Subaru recommends 91 or over for my FXT, so I almost always run 93 as that is the most common octane level for premium around here.
It's nice that the price is down, but I'm not burning too much gas these days...I'd go back to high gas prices with no pandemic conditions in a split second as opposed to the situation now.
The only 93 octane seen with some repeatability around here is BP, and not all have it. And to be blunt, between the price and the fact that monitoring what my ecoboost truck perceives as the octane has shown that 93 octane in the flavor found here is not worth the money. Two brands of 91 octane routinely deliver the same performance (Shell and Speedway).
And before anyone comments on it, yes, we do have several distinct sources of fuel available in this market, so there can be differentiation between brands most of the time.
My wife's Optima typically gets 87. We've never experienced knock or other issues so we go with it.
My '19 Escape gets the cheapest gas at the station as my company pays for it. 99.99% of the time it's 87.
I have owned two Audi Turbos and I only used 87 Octane. No knock and they were Fast !!
Tried some higher octane in the VW .
SOMETIMES it helped a bit with low and midrange torque under load+boost during break-in.
But once the Jetta got 5K miles on it - it does fine with 87.
And I want maxium torque and power.
You just have to get a GOOD and fresh 87 Doesnt always happen - and there are batch variations.
These VW small bore,super long stroke 4 bangers with DI seem to not care about octane.
Infact it seems to run BETTER on regular 87 E10.
That is completely fine by me!
It really depends on the particular setup. But with a knock sensor it's likely that it won't create problems. There are an increasing larger proportion of engines that can use 93 AKI fuel. Even that regular WRX these days comes with a recommendation to use 93. But there are probably a lot of the economy vehicles with turbos that are designed for maximum performance/economy with 87.
I mix 93 E-free with 93E, but I didn't notice much dif in 91E & 93E. Today is my half tank top off at Valero with higher grade offered at lower grade price. I'll try 91E at regular price. That lower cost would offset 93 E-free that is currently $2.52.
If me bum dyno detects a dip in performance I can always top off 93E-free a mite early.