FlexFuel Tune ?

[ReceRed5.0_I.T.]

Have a Flex fuel tuning question. I have searched but didn't see the complete answer. I am picking up a 18 intake and Lu-47 injectors this weekend.

Question is if I get a flex fuel tune can I run 87,91,93 or E-85 at any time. For instance 87 or 91 when i, just cruising around or 93 or E85 for when i want to go to the track?

Thanks for any help in advance.

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[LOL WUT]

Yes you can, however, the flex tune will likely need to learn the fuel after each fill up before providing optimal performance. At least that’s my understanding.

 

[1bad.s550]

I just finished refining my flex fuel tune. Now, it may vary between tuners but generally, you can run 91-93 as the lowest grade and then up to e85 or whatever you desire. I would not run 87 or 89 unless your tuner had you log with that gas in the tank. I’m running a conservative 87 tune and whenever I want to go crazy, I flash my flex fuel tune from Torrie at Unleashed and with that i can run from 91-e98 and the computer will auto-adjust timing.

 

[AZ18yote]

I just finished refining my flex fuel tune. Now, it may vary between tuners but generally, you can run 91-93 as the lowest grade and then up to e85 or whatever you desire. I would not run 87 or 89 unless your tuner had you log with that gas in the tank. I’m running a conservative 87 tune and whenever I want to go crazy, I flash my flex fuel tune from Torrie at Unleashed and with that i can run from 91-e98 and the computer will auto-adjust timing.

This. The flex tune will adjust for the inferred e content but not the lower octane fuel unless you specifically worked with your tuner for those. So typically you can run 91/93 or e85, or any combination of these. In states that actually have flex fuel which could be as low as e54 this will also work as it does adjust for the e content.

 

[onlyturbo]

Yes you can, however, the flex tune will likely need to learn the fuel after each fill up before providing optimal performance. At least that’s my understanding.

Yes correct. When I had my flex tune my tuner told me that every time I switch fuel grades, I need to wait 10 min idling, revving little here and there for the ECU to relearn the new fuel used. Once you do that you don't have to do the relearn procedure as long as you use the same fuel.

It is really best to use dedicated tunes for optimum performance though, if you are trying to squeeze every bit of power.

I wanted to add that 87 is not recommend, 91 is the minimum octane, unless you don't push the car hard at all.

 

[331GT]

I use a Livernois flex tune. they do not offer a tune for fuel below 91. They said the only thing they would consider doing is a transmission only type tune for the A10 on 87, but it would not offer any engine/power changes. I they sent me a 91 and up tune, and a separate Flex tune for 91 and up and also E85.

 

[EFI]

Question is if I get a flex fuel tune can I run 87,91,93 or E-85 at any time. For instance 87 or 91 when i, just cruising around or 93 or E85 for when i want to go to the track?

A flex tune is meant for varying levels of ethanol, that's the "flex" part.

You can run E10 to E85 and anywhere in between, but more than likely the E10 has to be set to a certain octane. You won't be able to run 87 or 91 or 93 E10, you must pick one. Tuners usually give you a 91 or 93 E10 tune and don't "flex" the octane rating.

Most people run E10 93 on the street, then add various amounts of ethanol to bring up the E value depending on their needs.

 

[White_Bear_92]

When I first got my flex tune, all I did when I initially switched from 91 to E85 was run the tank down to below 1/4, fill, park for 10-15 minutes, and then drive conservatively for about the same amount of time. Other than that, man do these cars rip on corn. You will absolutely love it.

 

[ChitownStang]

So I’m contemplating Livernois or PBD for a flex fuel tune in my Mach 1 A10z
$250 cheaper for Livernois.
Who’s better power and shifting for the street ? I’ll spend more if worth it.

 

[K4fxd]

When I had my flex tune my tuner told me that every time I switch fuel grades, I need to wait 10 min idling, revving little here and there for the ECU to relearn the new fuel used.

You had a tuner who does not understand Ford's flex fuel logic. Does the F150's owners manual say to idle 10 min. after each fuel switch? NO it does not. Just drive sane for a few miles. One of the learning triggers is Lbs of air through the MAF sensor. Idleing does not reach this min unless the tooner lowers it.

Question is if I get a flex fuel tune can I run 87,91,93 or E-85 at any time.

There is no reason you can't have a flex tune that allows all of this. That is how the F150 is set, same with the other Ford flex vehicles.

 

[AZ18yote]

There is no reason you can't have a flex tune that allows all of this. That is how the F150 is set, same with the other Ford flex vehicles.

I would venture a guess most tuners only have it set to 91+ as a baseline then logic for e %. That said if requested I'm sure a tuner could dumb down the timing to accommodate 87 and 89 but performance would really take a hit when running those lower quality fuels vs e.

 

[K4fxd]

That said if requested I'm sure a tuner could dumb down the timing to accommodate 87 and 89 but performance would really take a hit when running those lower quality fuels vs e.

The car is factory set for 87. How much do you think it will lose leaving the base alone??

Do you want a "flex" tune or a race tune?
The top end will be the same. You will get a midrange boost with the race tune or a dedicated 93 tune.

 

[AZ18yote]

The car is factory set for 87. How much do you think it will lose leaving the base alone??

Do you want a "flex" tune or a race tune?
The top end will be the same. You will get a midrange boost with the race tune or a dedicated 93 tune.

I was only saying it would likely have to be requested specifically from the tuner to accommodate. Not saying it couldn't be done just don't think many are doing it by default in their flex tunes.

As far as performance I can say there is a huge fall off from running e to 91 when switching fuels. It would be my assumption the drop off would be more significant if decreasing timing to allow 87. But I also never requested the capability to run that low of octane so never tested personally.

 

[K4fxd]

It's all relative. It will run stock like on 87. It will run E like on E85.

It's all in what you want. Do you want to flash a tune and forget it, run any available pump fuel, or do you want to flash and reflash if on a cross country cruise.

I don't part throttle race so I'll give up some midrange for the convenience of filling up with whatever is available when I need fuel.

Don't most of the tuners give a dedicated E85 tune with the flex?

 

[AZ18yote]

Don't most of the tuners give a dedicated E85 tune with the flex?

This is an option that many offer not sure about all.

Personally I run flex full time since AZ e is not everywhere and alot of it is what they call flex fuel which is more around e54. Only a couple of good verified e85-90 stations used for race days for convenience like you mentioned. But run 91 at the minimum.

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