Flex Fuel Tunes

[17P51GT]

Anyone here running these on their stock injectors? All my people with them talk about the power gains but from what I hear not all E85 stations are 85% ethanol.
It doesn't seem to be worth it for me if its just for a 20hp gain with a JLT intake and tune.

 

[7991LXnSHO]

Stock flex fuel vehicles have an optical sensor in the fuel line. At the minor cost difference, I do not understand why vehicles new as yours do not all come with this capability. There are kits to plug one into some cars that run with the stock computer.
From our flex fuel use, expect lower mileage per gallon, lower cost per gallon, and cooler running temps. Being ale (edit - able. Ale is weak ethanol, right?) to fill up anywhere and have an optimal tune is helpful.
Unless you need race fuel and higher octane for boost or higher compression and advanced timing, I think 20% is overly optimistic.

 

[Newfoundpower]

I am running the flex fuel tune from Lund on my 19. 18-19 model year do not need new injectors but to run on your car (I am assuming a 17) yes, you will need new injectors.

No, not all E85 stations have 85% ethanol. How much you truly need is debatable. Some say a minimum of 75%, others say 80%. If you have an nGauge, it will tell you what your percentage is in your car. To add a second check, I bought a ethanol tester off Amazon which will precisely tell you what your percentage is.

But also keep in mind, if you are running a flex fuel tune, you don't need to have 85% in your car. A flex fuel tune is just that. A flex fuel. You can have a combination of E85 and regular fuel and the car will run fine. You only need pure E85 if you are running a DEDICATED E85 tune.

I enjoy the Flex Fuel because in my area, E85 is about a dollar a gallon cheaper than 93.

And the difference for me with the Flex Fuel tune was night and day. Really opened the car up. One of the best mods I have done so far.

Hope that helps.

 

[slayr281]

You need to get yourself a glass vial to help measure your place's actual e85 content. I'm fortunate out here that my local suppliers are always in excess (usually 87-89%, no lower than 84%) and I was using my Flex tune to finish off the 91 that was in there before, because I didn't really have a good way of sucking all the 91 out of the tank cleanly. I haven't changed my injectors, and after I did 3 sessions, adding another 5 gallons of e85, felt rather confident that there was very little 91 left that I could switch to the e85 Race tune, which was amazing. I see you're in Los Angeles, and I'm down south, but my go-to bet is Pearson Fuels, which has been impressive, especially at about 2.45ish/gal. Differently though, I'm only running this car on the track, so your experiences with street driveability may differ slightly, as I'm towing to/from the track.

edit: If you have a CAI, and if it were me, I'd hold off on the e85 as you may not find much value in it. If you add some additional supporting mods and increase your power output a touch, it's not only for the additional power, but more importantly for the additional safety, as it's close to 110 octane for 1/4 the price. If you're not frequently doing things that would require you to use 100 octane, you're somewhat lowering your fuel consumption and your ability to gas up just about anywhere for a little reward.

 

[7991LXnSHO]

Driving frequently, on the street or not, will help keep the fuel fresh and from sucking in as much water.
On the old car groups, E-anything Fuel is often considered evil. That is unless you have upgraded the gaskets, hoses, accelerator pumps, and use StaBil 360 (or Lucas’ copy).
And do not use it in small engines. Honda and Brigs say do not do it.
There’s been reports of a fungus gungus algae growing in the water in E-X tanks of fuel, much like diesel has to consider. At 170 proof, it might not ever be a problem. But Stabil is a good idea in any tank that is going to sit, say two weeks or more, anyway. If you use it and win regularly, you might get a sticker and contingency $$, besides having fewer fuel issues.

You need to get yourself a glass vial to help measure your place's actual e85 content. I'm fortunate out here that my local suppliers are always in excess (usually 87-89%, no lower than 84%) and I was using my Flex tune to finish off the 91 that was in there before, because I didn't really have a good way of sucking all the 91 out of the tank cleanly. I haven't changed my injectors, and after I did 3 sessions, adding another 5 gallons of e85, felt rather confident that there was very little 91 left that I could switch to the e85 Race tune, which was amazing. I see you're in Los Angeles, and I'm down south, but my go-to bet is Pearson Fuels, which has been impressive, especially at about 2.45ish/gal. Differently though, I'm only running this car on the track, so your experiences with street driveability may differ slightly, as I'm towing to/from the track.

