I think you mean "MAF"
Is Your Car Tuned Correctly?
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I think you mean "MAF"
I don't think you have to be Sherlock Holmes to come to the conclusion that this thread was posted to make everyone question the safety of their tunes.
I feel the OP has an agenda by posting this thread.
There are many tuners that haven't the slightest clue what they are doing. I'll go out on a limb and say that the Ford tuners that have an honest handle on proper tuning are probably in the minority.
SCT provides base files for most common setups and there are many SCT dealers that only know how to load these files and have no concept of how the logic actually works. Pretty easy to spot these dealers, because they get stuck when they get a car in that actually requires a little tuning knowledge to properly dial in.
My $.02
I feel the OP has an agenda by posting this thread.
There are many tuners that haven't the slightest clue what they are doing. I'll go out on a limb and say that the Ford tuners that have an honest handle on proper tuning are probably in the minority.
SCT provides base files for most common setups and there are many SCT dealers that only know how to load these files and have no concept of how the logic actually works. Pretty easy to spot these dealers, because they get stuck when they get a car in that actually requires a little tuning knowledge to properly dial in.
My $.02
I dunno about where you live but around here in so cal I have yet to meet a tuner that didnt have a clue what they are doing.
I know just loading the files sct gives us on my setup the car barely even runs and stalls out like crazy. I have had RET, SWANSON, power train dynamics work on my car and now I do all the tuning and I can say they all have an honest handle on tuning. I asked questions and lots of them every time I took my car in and they all seem to know what they where doing, but that was before I did any tuning lol
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And create business...
I agree with Eric and Shaun, dcalson, ITZ101 and Ryan. Some of these guys are all at the top of their game in the tuning world. The OP presents some really good info, tainted with typical internet misinformation. Kinda like some political commentators, present a mix of good facts with BS to convince and scare people.
I'd love to see someone flow bench my SCT BA5000 maf in a 3.5" tube. but it'll have to have the procharger f1a, big red open bypass valve, and intercooler as well so I can get an accurate maf model for my car. lol. challenge OP?
Gentlemen,
As much as I enjoy seeing science posted (especially if I am the one being referenced!), it's important to avoid showing only that part that may be convenient to one's underlying cause. I won't get dragged into the "who's a better tooner" debate, so I'll stick to some facts about calibration.
1) Given an EXACT maf curve from a certified flow bench, I would prefer to use it in the calibration and not touch it. The trick here is that you must believe the calibration of the bench and make sure you test the entire inlet system from filter to throttle body if you want 100% accurate data. This is often just not an option in the aftermarket. Testing only the MAF housing and then installing it at a different angle, pipe layout, or location negates all that good work and just has you working based on bad ASSumptions. Be careful, but it can save a lot of time later if this is correct in the beginning.
2) Solving for MAF on a running engine is still a valid method. It doesn't matter if you're working toward a MAF sensor transfer function or a VE table, the science is IDENTICAL. However, this has a few requirements that MUST be correct if you are to get good data. You MUST know fuel flow. In an OEM engine dyno lab, we have fuel flow meters on the line feeding the engine and a set of exactly nominal fuel injectors that were hand selected from the supplier. If you know the exact relationship between ms of injector pulsewidth and mg of fuel delivery on that shot, you can effectively use the injectors to "meter" the fuel flow by monitoring INJPW. Incidentally, we have fuel injector flow test standards just the same as we do for the MAF. Anyone looked at SAEJ1832 recently?
Simply put: (fuel flow)*AFR = MAF <---Anybody want to challenge this?
As long as you have valid fuel flow assumptions, you can indeed solve for MAF, g/cyl or VE on the fly. This makes the "aftermarket" method acceptable as long as you start with good fuel flow data, which MUST include proper injector data for both linear and non-linear flow ranges as well as offset compensation for both voltage and pressure. So many guys miss this and just start tooning with bad ASSumptions about cheap injectors and bake errors into the MAF or VE.
3) As I mentioned above, injectors can be just as variable as the cold air kit/MAF placement. Yes, random production injectors can be all over the place on flow. The factory tolerance is +/-6%! This is why I strongly recommend starting with good known flow matched injector sets on high performance applications. In many cases, there is a valid argument for adjusting injector slopes in a vehicle calibration, but starting with flowed/characterized injectors prevents this just the same as a flow bench does for the MAF and intake assembly.
If you know the MAF data from the bench, and the fuel injector data from a bench, chances are that you don't have much work at all to do when the engine calibration is performed. We don't usually get this lucky in the aftermarket. It currently seems that injector data is a little easier to get from a good supplier (take Injector Dynamics, for example) than MAF curves for your unique vehicle intake. So the calibrator needs to figure out where he thinks the errors lie and recalibrate the ECU accordingly.
