I plan on running E85 and pump gas on my built motor (1.6 with forged pistons 8.5:1 h beam rods mls head gasket, upgraded dual spring valve springs, upgraded valves, oil pump, and cams, along with injectors bigger fuel pump and e85 lines) *save the 1.6 vs 1.8 **** for a different thread got most of my parts for cheap used.* can I manually switch tunes. Going to be dynoed with pump and e85 on 2 tunes. I don't want to use a switch because I have launch control set up and manually switching doesn't bother me. Can I switch between tunes as long as I save them both. Should I just put both tunes in there own folder?

 

Flex fuel sensor.

 

What ECU?

As HarryB stated, you can have the flex fuel sensor output adjust the mix between full e85 and pump gas.

That is, provided you have an ECU that can use a flex fuel sensor and can blend maps.

 

Megasquirt plug and play 2 I know you can add a flex fuel sensor but how does that work for the tune. Is the computer doing guesswork or does the tuner have to tune it all out

 

I don't know what I thought I knew...

Basically the way I thought I was going to recommend was to tune VE1 and Spark1 to 91 or 93 octane (whatever is available in your area). Then pump all the fuel out and replace with e100. Tune VE2 and Spark2. Then create a blend algorithm that takes your ethanol content sensor reading and blend between those two pairs of maps. (obviously you will never get to e100 at the pump, but you will at least have a full map to all levels of ethanol)

My car is in another state and I haven't touched tunerstudio in probably a year, so I don't remember all the basics. The MS2 MIGHT or MIGHT NOT be able to do this method. I know the MS3 can.

 

MS2 can only do fuel map.

 

You can switch between tunes like you describe, that's what I used to do when I had a MS2.

I never had a flex sensor back then, but I always retuned slightly after filling up again just in case I got a different blend of ethanol. If you are going through all this tune switching trouble I assume it's because you want to get everything out of it. If that's the case I'd get a flex sensor just so I knew exactly what I was running. I would not allow MS2 to do it's global scaling off the sensor values, way too many variables for that to work right. Just a check to make sure you actually have 80%+ before you go ripping...

 

Do basically have 2 tunes. Hook up the flex fuel sensor just to know what ethanol percentage is

 

This is exactly what i've done recently on my 90 w MS2. Flex fuel sensor wired into the launch control input just so i know what my percentage is at so i have an idea of where to base my fueling. I have a 93 fuel table that i just multiplied by 30% to get started and autotuned it to get myself close to my target table.

It took quite a few tanks of gas to get my percentage up to the garbage e70 at the pumps locally to me but i was able to scale my way up as i went thanks to the flex sensor.


In my experience i've found the default values of 100 for 93 and 163% for e100 to be waaaayyyyy out of whack and i simply leave timing alone entirely.

 

makes sense. I'm going to have the tank drained and have it tuned on e85 and 93. Makes sense u leave timing alone. If it doesnt detonate on 93 it definently wont on e85. Thanks for your input and sharing your experience