Input on Headers + E85/93 Flex Fuel Tune

[K4fxd]

Yes, all parameters are not in the Mustang's code. However with HP tuners you can tune a gen 1 or 2 coyote. With PCMtec you can tune gen 1, 2 or 3.

Ford believes in the system enough to offer it with a warranty, is it the best? I don't know.

Lund is going to offer PCMtec's can-bus flex system If they don't already. It makes good business sense for them to trash Fords system.

I say it is great to have a choice.

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[Pistol_91]

I agree and at that point I'd refer back to my original post. Screw a flex tune and just run strictly e85 or 93

 

[engineermike]

Couple points…

I originally thought flex worked by driving average fuel trims to zero via adjusting stoichiometry. I later came to learn that it just drives the average STFT down to zero while leaving LTFT alone, possibly even freezing LTFT while learning ethanol. In this way, it will still sense mechanical deficiencies in the system such as air leaks and if the LTFT strays too far you get an MIL. Pretty smart on Ford’s behalf.

There are a couple of ways to manage timing but if you’re NA then the stock tune will allow timing to advance to mbt on pump gas if no knock is sensed. So if NA, a tuner could actually just not change timing with ethanol. It will hit mbt just like stock, just take a bit to get there due to KA advance rate. If managed this way, it’s just as safe as stock. The only worry would be lambda momentarily incorrect on e85 if some learning problem happened.

 

[ZXMustang]

My flex experience is that the car uses the STFTs to drive down the inferred stoich. As the car starts to see the ethanol, as long as it is in learning mode not matured it would bring down the stoich as the fuel trims came down with it.
The problem is when you dramatically switch fuels and the car matures the inferred AFR too quickly before the higher content E makes its way through both fuel systems. DI/PI. At that point the inferred stoich is matured and it stops learning. But then the ethanol shows up and pushed the STFTs well into the +30% range to keep the car running at pump stoich. So that’s completely safe for baby driving but it’s on the bleeding edge of what the car can correct for and god help you if you whomp on it and it runs lean. It would throw a lean condition code before that in most cases. At that point is when you reflash the car or do a KAM reset to retrigger a learning cycle. Then best to let it idle the stoich down. Because if you are driving it when it’s learning and you coast, the car will go full lean and skew the AFR back up. Then you might run out of time again and your trims might be off a few + or -. Best to let it idle until the stoich is matured. That’s the cleanest transition.

 

[K4fxd]

The problem is when you dramatically switch fuels and the car matures the inferred AFR too quickly

This is an issue with Gen 3's. However with PCMtec you can tell the ECU how much fuel needs to pass before it starts the maturing mode. IE you can tell it how much fuel is in the lines and rails. This info is missing from the Ford tune in the Gen 3. It is populated in the Gen 1 and 2 Ford tune so HP tuners can be used to tune them.

 

[engineermike]

K4fxd is correct; there are iirc 9 parameters to specify how much fuel is in each part of the system. Ever since populating these, I haven’t had it mature too quickly.

 

[Zrussian13]

No what I'm saying is a flex tune may not be available.. and yes I'm repeating what I recall from a video from Flores. So you're somewhat right. In a dedicated e85 or 93 tune your stoichiometric ratio doesn't change. In a flex tune it can and will change. Not sure what you aren't understanding about that. Maybe watch the video and you'll understand what I'm referencing. Not sure where I mentioned wide bands being out of range but, go on.

You'd be safer running a flex tune full time than you would be watching that shit too much. He's a dumbass. Take what he says with a grain of salt.

 

[Pistol_91]

You'd be safer running a flex tune full time than you would be watching that shit too much. He's a dumbass. Take what he says with a grain of salt.

Oh I do, trust me... I see some of the shit he says... Lol. My point was big name tuners are opting out of the flex tunes for whatever their reasons are.

 

[Zrussian13]

Oh I do, trust me... I see some of the shit he says... Lol. My point was big name tuners are opting out of the flex tunes for whatever their reasons are.

I get that but it's basically the same logic ford uses for flex so I'd feel comfortable using it. In fact, I used it for quite a while before going boost and my stock motor is doing just fine at 95k miles now.

 

[Pistol_91]

I get that but it's basically the same logic ford uses for flex so I'd feel comfortable using it. In fact, I used it for quite a while before going boost and my stock motor is doing just fine at 95k miles now.

yeah i ran it for 2 years. no prob

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