So what does this mean?
It means that there is indeed more than one valid calibration method. However, both methods (if they're done right) should come to the SAME solution. That's right, you should end up with the same MAF transfer function whether it was derived on a certified flow bench or if it was solved for in the vehicle as long as the other assumptions were properly addressed. If you get the "right" MAF curve either way, load is by definition correct, and so is the torque model (all else being correct). On a modified car, you will still need to do plenty of ETC control calibration, but all of that cannot even start until you have confidence in your MAF reading and load calculation.
I've lost count of how many engines I have tuned either way. The trick is to follow the rules and make sure you are aware of your "knowns" in either case. Properly done, changes in weather or baro should not alter AFR control, knock control, driveability, or ETC safety.
Greg Banish
Calibrated Success, Inc.
As much as I enjoy seeing science posted (especially if I am the one being referenced!), it's important to avoid showing only that part that may be convenient to one's underlying cause. I won't get dragged into the "who's a better tooner" debate, so I'll stick to some facts about calibration.
1) Given an EXACT maf curve from a certified flow bench, I would prefer to use it in the calibration and not touch it. The trick here is that you must believe the calibration of the bench and make sure you test the entire inlet system from filter to throttle body if you want 100% accurate data. This is often just not an option in the aftermarket. Testing only the MAF housing and then installing it at a different angle, pipe layout, or location negates all that good work and just has you working based on bad ASSumptions. Be careful, but it can save a lot of time later if this is correct in the beginning.
2) Solving for MAF on a running engine is still a valid method. It doesn't matter if you're working toward a MAF sensor transfer function or a VE table, the science is IDENTICAL. However, this has a few requirements that MUST be correct if you are to get good data. You MUST know fuel flow. In an OEM engine dyno lab, we have fuel flow meters on the line feeding the engine and a set of exactly nominal fuel injectors that were hand selected from the supplier. If you know the exact relationship between ms of injector pulsewidth and mg of fuel delivery on that shot, you can effectively use the injectors to "meter" the fuel flow by monitoring INJPW. Incidentally, we have fuel injector flow test standards just the same as we do for the MAF. Anyone looked at SAEJ1832 recently?
Simply put: (fuel flow)*AFR = MAF <---Anybody want to challenge this?
As long as you have valid fuel flow assumptions, you can indeed solve for MAF, g/cyl or VE on the fly. This makes the "aftermarket" method acceptable as long as you start with good fuel flow data, which MUST include proper injector data for both linear and non-linear flow ranges as well as offset compensation for both voltage and pressure. So many guys miss this and just start tooning with bad ASSumptions about cheap injectors and bake errors into the MAF or VE.
3) As I mentioned above, injectors can be just as variable as the cold air kit/MAF placement. Yes, random production injectors can be all over the place on flow. The factory tolerance is +/-6%! This is why I strongly recommend starting with good known flow matched injector sets on high performance applications. In many cases, there is a valid argument for adjusting injector slopes in a vehicle calibration, but starting with flowed/characterized injectors prevents this just the same as a flow bench does for the MAF and intake assembly.
If you know the MAF data from the bench, and the fuel injector data from a bench, chances are that you don't have much work at all to do when the engine calibration is performed. We don't usually get this lucky in the aftermarket. It currently seems that injector data is a little easier to get from a good supplier (take Injector Dynamics, for example) than MAF curves for your unique vehicle intake. So the calibrator needs to figure out where he thinks the errors lie and recalibrate the ECU accordingly.
So what does this mean?
It means that there is indeed more than one valid calibration method. However, both methods (if they're done right) should come to the SAME solution. That's right, you should end up with the same MAF transfer function whether it was derived on a certified flow bench or if it was solved for in the vehicle as long as the other assumptions were properly addressed. If you get the "right" MAF curve either way, load is by definition correct, and so is the torque model (all else being correct). On a modified car, you will still need to do plenty of ETC control calibration, but all of that cannot even start until you have confidence in your MAF reading and load calculation.
I've lost count of how many engines I have tuned either way. The trick is to follow the rules and make sure you are aware of your "knowns" in either case. Properly done, changes in weather or baro should not alter AFR control, knock control, driveability, or ETC safety.
Greg Banish
Calibrated Success, Inc.
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This is some of the most mis-leading and false information regarding tuning that I have ever personally witnessed in public display.
According to Larocca's "blackshelby" method the Airflow remains the constant and only the injector data will be altered... This is 100% false...
