[Originyl]

Hi just some questions, i put in a mhd can eca in there and was just wondering how the tuning works now, i put it on the mhd multimap with all selected at 91 oct and enabled flex fuel, my monitor says 10% ethanol is what the can is reading (standard for pump fuels here) and so whenever i wanna run like e40 do i just pump some e85 in there to get to my desired ethanol content and the 91 oct tune will adjust itself? Or do i have to switch maps to like an e40 everytime.

Second, can i go higher than e40? Because i know bm3 has the option to do e50 and thats capable on the m340i because of the TU pump.

Third, whats the power difference between 91 and a e blend? Is there any power difference between a dedicated e40 tune and a 91 oct auto adjusted tune?

[CarGuy954]

93 is very noticeable from stock and tends to be between 425 whp to 440whp pending fuel quality, ambient temp, elevaton and downpipe (catted vs non-catted). The eMaps are where its at and the e40 map is very noticeable compared to the 93 map. The power tends to range from 460whp to 475whp. The full e85 map is compared to the e40 map due to conservative fuel tuning for safety and should be custom tuned but, you could see better numbers across all maps with custom tune.

[RTPenland]

On otherwise stock fuel system E30/E40 is really the sweet spot for these cars in terms of peformance and drivability. Keep in mind a stock 2020 M340 can run full E85 with simply a properlyu designed tune (I do on occasion with my mission flash) but that is strictly for economic reasons as I am making less power on full E85 vs E30/40.

[dustwhyn]

Originally Posted by RTPenland

On otherwise stock fuel system E30/E40 is really the sweet spot for these cars in terms of peformance and drivability. Keep in mind a stock 2020 M340 can run full E85 with simply a properlyu designed tune (I do on occasion with my mission flash) but that is strictly for economic reasons as I am making less power on full E85 vs E30/40.

This is incorrect. The stock fuel system can easily support up to but not over E60 for maximum power output. Keep in mind you will need a custom tune to achieve this, as the MHD OTS MultiMap makes its peak power at E40. That’s just the way it’s set up.

[RTPenland]

Originally Posted by dustwhyn

This is incorrect. The stock fuel system can easily support up to but not over E60 for maximum power output. Keep in mind you will need a custom tune to achieve this, as the MHD OTS MultiMap makes its peak power at E40. That’s just the way it’s set up.

You are largely correct when it comes to power, but my response addressed both performance AND drivability. When we move past E30/E40, compromises start to be made—there is no secret sauce, and all tuners are working with the same ingredients; it's just a matter of what a particular tuner wants to achieve and what they are willing to sacrifice to get there. The true art lies in balancing power and drivability—power is easy to achieve; maintaining drivability and comfortable driving dynamics is not.