Regarding Switching from Pump Gas to E85 at the gas station

[Cal3000]

I know this question has been asked many times before.

Will I need to completely drain the tank before I switch to e85 or can I have, maybe, 1 or 2 gallons of pump gas in the tank and fill the rest with e85?

I know most pump gas use about 10% Ethanol.

[pmccut]

It really depends on the tune. Some tuners might offer you a e70 map for this (assuming you get e85 year round). When I've switched I bought multiple 5gal jugs and kept going until I was well below E - fill it up at home so you don't look nuts at the pump with a harsh start.

[nelsmar]

Talk to your tuner. Especially since you are running a supercharger.

I typically run to E, drive XX # of miles, put in 1 - 2 gallons of E85 (depending on driving conditions / time) and then drive XX# of miles to burn that fuel off and then fill the tank that way I burn a "blended" mix while in closed loop only.

[Cal3000]

Or look nuts revving your engine down to E at the pump. 5gal jugs seem like a good idea. Do you have ECUTek? I'm thinking the tuner could possibly set up multiple maps for the map switch. Instead of reflashing all the time, you can turn the ignition to the 1 position and switch to the desired map, then start the car.

[Cal3000]

Originally Posted by nelsmar

Talk to your tuner. Especially since you are running a supercharger.

I typically run to E, drive XX # of miles, put in 1 - 2 gallons of E85 (depending on driving conditions / time) and then drive XX# of miles to burn that fuel off and then fill the tank that way I burn a "blended" mix while in closed loop only.

So you run pump gas to E, then place 1 or 2 gal of e85 which possibly mixes with pump gas. Run the car to let the ecu adjust in closed loop, then fill up with full e85?

[nelsmar]

Originally Posted by Cal3000

So you run pump gas to E, then place 1 or 2 gal of e85 which possibly mixes with pump gas. Run the car to let the ecu adjust in closed loop, then fill up with full e85?

1) Yes I use ecutek
2) I made my own maps including "Migration maps" that make life easier
3) Yes you can make an E85 dedicated map to switch to. I prefer to make people flash so they don't accidentally drive on the wrong map when tired as your car will not remember your map. Sometimes it does but never ever ever depend on it remember which map you were on.
4) You should talk to YOUR tuner
5) If you cant get ahold of him and you are on 100% oem fuel system drive down to where the light comes on. Once the light comes on reset your average MPG meter and trip B. Calculate burning 1.5-2 gallons (You can actually go further than this). So if you are getting 20MPG drive 30miles. Once you hit this point add 1-2 gallons of E85. Reset your average MPG meter & Trip B again, calculate the same for the amount of E85 you put into the tank. Assuming your tuner has not disabled long term fuel trims keep under 3,600RPM and 30% throttle.

Do not blip throttle with significant throttle angle on a supercharger even in neutral! This will produce boost!

If you are confused and want to talk on the phone you are more than welcome to PM me your number and I can give you a call!

[86viper]

Take this with a grain of salt. But when my light comes on, my obd reader still shows 25% fuel remaining. Which is about right when i go-to fill it. Aussie Spec Toyota 86