Tuner Can't Tune Car

[GregO]

Ford allows 10% as a good calibration. There are too many variables in mass produced engines to make it better than say 5%.

I’m referring to the +/- % relationship of Mass Airflow in KG/HR vs Voltage readings.
I’m beginning to see why Ford introduced a laminar airflow device into the newer OEM air boxes.

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[ice445]

@GregO you’re right but using our methods to “calibrate” the maf it gets pretty sloppy. For example I was driving myself nuts trying to get SD fuel trims under 5% on my Roush truck. Then I logged a brand new stock maverick and its fuel trims were regularly 8% and sometimes over 10.

Won't E10 fuel usually have a few % positive trims? I always get negative trims but I'm at altitude.

 

[K4fxd]

I’m referring to the +/- % relationship of Mass Airflow in KG/HR vs Voltage readings.

Ford doesn't use voltage it uses frequency. I'm sure the period tables from Ford equal the actual flow tested on a flow bench. Each MAF sensor has a tolerance each MAF tube has a tolerance.

What I do is try to match what the engine is seeing for airflow to match what the sensor is reading. Again this also needs other sensors to be perfect.
If we get a 10 % off reading, where do we make adjustments? Air? Fuel? Without a flow bench and injector flow meter we are stuck picking one. Easiest to modify the MAF.

I’m beginning to see why Ford introduced a laminar airflow device into the newer OEM air boxes.

Are you referencing the carbon filter? It may help laminar flow but is not there for that reason. It's there to satisfy the EPA, they don't like hydrocarbons entering the atmosphere from the intake manifold.

I do add a screen to my vehicles if not factory equipped.

 

[GregO]

Won't E10 fuel usually have a few % positive trims? I always get negative trims but I'm at altitude.

I’m learning as we go here so I can’t answer.
I’m a dog with a bone over calibrated MAF readings matching the voltage range. No different than 4-20 mA on mass flow meters used in Gas or Liquids. The numbers have to align or it’s simply corrupt information.

 

[GregO]

Ford doesn't use voltage it uses frequency.

Ok so Ford doesn’t use 0-5 volts ?

Are you referencing the carbon filter?

I’m referring to the honeycomb laminar flow insert..

 

[tdstuart]

@GregO what do you think about that sealant I said above? I don’t think your reply sent properly

 

[K4fxd]

Ok so Ford doesn’t use 0-5 volts ?

No, Ford uses frequency.
Here is a screen shot of a partial MAF table.

 

[K4fxd]

I think they quit using 0 to 5 volts in 2012

 

[GregO]

@GregO what do you think about that sealant I said above? I don’t think your reply sent properly

I do all this forum stuff on a iPhone 4SE so fat fingering happens a lot on my end.
I did answer, I don’t think typical pipe thread dope will do what you’re after.
I’ve done what Dan suggested with JB black two part plastic weld but Super Glue gel is close to Loctite 401.
Just stay away from the anaerobic thread locker on plastics.

 

[Nick the Crab]

Won't E10 fuel usually have a few % positive trims? I always get negative trims but I'm at altitude.

Stock stoich target is 14.08, so that is factoring in ~10% ethanol already.

 

[GregO]

Ford doesn't use voltage it uses frequency. I'm sure the period tables from Ford equal the actual flow tested on a flow bench. Each MAF sensor has a tolerance each MAF tube has a tolerance

I'm wondering what is the OEM allowable +/- % tolerance ?
I'm assuming the change from volts to Hz increased accuracy ?

 

[engineermike]

You guys should try calibrating a ford speed density model….

 

[GregO]

You guys should try calibrating a ford speed density model….

As in Speed Air density from the 80's ?

 

[engineermike]

As in Speed Air density from the 80's ?

Basically, but at least 100x more complicated. Roush cars and all trucks use speed density to determine airflow and fueling needs. It uses manifold pressure to calculate airflow, but it does so using a quadratic equation. Er, quadratic equationS because the tunable quadratic coefficients change as a function of rpm and cam timing. So it’s something like 1000-2000 quadratic coefficients to tune if you do all rpm’s and all cam timing combinations.

 

[HKusp]

That sounds REALLY fun, Mike.

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