91 or 93 octane?

[mcummings182]

I will be getting my first Accessport come tax return! Right now, I can only do stage 1 as I have an intake, cat-back exhaust but STOCK intercooler, so I can't do stage 2 or 3 yet. In the Spring I will be going stage 3 because I will be ordering an intercooler once that tax return comes.

I'm conflicted between 91 and 93 octane (I will be sticking to Cobb maps at first) That reason being most gas stations around me have 92 or 93 octane. I know that Cobb says you can go up 1 octane, but not go down. So if I go with 91 maps, I can use 92 octane. However, I would have to remember which gas stations only have 93 octane, because I won't be able to go there. This will really be a pain because if I need to fill up and there's only 93 around, I'm outta luck lol.

 

[OffTheWall503]

If 93 is readily available, use that tune. Or, you could use the 91 octane tune and use 92 or 91 in the event you can't find 93. It's always ok to use higher octane but never go below what the tune is rated for.

 

[Bretley]

Your accessport will have 91 and 93 ots maps that you can switch between.

 

[DangerMouse]

I haven't tried 91 in this car, but when I had my mazdaspeed3 91 felt way sluggish compared to 93 on the cobb tune. So for that reason I am sticking with 93 but luckily it's everywhere around me.

 

[mcummings182]

Your accessport will have 91 and 93 ots maps that you can switch between.

Is it easy to switch between though? Like can it be done quickly if need be?

 

[Bretley]

Yes it's really easy. Takes literally a minute at the most.

 

[mcummings182]

Yes it's really easy. Takes literally a minute at the most.

I guess the thing about that though, is don't you have to have close to an empty tank to switch from 91 to 93 octane then switch the map? I feel like it wouldn't be good to have half a tank of 92 and then fill up with 93 and switch the map.

 

[Bretley]

Yea, personally I wouldn't use the 93 tune unless there is a full tank of it. Otherwise you can risk the chance of running the car lean. But you can also check that with the accessport as it has many parameters your can monitor, and datalog.

 

[jpalamar]

I highly doubt there is any noticeable difference in 91 and 93 tunes on your power level. Just run the 91 and call it a day.

 

[Siestarider]

All this danger description assumes the driver has no discretion over his right foot. The ECU is more than capable of handling octane variations if driver does not ask for max performance.

Stay out of boost except as briefly needed and stay off tracks/autocross and giving in to street punks until you have a tune for the car and fuel you will run.

Running the 91 Cobb tune with 91 or higher octane will cause no problems. Theory says performance should slightly increase. One member has posted results from experiments with E25 that indicate even stock tune will produce higher hp/tq on E25 than on 93 octane.