E-85 With Canned 93 Performance Tune

[2010F150]

Will it be fine to run E-85 with my canned 93 performance tune until my custom tunes are sent?

[shotgun]

Not unless the E85 has a 91+ octane.

[2010F150]

its 102 octane just making sure it wont cause a lean condition

[shotgun]

Ford's OBDII system uses the O2 sensors to measure and then compensate for the higher alcohol content by adjusting the target AFR. This should eliminate the possibility of operating in a lean condition.


If the R+M/2 value is truly 105 (there is considerable debate on this true octane value), you should be able to advance the timing up to 6 degrees (this is the theoretical max based on 1/2 degree for each increase in octane; [105 - 93] / 2). <---Someone please confirm my memory!

Obviously you should make small changes until you detect knocking. If you advance too far (too quickly) the knock sensors will dramaticlly reducing the timing advance.

The relationship between PM and AFR is shown in the table below.

Stoich Air Fuel Ratio = 14.64 - 5.64 * PM

PM (percent alcohol)...Stoichiometric AFR
0.00 (100 % gasoline)...14.64
0.05... 14.36
0.10 (standard gasoline)... 14.08
0.15... 13.79
0.20... 13.51
0.25... 13.23
0.30... 12.95
0.35... 12.67
0.40... 12.38
0.45... 12.10
0.50... 11.82
0.55... 11.54
0.60... 11.26
0.65... 10.97
0.70... 10.69
0.75... 10.41
0.80... 10.13
0.85 (standard E85)... 9.85
0.90... 9.56
0.95... 9.28

1.00... (100% ethanol) 9.00


If you intend on using E85 all the time, I would recommend you discuss this with Bill (if you haven't already). He might be able to write your performance tune based on E85 (or even write you an E85 performance and towing tunes since the CS and CTS are capable of storing up to 20 tunes).

[cleatus12r]

It's going to run REALLY lean.

Just throwing that out there. There is more to this than just the octane rating of the fuel.

Thanks for throwing that list up there, shotgun!

[Jackpine]

Originally Posted by cleatus12r

It's going to run REALLY lean.

Just throwing that out there. There is more to this than just the octane rating of the fuel.

Thanks for throwing that list up there, shotgun!

Cody - why do you say that? I don't think I understand at all.

He's got a "flex-fuel" truck, which has been designed to burn the E85 crap and, like shotgun says, it should adjust the A/F mixture for the proper stoich (9.85) as long as that fuel is being burned.

Are you saying that the canned performance tune will try to hold the A/F ratio at or near 14.64 regardless of the fuel used? If that's the case, I understand and yes - I would not use ANY of the canned tunes with the fake gas. But, as you can tell, I didn't think it would work this way. Can you clarify?

Thanks in advance my friend. Hope you're staying warm up in the frigid north country!

- Jack