10° This week. e85 or 93

[Luckrider]

I've have run 4 tanks of e85 with Shiv's OFT tunes. I need to fill up after work and am trying to decide if I should stick with e85 or go back to 93. With the sub 10° temps, it takes at least two cranks to get fire in the morning. I'm getting about 20mpg but paying $3.18 as opposed to ~26mpg and $3.68 per gallon. I can't make up my mind.

Here is a bunch of my logs: http://datazap.me/u/luckrider

[1086]

Honestly - I have heard it is good to cycle your fuels i.e. For every 3-4 tanks of E85, fill up 50% or 100% of your tank with 91/93. Perhaps it is not necessary but I heard it is good practice.

[reeves]

I finally had to give up E85 when the temps dropped near freezing over night.. Cranking the car for 5-10min in the icy morning just becoming too much of a pain. I'll go back to it once the temps get warmer.

[Luckrider]

Cold starts above 15° seem to be just fine. It is the below 10° that makes it stumbling starting with a cold engine. I think my station is pumping ~e70.

[reeves]

You're talking about 15 Celcius I assume? In which I totally agree.. that's where I'm starting to see the cut-off for long crankings in the mornings too before the engine fires up. Makes me wonder how the factory Flex-fuel cars (my friend's Tundra, for example) start up so easily even when temps are freezing? If they can do it, I'm hopeful a good tuner will be able to figure it out eventually.

[Sterling Doc]

It's -2 right now. About to head out to start up the BRZ. Wish me luck! This should be a new record, but it has started on the first crank at 0 before (did stall once). Winter blend of E85 makes the difference. Fuel trims are still minimal, runs great.

[Luckrider]

Originally Posted by reeves

You're talking about 15 Celcius I assume? In which I totally agree.. that's where I'm starting to see the cut-off for long crankings in the mornings too before the engine fires up. Makes me wonder how the factory Flex-fuel cars (my friend's Tundra, for example) start up so easily even when temps are freezing? If they can do it, I'm hopeful a good tuner will be able to figure it out eventually.

Fahrenheit. My guess is that the flex fuel cars adjust their IPW with a special compensation table dependent on the e%. It has been figured out in our cars and I have a modified tune with different cranking Injector Pulse Width table values. I just haven't used it because the e85 tune gets better the longer you run it unflashed (because the learning of the computer us pretty good). I wasn't having starting issues so I didn't change anything.

[reeves]

Originally Posted by Sterling Doc

It's -2 right now. About to head out to start up the BRZ.

Originally Posted by Luckrider

Fahrenheit. My guess is that the flex fuel cars adjust their IPW with a special compensation table dependent on the e%. It has been figured out in our cars and I have a modified tune with different cranking Injector Pulse Width table values. I just haven't used it because the e85 tune gets better the longer you run it unflashed (because the learning of the computer us pretty good). I wasn't having starting issues so I didn't change anything.

You're talking Farenheit? Man, mine's won't even crank for ~10min if it's under 30 F degrees! I do miss filling up with the cheaper E85 price too. I got Ecutek so I gotta find someone who knows how to adjust the cold cranking for me.

[Luckrider]

@reeves, What tuning solution are you using?

[reeves]

Ecutek.. they allow you to modify your own tunes now, but I gotta dish out an additional $300 to get that upgrade. I'd rather just find someone who knows what they're doing to try & adjust it for me. I'm happy with my E85 tune, just not the cold cranking part.

[steve99]

Shiv reckons his tune is good for between E60 and E85, maybe you could do a Mix of E85/93 to drop your E content to around 60-70 for easier starts.

[Luckrider]

I thought you could actually tune the car yourself with the free software. I thought the upgrade was for multiple maps, custom maps, table comparisons and some other stuff that isn't needed to actually tune the car from scratch yourself. @jamesm can probably give better insight to that. With the OFT and RomRaider, I can edit the Cranking tables myself.

[Carlitoz3]

Originally Posted by Luckrider

I've have run 4 tanks of e85 with Shiv's OFT tunes. I need to fill up after work and am trying to decide if I should stick with e85 or go back to 93. With the sub 10° temps, it takes at least two cranks to get fire in the morning. I'm getting about 20mpg but paying $3.18 as opposed to ~26mpg and $3.68 per gallon. I can't make up my mind.

Here is a bunch of my logs: http://datazap.me/u/luckrider

Originally Posted by 1086

Honestly - I have heard it is good to cycle your fuels i.e. For every 3-4 tanks of E85, fill up 50% or 100% of your tank with 91/93. Perhaps it is not necessary but I heard it is good practice.

I can switch between premium and e85 as freely as I like?

[Luckrider]

With a tuning solution like the OFT or ECUtek, you just flash a new map for the fuel you are running. For about $2,000, you can get ECUtek and the needed hardware to run a true FlexFuel setup.

I think I might just flash the modified 1.42b map I have and stick with the e85.