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Old 12-17-2012, 04:14 PM   #6710
Scooby Specialist
Member#: 248202
Join Date: May 2010
Chapter/Region: MWSOC
Location: Columbus, Ohio
2013 WRX Sedan


Originally Posted by WRXt4cy View Post

1. I installed a flex fuel sensor and gauge in my 2011 for some piece of mind when I initially switched to E85. For a while I was testing every couple fill ups to check for changes in blends. Now, after tuning many cars on E85 at various blend levels, I learned that if you target the correct AFRs for a known blend percentage, AFRs stay with in a good range even if you run higher or lower ethanol blends. I've tested and verified this within 70% up to 90% ethanol blends. I haven't encountered anything higher or lower from a pump. I always strongly recommend having wideband o2 gauge with E85 so you know if you get a bad fill up (less than the normal 70% minimum) for some reason.

2 & 3. I initially though I would switch back every few tanks and then run 93 in the winter. Now that I've run E85 for so long, there's no way in hell I'm every putting gasoline back in my tank. I've had zero issues running E85 for 12,000 miles over 10 months now *knock on wood*. I plan on pulling my injectors soon to check that they are clean as I expect them to be. In cold regions, E85 is supposed to be blended down to 70% ethanol during the winter. This, in combination with the proper tuning from someone that knows what E85 needs for smooth cold starts and warm ups allows it to run just as well as gasoline year round.

4. That is hard to answer. Generally, E85 tanks are specific to E85. They are buried deeper and should not normally be used when a station feels like putting E85 in them. I've heard of stations dropping E85 completely due to lack of sales but I haven't seen in my area. I would say you should call the station and try to find out their long term plans with their E85 pump.

5. We don't have any 5th gen LGTs around here so I haven't tuned one myself but from what I've seen on the open source forums, there is plenty support for this platform if you wanted to go the open source route for tuning. I don't know about Cobb but would guess there is good support there as well. If you are already planning a turbo swap on your DD, you might as well go E85 as well. Its going to need a tune either way.

6. If you still decide to switch back to gasoline, you could get away with running the car down the E and filling up with the fuel you are switching too. It would be best drive easier for the first tank after you switch to be on the safe side.
Yup. What he said.
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