[Slyy Smilez]

I have a 2020 M340I (gen2 b58) and i have bootmod3 and a high flow DP, currently running stage 2 91acn map since i live in SOCAL and theres no 93 oct ANYWHERE withing an hour of me. I have a station that has e85 about 30 mins from me and was wondering if i used a e85 calculator, would i be able to safely run the e30 or even e50 maps in BM3? I know Cali's 91 is trash but i was hoping with e85 it would balance that out. I dont want to get a flex fuel kit unless i absolutely NEED it. Any responses would be greatly appreciated!

[mike@x-ph.com]

You could run it without the flex fuel sensor; it's fine if it's a one-time thing.
If you are running E85 constantly, I strongly recommend the flex fuel kit.

The E85 mix varies every time, and ideally, you want bm3 to know how much you have to adjust the boost accordingly.

Running too much E85 might max out your fuel pumps; running too little makes the map too aggressive and might damage the car.

[xnick101]

Yes, I've used E85cal on iphone to measure how much ethanol/pump gas you need in order to get to E50. You can run up to E50 on that map and then you have to wait until the gas light is on before you can run full 93 and flash back and vice versa.

[Slyy Smilez]

Originally Posted by mike@x-ph.com

You could run it without the flex fuel sensor; it's fine if it's a one-time thing.
If you are running E85 constantly, I strongly recommend the flex fuel kit.

The E85 mix varies every time, and ideally, you want bm3 to know how much you have to adjust the boost accordingly.

Running too much E85 might max out your fuel pumps; running too little makes the map too aggressive and might damage the car.

Yeah i get what you’re saying, a flex fuel sensor is definitely something i’ll be getting eventually, i was just wondering if i was okay to run e50 here and there like do a tank half e85 half 91, then a couple full tanks of 91, then another e50 blend. Thanks for the reply!

[Slyy Smilez]

Originally Posted by xnick101

Yes, I've used E85cal on iphone to measure how much ethanol/pump gas you need in order to get to E50. You can run up to E50 on that map and then you have to wait until the gas light is on before you can run full 93 and flash back and vice versa.

That’s what i was thinking okay great ill do that!

[mike@x-ph.com]

Originally Posted by Slyy Smilez

Yeah i get what you’re saying, a flex fuel sensor is definitely something i’ll be getting eventually, i was just wondering if i was okay to run e50 here and there like do a tank half e85 half 91, then a couple full tanks of 91, then another e50 blend. Thanks for the reply!

half and half would not be E50 that's the problem

You can mix and run a map close to that mix, but you are taking an unnecessary risk, in my opinion. At the end of the day, it's your car, so your decision, I would not do it in my car.

[RTPenland]

Yes for sure as long as you measure and do not exceed E50 and its not a super exact science meaning anything between e30-e50 you will be fine but don't exceed that. The BM3 flash running in that range is very nice

[Planoser]

You can get an ethanol content sensor to provide you real time readings of what’s in your tank and adjust accordingly.

[Slyy Smilez]

Update: i bought the flex fuel sensor seeing as it was cyber monday. I didnt feel comfortable putting E into the tank without it.