Confused about Flex Fuel Tune

[ChitownStang]

I’ve been running a Livernois flex tune for months and love it. No testing or monitoring, just fill up and go.

Same here, Livernois Flex Tune for over a year and it runs great. Just drive it easy for 15 min after fillup. I run E70 in summer and 93 in winter here in Chicago. All on the Flex tune without reflashing.
E70 is a noticeable bump in power down low and up high rpm's!
Noticable gas milaege loss but much cheaper than 93.

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[Mikepol2]

Same here, Livernois Flex Tune for over a year and it runs great. Just drive it easy for 15 min after fillup. I run E70 in summer and 93 in winter here in Chicago. All on the Flex tune without reflashing.
E70 is a noticeable bump in power down low and up high rpm's!
Noticable gas milaege loss but much cheaper than 93.

I messaged Livernois about running flex in winter and they said it’s no problem, in case you were considering that.

 

[ChitownStang]

I asked Wengard on here and on email and one said they don't recommend running flex all the time and other said they do so I'm a little skeptical about those kind of responses. I have not heard anybody's real world experience running a Wengard Flex tune all the time.
Only reason I was considering leaving Livernois for Wengard was because I hear the 10-speed tune is great and I find Livernois didn't make shifting any smoother.

 

[JetGray_Mach1]

I asked Wengard on here and on email and one said they don't recommend running flex all the time and other said they do so I'm a little skeptical about those kind of responses. I have not heard anybody's real world experience running a Wengard Flex tune all the time.
Only reason I was considering leaving Livernois for Wengard was because I hear the 10-speed tune is great and I find Livernois didn't make shifting any smoother.

Correct me if I am wrong, I believe Wengerd does not offer Flex tune. It is a E85 and 91/93 tune. You flash back and forth as needed as you fill up with different gas.

 

[ChitownStang]

N

Correct me if I am wrong, I believe Wengerd does not offer Flex tune. It is a E85 and 91/93 tune. You flash back and forth as needed as you fill up with different gas.

not what I was told when emailing with them.
And on another thread Wengard rep said it's not recommended but I do it on my car with no issues
It kills me with how vague their responses are when trying to communicate with them. Can't take it...lol

 

[LOL WUT]

I think the main reason some tuners have changed from providing flex tunes or guiding to use them all the time is from some individuals not understanding the tune requirements and expectations. I think most if not all tuners advise to let the car learn the E content in the fuel before driving aggressively. Tuners likely grew tired of people not heeding this advice, going from E85 to 93 and driving like they stole it immediately. Then when drivability was impacted by ridiculous fuel trims the tuners were slammed with inquires to fix things that weren’t broken.

 

[Jay_jay]

Question. I have a 2019 mustang gt. I want to run 91 most of the time, and then on a few occasions I would like to run e85.


Then I would like to go from e85 back to 91. Would I be able to do this with a flex fuel tune? From my understanding, when I switch from 91 to e85 I would have to flash the flex fuel tune. Then once the e85 is learned after a day or two, I would have to switch to the e85r tune. Is this correct? And if I wanted to switch from e85 back to 91, would i flash the flex fuel tune, wait a little bit then switch it over to the 91 tune? SOMEONE PLEASE LET ME KNOW IF THIS IS RIGHT

 

[engineermike]

It’s not really a flex tune if you have to reflash when switching fuels.

 

[ChitownStang]

Question. I have a 2019 mustang gt. I want to run 91 most of the time, and then on a few occasions I would like to run e85.


Then I would like to go from e85 back to 91. Would I be able to do this with a flex fuel tune? From my understanding, when I switch from 91 to e85 I would have to flash the flex fuel tune. Then once the e85 is learned after a day or two, I would have to switch to the e85r tune. Is this correct? And if I wanted to switch from e85 back to 91, would i flash the flex fuel tune, wait a little bit then switch it over to the 91 tune? SOMEONE PLEASE LET ME KNOW IF THIS IS RIGHT

I don’t with my Livernois tune.
Just fill up and drive easy for the first 15 min

 

[Magnetic Stang]

Question. I have a 2019 mustang gt. I want to run 91 most of the time, and then on a few occasions I would like to run e85.


Then I would like to go from e85 back to 91. Would I be able to do this with a flex fuel tune? From my understanding, when I switch from 91 to e85 I would have to flash the flex fuel tune. Then once the e85 is learned after a day or two, I would have to switch to the e85r tune. Is this correct? And if I wanted to switch from e85 back to 91, would i flash the flex fuel tune, wait a little bit then switch it over to the 91 tune? SOMEONE PLEASE LET ME KNOW IF THIS IS RIGHT

You're over thinking it. It can be intimidating when you haven't done it yet but when you flash a Flex Fuel Tune you can fill up with 91, E85 or any mix of the 2 and the car will adjust to it. I've been running a Livernois Flex Fuel tune for a couple years now and run E85 90+% of the time but when I do run 93, I just fill up can go. Like ChitownStang said, you just drive normal for the first 15 minutes or so to let the car adjust to the E content. I've only flashed a tune twice since running E85. The original and a revised tune about a year later.

 

[LOL WUT]

Question. I have a 2019 mustang gt. I want to run 91 most of the time, and then on a few occasions I would like to run e85.


Then I would like to go from e85 back to 91. Would I be able to do this with a flex fuel tune? From my understanding, when I switch from 91 to e85 I would have to flash the flex fuel tune. Then once the e85 is learned after a day or two, I would have to switch to the e85r tune. Is this correct? And if I wanted to switch from e85 back to 91, would i flash the flex fuel tune, wait a little bit then switch it over to the 91 tune? SOMEONE PLEASE LET ME KNOW IF THIS IS RIGHT

Thats overly complicated. If it’s a flex tune, load the tune, fill with the fuel of your choosing, give the car 10 min or so of light driving to sort out the fuel content and enjoy.

 

[Jay_jay]

You're over thinking it. It can be intimidating when you haven't done it yet but when you flash a Flex Fuel Tune you can fill up with 91, E85 or any mix of the 2 and the car will adjust to it. I've been running a Livernois Flex Fuel tune for a couple years now and run E85 90+% of the time but when I do run 93, I just fill up can go. Like ChitownStang said, you just drive normal for the first 15 minutes or so to let the car adjust to the E content. I've only flashed a tune twice since running E85. The original and a revised tune about a year later.

The thing is i’ve heard that flex fuel is meant as a transition tune, and that you aren’t supposed to be driving on it. so that’s why im confused.

 

[K4fxd]

The thing is i’ve heard that flex fuel is meant as a transition tune, and that you aren’t supposed to be driving on it. so that’s why im confused.

That's because the tuner doesn't want to put the time into making a real flex tune.

If you are going with a dedicated E tune a flex or intermediate tune is not required. it will just run like crap for about a minuet when changing fuels and tunes.

 

[LOL WUT]

The thing is i’ve heard that flex fuel is meant as a transition tune, and that you aren’t supposed to be driving on it. so that’s why im confused.

Some tuners stopped offering flex tunes and refer to them as a transition tune as you described. If you want a flex tune, get a flex tune, not a transition tune from someone that is calls it “flex”. If you’re still confused, ask you tuner and follow their advice. If what they tell you isn't what you’re looking for, find a new tuner.

 

[Jay_jay]

Some tuners stopped offering flex tunes and refer to them as a transition tune as you described. If you want a flex tune, get a flex tune, not a transition tune from someone that is calls it “flex”. If you’re still confused, ask you tuner and follow their advice. If what they tell you isn't what you’re looking for, find a new tuner.

Ah I see thank you for the advice

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