MAF versus MAP

[antarctica24]

So when I joined this forum, I was involved in a lot of conversations regarding whether this car used the MAF sensor or MAP sensor. Everyone gave me a bunch of grief when I suggested this car used a MAF sensor to determine fuel calculations.

So I get the list of items from Mountune that they want me to record, and I noticed something very interesting on the list.

One of the items says Airflow Mass lbs/min The calculated airflow through the engine and is used for almost all flow based tables.

Another item is the MAP or Manifold Absolute Pressure - Manifold absolute Pressure. This is post throttle.

It was further discovered that the US based Fiesta ST's are using MAS for fuel calibrations and the UK versions are using MAP sensors for Fuel tuning calibrations.

Now Im just saying, this looks an aweful lot like a MAF based tune and not a MAP based tune.

 

[me32]

Where did you find this info?

 

[dyn085]

The non-USDM FiST's have been using MAF-based tuning since day one, this shouldn't be news. The fact of the matter is that the USDM fuel calculations are absolutely not based on our MAF. Like it or not, that's just a fact.

 

[antarctica24]

The non-USDM FiST's have been using MAF-based tuning since day one, this shouldn't be news. The fact of the matter is that the fuel calculations are absolutely not based on our MAF. Like it or not, that's just a fact.

Im glad you chimed in, I dont want to argue about this, but instead of me just taking your word, as you have never given any evidence other than its just a fact, I provide documentation that I am using as my evidence.

You'll notice the first document, it clearly indicates that the MAF is used for almost all flow based tables. In case you were not aware, the flow based tables are what the car uses to determine the amount of fuel that is added to the engine, while running, is calculated. MAF works better and is more accurate than Manifold air pressure because it can take into consideration the amount of air and the temperature of the air with one reading. MAPs used to be used in the 70 and early 80's for turbos and superchargers, but as science progressed, the MAF sensor was created has been the main source for air reference since the early 80's. Today MAP sensors are used but are for backup, they assist in the calculation but are not the main source for the calculation.

One more thing, You can disconnect the MAF sensor, and this car will continue to function, because the MAP is a backup sensor, You can disable the MAF sensor and the car will continue to run because the MAP is a Back up sensor. The MAP sensor just does not have the resolution of the MAF sensor, and will not give you as accurate a measurement as the MAF sensor. Non of which makes the MAP sensor the main sensor in a normally functioning Ford ECOBOOST vehicle. In a normally functioning ECOBOOST vehicle, I am saying the MAF sensor is the go to sensor for reading all air flow, based on the document provided below.

For the sake of the conversation, lets just assume that Mountune is a reputable company and lets just assume that they have been around working with Ford products for more than a year. We could also add that they are the only aftermarket company that sells aftermarket parts for FORD that can be ordered on the car from the factory without voiding the factory warranty.

Just because you are using a MAP table to make your adjustments when tuning doesn't mean you've been doing it correctly.

Do you any evidence to provide, to back up your fact, other than your word posted in a forum?

 

[antarctica24]

Where did you find this info?

See my 2nd post.

 

[antarctica24]

By the way very impressive numbers in your signature on your mustang. I think the GT500 is one of the best looking mustangs Ford has ever created.

 

[dyn085]

I think you're misreading the document you posted. The definition of airflow mass specifically states 'calculated' and not 'measured'. That, in and of itself, should tell you enough. If you're sliding to something else then you're going to have to point it out because I apparently don't see it.

Anywho, here's a link to Cobbs tuning guide: https://cobbtuning.atlassian.net/wi...bile?contentId=30900388#content/view/30900388

Attached is a screenshot of the second paragraph in the link. Also attached is a post from Braden, their lead calibrator, from way back in 2013.

Are we going to assume that Cobb is a reputable company also, seems how they were the first to be tuning the USDM FiST? I'm sure you can contact any FiST tuner in the US and they will clarify your incorrect thoughts for you.

Also, the reason that you can unplug your MAF sensor without issue is not because there is some sort of MAP backup, rather, the MAFs only function on the USDM is that of the intake temp sensor. You can datalog all of this yourself if you don't believe everyone else.


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[berlow94]

Having purposely removed the MAF sensor in favorite of a MAP sensor for speed density calculation on many BMW race cars, I agree that MAP and specifically MGP is a better for performance tuning.
For OEM implementation, partial throttle conditions, and drive ability, I definitely think that MAF sensors have there place.

We've come a long way from the old barn door AFM's of the 80's.


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[me32]

By the way very impressive numbers in your signature on your mustang. I think the GT500 is one of the best looking mustangs Ford has ever created.

Thanks. I appreciate it. It's for sure a fun car. Has power just about all rims.

On the us version they only use the temp sensor on the maf. You can unplug it and the car will still run. It will pop a check engine light but the car will still run. A car that actually uses the maf will shut off if you unplug the maf.