I have dozen upon dozen of flow sheets from different MAF's and they are all different as the consistency among them is within 7-10% at best.
The MAF is the single most inconsistent sensor on the vehicle due to its construction and design. We see older 100% stock vehicles with the fueling off up to 7% or more very frequently and this trend follows the MAF.
It is not possible to correctly calibrate a vehicle without altering the most in-accurate and in-consistent sensor in the process.
While I agree the in a perfect world every MAF and Inlet assembly would be flowed and tested this just isn't possible due to time and financial constants. Therefor the next best alternative is using the Fuel System as a constant and tweaking the MAF on an individual basis to dial in fueling.
Example with 2 2003 Cobras with the exact same and very common mods....
Test Vehicle:
JLT CAI
SCT-2400 MAF
Stock Injectors
BAP
2.76 upper
Everything else is unmodified.
If you swap MAF's from one vehicle to the other the calibration will most certainly change....if you swap injectors the calibration will be very very close
No one in the industry will argue the facts that I just presented and this exact combination has been done hundreds of times....
Another example to falsify the previous claims....
Stock 2003 Cobra with the same mods as above with Stage 3 Camshafts.... this vehicle will have revision due to the overlap in the cam profile and will require changes to the Air Model to compensate. Regardless of what the Flow bench tells you about the transfer function when it is on a vehicle with a very low vacuum signal that has inlet revision and the heated elements are not being cooled in the same manner as a constant flow on the bench it will skew the results.
There are most certainly applications where slope tuning would be a preferred method of calibration but to say "never touch the MAF transfer" is incorrect and mis-leading information.
According to Larocca's "blackshelby" method the Airflow remains the constant and only the injector data will be altered... This is 100% false...
I have dozen upon dozen of flow sheets from different MAF's and they are all different as the consistency among them is within 7-10% at best.
The MAF is the single most inconsistent sensor on the vehicle due to its construction and design. We see older 100% stock vehicles with the fueling off up to 7% or more very frequently and this trend follows the MAF.
It is not possible to correctly calibrate a vehicle without altering the most in-accurate and in-consistent sensor in the process.
While I agree the in a perfect world every MAF and Inlet assembly would be flowed and tested this just isn't possible due to time and financial constants. Therefor the next best alternative is using the Fuel System as a constant and tweaking the MAF on an individual basis to dial in fueling.
Example with 2 2003 Cobras with the exact same and very common mods....
Test Vehicle:
JLT CAI
SCT-2400 MAF
Stock Injectors
BAP
2.76 upper
Everything else is unmodified.
If you swap MAF's from one vehicle to the other the calibration will most certainly change....if you swap injectors the calibration will be very very close
No one in the industry will argue the facts that I just presented and this exact combination has been done hundreds of times....
Another example to falsify the previous claims....
Stock 2003 Cobra with the same mods as above with Stage 3 Camshafts.... this vehicle will have revision due to the overlap in the cam profile and will require changes to the Air Model to compensate. Regardless of what the Flow bench tells you about the transfer function when it is on a vehicle with a very low vacuum signal that has inlet revision and the heated elements are not being cooled in the same manner as a constant flow on the bench it will skew the results.
There are most certainly applications where slope tuning would be a preferred method of calibration but to say "never touch the MAF transfer" is incorrect and mis-leading information.
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blackshelby
New Member
Misleading........
I really believe you miss quoted me, or want people to believe something else was quoted that wasn't.
In fact my beliefs agree with Greg's. and some others here.
I believe in real air flow data .(Like Ford) That's a fact...... no arguing there.
I will not do it any other way, it is the most accurate way.
Not to mention is actually easier to do it that way.
I use the flow bench for transfer function's and only the flow bench.
Done it that way for the past 20 plus years .(I learned this method directly from the Ford engineer who actually designed the systems for Ford. )
I do it this way for many reasons... all inline why Ford does it.
One reason, in a car its basically impossible to know what your completed fuel system flow is.
You have a BAP in the two cars you used for an example.... do you know what your fuel flow is in both cars ?? I doubt it .........
So you have fuel flow differences but you go and change a MAF transfer curve or say it is the MAF?
You must understand the complete fuel flow/system from pumps to injectors and everything in-between it, if you want to even try to back into figuring out a unknown meter curve. If not you will make a correction to your MAF/airflow for an unknown value in your fuel system. Some want to believe moving a MAF curve is the fix all and never even think about fuel. This is usually the same people that believe it is ok to adjust the MAF curve for nothing more than a A/F ratio.
