Is Your Car Tuned Correctly?

[TBCobra]

Damn most of this stuff is over my head. Seems like there is more to tuning that people really think. The first question I always hear after a tune is "what was your a/f?" and depending on what I say you either get "hmm thats a little rich" or "him thats a little lean." lol

 

[iggster]

Just going to address tuning the MAF curve on the dyno. Can it be done... yes, but it is tedious and prone to errors. You have to turn off all adaptive controls in the PCM, set the Desired A/F for ALL load conditions to be the same, and disable all A/F modifiers and preferably lock the timing and disable spark modifiers as well. Then you can datalog MAF voltage and plot against wide band O2 and adjust the MAF table to achieve programmed A/F ratio. Once that is done, re-enable adaptive controls and verify that in closed loop you run at 14.7:1 A/F with little if any short or long term fuel corrections. If you have ANY substantial fuel corrections, you may get the tune right on the dyno, but driveability will suck.

For this reason, it is FAR better to have a meter that is calibrated on a flow bench. You're MAF tells the computer how much air that is going into the motor. This is used more importantly to calculate load. You may be able to get 11.5:1 a/f by putting 10.5 in the table thus bandaiding a bad MAF curve. Makes for nice dyno charts. But what you don't see is that the MAF is also used to calculate load. Load is then used to select where in the timing map you are. A/F may look great, but if your computer thinks there is less air, you can end up in a lower load cell and detonate. NOT because you are lean, but because there is too much timing due to an incorrect MAF calibration.

Mike

1. where in the heck do you just put 10.5 in the maf table to get any desired a/f? :??: the only thing that gets adjusted is the #/mn etc

Also when you say on the dyno do you mean at wot or just cruising on a dyno? You can and should tune it on a "good" dyno, any that can vary load. It really isnt safe to try to get a high load at low rpm or even a high load at high rpm especially on a high HP car on the street

load vs timing can be changed...

Also depending on the year of "mustang" some ecms are limited load wise, A n/a mustang say a 1999 cobra will only come stock with 100% load but you can change this in the tune to 190% and should if you add a supercharger/turbocharger etc, on 2005 and newer you can have high load values.

 

[iggster]

Damn most of this stuff is over my head. Seems like there is more to tuning that people really think. The first question I always hear after a tune is "what was your a/f?" and depending on what I say you either get "hmm thats a little rich" or "him thats a little lean." lol

Allot more involved, most tuners wont even touch 1/4 of the settings cause you will never know and then you run into drivebility problems.

Honestly the A/f numbers are not really everything you should stick to, READING PLUGS is VERY important.

Here are some plugs out of my mustang, car was dynoed at 12.0 a/f with 2 different widebands on the car one from the dynojet and one located on my down pipe. both read within .1 of each other, but as you can tell the car is running rich and I leaned it to 12.5 and car made an extra 50horse and the plugs where still a little gray but I know its safe still and not to lean.

I run c16 leaded gas so it doesnt foul plugs black it fouls them gray.

 

[iggster]

Oh ya heres another picture of some spark plugs out of my mustang from a couple years back from relying on numbers only from the wideband (wasnt tuned by me then)

 

[iggster]

What I am trying to get at that EVERYONE thinks "oh get it to 11.5, 18 degrees of timing it will be safe" well what was the timing curve like? what kind of precautions are in the tune? like retarding timing vs ect,act,knock. Then the air fuel where was it read from and how old was the wideband? when was it last calibrated. etc etc

 

[blackshelby]

1. where in the heck do you just put 10.5 in the maf table to get any desired a/f? :??: the only thing that gets adjusted is the #/mn etc

Also when you say on the dyno do you mean at wot or just cruising on a dyno? You can and should tune it on a "good" dyno, any that can vary load. It really isnt safe to try to get a high load at low rpm or even a high load at high rpm especially on a high HP car on the street

load vs timing can be changed...

Also depending on the year of "mustang" some ecms are limited load wise, A n/a mustang say a 1999 cobra will only come stock with 100% load but you can change this in the tune to 190% and should if you add a supercharger/turbocharger etc, on 2005 and newer you can have high load values.

I don’t believe he was saying you put 10.5 in a MAF transfer function. I believe what was meant that it yields 10.5 a/f out the tailpipe.

