The difference is that this bike probably had a two-stroke engine. Whereas a four-stroke engine is a positive-displacement air pump that can build up a lot of pressure in the exhaust system (i.e. typically enough to blast out any fruity obstruction) before suffocating itself, a two-stroke engine relies on a dynamic gas exchange process; even a slight excess pressure in the exhaust system will inhibit air flow through the engine and kill it.

I saw the same thing as you with a 250cc motocross bike, also with a two-stroke engine. A friend had loaned us the bike for a day, and although he had reminded us to remove the rain cork from the tail pipe before riding, we forgot about it. The bike of course ran like shit for several minutes, until we realized the problem.

Some punks in my old neighborhood did this to an old guy’s car. He had trouble starting it; on the third try, the potato flew out of the exhaust pipe.

A banana may not be effective in the exhaust pipe, but it will make a mess of things if introduced into the air inlet, especially in a carburertor. It would also be effective in the fuel line, and you might be able to cram enough banana into the ignition keyhole to stop a car from working. If you smear it all over the windshield it will slow things down for a while. You could also use the hard part at the tip to force open a tire valve releasing all the air. Introduced into the brake lines it might make the car disable itself at the bottom of a steep incline. And of course, the peel left on the driveway could disable the driver.

I’ve heard of a truck that couldn’t start after backing into a pile of dirt that clogged the tailpipe. Didn’t see it myself though.

Back in Texas, they sold fireworks twice a year – in the two weeks leading up to the 4th of July and the two weeks before New Year’s. There was one type called a Texas Twister, sort of a long cigar shape, and it would shoot around along the ground while whistling and sparking, then explode in a loud pop. The whistling was LOUD. They had a version with two wires instead of a fuse, and you wound the wires onto a couple of spark plugs. Then when the driver started the engine, it sounded like all hell was breaking loose undeneath the hood. I used to pull that on my father. It didn’t exactly disable the car, but he claimed it was as sluggish as a tank until I took the wires off the plugs.

I’ll admit that I seem to have seen far fewer cars with bits of the exhaust system falling off or dragging on the ground in the last several years. Hasn’t happened to anything I’ve owned since about the early 90s. And I remember repairing a few by clamping a soup can around the break in the tailpipe. I’ll stand by the remark that if you have an exhaust system in that kind of shape, it may leak, or the back pressure will simply finish the job of making it fall apart.

Demolition derby cars often route the exhaust straight up and out to avoid killing the motor with a crushed exhaust pipe.

Happened to me once too. Doing a three point turn on a dirt road, the shoulder sloped off more steeply than I’d realised. I braked too late on the reversing part and embedded the exhaust pipe into the dirt embankment. Had to dig out space behind it with a stick to get the car to start again.

Potato. Preferably 2.

Jam them up in there solid & you’ve got a stranded enemy or cute girl that now needs a ride home…

Ahhh, high school. Good times.