Fuel needed calculator?

[k4nnon]

Hey all LinkG4x PnP for Evo 9 user here,, I had an idea that may or may not work. Seems like it might, I understand it in my mind, I just don’t know about how to set it up in Link to see if it will work or not so I’m seeking help of more experienced users to verify my idea. 
 

Here’s my idea/question. Would there be a way to set up a math block channel to figure out exactly how much fuel is needed to get a certain ethanol content mixture? Knowing the fuel tank capacity, and current ethanol content from a sensor. Like say I want to run a consistent e70 mixture. But the ethanol content from the pump varies through the year from e66 in winter to e85. But I want to run e70. Is there a way to set something up to where it will give me a number saying I need 6gallons of ethanol doesn’t matter the content as long as it’s above 70% because sensor will be readinand then I need however many gallons of gasoline to complete the mixture and have it accurately be e70? 
 

Soo my entire fuel tank capacity is 14gallons, I could tap into the fuel level sensor wire and configure to get fuel level in link, I could then use the ethanol content sensor to measure current ethanol content in the tank, I would just need to configure the equation to get the amount of ethanol needed and gasoline needed to get the desired ethanol content. 
 

Let me know if anyone has any further info on if this may be possible or how to do it. Thanks!! 

[Adamw]

It would need to know the ethanol content of the fuel that you intend to add to be able to tell you how much to add.  

[k4nnon]

25 minutes ago, Adamw said:

It would need to know the ethanol content of the fuel that you intend to add to be able to tell you how much to add.  

Hey Adam thanks for the reply. I see what you are saying. This may end up being a static value. By this I mean that when the pump stations switch to summer blend it stays consistent 85% until the colder months. I routinely test with a glass tester. But if I test and Ethanol content is showing it is 85% and I can assume it should be that. Could I then somehow set up something that would tell me now much e85 and then gasoline needed to get a mixture of e70? I would like to run consistent e70. 

[Adamw]

10 hours ago, k4nnon said:

Could I then somehow set up something that would tell me now much e85 and then gasoline needed to get a mixture of e70? I would like to run consistent e70. 

In theory yes, although I suspect there will be some error depending how well the measured fuel level can be converted into fuel volume.  The shape of the tank, sensor resolution and calibration table breakpoints etc may not allow an accurate approximation of the current fuel volume in the tank.  Do you want it to calculate based on the assumption you are going to fill "to the brim", or to some other fixed level - ie "3/4 full" or similar?

[k4nnon]

10 hours ago, Adamw said:

In theory yes, although I suspect there will be some error depending how well the measured fuel level can be converted into fuel volume.  The shape of the tank, sensor resolution and calibration table breakpoints etc may not allow an accurate approximation of the current fuel volume in the tank.  Do you want it to calculate based on the assumption you are going to fill "to the brim", or to some other fixed level - ie "3/4 full" or similar?

I get what you’re saying. It may be more of a headache than just filling up with e85 and leaving it there. I’ll be incorporating the flex tuning so all of that will be fine. Thanks for the input as alway.