Load on a dyno, (putting load on a car) and the load tables are two different things.
You can increase your loads tables in a tune over 100 percent etc., but that still doesn't mean the load tables are lining up correctly or pointing to the correct cell.
You can never really change load itself, just how many tables you can add or minus in the tune.(allows to fine tune or give you more tune-ability)
Load is directly related to airflow......... Real Load is calculated by real airflow.
So if someone is tweaking or moving the MAF curve, load will be wrong plain and simple.
Load will not be pointing to the correct load cell in the tune......
A MAF/transfer curve needs to be accurate and real.(calibrated) not tweaked or created moving a curve up or down on a dyno to achieve and A/F ratio or where you think load should be.
So you put a better fuel pump in the car or raise the fuel pressure(any fuel system upgrade) do you move the MAF curve to change the fuel curve?
Why would someone one move the MAF curve in this case? The motor didn't change how much air it is seeing or moving. Yet this is commonly done and is simply wrong to do.
If you move a transfer function lower it will lean out a car (why because you are telling the motor it's moving less air) but does it represent real airflow? (Is the motor really moving that much air)?
The only way a maf transfer function can represented real airflow is first to make sure its transfer function was obtained from a flow bench .
A flow bench will yield a true representation of airflow from 0-5 volts(or if freq )through its full range.
Once a real transfer function is obtained either by buying a meter where the company supplies this information or the tuner or whoever knows it is a real curve.
The transfer function should be put in the tune and NEVER touched again. All tuning from that point on should be done in different areas.
The MAF is the heart of the system and very easy misunderstood.

 

[mustangtw]

So if the maf curve is on the rich side load will show higher than what it really is and you will be running less timing than what you really need?

 

[iggster]

What happens when you peg the meter and need to add a mafia or when the meter you are using can flow more then what the ecm can see and you have to re scale engine displacement and injector slopes that will throw off load

I do know the transfer functions for the sct and hpx mass air are way off from what sct gives you and just like the values for some injectors like 80lb


Who does flow benching on mass air meters?

 

[blackshelby]

So if the maf curve is on the rich side load will show higher than what it really is and you will be running less timing than what you really need?

If the MAF transfer curve is higher than actual airflow yes that could happen.
It all depends on the load cell it is pointing too.

 

[blackshelby]

What happens when you peg the meter and need to add a mafia or when the meter you are using can flow more then what the ecm can see and you have to re scale engine displacement and injector slopes that will throw off load

I do know the transfer functions for the sct and hpx mass air are way off from what sct gives you and just like the values for some injectors like 80lb


Who does flow benching on mass air meters?

Pegging a meter means you are out of range .
A sensor that has more range will be needed or a larger housing . A mafia basically changes the range of the sensor. So if you were to use a mafia that should be flowed along with the meter on whatever setting you are using on the mafia to obtain an actual flow curve for that sensor/housing mafia combo.(It basically like starting with a new meter sensor)
It is more a software limitation than a PCM issue when you have a MAF curve larger than what is allowed to be entered in certain templates.
That question really is more tuning basics how to tune than understanding the importance of a MAF itself and how it works.
When you have a PCM,s(software) that will not allow the full range of a transfer function you must divide the displacement and injector by whatever amount you need to scale the curve down.
Most times dividing the curve in half or a third will allow the full range to be entered into the template. Since airflow is directly associated with load ,it is the main reason why you need to divide displacement by the same amount you divide the MAF transfer curve to keep load in check . Fuel delivery is dependent on airflow and is the same reason why it needs to be scaled down the same amount to keep fuel in check.
If all is scaled down equally load will be dead on. Ford themselves actually uses the scale down method because of software limitations in certain PCM’s templates in a few cars .(one example is the ford gt 40 supercar )

 

[itzl0l]

I'm going to disagree with the majority of this....heres why:

Take for example:

03 cobra, Stock. Only change being a ram air intake.....STILL the stock Maf/housing. Changed the filter b4 the maf and the inlet pipe after the maf. Lets call this a "last gen" popular ram air.

Suddenly..due to a change in laminar air flow charactaristics, my maf curve is off a few percent, not alot, but enough to require a tweak in prp. Now...I havent changed the MAF/Housing (but suddenly the oem values arent 100% correct any longer).

I tweaked this.....as nearly every tuner does, by adjusting the MAF xfer curve in prp. Why on earth would I muck around with fueling/injecters/slopes ect...WHEN that is not what changed?? ...you tweak the variable that changed....airflow.

Value files for injectors are known and are normally rock solid. (yes there are certainly exceptions). MAF's however....due to variences in airlow....manufacture, tolerances in housings and filters can vary a good deal off from their published flow charts. Thats a fact of life.

Granted, this is not how ford tunes a factory car. But my car didnt come with aftermarket mods either. There is no way to use flow bench #'s for a MAF unless it was flowed with your EXACT intake/filter/meter/housing.....and even this....in the actual car...on the road....i bet it would STILL need to be tweaked.

