Thursday, September 29, 2016

Debunked debunking, part 2

Another “debunked” automotive urban legend is the “Sugar in the gas tank will destroy your engine!!!11!” story.  Let’s take a look at this tale, and look at a few angles folks often miss when discussing it.  This myth has been thoroughly debunked, by people both smart and not-so-smart, but let’s look at it again.

First and foremost, sugar does not dissolve in gasoline.  You might be able to stir it into some kind of suspension, but it won’t really dissolve.  (Sugar doesn’t dissolve well in alcohol, either, but that’s a topic for my other blog.)  That would seem to thoroughly debunk the story by itself, and in modern vehicles in good condition it pretty much does.

Modern, good condition… I just opened two interesting views into one angle to the tale.

Second, modern (there’s that word again) vehicles have very thorough fuel filtering which will prevent sugar granules from making it anywhere near the engine.

And finally for this post, even if sugar did dissolve in gas (which it doesn’t) and sugar made it through the filter(s) (which it won’t), the sugared fuel would only flow through the fuel, intake, and exhaust systems.  I suppose it might make it into the lower parts of the engine if the pistons/rings/cylinder walls were junk but then the engine is already trashed.

Let’s talk about what could happen in the scenario above, assuming sugar did dissolve in gas and/or filtration didn’t stop it.  It is a safe bet that fuel injectors wouldn’t like it, they might gum up eventually as the sugar burned (caramelized?) due to engine heat.  I suppose, since we’re suspending disbelief, that sugar could build up on the valves and contribute to burned valves- but the operating temperatures of modern valves are extremely high and  since they’re designed to function at such temperatures that I doubt it would be a problem as the sugar would burn off without building up.  Continuing with the fantasy, maybe turbochargers and catalytic converters wouldn’t enjoy the sugar solution- but again the extreme heat would burn the sugar somewhere in the process and probably burn it cleanly with no significant ill effects.

So there we have it, thoroughly debunked.  Except maybe not.  What if we scale back the expected damage from catastrophic to annoying, and go back in time?  In the first post on debunking going back in time was also a key to understanding the battery myth.

The rest of this story comes tomorrow (really).