 

[slayr281]

Driving frequently, on the street or not, will help keep the fuel fresh and from sucking in as much water.
On the old car groups, E-anything Fuel is often considered evil. That is unless you have upgraded the gaskets, hoses, accelerator pumps, and use StaBil 360 (or Lucas’ copy).
And do not use it in small engines. Honda and Brigs say do not do it.
There’s been reports of a fungus gungus algae growing in the water in E-X tanks of fuel, much like diesel has to consider. At 170 proof, it might not ever be a problem. But Stabil is a good idea in any tank that is going to sit, say two weeks or more, anyway. If you use it and win regularly, you might get a sticker and contingency $$, besides having fewer fuel issues.

True that, but you're also talking about old cars, the 18+ Mustangs are slightly different. If you look at the integrated gas filler neck, it says flex fuel e0-e15, and don't quote me, but I'd be rather certain that the stock computer would then have something to calculate the ethanol percentage, and probably some routines that when conditions are met, it'll give you a little more pep in your step because it knows it can take advantage of it. If you've got an aftermarket programming device, and you work with your tuner, you can go even further, again, supposing you've got supporting modifications and the intended goal to take full advantage of it. In California, 91 is the best we get, no 92 or 93, and if you're racing, 91 is a scary place to be that is greatly limiting your potential, as well as your safety. Depending on where you go, 100 and 110 are much closer to $10/gal, and generally not legal for sale without some firstborn and whatnot. If you can get the same benefit for 1/4 the cost... boy howdy, what a bargain. But you are totally spot on with the storage/usage of it though, having e85 sit for a few months isn't a great thing. I recall a few times where people were pretty much looking for others to give their unused e85 to at the end of a track day... now, if I could only find a flex fuel tow rig ...

 

[7991LXnSHO]

The flex fuel tow vehicle sounds great. As long as the fuel stays fresh, the newer vehicles should not have issues with E-15 without any mods, at least that’s in the reports I have read.
Our last mini van (Band Wagon) ran all over the state, Fully loaded, and it ran cooler and smoother with E-85 in it. The mileage took a 20% hit, but the fuel was cheaper. The newer one does not have that option, which seems like a rip off. I liked the system not needing to be told what fuel was in it or what tune to run.

I have run E-10 in my classics for the octane since I started driving, and once the rubber parts were upgraded (A good idea anyway!), I have had no issues - unless I park something for the winter without Stabil. Then that tank runs really rough with white smoke in the spring! It’s quite embarrassing.
I remember the barrels of race fuel being sealed up like brake fluid after each fill at the circle track in my hometown and it probably ending up in the tow rigs at the end of the season. E-85 is a lot cheaper.

 

[mweisslaw]

I am running the flex fuel tune from Lund on my 19. 18-19 model year do not need new injectors but to run on your car (I am assuming a 17) yes, you will need new injectors.

No, not all E85 stations have 85% ethanol. How much you truly need is debatable. Some say a minimum of 75%, others say 80%. If you have an nGauge, it will tell you what your percentage is in your car. To add a second check, I bought a ethanol tester off Amazon which will precisely tell you what your percentage is.

But also keep in mind, if you are running a flex fuel tune, you don't need to have 85% in your car. A flex fuel tune is just that. A flex fuel. You can have a combination of E85 and regular fuel and the car will run fine. You only need pure E85 if you are running a DEDICATED E85 tune.

I enjoy the Flex Fuel because in my area, E85 is about a dollar a gallon cheaper than 93.

And the difference for me with the Flex Fuel tune was night and day. Really opened the car up. One of the best mods I have done so far.

Hope that helps

I have a 2019 - 6 speed - GT. Looking to do the flex fuel - what did you have to do to allow your car to run the flex fuel?