A Different Question Re: Pilot Fuel Octane

[Eman]

I know about the manual misprint, and have read some of the engine ping posts (I've got pinging with my '05 Pilot on strenuous hills). However, I don't know a whole lot about engines, etc., so I've got a quick question...

Does running a higher octane level make a car's engine become almost dependent on that higher level? And does running with the engine ping/knock hurt a vehicle?

The reason I ask is that a few folks at my dealership emphatically said to run Regular Unleaded (87 Octane) ONLY.

[iglesias]

Originally posted by Eman

Does running a higher octane level make a car's engine become almost dependent on that higher level?

I've heard from others on the Ford Explorer newsgroup that running premium gas in the Explorer caused problems (carbon buildup, pinging, etc). I never put anything other than regular in my Explorer.

I have not heard any pinging in my Pilot, but then I have not tried any long hills yet. I've used regular so far.

[ctrim]

I've heard that running a higher octane makes the engine run cooler. Any truth to that?

[dgipalo]

Originally posted by ctrim
I've heard that running a higher octane makes the engine run cooler. Any truth to that?

Only the oil company marketing variety.

The reason Honda recommends a higher octane for max-effort towing has more to do with heat build-up from high power demands contributing to a tendency to detonate than the engine running cooler with higher octane. A higher RON value for a fuel will help it resist pre-ignition under adverse conditions.

[ARwebpilot]

Quote: "And does running with the engine ping/knock hurt a vehicle?"
End Quote

Most mechanics will tell you that going any significant distance (hundreds of miles?) with the engine constantly pinging/knocking WILL cause permanent damage. The pinging/knocking sound is caused by combustion problems in the combustion chamber. I've been told that it is possible to melt the top of a piston - luckily, never had that happen. Perhaps some of the more experienced motorheads in the group can provide additional details on the cause and danger of engine pinging.