How could putting 154 octane into a '99 Camaro hurt the engine?

Answer 1

Let's see........

1. Bent valves

2. Caved pistons

3. Burned spark plugs......need I go on?

DON'T DO IT

You can run a higher octane in your engine if you like without worry about doing damage; except to your wallet. If you WANT to "bend valves" and "dish pistons" Camp Stove fuel will do a great job trashing your engine. It has almost a 0 octane rating. 

Read "Octane Rating" http://en.wikipedia.org/wiki/Octane_rating here for more details.

In a nutshell, the octane rating describes a fuel's resistance to self- or pre-detonation when compressed, as in "pinging", "knocking" or "Dieseling". These undesirable effects will destroy a spark ignited internal combustion engine quickly and are hence VERY undesirable. For high performance (high compression) engines a higher octane rating is needed to prevent this pre-detonation.

SO, using a higher octane rating in an engine that does not develop relatively "high" cylinder pressures is largely a waste of money.

One point that the above web page makes clearly is that higher octane does NOT denote a slower burn rate for the fuel. Although slowing the burn rate does anecdotally produce a little more power, since power is developed longer throughout the power stroke. This is generally a desirable fuel characteristic that some have achieved by adding water vapor to the fuel/air mixture, which also raises compression slightly. But this is a very different topic… Fact is, most higher-octane fuels do burn slightly slower, or at least ignite slightly later in the stroke. Effectively this equals a small (almost imperceptible really) retarding of the ignition.

So, unless you're going to milling your heads, putting in a 'hot' cam and a "blower" and running at very high RPM much of the time, you neither need nor want a fuel designed for a high compression engine. It just a huge waste of money. You'd do much better re-tuning (reprogramming?) your fuel/air mixtures and timing curves.

BTW, I run a higher than recommended (87) octane fuel in my vehicle (93 usually) because it MEASURABLY lowers engine temperatures and improves my mileage slightly, especially since I tow often, requiring a rather high throttle opening (higher cylinder pressures).

Good luck.