intenseapple

Lot's of info out there on this, but I can't figure out if it's best to run SEPARATE tunes for E85 and 93 or if using a 93 tune and setting up linear timing addition for E85 is good enough. Lot's of people recommend separate maps, but whats the point of having the timing addition if you need to load a separate map when switching fuels anyway? I'll be running ethanol the vast majority of the time, only switching to 93 if I end up somewhere that I can't get ethanol (I'm from Iowa so this is unlikely). I'll be getting the car professionally tuned so I want to know whether to get two separate maps tuned, which sounds like a pain because I'd have to switch out fuel completely between tunes.

Iamwill

Separate maps for the MS2 units. With the ms3 it has the necessary provisions to run flex fuel. The older ECUs to my understanding just aren't as compatible with that feature at least not without modifying the board probably but someone else would have to chime in for that.

intenseapple

hmmm that sucks, not really much of a flex fuel option at all if you need two separate tunes. I might be able to set up table switching so I can switch easily though right?

Matthew Roberts

How good do you want your tune to be on 93? I'm working on this now (though I'm N/A for now) and I'll be running E85 normally, but I've installed the sensor and I'll be setting the Flex Fuel options in MSPNP2 to provide a 'limp mode' for times that I can't find E85 and don't have a laptop to switch tunes.. This will probably be trickier once I go FI.

intenseapple

well if I’m only using tableswitching, I won’t be able to turn the boost down, which might cause problems. When I get the car tuned I’ll find out just how far I can push a 93 octane tune...