e85 and 93 mixed

Just wondering how low you would have to go on a tank either 93 or e85 to run the other without and huge problem.

 

Example: Tanks filled with 93 run it to alittle below 1/4 then want to fill up with e85 and switch maps. Will it run fine or does the tank need to be lower on 93.

 

and then vise versa filled with e85 1/4 tank left switch to 93 and switch back to 93 map.

 

Just wondering since there arent too many e85 stations near me. And anytime im near the e85 station i would like to fill up with that once all the rest of my fuel mods are done.

Run the car until the low fuel light comes on. When I got my e85 tune the tuner recommended this as well as bringing along 10 gallons of e85.

I think a quarter tank is just fine. The fuel trims have enough authority to deal with that. I'd shoot more for an 1/8th tank or less if you can though. One thing you'll need to be careful about is going WOT just after changing fuels. You'll need to get AFR Learning D set up (by driving 5th gear with very light throttle and accelerating from 50mph to 80mph a few times) or by just driving around for a few days.

 

I run E85 all the time but I augment with straight gas either to extend range or in the winter if I think I'll be parking the car outside under 20F. When I augment I use 2.0-2.5 gallons of gas.. no problems, no CELs.

i was told by my tuner to keep 5-10gals of 92 in the car and run it till the car dies, then switch maps. and fill it up with 92

i was told by my tuner to keep 5-10gals of 92 in the car and run it till the car dies, then switch maps. and fill it up with 92

That is neither required or the safest thing to do.

Regardless, gasoline will only make the mixture richer (ie: not dangerous). Then vice versa, the ethanol will cause you to lean out a bit however it will still have the higher detonation resistance.

So did we ever figure out the best way to do this? im right on the red line on E, and I need to switch back over to 92. Should I empty my tank, or just go fill up with 92?

When I switch (which I try to do as little as possible) I get 2 gas cans (10 gallons) of whichever gas I'm switching to. I drive till the gas light goes on then I disconnect the return fuel line and let the car idle while it pumps the fuel out into a 3rd gas can. When the flow stops, I shut it down and fill up with the new fuel.

is there any problem with having a gallon of e85 in my tank when I switch? If I recall correctly the reserve is 2.4gal. So if I add 13 gallons of 92, since its already 10% ethanol as-is, id be adding another 6-8% ethanol into my new tank. Could this cause any issues? Its getting in the high 40's here at night, and its taking longer and longer to start. I could milk it for another week I guess. Im just on E really low right now, so this would be the time to do it. Infamous told me that you were never supposed to completely empty your tank.

When I switch (which I try to do as little as possible) I get 2 gas cans (10 gallons) of whichever gas I'm switching to. I drive till the gas light goes on then I disconnect the return fuel line and let the car idle while it pumps the fuel out into a 3rd gas can. When the flow stops, I shut it down and fill up with the new fuel.

 

Good grief that's pretty meticulous in keeping the fuel and the tune on the same track but it's overkill. I haven't switched back and forth but if I did I'm really comfortable with the ecu +/- 15% FT authority and keeping my foot out of it until the FT's dial in. I'd just hate for someone to think to switch back and forth people had to carry gas cans and mess with disconnecting fuel lines.

Since the 92 map will be dumping in less fuel, if i have a higher percent ethanol, wont that cause my car to lean out a bit? In my case were only talking a gallon or so of E85 mixed with 14gals 92oct. Im going to do it and monitor my af/r, then when i hit 3/4 tank, ill just top off. Seems like on E85 my car is much more tempermental when cold. It bugs me, plus I have never driven my car on the 92 map.

that's why I only switch fuels once or twice a year

I switched fuels at one point about every other week. No extra cans required.

I always just run it down to the point where the trip computer shows "---" for miles left on the tank and then fill up. I let the fuel pump prime and start the car. The start can be a little bit hard since it will initially be very rich or very lean. Idle will be rough at first. Let the car sit and idle for a few minutes until the idle evens out. If you have a way to watch the fuel trims, then keep an eye on them. Don't start driving until these settle - Usually within 5 minutes of starting. Drive easy for the first few miles. Fuel trims will be further off than normal for the first tank after a switchover.

I had about .7 gals of e85 left in my tank. this morning i filled up with 92, and I started it on the E85 map and idled for about a minute. Idled/started fine. Then, I switched it to the 92oct 15psi map. I stayed out of boost on my way to work, and ran/started perfect. My AF/R's were mid 14's on idle, and seemed to be right in check. I will top it off when I get down to about 1/4 tank. I wont run more than 15lbs till I get through my first tank.

switching over for the winter already?

yeah, even though I park in the garage, Its still touchy. What temp do most people switch over at? this is my first time running E85. In the mornings. Also, I haven't even ran my pump map yet, so Id like to see what its like, and how it runs. It will start getting into the 40's at night here pretty soon.

I just put in a new battery and it still takes some extra cranks to get the E85 up and going.

 

I figured I would have to change in the next month or so. Sure gonna miss the E85

I put a block heater in... gonna try and run it all winter. I should have easier starting with my higher CR.

Yeah Im only on my 15lb map and I can def feel the power loss. I think I picked up 40 wtq at the same psi, when I switched to E85. I wonder how E85 vehicles weather in the winter? do they use heated lines or something?

Threw a pffe code and a cylinder 3 misfire today. I threw it this morning after my switch. cleared it, drove another 38 miles. Went to the gas station and put 1.8g of 92 in. just threw the codes again. I dont think its a coincidence. I wonder why when I run a tiny bit of e85 mixed with 92 its misfiring. Im driving it easy, but I do notice It Idles a little rougher. I will probably just keep an eye on it till I get through this tank.

I always just run it down to the point where the trip computer shows "---" for miles left on the tank and then fill up. I let the fuel pump prime and start the car. The start can be a little bit hard since it will initially be very rich or very lean. Idle will be rough at first. Let the car sit and idle for a few minutes until the idle evens out. If you have a way to watch the fuel trims, then keep an eye on them. Don't start driving until these settle - Usually within 5 minutes of starting. Drive easy for the first few miles. Fuel trims will be further off than normal for the first tank after a switchover.

This was my exact procedure as well

PFFF or PFFE are impending misfire codes

 

 

45degrees out today. Car parked outside for at least 5 hours, the last 2 with the block heater plugged in. Started right up.

Mrweiner what type of block heater did you get? It would be nice to have regardless of E85 or not.

OEM one from subaru. Comes as a kit with a new plug w/ the heater in it and the cord and zipties and everything. You're gonna have to drain ALL of the coolant. I did it when I put the new engine in

Schweet, might think about doing that. I park my garage and put in a block heater, man my GF is going to be jealous. Seemed like even with my car in my garage it was getting harder to start...Someone should make a sticky on the correct way to swap fuels. So far so good for me. Although E85 right now here is 2.05/gal, and prem is $3.07. E85 is more miles per dollar.