This is how EVERYone tunes...we are talking Rick, Justin, Eric, Don, Herman ....and this is what Greg Banish agree's with as well.

Im 110% sure that others are reading this ....and agree with the accepted method, but dont feel like arguing...

 

[01yellercobra]

Tweaking the MAF transfer is how I was taught to tune. Make sure it's ajusted correctly and then the load will be what it will be. I saw a lot of guys trying to tune for load and their cars always had issues. It's not hard to adjust a timing table to reflect the load that is being shown during datalogging.

You also have to figure on guys that don't use a stock MAF housing. I took my MAF sensor and put it in a 3.5" pipe. That's smaller then the MAF housing it came in. So any flow data used on the original meter set up no longer works for my new setup.

 

[breoland]

I'm going to disagree with the majority of this....heres why:



Granted, this is not how ford tunes a factory car. But my car didnt come with aftermarket mods either. There is no way to use flow bench #'s for a MAF unless it was flowed with your EXACT intake/filter/meter/housing.....and even this....in the actual car...on the road....i bet it would STILL need to be tweaked.

This is how EVERYone tunes...we are talking Rick, Justin, Eric, Don, Herman ....and this is what Greg Banish agree's with as well.

Im 110% sure that others are reading this ....and agree with the accepted method, but dont feel like arguing...

So you are saying FORD tuning the cobra jets, fr500's and other specialty vehicles for FORD RACING are tuning incorrectley? Those are highly modded Mustangs, fusions, raptors and focus that are being pushed to the limits

If ford Tuning GURUS are telling us to get a mass air meter with the correct mass air transfer curve, i am going to do what ever i can to get it done right

On a side note, Shelby super snakes, shelby 1000's, terlingua are modded and are all tuned with the correct mass air transfer curve. Have you ever herd of any of those cars that were shipped out to any of the locations running poorly due to bad gas, or searching for an idle?

also forgot to mention roush and saleen

 

[iggster]

I'm going to disagree with the majority of this....heres why:

Take for example:

03 cobra, Stock. Only change being a ram air intake.....STILL the stock Maf/housing. Changed the filter b4 the maf and the inlet pipe after the maf. Lets call this a "last gen" popular ram air.

Suddenly..due to a change in laminar air flow charactaristics, my maf curve is off a few percent, not alot, but enough to require a tweak in prp. Now...I havent changed the MAF/Housing (but suddenly the oem values arent 100% correct any longer).

I tweaked this.....as nearly every tuner does, by adjusting the MAF xfer curve in prp. Why on earth would I muck around with fueling/injecters/slopes ect...WHEN that is not what changed?? ...you tweak the variable that changed....airflow.

Value files for injectors are known and are normally rock solid. (yes there are certainly exceptions). MAF's however....due to variences in airlow....manufacture, tolerances in housings and filters can vary a good deal off from their published flow charts. Thats a fact of life.

Granted, this is not how ford tunes a factory car. But my car didnt come with aftermarket mods either. There is no way to use flow bench #'s for a MAF unless it was flowed with your EXACT intake/filter/meter/housing.....and even this....in the actual car...on the road....i bet it would STILL need to be tweaked.

This is how EVERYone tunes...we are talking Rick, Justin, Eric, Don, Herman ....and this is what Greg Banish agree's with as well.

Im 110% sure that others are reading this ....and agree with the accepted method, but dont feel like arguing...

Exactly what I agree with its how I tune, and then the op gets stuck up on load vs timing but all of that can be changed in the tune also

It's how I was taught to tune also so pretty much everyone I have ever talked to is wrong and this is right?

Kind of doubting this but I am open to anything

 

[itzl0l]

So you are saying FORD tuning the cobra jets, fr500's and other specialty vehicles for FORD RACING are tuning incorrectley? Those are highly modded Mustangs, fusions, raptors and focus that are being pushed to the limits

If ford Tuning GURUS are telling us to get a mass air meter with the correct mass air transfer curve, i am going to do what ever i can to get it done right

On a side note, Shelby super snakes, shelby 1000's, terlingua are modded and are all tuned with the correct mass air transfer curve. Have you ever herd of any of those cars that were shipped out to any of the locations running poorly due to bad gas, or searching for an idle?

also forgot to mention roush and saleen

You do realize (you do right?) that no1 buys a Cobrajet and then goes immediately to the track and expects to be competitive in their class. Many of these cars run full standalone ECU's...Bigstuff...fast...whatever. I know Kurgan has tuned his fair share.

