I wasn't originally going to do this, but the longer I've thought about things knowing that I'm heading towards E85 made me question my ability to manually keep up with all of the different variables that come with obtaining and using E85. A tune in true 85% ethanol is very different from a 50% ethanol tune, and I would hate to have to literally butt dyno my shit everytime I fill up, which would be a reality if doing things manually. I would also have to test the fuel at the pump to make sure it contained satisfactory ethanol content or not. Without testing the fuel and tweaking your tune as necessary, is like using a shotgun in a dark room.
Variability in ethanol content in my area is a thing, knowing this from other guys around me who run E85 in their setups. They don't worry about their tunes because they are setup for true Flex Fuel, sensor and all.
I started doing some research, and found out that Hondata and latest SManager and S300 have native Flex Fuel sensor support, which means they can accept the Flex Fuel sensor signal as is (which is a frequency signal rather than a linear 0-5v signal) without needing a translator medium. These Flex Fuel sensors are pretty much all the same device made by Continental, and operate in the same way since I first started working on GM flex fuel vehicles as a tech in the aftermarket. The first generation of sensors were terrible, needing to get replaced every year almost like clockwork. The sensor would drift and provide false ethanol content readings to the ECU which would cause drivability issues. Replace the flex fuel sensor, reset learned alcohol and adaptives, good to go.
It seems 10 years has been enough time for Continental to have worked out some quality issues with the sensors, with people reporting almost 3 years out of them now! Lol.
Since I have a Demon2 and Neptune, there are no provisions for Flex Fuel sensors or even software implementations in a similar way as offered by most aftermarket GM tuning solutions, but Neptune does have this:
Sensor adjustments! Think of this as a generic active override to pre-existing fuel and ignition tables, as well as the PWM boost control settings for any 0-5v type sensor.
You can specify for a given input somewhere on the ECU or Demon2 board to look for a 0-5v voltage range. Using an interpolated scale across 1v breakpoints, you have the ability to tell the Demon to override fuel, ignition and PWM boost tables, with a plus or minus correction value that you program into it.
I started looking to see if anyone had developed a translator device that could convert the Hz signal developed by the Continental sensors into a linear 0-5v scale that correlates to ethanol content. Lo and behold:
My favorite odd ball honda tuning stuff supplier, Xenocron.com, has a Flex Fuel sensor signal converter AND cheap Continental FF sensors!
One and done purchase guys, I'm going full Flex Fuel!! These parts will be here from Xenocron this week, and I will get them installed and wired to ECU while I'm still waiting on engine machine work type things
Maybe this will help others wanting to go flex fuel on ECU tuning solutions that don't natively support flex fuel but have provisions for allowing generic 0-5v sensor automatic adjustments. This should be a viable work around, although not as precise and feature rich as a dedicated flex fuel tuning solution, this should allow me to add the correct decreases in fuel, timing and boost when ethanol content begins to drop.
FF sensor gives you night vision goggles so you can continue to use your shotgun in a dark room lol.