Well, the claim about Mobil gas seems ridiculous as Porsche's OE engine oil for the 991 Turbo is made by Mobil, but OK.stitch2k1 wrote: Wed May 21, 2025 8:22 pm I have never subscribed to 'Top Tier' gas stuff. If it was established in 2004, then what benefits could be had in an engine from 1980? Possibly under highly highly highly modified engines, but in normal 944 motors? No, I don't think so.
I am open to having my mind changed with evidence to back up claims, but all I have heard over the years is hearsay and claims. The best was a Porsche dealership telling this guy with a 991 Turbo that because he used Mobil1 gas he destroyed three of the direct injectors in it.
I'm all about "top tier" or any company that portends adherence to the standard. What is the downside of such a thing? It may not be the be all, end all, but it is something. All engines from the early 1900s to 944s and beyond can benefit from a minimal standard of decent detergents in gasoline.
I've only had a few cases of bad gasoline causing serious issues in 20 years of working on Porsches for a living, and they have all been from "no name" gas stations. I'm not claiming that "top tier" will cure any ills, but it is at least a minimal standard for cleanliness. I also advise to drive on if you see the gasoline tanker truck filling the underground tanks, that can stir up whatever sediment might be at the bottom!
