Are you getting tuned by Moncef? By default he'll give you the performance tune and an eco tune, which I assume is just stock. That's all I have and have never switched. If you do tune on a different fuel, you'd have to drain the tank and refill. I say keep it simple and drive conservative if you need to conserve fuel.

 

All good comments, but getting off track of the basic question:

 

This is in my opinion all on the tuner itself. I've seen plenty of forced induction cars making power on 91 where 93 was just not available however it is proven that 93 will give you the smoothness you want. Anyone that objects to that has not had their vehicle tuned properly on both octanes.
With 93 you can safely add some timing at part throttle and cruise will feel much smoother since timing wont need to lower as much to avoid detonation. Same math applies higher octane GASOLINE fuel. Vehicles that loose power on higher octane has everything to do with compression, Volumetric efficiency and tuning. By now we have sufficient data on what the VHR likes and doesn't. Good oils + catch cans + Premium fuels + correct tuning are the keys to longevity of these engines.

In all honesty this is the worst with OCD. Options, many of them, it's so stupid at times. The likenesses of you not being able to get to a station with 93 just doesn't seem like the type of behavior you would display the same goes for Mexican 89

 

In Mississippi I got 80 octane once at a literal bodega. My (nonturbo) RX7 loved it.

I can't speak to where Rochester drives when there isn't a pandemic - in my case, I regularly drive 6-10 hours away to friends in one direction and inlaws in the other... and a few times a year I drove 14 hours to my mother's house. So I see lots of sketchy gas stations, and on back roads rather than interstate, you get what you get.

I do need to look into the catch can part of the equation. I was looking for the thread-in valve cover adapters to make my own.

So... maybe a good question for Moncef? He might have an insight that the rest of us do not.

 

As stated, around here (Western NY and Finger Lakes Region), I've never ever seen a gas station where 93 is unavailable. It's ubiquitous. Moreover, when a station only has Regular and Premium, the Premium is always 93. Finding a station with 91 Octane, however, that's hit or miss at maybe 1/3 or half the stations. Given the complete availability, and the rarity of taking the G on a road trip, I'm going to commit to the 93 Octane tune. For that rare road trip, I'll probably fill the tank with 91 and switch over to the Eco map.

Maybe I'm over-thinking things (again) with this topic. In a nut-shell: 93 is available everywhere for me, so get a tune for 93. /done

I haven't reached out to him on this project yet. Targeting that contact for the end of February with a license purchase in March, and the tune in May.

 

Moved Bull's post on catch can plumbing over to my build thread since it doesn't really fit here.

 

Been a month since I recognized this Spring's tune was going to be for 93 octane. Unfortunately, I filled the tank right about then, and have been going out of my way to find nice days to drive around, so I can burn off a full tank of 91. But between working at home, the pandemic, and a suddenly harsh Winter... it's not like it gets driven much. It's been a month, and the tank is still half full.

First world problems are lame, but there it is anyway.


[edit]

I'm closing this thread. Short answer... tune for 93 Octane. /done

...unless you're tuning for e85, which is tech above my pay grade.