Starting with a real transfer function not only gives you the COMPLETE FULL RANGE of the MAF something that is basically impossible to do in a car it will also insure your load calculations are correct.
MAF being incorrect will effect load along with many other things.. Making a change to your fuel system to correct your A/F will not. Especially when you start with known data for you MAF......................
As for CAI being off 7-10 percent well maybe depending what CAI type you are using...
I flowed many different Ford meters housing including sensors and never seen them vary even close to what you stated.
The design of the MAF/Housing and sensor type makes a huge difference.
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Assuming you have good injector data, fuel flow is easy. (Injector size x number of injectors) / 60 will give you fuel flow in #/min.
oke:Jimmy, I will agree that it would be convenient to have all of this data on each and every car we tune, but that just isn't realistic. Sure Ford does this type of stuff, Ford has a handful of calibration engineers that work on one car for months and months at several powertrain testing facilities in different climates. Do you take each car you tune all over North American adjusting the calibration until it is perfected to the .00000001 %?
And how about a blow thru MAF setup with a Procharger? Surely you aren't flowing those on a bench for the purpose of tuning a customers hotrod.
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FYI - On the example Bobcat gave, 03/04 Cobras have electronic returnless fuel systems. A BAP increases voltage to the fuel pump but Ford's excellent control system still attempts to keep the delta-P at a constant preset level - in the case of an AMZ2 - 39. delta-P will only change (assuming you have properly calibrated the FPVT) if you hack the 'Desired Pressure Drop Across the Injectors' function to get more headroom for inadequate injector size. And this should just be used as a temporary measure until adequate, good injectors can be installed. In other words - if done correctly BAPs do not normally affect delta-P (which is the important part of the puzzle, not fuel pressure), just pump capacity.
So if you calibrate it properly and log the right PIDs - you know for sure the delta-P is the same as factory. Yes, flow to the injectors will increase from the pump(s) but delta-p will be maintained. That's why you add a BAP to begin with. It's important not to confuse a BAP with with an FMU used on a return style fuel system which DOES increase fuel pressure directly to the injectors. Completely different animals.
In Bobcat's example the only real unknown is the air model.
Hope this helps!
Don
So if you calibrate it properly and log the right PIDs - you know for sure the delta-P is the same as factory. Yes, flow to the injectors will increase from the pump(s) but delta-p will be maintained. That's why you add a BAP to begin with. It's important not to confuse a BAP with with an FMU used on a return style fuel system which DOES increase fuel pressure directly to the injectors. Completely different animals.
In Bobcat's example the only real unknown is the air model.
Hope this helps!
Don
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blackshelby
New Member
Assuming you have good injector data, fuel flow is easy. (Injector size x number of injectors) / 60 will give you fuel flow in #/min.
Remember fuel pressure will affect injectors.
Pressure will vary with fuel pump flow.
Voltage also affects fuel pump flow.
Boost pressure changes fuel pump flow since fuel pressure needs to be raised at least 1 psi for 1 pound of boost if you want injector to stay consistent. Higher the pump pressure less flow
Fuel system are not consistent
.
I dont think anyone would disagree that real airflow data is the way to go. The issue becomes when something changes and you only want to use that data. For example, put a ram air hood on and the car starts to lean out at wot because the path across the meter changes. Your flow bench will not compensate for that and your load values WILL be incorrect. Now granted that would be a hardware change that caused the issue and the correct fix would be to fix the hardware but if you didnt catch it and left the data you copied and pasted from the flow bench, the pcm would have an improper load calculation using your method.
He mentioned an 03 cobra with stock injectors and a bap. If the bap is pre-fpdm, then the pcm still regulates the rail to 39psi. There is no reason you cant back calculate the airflow values from there since nothing is working different than stock. You are not introducing any fueling errors into the equation with a bap that way. The only thing off on those two scenarios he mentioned would be the maf curve and doing it the way Greg mentioned would ensure load calculations would be correct.
You are exactly correct here. It is not the end all be all or magic fix for fueling. However simply inputting data like you say is not the end all be all either and that is what most people here are disagreeing with you on.
It is a good and preferred starting point but not impossible. Greg already explained how it is done.
The key is the tuner needs to recognize and understand where the fueling error is coming from and that is where most fall short. If it is a 3 or 4% fueling error, putting that extra fuel into the maf isnt going to hurt a thing but you correct what needs correct. You dont simply just add it to the maf because it is there. I think that is the point you are trying to make but the way you are presenting it is that if someone adjust the maf other than the way you do it then they are doing it wrong which is simply inaccurate.
