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Don't know if it's right or not but I had better luck changing the injector flow rate. Also once you get 50% + E85 mix you will have to mess with the VE table to keep it crisp.
How are you calculating the new stoich with your wideband? Run in open loop and do the math on the error between the previous actual ratio in open loop and the new one with the E85? Do you have your gauge display lambda units as opposed to AFR? Seems like using 14.7 for blends of E85 can be confusing.
Im not using my wideband to calculate the new stoich...I am using my worksheet for that. I use lambda for the exact reason that it becomes confusing to use AFR when mixing different fuels.
Originally Posted by lglowe
Will this work for a 2 bar speed density tune?
And what about adding 20% straight methanol to 93? Just use the stoich for meth in the equation?
Yes, the OS shouldnt matter. The only thing you should need to change is what AFR the pcm thinks is stoich.
Originally Posted by stock48
Don't know if it's right or not but I had better luck changing the injector flow rate. Also once you get 50% + E85 mix you will have to mess with the VE table to keep it crisp.
Thats one way to do it, but is kind of a hacked way....if your VE is perfect and you change nothing but the fuel, simply changing the stoich afr value to the new correct one should result in perfect fueling. Thats the theory, but fine tuning of the stoich value, not the ve table, should be all thats needed.
Originally Posted by lglowe
How did you figure up what you had to change based on how much e85 you added?
I made the worksheet to calculate the new afr based on the mix of fuel in the tank. The pcm references the stoich afr value for all fuel calculations.
To a point but the E85 likes to be fatter during quick transitions.
Did you change the alcohol evaporation rate values in transient fueling? I don't ever really have to mess with them because factory calibration is pretty good, but your ported heads are gonna change it quite a bit.
Did you change the alcohol evaporation rate values in transient fueling? I don't ever really have to mess with them because factory calibration is pretty good, but your ported heads are gonna change it quite a bit.
What are good values in this table? Care to share a screen shot of it?
06-21-2012, 10:18 PM
