BOSS APPROVED!
I just found out..
It is a MAF tune. I bought the car Last January and the guy I bought it from did all the work, I drove it on and off for a month or so then the clutch and trans went so it was down all summer, I got everything put back together and drove it twice, and the last time I had it out I noticed the narrow band air/fuel guage was all over the place so I started asking some questions, the guy I bought it from said it had been tuned by nelson performance, well I just got a hold of them yest and they told me that the tune on the car was for an sts kit wich is what the guy told me he had on the car before the procharger and they also said that they locked the pcm , what does this mean? Can I even drive the car?
I don't understand, how come SD is different? I have an SD tune on mine from the old pulley but I assume I need a retune since I downsized now?
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A SD tune will recalculate for the amount of boost being forced in, a maf tune does not recognize boost unless you tell the computer that its there, someone correct me if Im wrong
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Verdad Gallardo A MAF tune has no concept of boost. In PE/WOT mode, it uses the value measured from the MAF sensor to index into the MAF table. It uses that value from the table along with with the PE multiplier from the PE table for the current RPM to calculate how much fuel to be delivered. This is why MAF tunes are 'bad' for FI application. Once the MAF is maxed out, the amount of fuel being delivered is pretty much based on the PE table. If conditions change like weather, the AF ratio will be way off. For example, the weather gets colder, allowing the intake charge to become more dense with more O2, and it will make the car run lean because not enough fuel is being delivered.
Speed Density is from your MAP sensor. your map sensor stands for manifold absolute pressure. It works on "psi" if you will and for your setup with know what to fuel it as long as it has been tuned to do so. So if you have been tuned to 10psi on a setup and only change boost levels below 10psi then you are good. Now if you go above 10psi like 12or 13psi it won't have know what to do because essentially you are in no man's land and unchartered territory for that setup. Now if you start changing components i.e. (headers, heads, yada, yada) then obviously that 10psi is a different relation to cfm.
A MAF sensor is a mass air flow and does not work off of pressure. This is why it gets skewed after 6-8psi because it finds it hard to count the O2 coming in. Imagine trying to count cars going 25mph on a side street. You could probably do it. Now try to count cars on a busy highway that is going 75mph with 200% more cars. Much harder to do. I'm no scientist but this is the dumbed down version of how to explain it.
A MAF sensor is a mass air flow and does not work off of pressure. This is why it gets skewed after 6-8psi because it finds it hard to count the O2 coming in. Imagine trying to count cars going 25mph on a side street. You could probably do it. Now try to count cars on a busy highway that is going 75mph with 200% more cars. Much harder to do. I'm no scientist but this is the dumbed down version of how to explain it.
A MAF tune has no concept of boost. In PE/WOT mode, it uses the value measured from the MAF sensor to index into the MAF table. It uses that value from the table along with with the PE multiplier from the PE table for the current RPM to calculate how much fuel to be delivered. This is why MAF tunes are 'bad' for FI application. Once the MAF is maxed out, the amount of fuel being delivered is pretty much based on the PE table. If conditions change like weather, the AF ratio will be way off. For example, the weather gets colder, allowing the intake charge to become more dense with more O2, and it will make the car run lean because not enough fuel is being delivered.
Beat me to it by seconds but we explained it a little different.. Nice draw!!
