Input on Headers + E85/93 Flex Fuel Tune

[MarquanTR]

I have Kooks 1 7/8’s headers with green cats connected to a corsa double H pipe welded to the GT 500 borla atak on my Mach 1 tuned by wengerd on E85/93. I’m also in Delaware and frequent NJ. The volume is very tolerable, especially with active exhaust. It definitely wakes the car up and driveability is amazing (10r80) with wengerd tuning.

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[ZXMustang]

I vote skip headers unless you are preparing for boost. I went identical times on JLT/E/Wengerd tune vs the same + Offroad TSP headers. No gain in ET or MPH. The car just plain ole didnt pick up from the $2k worth of installed headers. And ALSO its so goddamn loud now, I wish I had the stock cats back. Plus the smell. ONLY get headers if you are going for real FBO or getting boost. Otherwise leave them alone. All the gains are from the intake/E and tune. Wengerd for the win btw.

 

[engineermike]

The Ford flex fuel logic works pretty good. It does have some limitatrions as the F150 tune file has more flex parameters available and these cannot be added to the mustang tune file.

If you are N/A there is nothing to worry about just wait till your in dash A/F gauge settles down before you hammer the car.

Lund and a few others are coming out with a canbus flex system that uses a fuel sensor. The tuning software is from PCMtec.

@engineermike has the ford flex fuel system working reliably on his FI 3rd gen mustang.

Not just the 3rd gen mustang, but also a 2020 Roush Nitemare. And the kicker is the Roush Nitemare is running the stock F150 pump and no BAP; just some fancy tuning.

The Ford Flex logic works really well as long as you follow Ford's instructions (Flex Fuel GSB under "Advise Customer").

There are a couple of caveats, though. The MAF and injector calibration has to be good for it to work right. Fuel trims need to be 3% or less. Also, hptuners (which many shops use) lacks some key parameters to make it work right in the car, namely the fuel line and pump volumes. These are key to preventing premature locking in after a refuel. With this change, plus all the usual stuff, it works pretty darn good in the car, but there are other tables that make it even better. Of course, all of these are parameters are available in PCMTec because they give you access to pretty much everything that's there.

@K4fxd is right to watch the a/f gauge when switching fuels. At steady state, it will show you the learned stoichiometry and it takes about 10 miles for the new fuel to fully make it's way to the motor. I have mine set up to "turn on" the extra timing at 11.8/1. It's easy to remember 12/1, so I know if it's above 12/1 at steady state then it's using pump gas timing and if it's below that, then it's using E85 timing.

 

[vinny89gt]

Not just the 3rd gen mustang, but also a 2020 Roush Nitemare. And the kicker is the Roush Nitemare is running the stock F150 pump and no BAP; just some fancy tuning.

The Ford Flex logic works really well as long as you follow Ford's instructions (Flex Fuel GSB under "Advise Customer").

There are a couple of caveats, though. The MAF and injector calibration has to be good for it to work right. Fuel trims need to be 3% or less. Also, hptuners (which many shops use) lacks some key parameters to make it work right in the car, namely the fuel line and pump volumes. These are key to preventing premature locking in after a refuel. With this change, plus all the usual stuff, it works pretty darn good in the car, but there are other tables that make it even better. Of course, all of these are parameters are available in PCMTec because they give you access to pretty much everything that's there.

@K4fxd is right to watch the a/f gauge when switching fuels. At steady state, it will show you the learned stoichiometry and it takes about 10 miles for the new fuel to fully make it's way to the motor. I have mine set up to "turn on" the extra timing at 11.8/1. It's easy to remember 12/1, so I know if it's above 12/1 at steady state then it's using pump gas timing and if it's below that, then it's using E85 timing.

Well that's concerning because the shop I have slated to do my tune has HP tuners. National Speed in Richmond VA. They seem to be highly reputable and the guys I've talked to there seem very knowledgeable. I'm a bit of a neophyte to this, can you explain what "premature locking in after a refuel" means @engineermike ?

 

[K4fxd]

It means the ECU learns the A/F ratio too soon, before all the old fuel is purged from the lines and rails. In a N/A setting this is not too bad because it will be close enough for the fuel trims to compensate. FI this can be a problem.

 

[engineermike]

Yea, what he said.

When you refuel, it triggers the learning process. When the stoichiometric A/F ratio becomes stable, the PCM locks in until learning is re-triggered by either a KAM reset or refilling the tank. But it takes a bit for any of the ethanol to reach the engine, so the PCM could lock into the wrong stoichiometry. The fuel rail/pump/line volumes are used to delay the locking in until old fuel is purged and are generally defaulted to 0 in the mustang tune, so it is allowed to lock in immediately after a refill. The only way to fix this using HPT is to get someone really sharp in hex and binary editing to create user-defined parameters for these things.

 

[ZXMustang]

It means the ECU learns the A/F ratio too soon, before all the old fuel is purged from the lines and rails. In a N/A setting this is not too bad because it will be close enough for the fuel trims to compensate. FI this can be a problem.

Yeah that is problematic. I've seen it in real time with mine.

 

[vinny89gt]

It means the ECU learns the A/F ratio too soon, before all the old fuel is purged from the lines and rails. In a N/A setting this is not too bad because it will be close enough for the fuel trims to compensate. FI this can be a problem.

Thank you for the info.

 

[shogun32]

because the shop I have slated to do my tune has HP tuners

I would cancel the appointment and introduce them to pcmtec.

 

[Pistol_91]

Many tuners are starting to stray away from flex tunes because of how our cars read the alcohol content. They're reading it via o2 sensor, hence after its already been through the engine. If you have a vacuum leak or something to induce unwanted air into the engine the tune will adjust as more air and change the stoichiometric ratio. Makes sense, but I've ran a flex tune for awhile and it was decent. I'd rather run a strictly e85 or 93 tune though because they're set up better timing wise. Flex tunes are for transitions between fuels and they should stay that way. Even though many people run them all the time. I have stainless long tubes and the fitment is really good. Doesn't bump the A/C line. It's very close but it does not touch

 

[K4fxd]

They're reading it via o2 sensor, hence after its already been through the engine. If you have a vacuum leak or something to induce unwanted air into the engine the tune will adjust

Yes it will, to a point.

I think you are saying the flex isn't safe because you could get a vacuum leak?

It works the same if you have a flex tune, a dedicated E85 tune or if you are on a factory gasoline tune. Once the widebands are out of range the car goes into limp mode.

 

[Pistol_91]

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.

 

[K4fxd]

I do understand the system

Carry on

 

[K4fxd]

I watched about as much of the douche bag as I could stand.

Yes it is inferred. The F150 and Focus and every-other Ford flex fuel vehicle is also inferred.

Lund is just getting ready to sell the can-bus system. Read into that what you will.

 

[Pistol_91]

I never realized how sensitive some so called males are on this forum. All I was saying was, the flex tunes may not be available much longer because of example A, reasons. I can agree he is a douche but makes a decent point in the video whether you agree or not, or if it's even truthful. But the fact is they're going away from the flex tune so that's the bottom line. Just because other Ford cars use the same logic and system doesn't mean it's the best or one that makes the most sense. Wouldn't you rather have your fuel read BEFORE it goes into the engine? Yes, I know I would.

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