OEM, mass produced cars like the Shelby's, Roush, Saleens, Focus, Rapors ect (that you named) CERTAINLY do have their mass air curves created on a flow bench (per the OP)...thats how oems do it. (where nearly every combination is identical)

The AFTERMARKET ....changes all that around....you start running one-off combinations of MAF housings/intakes...you change anything that effects flow across the sensor and guess what...your curve is off. There is no feasable way to take my exact intake combination to a flow bench and get exact numbers. So you do what any competant tuner does....you adjust the mass air xfer to correct for these variations. Why would you change the fueling side of things? Those are known/good values?

Again...this is EXACTLY what the most highly regarded tuners do.

The OEM calibrators use a known curve for their exact, repeatable situation.....as soon as that changes it is up to us to make the corrections to the curve for our application. Simple.

Granted, you cant get all willy nilly with the corrections.....I've seen some hacked up maf curves. This is bad. You cant tune around a mechanical issue. But to say that adjusting the MAF xfer is wrong...its well....wrong.

 

[blackshelby]

I'm going to disagree with the majority of this....heres why:

Take for example:

03 cobra, Stock. Only change being a ram air intake.....STILL the stock Maf/housing. Changed the filter b4 the maf and the inlet pipe after the maf. Lets call this a "last gen" popular ram air.

Suddenly..due to a change in laminar air flow charactaristics, my maf curve is off a few percent, not alot, but enough to require a tweak in prp. Now...I havent changed the MAF/Housing (but suddenly the oem values arent 100% correct any longer).

I tweaked this.....as nearly every tuner does, by adjusting the MAF xfer curve in prp. Why on earth would I muck around with fueling/injecters/slopes ect...WHEN that is not what changed?? ...you tweak the variable that changed....airflow.

Value files for injectors are known and are normally rock solid. (yes there are certainly exceptions). MAF's however....due to variences in airlow....manufacture, tolerances in housings and filters can vary a good deal off from their published flow charts. Thats a fact of life.

Granted, this is not how ford tunes a factory car. But my car didnt come with aftermarket mods either. There is no way to use flow bench #'s for a MAF unless it was flowed with your EXACT intake/filter/meter/housing.....and even this....in the actual car...on the road....i bet it would STILL need to be tweaked.

This is how EVERYone tunes...we are talking Rick, Justin, Eric, Don, Herman ....and this is what Greg Banish agree's with as well.

Im 110% sure that others are reading this ....and agree with the accepted method, but dont feel like arguing...

Great example and great example why so many tuners are missing the big picture . Also the same reason why so many tuners have issues with hanging idles, pinging, start up issues etc and don’t understand why........................

I believe that is main point of the Article by the OP. He posted direct quotes made by Ford on the correct method... not a method used by some aftermarket tuners that are maybe close and get you by.
I really doubt these tuners are smarter than the people who designed the system.

It’s pretty plain and simple but wrong to do what you are suggesting as correct or acceptable. (I know those setups very well since I personally tuned hundreds of them, I also sent out that setup to be flowed and the curve is dramatically different compared to the stock setup. I flowed every meter combo that I ever used and created a library of all the transfer curves I obtained for those setups. This ensured they could be used in other cars and have been with zero issues.

Many people you refer to might argue..... why ?? because they were taught that way.... by who? the aftermarket? ( mostly SCT classes) .
If they were taught by the people who designed the system they would be shown why it is wrong and their opinion would change completely. The problem is the aftermarket taught many tuners a short cut. Sometimes you can get away with being close but again it will never 100% prefect.

You say injector slopes are known... but what about fuel pump flow ,fuel line flow, fuel pressure, pressure drop, fuel temp? Fuel pressure will directly affect injector slope values as will pump voltage. These injector slopes are not rock solid and depending on fuel systems. You do not know the correct fuel flow values for the complete system nor do you know if they will stay consistent? Example: What happens when you put a “boost-a-pump in the system? Unless you have every value of known fuel flow thinking you know the injector values alone will simply not cut it.

One could back track and obtain a pretty accurate MAF transfer curve by measuring a/f but one would need to also monitor your complete fuel flow, fuel usage. etc. at the same time.(pretty sophisticated equipment is needed and really should be done in a controlled environment ) You need to be dead on with all your fuel flows from fuel pumps, to fuel pressure etc to back track and that will get you close but never a perfect MAF curve.

