What Happens When You Put a Potato in a Tailpipe? Seriously.

Dear Car Talk

Dear Car Talk | Nov 05, 2015

Dear Car Talk:

When I was a kid, many years ago (wearing my Davy Crockett coonskin cap), my friends and I wondered what would happen if we crammed a potato into the exhaust pipe of a car. We figured the exhaust would build up and eventually shoot out the potato like a cannonball from a cannon.

Fortunately, we never tried it. For one thing, we wouldn't be around to see what would happen. For another, our mothers wouldn't give us a potato. Now, all these many years later (and without the Davy Crockett cap), I'm still wondering: What would happen? Thanks!

-- Dave

It's not too late to try it, Dave. I'm sure you can find a Davy Crockett cap on eBay.

And your mother's probably pretty old by now, so you probably can slip a potato by her at this point. Then you can try to lodge the potato in your wife's car.

What'll happen -- if the engine's running, and you secure the potato in there tightly -- is that the car will stall. If you block the exhaust gases from getting out through the tailpipe, there will be no room for fresh air to get into the combustion chambers, and the engine won't be able to run.

Or, if the car is not running when you "install" the potato, the car will start up and run briefly, and then stall.

If you want the potato to shoot out of the tailpipe, you'll have to be a little more deliberate. Try one of those little, red "new potatoes." You'll have to make it fit perfectly inside the tailpipe -- not too loose, not too tight. Bring a potato peeler with you so you can make last-minute adjustments.

Then it should work like a peashooter. If you have a buddy punch the gas and rev the engine, that potato ought to come flying out pretty quickly.

So, if you try this at home, make sure you wear your Davy Crockett coonskin athletic protector. Have fun.


Get the Car Talk Newsletter