[mg711]

Is a flex fuel kit needed for running e50 on gen1 b58 with ds2.5 or is the stock lines etc capable of running ethanol?

[nosam1g]

no , a flex fuel kit allows you to run 91 to e85 without adjusting your map(it selfs tunes base on the gas-ethanol in the tank). The stock lines you can run full e85 to 91.
Im assuming your on boot mod3 ? mhd gos up to e40 on stg2+ and full e85

[mg711]

Originally Posted by nosam1g

no , a flex fuel kit allows you to run 91 to e85 without adjusting your map(it selfs tunes base on the gas-ethanol in the tank). The stock lines you can run full e85 to 91.
Im assuming your on boot mod3 ? mhd gos up to e40 on stg2+ and full e85

Yes my plan is to have a map for e50 and a map for like 93.

[johnung]

Originally Posted by mg711

Yes my plan is to have a map for e50 and a map for like 93.

BMW fuel systems for decades have been made with components that are compatible with ethanol.

FYI It would be archaic to have separate tunes for 93 and E50, and have to reflash to change tunes. It’s so much simpler to install a FlexFuel sensor. Then just flash Bootmod3 Stage2/2+ MultiMap and set it internally to 93 Octane. When a MultiMap tune sees an ethanol sensor it automatically scales the tune from its minimum (93 in this case) up to whatever percentage of ethanol is in the tank. The goal is to obtain the maximum performance from whatever fuel the engine is receiving.

Of course the engine must have whatever hardware upgrades are necessary to run the grade of fuel in the tank such as HPFP, LPFP AND Fuel injectors.

[mg711]

I don’t mind the map switching. Also for my build I think just the hpfp is fine from what I’ve been told.

Flowmac 2.5+, ds25, catless dp with straight pipe, e50/93

[sigterm2.0]

...yeah, and with the multi map, you don't need to reflash, you can just switch in real time using the Res cruise control button and the Tach readout.

I am will be getting the BM3 flex fuel kit eventually, but right now, everything is running fine without it and I just switch between maps on the fly when I fill up depending on what I have available to me. So for me having the Stage 2+ multi map with 91, 93, E30, and E50 tunes is perfect for me.

I have VRSF catless downpipe, TU pump, and RKTunes FM CAI...

[nosam1g]

Wait a sec.. so you got a upgraded turbo and your using ots maps? Def get a custom tune lol .. highly recommend getting flex fuel or tuner might charge to tune multi maps .. as if you had flex it would be 1 map 91 to e50 upgraded turbo. Flex fuel is a sensor that gos from you lpfp to hpfp by the firewall and a power unit stored in brake area

[mg711]

Originally Posted by nosam1g

Wait a sec.. so you got a upgraded turbo and your using ots maps? Def get a custom tune lol .. highly recommend getting flex fuel or tuner might charge to tune multi maps .. as if you had flex it would be 1 map 91 to e50 upgraded turbo. Flex fuel is a sensor that gos from you lpfp to hpfp by the firewall and a power unit stored in brake area

No I’m going to do upgraded turbo and a Odin tune (2 maps) 93/e50

[mg711]

Originally Posted by mg711

No I’m going to do upgraded turbo and a Odin tune (2 maps) 93/e50

Unless I’m reading wrong, going with the 2 map option is cheaper than the flex fuel option but I don’t mind having to change the map

[nosam1g]

idk id recommend flex fuel kit , its 500 bucks , and will be better in long run. some tuners charge based off 1 map ex. tune for 91 $300 tune for e50 ex $300 ... ex flex fuel $600

[mg711]

Originally Posted by nosam1g

idk id recommend flex fuel kit , its 500 bucks , and will be better in long run. some tuners charge based off 1 map ex. tune for 91 $300 tune for e50 ex $300 ... ex flex fuel $600

Odin is $850 for flex fuel and $750 for dual map

[nosam1g]

get flex trust ^^

[mg711]

Originally Posted by nosam1g

get flex trust ^^

Okay

[Dantesboyz]

I don't recommend a flex fuel kit
Kern417 touches on this in one of his flex fuel videos too.
Essentially you'll lose one of the advantages running ethanol gives us as tuners.