 

[antarctica24]

Thanks. I appreciate it. It's for sure a fun car. Has power just about all rims.

On the us version they only use the temp sensor on the maf. You can unplug it and the car will still run. It will pop a check engine light but the car will still run. A car that actually uses the maf will shut off if you unplug the maf.

Im not ready to concede to that just yet. That's not what the Mountune document says. When I was tuning with hptuners, I could unplug the maf sensor and tune 100% with the map sensor.

Using the maf for temp only would indicate the waste of a sensor when they could just you a temp sensor. The Mountune doc clearly states the maf issued for almost all flow based tables. That does not say only temperature. I'm not saying your wrong and I'm not disagreeing with you but I believe we need more information.

Remember all cars prior to the 80's after the introduction of the pcm used a map sensor. The maf is a much more advanced system of measurement taking into account altitude, water content, temperature, and amount of air in one sensor whereas the map sensor only measures atmosphere of pressure and only does so one atmosphere at a time. You can tune a car on only map readings but the resolution is terrible and you go up it is only a 5 volt sensor. So going to a 2 bar map cuts resolution in half and going to 3 bar cuts resolution by a third. Fuel economy is much easier to control with a maf sensor because it can take into account so many more variables than just boost.

You can tune with just the map sensor but it is not the most efficient way to tune. When I had my trans am, I was pushing 15 lbs so we disconnected the maf and tuned with a 2 bar map. With the maf it would only read to about 12000 hertz which was about 10lbs of boost then when it maxed iout the system just starts to dump fuel so you would use the 02 sensor to help determine how much fuel you were dumping. In 2005 a new maf was created with higher resolution my guess is that is what they are using now, but to install a maf just just be used for temp reading would be a waste of money and ford would not install anything to waste money. In fact everything in this car is built for two purposes. To maximize output using the least amount of fuel possible and you cannot do that with a map sensor.

Using a map to measure air pressure post throttle would be a backup reference at best and based on the documents I posted Mountune clearly things the maf is reading air mass to calculate fuel delivery in the flow tables.

 

[M-Sport fan]

Do we actually have TWO MAP sensors on these cars?

I.E.; One up on the intake manifold, and one down on the factory cold side charge pipe.

(I'm guessing to sense boost/vacuum differences on either side of the throttle plate??)

 

[dyn085]

Im not ready to concede to that just yet. That's not what the Mountune document says. When I was tuning with hptuners, I could unplug the maf sensor and tune 100% with the map sensor.

Using the maf for temp only would indicate the waste of a sensor when they could just you a temp sensor. The Mountune doc clearly states the maf issued for almost all flow based tables. That does not say only temperature. I'm not saying your wrong and I'm not disagreeing with you but I believe we need more information.

Remember all cars prior to the 80's after the introduction of the pcm used a map sensor. The maf is a much more advanced system of measurement taking into account altitude, water content, temperature, and amount of air in one sensor whereas the map sensor only measures atmosphere of pressure and only does so one atmosphere at a time. You can tune a car on only map readings but the resolution is terrible and you go up it is only a 5 volt sensor. So going to a 2 bar map cuts resolution in half and going to 3 bar cuts resolution by a third. Fuel economy is much easier to control with a maf sensor because it can take into account so many more variables than just boost.

You can tune with just the map sensor but it is not the most efficient way to tune. When I had my trans am, I was pushing 15 lbs so we disconnected the maf and tuned with a 2 bar map. With the maf it would only read to about 12000 hertz which was about 10lbs of boost then when it maxed iout the system just starts to dump fuel so you would use the 02 sensor to help determine how much fuel you were dumping. In 2005 a new maf was created with higher resolution my guess is that is what they are using now, but to install a maf just just be used for temp reading would be a waste of money and ford would not install anything to waste money. In fact everything in this car is built for two purposes. To maximize output using the least amount of fuel possible and you cannot do that with a map sensor.

Using a map to measure air pressure post throttle would be a backup reference at best and based on the documents I posted Mountune clearly things the maf is reading air mass to calculate fuel delivery in the flow tables.

Lol, there's literally nothing for you to concede. You're just as wrong now as you were a year ago. You aren't going to find a tuner that will tell you that the USDM FiST is MAF tuned no matter how much you try because it's not, and they're smarter than that.

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[antarctica24]

Maf vs map

Do we actually have TWO MAP sensors on these cars?



I.E.; One up on the intake manifold, and one down on the factory cold side charge pipe.

Based on the Mountune doc the maf measures before manifold and map measures post throttle So only one map

 

[M-Sport fan]

Based on the Mountune doc the maf measures before manifold and map measures post throttle So only one map

What is the sensor, (and it's function) on the factory cold side charge pipe?

