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"The MAF sensor will compensate for your mods".
No, it wont. It will accept mods, including boost a lot easier than a MAP sensor setup did, because the computers are programmed with the ability to read boost values and higher airflow through the MAF sensor. However, the computer is programmed with hard set tables for the MAF sensor inputs to be converted to g/sec of air. The problem with thinking that the computer will tune itself is that it really doesn't tune. It just adjusts to keep the engine running.
If you are lean, you will have knock, which the knock sensor will pick up and then the computer will retard your ignition timing. This isn't tuning your spark table, its killing your performance. Its not tuning your fuel tables, its catching up and trying to learn. However, all its really learning is that you have KR at x amount of air and need x amount more fuel. Tuning would be telling the computer what it needs to give the engine the right amount of fuel and then see what your ignition needs to be set at.
Stock setups aren't even perfect. This is why you can gain power from a tune on a stock motor (kinda obvious right?). If its not perfect or damn close on a stock motor, it can't have a chance when you start to mod. Stock 01 grand am had 5-8 degrees KR and LTFT (thats long term fuel trim, or the BLM for those that have messed with OBD1) of what was supposedly -2 to +5%. Funny thing happens when you start to adjust it though. It gets further off. It went from wanting 5% more fuel in some areas to wanting another 10%! How can that be? Perhaps the KR it was getting was making the fuel requirement less. How will it fix itself if its compensating fuel and spark when fuel was the main factor? Granted it still had KR but it went down as fuel was added, accelerator fuel added, and PE kick in vs TPS % reduced. If you don't understand that, ill put it simply. It wasn't tuned for stock in stock form.
If you are reading this, and happen to be thinking about a first mod, let me make a suggestion. Make sure you can tune your car, or have it tuned before you do anything. I'm not saying you are gonna blow your motor with a cold air intake. I'm saying you aren't going get the most out of it without the ability to tune.
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Channel: Myths
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Channel: Myths
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Channel: Myths
05-31-2010, 05:30 PM -
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by bszopiThere are several different versions of this myth floating around.
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Channel: Myths
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Channel: Myths
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by bszopiIAT stands for Intake Air Temperature. It is a simple thermistor that changes its resistance according to the temperature it is at. The idea beind this modification, is that by changing the resistance to that of a cooler interpreted reading, you will get more fuel. While it is true that you will dump more fuel...its false that this is a good idea. Running rich is bad for performance, so you are just wasting your time with adding more fuel in this fashion. ...
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Channel: Myths
05-31-2010, 05:07 PM -
problem was that due to the extended RAM not being NV, every time the key went off, the data was lost, so if you wanted to have the PCM learn on it's own with something like 128 or 256 BLM cells, you needed to dump that data before key-off, apply it to the calibration and burn it. otherwise, you would just have a bunch of BLM cells that don't retain data after key-off. while it would work and be considered self-tuning, it would have to relearn every time you start the engine.
if you used NVRAM(or somehow converted the existing RAM to NV), then at key-off, you could run through a subroutine that would take all of the BLM cells, apply correction to existing VE tables, save those to the NVRAM area and run off of that. that would certainly be self-tuning and effective at that. every time you shut the engine down, new VE tables would be generated automagically. just be sure that your O2 sensor doesn't get bad enough to start reporting false readings and you'll never have to touch a VE table beyond an initial guess.
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