What do you guys feed your P300?

 

2020 D110 P300 Always premium -- 91 or 93 . . . whichever is available.

 

Agreed. Especially in a turbo. Engine would try to adjust to compensate for low octane slower burn to prevent knock but it would cut power and mpg.

 

93 in mine also...getting 21 mpg which is far better than I expected.

 

93 or best available.

 

Unless they are our of stock, 91 (best you can do here on SoCal, usually.) Not worth saving 5 or 6 bucks per fill-up for the potential downsides of using lower octanes on a regular basis - as someone else already mentioned, reduced performance, mileage and - eventually - light engine knocking. Nothing bad will happen by filling up with 87 or 89 occasionally, however.

 

Like others I have been using premium (93). However out of habit I put in a tank of regular 87 and can confirm it didn’t cause any problems.

 

I use AV gas - 100 octane - fill up at city airports - of course it is $9 a gallon but I don't care I have Federal Gov. credit card

 

Generally speaking one should run the recommended octane. Lower octane costs performance (and can create damage in vehicles that don't contain knock or ion sensing ignitions to retard timing, not an issue on most modern cars).

But higher octane than specified can be problematic over the life of the engine as well leading to excessive carbon deposits.

Avgas is even worse as it contains lead and will lead to lead deposits on valves, as well as potentially fouling cat-cons and O2 sensors.

https://www.fuelexpert.co.za/canirunavgas.php

Then there are issues with legality. I wonder if it's sticky to use a federal credit card to break the state or federal laws with regards to using untaxed fuel on roadways?

 

I fill up my P300 with 93 octane premium, runs great on it so far, When I took a road trip recently I was in the Saratoga area and was surprised that the gas station only had 90 as premium and it was ethanol free 90. I hesitated but I was too low at the time to not buy at least some of that, so I think I put a couple of gallons in to get me on my way back to the hotel. Seemed to run ok. When I got back home it was back to filling up with 93. The pumps around here (Western NY) all say 10% ethanol I believe. FWIW.