Originally Posted by AEHaas
I chose to put in 5-20 Mortorcraft oil at the 3,000 mile mark. I was hoping to maybe get a little better fuel economy. No change.
20 weights won't always get better fuel economy in an engine speced for a 30 weight. (The 4:00 minute point of Angela's presentation at
https://www.youtube.com/watch?v=0B6SHa4qv60 )
I would suggest using a thin-side 5w30 with great specs, as in Pennzoil Platinum 5w30 which should give you optimal results (kv100 9.8, add some fuel dilution, only a little, and it's a heavy-side 5w20).
Originally Posted by CharlieBauer
Originally Posted by Wolf359
Wow, that's a really big spread between regular and premium. The mid grade is a real money maker though, should be half of regular and half of premium so it should be $3.25 instead of $3.70. So they make an extra 45 cents per gallon.
The 91 does not say "Contains 10% Ethanol" either. Costcos in CA have a 20c to 30c spread between 87 & 91 so about 5%.
Yet ethanol or methanol can increase octane rating. You did NOT want to be chased by an ME 109 with methanol-water injection activated, as one example from 1944.
You only need it injected at the right times:
"Cohn and Bromberg dealt with that problem using alcohol. When the SI engine is working hard and knock would otherwise occur, a small amount of ethanol or methanol is injected into the hot combustion chamber, where it quickly vaporizes, cooling the fuel and air and making spontaneous combustion much less likely. In addition, because of alcohol's chemical composition, its inherent knock resistance is higher than that of gasoline. The alcohol can be stored in a small, separate fuel tank — as exhaust-cleanup fluid is stored in a diesel engine vehicle. Alternatively, it could be provided by onboard separation of alcohol from gasoline in the regular fuel tank. (Almost all gasoline sold in the United States is now a mix of 90 percent gasoline and 10 percent ethanol.)" --
http://news.mit.edu/2018/mit-researchers-gas-alcohol-engine-getting-world-off-dirty-diesels-0613