TDStuart Tuning Adventure

[K4fxd]

I also do think the maf cal needs work because an air load of .76 at wot is very level even considering the high ambient.

He took the maf period from PMAS's tech sheet. You really think it is more than 5% off?

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[engineermike]

He took the maf period from PMAS's tech sheet. You really think it is more than 5% off?

Airload is .75-.77 at WOT and fuel trims are 10%. There's two indications that the MAF curve is off. The reasons why, I don't know.

That said, there is no way I would fudge injector data to fix the fuel trims. There are at least 3 sets of credible injector data available, questionable implementation of said data, and we don't even know if the fuel pressure is what it's supposed to be.

 

[WildHorse]

It is strange that your IAT's are climbing under acceleration....

yeah it shouldn't. my non-fenderwell PMAS temps drop like a stone when accelerating.

 

[GregO]

There's two indications that the MAF curve is off. The reasons why, I don't know.

My unprofessional guess is the PMAS transfers are for the standard engine bay mounted CAI. He is using the fender well kit which moved the MAF sensor lower and significantly further away with one additional 90° elbow introduced post MAF sensor.

 

[Pistol_91]

If injector data is confirmed and right id adjust the MAF. It's simple and shouldn't take long to see if it works out in the end. You can always go back to their values too. OP don't forget not to overwrite any tunes you'll regret it.

 

[K4fxd]

Airload is .75-.77 at WOT and fuel trims are 10%. There's two indications that the MAF curve is off. The reasons why, I don't know.

I've had 3 sets of LU47's and all needed tweaking from Roush data. This when used with a confirmed MAF.

His air load is low in the Lund tune too.

My unprofessional guess is the PMAS transfers are for the standard engine bay mounted CAI. He is using the fender well kit which moved the MAF sensor lower and significantly further away with an additional 90° elbow introduced post MAF sensor.

This might be the case. I've never tried moving the sensor further away so I don't know what effect it will have.

PMAS uses the same data for both, so IDK

 

[WildHorse]

always heard with NA engines : The MAF should be 12-18" from the TB.

 

[tdstuart]

Air load has been low since the new engine. Not .70s low but like high .80s to mid .90s vs what use to be over 1.00 or very high .90s.

 

[tdstuart]

I believe they all have pressure multipliers, and if your inferred pressure comes out to 55, it will just multiply the value for 39 appropriately to correct them.

If you want to correct it so that multiplier 1 is for 55, that's fine, but what you really want is to cover up to pressure delta near 70psi.

I'd you do adjust the high slope, just be aware or will effect the entire MAF. You should see what I describe as a pivot in the trims as fuel demands go up. Your goal would to be a consistent off set like -5% across the transfer. Not +10 in the high fuel demands areas, and +2 in the low demand areas.
If that makes sense.

It looks like I have to correct the static values that are calculated for 39.15 to 55 as the pcm expects those values are for 55 psi. The slopes I can leave because they have the pressure vs value so the pcm will know which ones to use.

 

[tdstuart]

yeah it shouldn't. my non-fenderwell PMAS temps drop like a stone when accelerating.

I’ve had some weird iat readings with the fenderwell kit. I have a video of the iats randomly dropping like 20* while driving on the free way and jumping back up and down wildly.

I can’t think of any physical reason for the weird readings.

I removed the fog light so the cai should be getting nice fresh air. I even made a nice metal and water proof screen so it wouldn’t shoot water and rocks right into the filter

 

[GregO]

I can’t think of any physical reason for the weird readings.

I have an off the cuff idea.
Convection inside the vertical riser CAI tube. That’s a big vertical column at 4.75” diameter.
Whats the measured distance on the vertical CAI tube between the MAF sensor and the 90° elbow ?

Put the fog light back in.

 

[tdstuart]

I have an off the wall idea.
Convection inside the vertical riser CAI tube. That’s a big vertical column at 4.75” diameter.
Whats the measured distance on the vertical CAI tube between the MAF sensor and the 90° elbow ?

I wish it was easier to access. I would have to take the entire cai apart. I have to pull the fenderliner out and take the wheel off. Good hour and a half process and its 110*+ today and I would have to do it in my driveway as the garage is packed right now.

 

[WildHorse]

Whats the measured distance on the vertical CAI tube between the MAF sensor and the 90° elbow ?

i'd guess 24-36 inches.

 

[K4fxd]

I’ve had some weird iat readings with the fenderwell kit. I have a video of the iats randomly dropping like 20* while driving on the free way and jumping back up and down wildly.

That sounds like a failing MAF sensor.

 

[tdstuart]

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

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