 

[antarctica24]

Lol, there's literally nothing for you to concede. You're just as wrong now as you were a year ago. You aren't going to find a tuner that will tell you that the USDM FiST is MAF tuned no matter how much you try because it's not, and they're smarter than that.

Sent from my SM-G930V

You have not provided any facts

How is it that plain English eludes you? Your bs means nothing without proof. I have provided evidence from the tuner. The expert on the ford products. Their document clearly indicates air flow is calculated through the maf.

If you don't any any proof other than no tuner is going to tell me is bs. If that is the only proof you have you need to pack it up and go back to the big wheel park.

 

[dyn085]

You have not provided any facts

How is it that plain English eludes you? Your bs means nothing without proof. I have provided evidence from the tuner. The expert on the ford products. Their document clearly indicates air flow is calculated through the maf.

If you don't any any proof other than no tuner is going to tell me is bs. If that is the only proof you have you need to pack it up and go back to the big wheel park.

You have provided zero evidence from a tuner, lol, just a picture of a paper that says exactly what I've been telling you. I also gave you tuning advice linked directly from the company that created your AP3 and the associated tuning software. Finally, I also provided you a quote from their ST lead calibrator.

This is super simple and you're not going to find any legitimately qualified ST tuner that will support your random tuning guesses. If you're so convinced that Mountune believes that the USDM FiST is a MAF-based tune then ask Randy to come say it publicly.

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[antarctica24]

You have provided zero evidence from a tuner, lol, just a picture of a paper that says exactly what I've been telling you. I also gave you tuning advice linked directly from the company that created your AP3 and the associated tuning software. Finally, I also provided you a quote from their ST lead calibrator.

This is super simple and you're not going to find any legitimately qualified ST tuner that will support your random tuning guesses. If you're so convinced that Mountune believes that the USDM FiST is a MAF-based tune then ask Randy to come say it publicly.

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Randy responded to my question

"There is no active MAF signal on the North American models. The hardware is there, but it's just reading temps. So yes and no to your question and the MAP is the main governing element in that regard.

Randy Robles
Calibrator"

I pains me more than being stabbed to death, brought nack to life, shot to death by a 50 calibur machine gun with a full box of ammo, being brought back to life, having a nuclear bomb dropped on me, brought back to life, then hung in the desert by the neck until dead a final time.

 

[me32]

Randy responded to my question

"There is no active MAF signal on the North American models. The hardware is there, but it's just reading temps. So yes and no to your question and the MAP is the main governing element in that regard.

Randy Robles
Calibrator"

I pains me more than being stabbed to death, brought nack to life, shot to death by a 50 calibur machine gun with a full box of ammo, being brought back to life, having a nuclear bomb dropped on me, brought back to life, then hung in the desert by the neck until dead a final time.

This is correct.

 

[Truth in Ruin]

Randy responded to my question

"There is no active MAF signal on the North American models. The hardware is there, but it's just reading temps. So yes and no to your question and the MAP is the main governing element in that regard.

Randy Robles
Calibrator"

I pains me more than being stabbed to death, brought nack to life, shot to death by a 50 calibur machine gun with a full box of ammo, being brought back to life, having a nuclear bomb dropped on me, brought back to life, then hung in the desert by the neck until dead a final time.

That would be the hardest one for me to bear.

 

[dyn085]

Randy responded to my question

"There is no active MAF signal on the North American models. The hardware is there, but it's just reading temps. So yes and no to your question and the MAP is the main governing element in that regard.

Randy Robles
Calibrator"

I pains me more than being stabbed to death, brought nack to life, shot to death by a 50 calibur machine gun with a full box of ammo, being brought back to life, having a nuclear bomb dropped on me, brought back to life, then hung in the desert by the neck until dead a final time.

Well shit, I didn't even have a speech prepared because I didn't think this day was going to come.

Look, way back in the beginning you were just a guy with a high mileage car and I was just a guy that was interested in seeing what shape the valves were in to give me more of an idea of how well Ford had mitigated (or tried) issues that other DI communities were fighting tooth-and-nail. It could have literally been that simple and all of this nonsense could have been avoided. None of this should have ever even been a thing.

This is a great example of why I've basically left the community though; it seems that we have become (or at least have been) a very fact-resistant community. People are too busy trying to feel like they're important to actually worry about whether they're correct. I've tried posting information to help people become informed, but that didn't seem to have the effect I hoped because I'm not the best communicator online. Using this example, it should never have taken over a year for someone to understand this particular basic and easily-tested concept.

I appreciate the fact that you at least posted up on here when you had supporting information from a source you trusted, even though it was against your opinion. You could have just as well gone on forever never admitting that you had the info, and it takes a lot to admit publicly when you're wrong. Take a rep point and bury the hatchet, just know that you're obligated to correct the next clown that thinks the USDM FiST is MAF-tuned.