The big problem is tuners don’t want to send something out or spend the extra time to do it correctly so they basically take a short cut that is flawed. In the older cars pre 05 this method was fast and could get you close enough were most issues would not be seen. That still doesn’t make it correct just a way to get by/close)

Lets take your example and understand why you have a factory MAF and factory MAF transfer curve which needed to be changed..
Anytime you change the tubing especially in front of the meter itself you change the way the air flows past the sensor (your example of laminar air flow). You basically put a new meter on the car. You changed the way the air goes past the sensor...... you will need a completely new transfer curve because the air is not going straight past the sensor like it did before the tube was placed in front of it.
You are correct about flowing your exact setup to get a real flow curve. Flowing a meter on a flow bench is the way Ford /GM and all tuners who really understand it do it. (they do not do it on the car). Flowing the complete MAF setup on a bench also gives you the full range of the sensor in that MAF housing combo. A full flow range can never be achieved with the method you suggest unless you basically pegged the meter. A mass produced or a “one off” meter should all be calibrated the same way, on a flow bench. There is no reason it cannot be done that way. There are plenty of company’s that offer that type of service for the BEST/ELITE tuners.

When Electronic Throttle Control (DBW) was introduced in 2005 it virtually eliminated the fudge factor tuners were getting away with. Further, now with the new digital meters (frequency sensors) on all 2011 and up cars it is even more critical than ever.

 

[blackshelby]

QUOTE=itzl0l You do realize (you do right?) that no1 buys a Cobrajet and then goes immediately to the track and expects to be competitive in their class. Many of these cars run full standalone ECU's...Bigstuff...fast...whatever. I know Kurgan has tuned his fair share.
You do realize the fastest cobra jet in the country (TASCA Ford ) has gone deep in the seven second zone at 170+ uses the same setup the car was delivered with?
You also realize if the cobra jets want to run and be legal they must retain the setup the way the car was delivered with (IF running NHRA classes)

OEM, mass produced cars like the Shelby's, Roush, Saleens, Focus, Rapors ect (that you named) CERTAINLY do have their mass air curves created on a flow bench (per the OP)...thats how oems do it. (where nearly every combination is identical)
Doesn’t matter if mass produced or one off setups are used all MAF should be calibrated on a flow bench. That is the only true correct method acceptable to calibrator a MAF.

The AFTERMARKET ....changes all that around....you start running one-off combinations of MAF housings/intakes...you change anything that effects flow across the sensor and guess what...your curve is off. There is no feasable way to take my exact intake combination to a flow bench and get exact numbers. So you do what any competant tuner does....you adjust the mass air xfer to correct for these variations. Why would you change the fueling side of things? Those are known/good values?
Who says there is no feasible way to get a one off setup flowed? That is wrong and simply a false statement trying to justify the other method.

Again...this is EXACTLY what the most highly regarded tuners do.
I wouldn’t consider any tuner highly regarded if they are tuning the way you described and neither would the calibrators at Ford think so.

The OEM calibrators use a known curve for their exact, repeatable situation.....as soon as that changes it is up to us to make the corrections to the curve for our application. Simple.
So that justifies calibrating a MAF in a non preferred method?

Granted, you cant get all willy nilly with the corrections.....I've seen some hacked up maf curves. This is bad. You cant tune around a mechanical issue. But to say that adjusting the MAF xfer is wrong...its well....wrong. end QUOTE
I would consider every maf transfer function hacked if not flowed.

 

[iggster]

Great example and great example why so many tuners are missing the big picture . Also the same reason why so many tuners have issues with hanging idles, pinging, start up issues etc and don’t understand why........................

I believe that is main point of the Article by the OP. He posted direct quotes made by Ford on the correct method... not a method used by some aftermarket tuners that are maybe close and get you by.
I really doubt these tuners are smarter than the people who designed the system.

I took classes from greg banish he tunes for the OEMs and the way I tune through MAF is the way he tunes AFTERMARKET cars.

Classes where not cheap eather 1,500 each and its the only way you can unlock features on the pro racer program to tune ETC and transient tables and some other things.


Honestly this topic has allot of misinformation its gonna mislead allot of people.

 

[iggster]

Calibrated Success - Load Bearing Dyno Article


Dunno if it says his background on his web page but he has or does tune for the oems.....

 

[breoland]

I took classes from greg banish he tunes for the OEMs and the way I tune through MAF is the way he tunes AFTERMARKET cars.
.

Im still trying to figure out what you mean by aftermarket cars?

Lets take a for isnstance... 2013 gt500, with a 2.4 pulley, jlt maf, and a ford racing 65mm tb, would this be considered aftermarket? Should it be tuned with the correct mass air transfer curve or should the curve be adjusted by the tuner?