E85 newb question

[jswansti]

So I scanned through the E85 sticky but didnt really find my answer while doing it. Im getting two tunes next week, one for E85 and the other for 91. This may be a stupid question, but how simple is it to change between the two fuels? I dont mean flashing the appropriate maps from the AP, but when refueling the car. Can you just run your tank really low on one and fill up with the other, or does it require the tank to be drained? Sorry if the answer is posted and I just didnt find it, but thanks for any info!!

 

[jswansti]

Hadnt thought about the guage, good suggestion. And thanks for the response! He has a station literllay across the street from him with E85 and he uses their fuel all the time (also the place i'll be getting it from) so its probably decent, although I know the concentration could change with each new refuel.

 

[jswansti]

Zeitronix looks like they have a good gauge setup, but its a bit pricey for me right now. Now that I know they actually exist im sure ill get one at some point, but it doesnt fit in the current build budget.

 

[BAD STI]

I'd recommend draining the tank completly. Its easy to do (theres a bolt on the bottom).

As far as monitering the content all you need is a 100ml graduated cylinder. PM me your email and I'll forward you the excel sheet I use to calculate the ethanol %.

 

[jswansti]

I've heard both sides, run the tank down really low (I usually have 2 gallons or so when I fill up typically), and drain it. I'm gonna ask my tuner what he suggests to do. Draining it just seems like such an inconvenience when I wanna fill up with something different. Thanks BAD!

 

[icudruln]

Everyone I know just runs it down really low (as low as possible without running out of gas).

 

[BAD STI]

I've heard both sides, run the tank down really low (I usually have 2 gallons or so when I fill up typically), and drain it. I'm gonna ask my tuner what he suggests to do. Draining it just seems like such an inconvenience when I wanna fill up with something different. Thanks BAD!

Leaving some gas in there when switching to E85 shouldn't be an issue (post tune). It will simply cause it to run a little richer. You will want to drain your tank pretune though.