That's a pretty thread OP. Lots of colors. I like colors. Do you actually tune cars or do you just tell everyone that their tune is not done right? If you tune, why don't you become a paid vendor and start selling tunes?
Is Your Car Tuned Correctly?
- Thread starter 91svtbird
- Start date
So what your saying is if you tune the maf transfer to match commanded air/fuel, load and spark could be off???
The bible for sct tuning ?
SCT EFI Tuning Guide
SCT EFI Tuning Guide
its others like myself suggesting people to go to so they can get a tune done correctly. the OP is educating people on what to look for. he hasnt suggested anybody from what i understand. be a paid vendor to share information? great idea!!!:burn:
Good read OP
Comprehension of english. Very important! Not everyone is equipped with it
Comprehension of english. Very important! Not everyone is equipped with it
Correct
So how would i know if my load and spark was right? I dont have or know anyone who tunes with a flow bench.
being that I am a self taught amateur tuner using SCT PRP I have a few questions.
1. isn't tuning the maf curve via datalogged info the same as obtaining flow data from a work bench.
2. if you were to use a flow bench method what is to say that the data will hold true in the vehicle? I have seen 1/8 of a turn on a maf housing take a perfectly running car to not able to start even. and I'm talking about slot mafs, much less a non slot maf.
3. I understand the theory behind changing injectors slopes etc, just like on standalone systems, but those systems also work with VE tables that maf based systems don't have- so isn't that where the maf tables come in? thanks
1. isn't tuning the maf curve via datalogged info the same as obtaining flow data from a work bench.
2. if you were to use a flow bench method what is to say that the data will hold true in the vehicle? I have seen 1/8 of a turn on a maf housing take a perfectly running car to not able to start even. and I'm talking about slot mafs, much less a non slot maf.
3. I understand the theory behind changing injectors slopes etc, just like on standalone systems, but those systems also work with VE tables that maf based systems don't have- so isn't that where the maf tables come in? thanks
Well you can buy a Ford tune and feel safe however I would guess- guess is just that a guess on my part- the Ford tune could be tweaked a little however Ford Racing does not even like a pulley change. So someone out there must know how to get the most out of a Ford tune map and offer it to those of us who do not want to live in the twilght zone yet want to safely manage our mods to a safe tune. Most of the newer mustangs are already fast as standards go and a little help from a tune can add to the fun.
for
for
tune correctly but by whom
Well you can buy a Ford tune and feel safe however I would guess- guess is just that a guess on my part- the Ford tune could be tweaked a little however Ford Racing does not even like a pulley change. So someone out there must know how to get the most out of a Ford tune map and offer it to those of us who do not want to live in the twilght zone yet want to safely manage our mods to a safe tune. Most of the newer mustangs are already fast as standards go and a little help from a tune can add to the fun.
for
Well you can buy a Ford tune and feel safe however I would guess- guess is just that a guess on my part- the Ford tune could be tweaked a little however Ford Racing does not even like a pulley change. So someone out there must know how to get the most out of a Ford tune map and offer it to those of us who do not want to live in the twilght zone yet want to safely manage our mods to a safe tune. Most of the newer mustangs are already fast as standards go and a little help from a tune can add to the fun.
for
You don't "tune" off a flow bench. A professional flow bench is used only to obtain accurate transfer functions for the particular meter tube, sensor combo.
Once the new CAI combo is installed on your car those transfer functions then would be inserted in the tuning tables in the PCM by whomever is tuning the car.
Note: Once you have that accurate flow data (transfer curve) for a particular CAI combo that data can then be used in any car using that MAF combo.
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encasedmetal; being that I am a self taught amateur tuner using SCT PRP I have a few questions.
1. isn't tuning the maf curve via datalogged info the same as obtaining flow data from a work bench.
Absolutely not the same. A flow bench measures actual air flow and plots it in terms of voltage or frequency depending on what type of sensor you are using. You are only looking at the MAF. The flow bench is only used to obtain a real and actual transfer functions for that particular MAF housing combo.
When Data-logging you are looking at voltage and RPM and you are changing the transfer functions to adjust for desired air fuel. By doing so you are telling the engine it is moving either more or less air than it actually is. By doing this you are not really taking into consideration all of your fuel system's flow. (which can affect your A/f ratios)
Load is directly related to "Airflow" if the airflow reading is not accurate the load tables will never be correct.
2. if you were to use a flow bench method what is to say that the data will hold true in the vehicle? I have seen 1/8 of a turn on a maf housing take a perfectly running car to not able to start even. and I'm talking about slot mafs, much less a non slot maf.
You will see that more if you have a "bend" in front of the meter which will change the way the air goes past the sensor depending on the position of the bend. In this case you would have to have that setup flowed in the exact position you are running it in the car. Then it would be fine.
A straight through meter doesn't have this issue because you are not changing how the air goes past the sensor.
3. I understand the theory behind changing injectors slopes etc, just like on standalone systems, but those systems also work with VE tables that maf based systems don't have- so isn't that where the maf tables come in? thanks
Mass Air is actual air flow VE is speed density which is not actual air flow. Two totally different systems. Different discussion..
1. isn't tuning the maf curve via datalogged info the same as obtaining flow data from a work bench.
Absolutely not the same. A flow bench measures actual air flow and plots it in terms of voltage or frequency depending on what type of sensor you are using. You are only looking at the MAF. The flow bench is only used to obtain a real and actual transfer functions for that particular MAF housing combo.
When Data-logging you are looking at voltage and RPM and you are changing the transfer functions to adjust for desired air fuel. By doing so you are telling the engine it is moving either more or less air than it actually is. By doing this you are not really taking into consideration all of your fuel system's flow. (which can affect your A/f ratios)
Load is directly related to "Airflow" if the airflow reading is not accurate the load tables will never be correct.
2. if you were to use a flow bench method what is to say that the data will hold true in the vehicle? I have seen 1/8 of a turn on a maf housing take a perfectly running car to not able to start even. and I'm talking about slot mafs, much less a non slot maf.
You will see that more if you have a "bend" in front of the meter which will change the way the air goes past the sensor depending on the position of the bend. In this case you would have to have that setup flowed in the exact position you are running it in the car. Then it would be fine.
A straight through meter doesn't have this issue because you are not changing how the air goes past the sensor.
3. I understand the theory behind changing injectors slopes etc, just like on standalone systems, but those systems also work with VE tables that maf based systems don't have- so isn't that where the maf tables come in? thanks
Mass Air is actual air flow VE is speed density which is not actual air flow. Two totally different systems. Different discussion..
In response to our convo: would it be better to datalog the air #/min and adjust that way? guess you would need ad counts o volts as well to know where to adjust though.
also- to add to this- if you're saying that the value files for mafs in say SCT PRP aren't accurate- then where do they come from? or are you saying that they are to be left alone once loaded?
Once you load the accurate transfer functions in the tune you should not touch them period.
I'm not going to say which SCT files are accurate or not. It's the tuners responsibility to be sure he is using correct data derived from a professional flow bench.
my first question was kinda aimed at saying "if you don't have access to a flow bench" can you just load the value file for the maf, then datalog air in #/min in livelink and compare?
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
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
understood. thanks. It really irks me that no one has put out software that will tune the car itself. I know it's possible.
Very informative, even if I didn't understand it all. I haven't 'tuned' a car since I had to adjust points! But I WILL check with my tuner.
Thank you OP !
Thank you OP !
This thread definitely needs a sticky !
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