Another gas question

[Bjammin]

I'm going to flash my ecu and trying to decide between 91 ots or 93 ots. I'm in California where 91 is the highest octane available. I live a couple blocks away from a station with 100 octane. I know mixing in 3.5 100 octane with 91 octane will equal about 93 octane. Should I go with the 91 ots and utilize the 91 gas for daily driving or flash 93 and mix 100 with 91 every fill up?

[IVM3]

You'll end up in situations where you don't have access to 100 octane to mix in. I would definitely use the 91 map.

[Bjammin]

Originally Posted by IVM3

You'll end up in situations where you don't have access to 100 octane to mix in. I would definitely use the 91 map.

That's a good point, didn't think about scenarios where I would be driving out of town.

[HotRodM4]

91. You'll appreciate the convenience.

[Blackhawk878]

You can carry a bottle of Boostane with you. That's what I use to make up for the shit gas here in Az (similar to Cal).

[AlmondJayRoM3]

Bootmod3 OTS multimap.

[Humdizzle]

better off with the 91 map.

you could run the 93 map and still put 91 in it just to get home as long as you're not doing full throttle pulls. then put the 93 in it once you get home. honestly though the performance difference between 2 octane points isn't that huge to be worth it

[McBobby Jr]

Originally Posted by AlmondJayRoM3

Bootmod3 OTS multimap.

This would be your best choice, as with the Multimap you'll be able to switch maps on the fly so in the case you can't get your 93 Octane, you can run the 91ACN Map or the 91 Map. As for getting your 91 Octane up to 93 Octane for the 93 Map. An Octane Booster, or a few gallons of 100 Octane at the pump will work well. A couple gallons of E85 will work great, and if you want more power, an E30 map would work even better. This is assuming you have 100 Octane or E85 at the same pump where your 91 Octane is.

[TR930]

I run the 93 Oct map on 91 here at altitude (CO). No issues so far.

[Bjammin]

Originally Posted by Blackhawk878

You can carry a bottle of Boostane with you. That's what I use to make up for the shit gas here in Az (similar to Cal).

How much boostane do you use to get 93?

[rosemont83]

Originally Posted by TR930

I run the 93 Oct map on 91 here at altitude (CO). No issues so far.

You probably have issues you just don't know it yet..

OP just run the 91 tune. Why would you want to risk detonation for the very little bit of power? Pretty sure all of those maps override the safety parameters..

[Bjammin]

Originally Posted by rosemont83

You probably have issues you just don't know it yet..

OP just run the 91 tune. Why would you want to risk detonation for the very little bit of power? Pretty sure all of those maps override the safety parameters..

That's true, it's my daily driver so I don't need so much extra power. I'll do multi map if I ever track it in the future. Thanks everyone for your help, much appreciated.

[F82 ZCP]

I had an AMG C63S Coupe that had catless DP and a tune.

I had a 100 octane tune for when I went to the track or 1/2 mile racing.
But my 91 tune map was so aggressive that it was more like a 93 map and I used to throw 3-4 gallons of 100 octane in with each fill up (back before gas was so high) and the car ran great.
For going out of town (away from my 100 octane station) I could throw a bottle of Torco octane booster in the car if needed and this worked well.

It is nice to have 100 octane right around the corner like I did also...I say go for it and you will figure out the fuel part and enjoy the added power.

[TopJimmy]

Originally Posted by Bjammin

How much boostane do you use to get 93?

Boostane can clog your O2 sensors.
Use Ethanol to boost octane ratings.

[hellokitty]

Originally Posted by TopJimmy

Boostane can clog your O2 sensors.
Use Ethanol to boost octane ratings.

+1

You can add 2 gallons of E85 then fill the rest up with ACN91. That will get you to E19 and 92.1 octane approximately.

You should be fine with that setup on either stage 1 or stage 2 91 maps.

[McBobby Jr]

Also for Boostane/Octane related stuff, use this thread for reference.

BOOSTane to bring CA 91 gas to 93 https://f80.bimmerpost.com/forums/sh....php?t=1642951

[TR930]

Originally Posted by rosemont83

You probably have issues you just don't know it yet..

OP just run the 91 tune. Why would you want to risk detonation for the very little bit of power? Pretty sure all of those maps override the safety parameters..

Would care to elaborate on the issues I don't know yet, but you claim I probably do?

[TopJimmy]

Originally Posted by TR930

Would care to elaborate on the issues I don't know yet, but you claim I probably do?

I think he was eluding to how running 91 on a 93 tune probably causes some minor ping/knock and the DME would reduce timing as a preventative to damage. If you drive easy then the 93 tune still works (no high demand for timing) but running the 91 tunes would be a better choice.