NHTSA opens preliminary probe into more than 870,000 GM vehicles

[Jay P Wy]

Oh I have no doubts there is some contribution from low octane fuel. Pinging / Rod bearing taking a beating ? All of that makes sense.

Does the fuel door on these 6.2L vehicles have a warning not to use below 91 ? My 2014 challenger manual had a specific warning on the gas cap saying 91 or higher had to be used. GM ought to know some of the consumers are clueless on what fuel octane is so hopefully they made it fool proof.

The two I had had didn't and the owners manual says it's recommended but if you run 87 oct you will loose performance. It's even worse if you live at higher elevation where regular is 85 octane.

 

[jfoj]

Fuel door has a sticker on the inside that states "Premium Fuel Recommended", it does not indicate the "recommended" octane rating.

L87 spec info from GM Power Solutions indicates Fuel Type Regular Gasoline (87 Octane), with 11.5:1 compression ratio!!

L87 Spec Info

Seems the owners manual for the 2024 indicates that "Premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating (R+M)/2 of 91 or greater is recommended." Not sure what earlier versions listed.

With how the 6.2l is configured to be a Low RPM Torque monster on the highway with 11.5:1 compression, I would never dare to run anything other than 93 Octane.

 

[Scarey]

I don’t think I’ve ever seen 93 at the pump only 91. I’m west coast, is it readily available in other geographic areas?

 

[jfoj]

Yea, the problem with "Premium" fuels is they vary in Octane based on region from what I have seen. West Coast seems that 91 tends to be the typical for Premium. Some higher altitude areas may vary and then Winter blends are also different in colder climates. Winter blends are not supposed to be lower in octane, they tend to be more volitile (lower RVP) to make them easier to "ignite" in colder temps, wonder how this all plays into LSPI in the real world?

 

[KMeloney]

I don’t think I’ve ever seen 93 at the pump only 91. I’m west coast, is it readily available in other geographic areas?

Three's plenty of 93 here on the east coast.