Some of us with ethanol tunes and $hitty local 93 actually need to run a higher percentage of ethanol in the mix than the map targets for knock protection.

For example I run an E45-E47 mix on E40 map in MHD per recommendation of MHD. If I run eE40 on that same map, I get noticable timing pull on all cylinders.
Running the higher mix will clear it up, or yield negligible pull on one or two cylinders.

To each their own, I'm a bit OCD, I have the Spool analyzer to watch my ethanol content, yet i still least measure the ethanol content of the e85 out of the pump at least once a month.

[mg711]

Originally Posted by Dantesboyz

I don't recommend a flex fuel kit
Kern417 touches on this in one of his flex fuel videos too.
Essentially you'll lose one of the advantages running ethanol gives us as tuners.

Some of us with ethanol tunes and $hitty local 93 actually need to run a higher percentage of ethanol in the mix than the map targets for knock protection.

For example I run an E45-E47 mix on E40 map in MHD per recommendation of MHD. If I run eE40 on that same map, I get noticable timing pull on all cylinders.
Running the higher mix will clear it up, or yield negligible pull on one or two cylinders.

To each their own, I'm a bit OCD, I have the Spool analyzer to watch my ethanol content, yet i still least measure the ethanol content of the e85 out of the pump at least once a month.

That’s why i was thinking the map switch. I don’t remember his exact words but he was saying something along the lines that you can get more hp out of say e30 on a e30 tune than a flex fuel tune.

[mg711]

https://youtu.be/TuuuCit1u-M?si=GUM8gAnUEEjlfr1Z

[Dantesboyz]

That is correct, the standard e30 tune works better than flex fuel e30 tune, especially like 60-130 runs

E30 ots tune is targeted specifically for that function

The flex fuel map does not challenge the targets as intently as the ots map does. Something about how the tune automatically tapers its targets throughout the E range

[mg711]

Originally Posted by Dantesboyz

That is correct, the standard e30 tune works better than flex fuel e30 tune, especially like 60-130 runs

E30 ots tune is targeted specifically for that function

The flex fuel map does not challenge the targets as intently as the ots map does. Something about how the tune automatically tapers its targets throughout the E range

Okay so maybe you can answer the main question then since you seem a little more knowledgeable. Will I need anything extra to run ethanol with a ds2 hpfp.

[sigterm2.0]

So I got my BM3 flex fuel kit installed... Just my personal experience so far but my car pulls much harder than it did without it (maybe there is some factor about my situation that caused this).

This was just right out of the driveway. I didn't change my tune, only turned on FlexFuel since I had disabled it and manually told the DME I was running E30. Started the car and drove down the street. Before, I could do a a pull with just a little clutch slippage (BM3 MultiMap Stage 2+ E30), now, with the FlexFuel kit enabled my clutch slips anywhere after about 40-50% throttle! I can't even wide open throttle and that is in comfort mode. Sport and Sport+ are useless. (Obviously, next purchase is an upgraded clutch...)

But my point is, in my situation, my car truly is running better with the kit feeding E information to the DME. 🤷🏻

[Dantesboyz]

Originally Posted by mg711

Okay so maybe you can answer the main question then since you seem a little more knowledgeable. Will I need anything extra to run ethanol with a ds2 hpfp.

Assuming you have a good downpipe and tune you should be fine.
I've been running the ds25 for almost a month now
Car is really happy E49-E51ON e40 map
Log from earlier today
https://datazap.me/u/dantesboyz/yes?...46-47-48-49-63

[mg711]

Originally Posted by Dantesboyz

Assuming you have a good downpipe and tune you should be fine.
I've been running the ds25 for almost a month now
Car is really happy E49-E51ON e40 map
Log from earlier today
https://datazap.me/u/dantesboyz/yes?...46-47-48-49-63

Alright cool thanks!