Which N/A induction pieces work better with PCM learning?
Thread Starter
Joined: Jan 2002
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From: Casselberry FL
Which N/A induction pieces work better with PCM learning? I just put on a ported TB, and I don't understand the logic on why a ported/epoxied TB would need time for the PCM to adapt. I've heard the porter recommends driving time to gain the full benefit.
I call <img border="0" alt="[bullshit]" title="" src="graemlins/gr_bs.gif" /> , unless someone can elaborate here. FWIW, I "gained" 3RWHP by dynoing stock TB, swapping to ported version, and immediately re-dynoing. Very disapointed compared to people posting 6-10RWHP gains on HCI engines, and my "gain" was all above ~5000RPM.
I call <img border="0" alt="[bullshit]" title="" src="graemlins/gr_bs.gif" /> , unless someone can elaborate here. FWIW, I "gained" 3RWHP by dynoing stock TB, swapping to ported version, and immediately re-dynoing. Very disapointed compared to people posting 6-10RWHP gains on HCI engines, and my "gain" was all above ~5000RPM.
Launching!
Joined: May 2002
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From: Podunk, VA
Re: Which N/A induction pieces work better with PCM learning? The PCM basically controls fuel and timing. It makes the determination of how it is supposed to do its job by also gatherign data about how the car is running . It needs to get a general "average" based on a certain amount of data so it knows it is delivering the optimal amount of fuel and timing. Basically its trying to relearn how to perform its engine management functions optimally.
The key here is it needs a big enough sample of data in order for it to stop readjusting itself all the time in order to find its "sweet spot".
That is basically the easiest way I can explain it. The reason your probably not seeing the gains is that it doesnt know (yet) what the correct fuel/timing should be in order to run optimally. You just have to give it some time and drive it 50 or so miles so it can get a large enough sample for its PCM algorithms.
The reason your not seeing the gains when you put the new TB immediately is that the computer is running based on the data on the airflow from the previous TB. It just needs to make more adjustments based on the additional airflow in order to get back to its "sweet spot'
Does that make sense to you?
<small>[ September 15, 2002, 03:41 AM: Message edited by: cobray ]</small>
The key here is it needs a big enough sample of data in order for it to stop readjusting itself all the time in order to find its "sweet spot".
That is basically the easiest way I can explain it. The reason your probably not seeing the gains is that it doesnt know (yet) what the correct fuel/timing should be in order to run optimally. You just have to give it some time and drive it 50 or so miles so it can get a large enough sample for its PCM algorithms.
The reason your not seeing the gains when you put the new TB immediately is that the computer is running based on the data on the airflow from the previous TB. It just needs to make more adjustments based on the additional airflow in order to get back to its "sweet spot'
Does that make sense to you?
<small>[ September 15, 2002, 03:41 AM: Message edited by: cobray ]</small>
Launching!
Joined: May 2002
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From: Podunk, VA
Re: Which N/A induction pieces work better with PCM learning? The PCM is going to have to adjust because now the TB is different. So the MAF reads the air in, so what? Theres more air because of a bigger TB which means more fuel is needed and the PCM is going to have to adjust for that. The entire system works together as a whole.
Thread Starter
Joined: Jan 2002
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From: Casselberry FL
Re: Which N/A induction pieces work better with PCM learning? Well, no, not really. It's the MAF which calculates the airflow based upon the heat measured from the MAF wires.
The air has already been measured by the MAF before it enters the throttle body...?
The air has already been measured by the MAF before it enters the throttle body...?
