Today: The Firebird and the Angry Little Brother

Dear Car Talk

Dear Car Talk | Nov 15, 2011

Dear Tom and Ray:

When I was younger, I had a friend who had an early-'80s Pontiac Firebird. It was in rough shape, and it had the 305 small-block engine with a four-barrel carburetor. It never seemed to run smoothly, and it could have used a tuneup. During this time, the owner of the Firebird was living with a mutual friend, who had a little brother. The little brother and his friend didn't like owner of the Firebird, so for a week they urinated into a plastic gallon jug behind the garage, with the intent of dumping it into the gas tank of the Firebird.

So, one morning the owner of the Firebird showed up at my door and told me to hop in. He was really excited, and when I got into the car, he went on about how his vehicle was running the best it had ever run, and he couldn't figure out why. It was true -- the engine ran like a clock, and the dual exhaust sounded great. I had learned the night before that the "homemade octane booster" had been added to the tank. My question is this: Was this just a fluke occurrence? Or is every portable potty a fuel source just waiting to be discovered?

-- Rob

P.S. My apologies to the man in the convertible behind us on that fateful day.

TOM: Well, I think we've finally discovered the secret behind Marvel Mystery Oil!

RAY: We don't have any idea, Rob. I've never tried this, never wanted to try it and don't intend to ever try it.

TOM: I'm glad to hear that, because now I can eliminate that as the reason my '78 Fiat has been running so well lately.

RAY: The only possible explanation I can even make up is that the urea in the urine served as a cleaning solvent of some kind and removed some gums and varnishes from the Firebird's carburetor and allowed it to deliver fuel more evenly.

TOM: You could say they put a tiger in his tank!

RAY: But the fact that we have other fuel-system cleaners designed specifically to remove varnishes that don't -- as far as I know -- contain urea reinforces my belief that this answer has no basis in reality.

TOM: Of course, that could be said about most of my brother's answers.

RAY: I think this is best left to the chemists and chemical engineers who read our column. Guys and gals? Got any thoughts? Send them to us at

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