TDStuart Tuning Adventure

[GregO]

i'd guess 24-36 inches.

I was referring to the 90° elbow circled in white.

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[Mike Pfeifer]

That sounds like a failing MAF sensor.

This was my first thought as well. Erratic readings from MAF are usually cause for me to try a known good part before trying to dig any deeper.

 

[tdstuart]

Should I just buy a new oem maf sensor? I know PMAS sells sensors that supposedly don’t need tuning for the maf

 

[GregO]

Personally I believe the fog light removal, home made metal filter guard and the vertical CAI column needs revisiting.
Think for a moment of how the incoming air through the gutted fog light is traveling across the metal guard and how that air flow movement might be disturbing the fender well located MAF reading.

 

[K4fxd]

I know PMAS sells sensors that supposedly don’t need tuning for the maf

If it's sending bad temp information I wouldn't trust the period either. I would buy a Ford stock sensor.

 

[tdstuart]

Personally I believe the fog light removal, home made metal filter guard and the vertical CAI column needs revisiting.
Think for a moment of how the incoming air through the gutted fog light is traveling across the metal guard and how that air flow movement might be disturbing the fender well located MAF reading.

The filter won’t be getting a direct stream of airflow. The metal screen and hydrophobic screen block/significantly reduce the air going right into the filter.

 

[GregO]

Should I just buy a new oem maf sensor? I know PMAS sells sensors that supposedly don’t need tuning for the maf

Did you use the same MAF sensor in the JLT that is now installed in the PMAS ?

 

[tdstuart]

Did you use the same MAF sensor in the JLT that is now installed in the PMAS ?

Same sensor

 

[GregO]

The filter won’t be getting a direct stream of airflow. The metal screen and hydrophobic screen block/significantly reduce the air going right into the filter.

The air traveling across and around the apparatus you made might be creating a low pressure area around the filter area. Depending on vehicle speeds and throttle angles that low pressure may cause a temporary depression inside the MAF housing.

 

[WildHorse]

I was referring to the 90° elbow circled in white.

probably less than 20".

 

[markmurfie]

Here is the data I am going to be trying. Ford Performance data attached. Its all in 39.15 psi. I will use the charts to convert it to 55 psi.

What's confusing is the hptuners thread I read said that minimum pulse width (minpw) does not change but ford specifically calls out that its for 39.15 psi. Ill leave it as frpp has it.

Here is the data converted (slopes and pressure multipliers stay the same so only voltage and static values listed):

ALOSL (lb/s)	0.016979
AHISL (lb/s)	0.0155345
FUEL_BKPT (lb)	0.0000128700
MINPW (ms)	0.687

VBAT (volts)	Voltage Offset (ms)
6	8.019
8	2.765
10	1.803
11	1.526
12	1.307
13	1.137
14	0.988
15	0.874

Definitions:
ALOSL: "low" injector slope
AHISL: "high" injector slope
FUEL_BKPT: Fuel mass at which to switch from low to high injector slope
MINPW: Minimum repeatable fuel pulsewidth at 39.15 psid
FNPW_LSCOMP: Multiplier to low slope as a function of injection pressure in psid
FNPW_HSCOMP: Multiplier to high slope as a function of injection pressure in psid
FNPW_BKCOMP: Multiplier to FUEL_BKPT as a function of injection pressure in psid
FNPW_OFFSET: Injector voltage offset as a function of battery voltage
FNPW_OFFCOMP: Multiplier on
FNPW_OFFSET: as a function of injection pressure in psid

Honestly doesn't make sense why I manually have to convert these as I feel like the ecu would just use the slopes I give it to do the conversions... Ill try it both ways just giving these conversions for now.

*Ford Data Attached

I have never liked how the multiplier and pressures are obviously out of order on this charaterization sheet.

the 11-14 mustang Roush tune should have proper data in it, and those cars use the same 58psi I would find a tune on HPT forums and get it out of that.
The 07-12 GT500's are LU47 injectors as well, with a longer body, the data isn't that different, and can't be far off.

Last but not least, if you purchase Greg Banish's 270$ DVD, I believe he will provide charaterization data for those exact medium body LU47's up to 125 PSI covering the 18+ mustangs and new GT500s fuel pressures data gathered right on his own injector flow bench.
This is good if you ever go return style fuel system and increase fuel pressure delta well above the stock 55psi.

 

[tdstuart]

I have never liked how the multiplier and pressures are obviously out of order on this charaterization sheet.

the 11-14 mustang Roush tune should have proper data in it, and those cars use the same 58psi I would find a tune on HPT forums and get it out of that.
The 07-12 GT500's are LU47 injectors as well, with a longer body, the data isn't that different, and can't be far off.

Last but not least, if you purchase Greg Banish's 270$ DVD, I believe he will provide charaterization data for those exact medium body LU47's up to 125 PSI covering the 18+ mustangs and new GT500s fuel pressures data gathered right on his own injector flow bench.
This is good if you ever go returnless fuel system and increase fuel pressure delta well above the stock 55psi.

I’ve been using the roush data just wanted to try this data and see what happens.

Good info

 

[engineermike]

The problem with the fr data is there is no rail temp offset and slope.

 

[markmurfie]

The problem with the fr data is there is no rail temp offset and slope.

Fuel pressure is inffered, rail temperature is inffered.... it doesn't make that big of a difference having it or not. Also seeing as the FP in the 15-17 is basically low flow or full on to control impending vaporization theres not much for the ECU to do. The 18+ may be a bit more sophisticated.

 

[tdstuart]

Okay here is a log of the roush data (R7), the ford data where I multiplied the things I outlined above, and the ford data unchanged.

Whats weird is I am not seeing much of a change in the fuel trims especially at wot. I do see air load up a lot more with the ford data multiplied.

Let me know what you guys think. I would have figured that me changing the injector data so much would have shown big differences.

Note that the ford data multiplied also changes what the car thinks the injector duty cycle is.

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