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Old 12-17-2012, 03:53 PM   #6709
Scooby Specialist
Member#: 172698
Join Date: Feb 2008
Chapter/Region: MWSOC
Location: Des Moines, IA
11 STi BW 8374 E85
02 v8 Spec C E85


Originally Posted by acumenhokie View Post
I'm looking to make the switch to e85 in the spring when I swap turbos. As someone who is new to the concept are there any threads or websites you'd recommend? I have some newb questions and looking to learn more from those of you who have already made the switch.

1) Do you test the e85 for every fill up or just spring/fall when they could have gone to the winter mix? Along the same line of thought if I'm filling up from the same e85 station once or twice a week should I just test monthly?
2) How often (if ever) do you switch back to unleaded (I heard one person say they recommend running a tank of 93 for every 10 - 12 tanks of e85?
3) I am planning to run 93 in the winter and e85 in the summer since the car is a DD? Are others with "real" winters doing the same?
4) There is one station 10 minutes from my house but the next 2 closest are 30 - 40 minutes away. Do e85 stations have it available all the time, every time?
5) As far as I can tell from the forums I'd have only the 2nd ever 5th gen legacy running on e85 so there's not a whole lot of knowledge on the subject. Even called IAG about tuning and it's something they said they weren't very familiar with. Should I just stick to 93 rather than run e85 on an untested platform with a daily driver?
6) When switching back and forth do I need to pump the gas tank dry or just run it till it's on E and fill all the way up with the other (I'm guessing it's the later)
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.
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