E85 & ID1000 Experience...

[FordEvangelist]

For those running E85 and ID1000's - did anyone modify the injector values to get the fueling right?

I've been running E85 awhile and relatively successfully but the tune is a bit of a hack in that I tuned the car on 93 octane originally then switched to E85. I changed stoich of course but had to modify the maf a bit to get the fueling right. I know that's not a solid approach since it jacks with load calculation.

For those who have done this, is there a set formula to apply to the injector values for E85 or is it trial and error?

Thanks.

 

[03Steve]

The specific gravity of the fuels are different. E85 is 12% heavier.

Here is a snippet from my notes....

The specific gravity (mass) of gasoline and ethanol are different. Fuel injectors are rated in mass (lb/hr).

Let's say you have two injectors flowing at a uniform rate. One is flowing angel food cake. The other is flowing gold. Which cylinder will have a heavier mass of product? In my opinion thus far, not only does the stoich point of the fuel need to be accounted for, but the specific gravity of the fuel needs to be calculated for as well. There's more to it than just a stoich adjustment.

I put this into practice on Friday night. By increasing the injector low/high slope scalars by the ratio of ethanol to gasoline, and putting the stoich point to 9.85, the car responded exactly like it should. It's performance was identical to the gasoline calibration.

There are other ways of compensating for fueling in a tune. You can adjust the MAF transfer, you can adjust the open loop fuel table, etc. However...if the air model is already built and perfectly matching the open loop fuel table, in my opinion, you are working in the wrong area. It is the mass of what the fuel injectors are flowing that is the item at hand that needs to be addressed.

http://www.modularfords.com/threads/176389-03-pumps-BAP-60s-4-quot-upper-amp-E85/page2