Well, if you input your flow bench data and you have an intake that is 7-10% off from your flow bench data, then you just affected your load by the same margin......Im assuming you do realize this right?
We have the injector data that has the pressure multipliers, and there has been a Injection Pressure Sensor on the Mustangs from 99-2010
That pretty much covers it.
Yes fuel pressure will affect the injectors. That is why Ford models the pressure characteristics of the injector in the pcm......Since he is using stock injectors this data is already correct and adding the bap will not affect it.
Hopefully you realize that the returnless systems maintain a target rail pressure, in the o3 cobra it would be 39 psi and the pcm compensates for the boost pressure keeping the injector consistent. Now several other things have to be correct in the pcm for this to work properly but that is what it is there for.
Remember fuel pressure will affect injectors. True - on a return style fuel system, but on an electronic returnless system as in the examples, False.
Pressure will vary with fuel pump flow. True, but the control system will maintain the same delta-P, i.e. pressure drop across the injectors. So as far as the injectors are concerned, pressure they see is the same as when it was driven out the factory doors.
Voltage also affects fuel pump flow. True, but the control system will maintain the same delta-P.
Boost pressure changes fuel pump flow since fuel pressure needs to be raised at least 1 psi for 1 pound of boost if you want injector to stay consistent. True, but the control system will maintain the same delta-P. We are not talking Fox body with a return fuel system here.
Higher the pump pressure less flow True, but the control system will maintain the same delta-P.
Fuel system are not consistent Not true. If calibrated properly, yes, in fact delta-P will stay rock solid.
Didn't I already say all that? Don't mind repeating myself so everyone has a good grasp of what goes on! Education is the key to understanding!
Hope this clears up confusion.
Don
Pressure will vary with fuel pump flow. True, but the control system will maintain the same delta-P, i.e. pressure drop across the injectors. So as far as the injectors are concerned, pressure they see is the same as when it was driven out the factory doors.
Voltage also affects fuel pump flow. True, but the control system will maintain the same delta-P.
Boost pressure changes fuel pump flow since fuel pressure needs to be raised at least 1 psi for 1 pound of boost if you want injector to stay consistent. True, but the control system will maintain the same delta-P. We are not talking Fox body with a return fuel system here.
Higher the pump pressure less flow True, but the control system will maintain the same delta-P.
Fuel system are not consistent Not true. If calibrated properly, yes, in fact delta-P will stay rock solid.
Didn't I already say all that? Don't mind repeating myself so everyone has a good grasp of what goes on! Education is the key to understanding!
Hope this clears up confusion.
Don
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BTW - If anyone would like really good, in depth knowledge on how this all works, Greg Banish, who posted here has an excellent tuning DVD and he also presents terrific advanced Ford Tuning Courses. There is also some guy, LaSota or something like that that sells Ford Tuning books that go into all this.
Hehe....yea....i have some of those LaSota books that fella wrote
I learned to tune reading those and some of the books by Banish and the prp software i bought from LaSota ....best thing I ever did
I really recommend every1, at the least, learn what is going on....read the readily available information that is out there. It seems overwhelming at 1st but once it "clicks" its like a light bulb goes off. I fully recommend tuning yourself... Data logging and making changes to YOUR car on the street and then seeing those changes directly effect how the car runs/drives is an amazing thing. Start slow, ask questions...you arent gonna blow it up.
Scott
I learned to tune reading those and some of the books by Banish and the prp software i bought from LaSota ....best thing I ever did
I really recommend every1, at the least, learn what is going on....read the readily available information that is out there. It seems overwhelming at 1st but once it "clicks" its like a light bulb goes off. I fully recommend tuning yourself... Data logging and making changes to YOUR car on the street and then seeing those changes directly effect how the car runs/drives is an amazing thing. Start slow, ask questions...you arent gonna blow it up.
Scott
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eficalibrator It means that there is indeed more than one valid calibration method. However said:
Thanks Greg for clearing this up.
I was thinking dsm maybe I didn't pay attention in the classes or something lol or from all the books I've read,.
I am not 100 percent sure but I think if any tuner that wants to become advance certified has to take one of gregs classes if I remember correctly. So he obviously knows what he is talking about.
Now if only sct could give us good values for the 80lb injectors and hpx pmax then all would be good :/ I know the 80s have flaws a topic over in the pro racer forum has been going on for quite some time
I know vmp doesn't like tuning with them and other tuners and I know Steve over at power train hates the hpx pmax.
The dvd is really good but I like the lasota book cause whenever I forget something I just open it up on my laptop and bam most of the time I get an answer both very in depth and worth every penny
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