Originally Posted by LoneRanger
My wife, her mother, and her two sisters will be taking the new GMC out east towards end of July, about a 12 hour drive each way. Car will be close to gross weight. My question is, although the engine is spec'd for regular unleaded 87, would it be a good idea to probably ask her to use 93 premium instead for the entire trip? I'm considering this in light of the conditions which will be expected to be hot and the car loaded near gross weight.
Main consideration is minimization of the ever present possibility of LSPI on these small gasoline direct injection turbo engines. Seems wise to feed it premium for a long heavy haul in the heat. The cruise on the interstate not being the risk factor, but instead the low rpm high boost condition that would arise when, say, departing rest stops, which will be a frequent occurrence given the occupant demographic. Car parked just long enough at the bathroom stop to bloom excess engine heat, then start-up and getting back on the highway may represent an increase in the potential for low rpm high boost. It would be better to leave the car idling (take turns going to pee) so the cooling system can control heat, but that won't be happening.
Over thinking it? Yes. But this is BITOG. It's what we do.
If you can afford to run Premium fuel on that trip, your engine will thank you later. It may even thank you 300 miles into the trip. My GMs run better on 93 Top-Tier.
