E85 Max quantity allowed mixed with Premium?

[pistero701]

Hello Guys,
What is the max percentage allowed of etanol e85 that can be threated with Premium 91 octanes running stock and with tune for 91 octanes? How many gallons of premium per gallons of ethanol?

Willing to use some etanol in the tank to increase a little bit the perfomance of my ST when running 1/4 mile in Mexico .

Whats your experience?

 

[2020FordRaptor]

It’s not just gallons of it, you have to calculate your mixture. E30 which is 30% ethanol in your tank is the max the factory tune and usually a 91 tune can account for.

 

[UNBROKEN]

Without a specific tune for E50 you’re limited to E30 on a 91 or 93 tune

 

[pistero701]

It’s not just gallons of it, you have to calculate your mixture. E30 which is 30% ethanol in your tank is the max the factory tune and usually a 91 tune can account for.

Thanks bro, does that 30% in the fuel tank makes some difference in terms of adding more power so far?

 

[2020FordRaptor]

Thanks bro, does that 30% in the fuel tank makes some difference in terms of adding more power so far?

Not on factory tune, but if your tune for sure. Big difference when tuned with ethanol.

 

[STTuner]

Hello Guys,
What is the max percentage allowed of etanol e85 that can be threated with Premium 91 octanes running stock and with tune for 91 octanes? How many gallons of premium per gallons of ethanol?

Willing to use some etanol in the tank to increase a little bit the perfomance of my ST when running 1/4 mile in Mexico .

Whats your experience?

On a stock fuel system with a 91 tune, most guys stay around an E20-E30 mix max. That’s usually enough to pick up a little timing/performance without pushing things too hard. Roughly speaking, for a full tank you’re looking at maybe 2-3 gallons of E85 and the rest 91 pump gas depending on the actual ethanol content at the pump.

I’d definitely recommend monitoring knock/timing if you start mixing though. These Ford Explorer STs respond well to ethanol, but once you go higher blends you really want an actual E blend tune for it.