LTFT and WB O2 MAF settings
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Burning Brakes
Joined: Nov 2008
Posts: 862
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From: Gaithersburg MD
LTFT and WB O2 MAF settings
Just learning about tuning and cant figure out LTFT effect on WB 02 tuning.
I understand how STFT drives LTFT values, and I think I understand the adjustments to the MAF air flow model. So if we tune the MAF table to optimize for power and hence of the range of the NB sensors that drive the STFT and then the LTFT then the LTFTs will show errors from our desired operating A/F points. So why don't the LTFTs cause the complex filters in the ECM to use these LTFT values to move the tune off of the desired performance settings.
I understand how STFT drives LTFT values, and I think I understand the adjustments to the MAF air flow model. So if we tune the MAF table to optimize for power and hence of the range of the NB sensors that drive the STFT and then the LTFT then the LTFTs will show errors from our desired operating A/F points. So why don't the LTFTs cause the complex filters in the ECM to use these LTFT values to move the tune off of the desired performance settings.
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Just learning about tuning and cant figure out LTFT effect on WB 02 tuning.
I understand how STFT drives LTFT values, and I think I understand the adjustments to the MAF air flow model. So if we tune the MAF table to optimize for power and hence of the range of the NB sensors that drive the STFT and then the LTFT then the LTFTs will show errors from our desired operating A/F points. So why don't the LTFTs cause the complex filters in the ECM to use these LTFT values to move the tune off of the desired performance settings.
I understand how STFT drives LTFT values, and I think I understand the adjustments to the MAF air flow model. So if we tune the MAF table to optimize for power and hence of the range of the NB sensors that drive the STFT and then the LTFT then the LTFTs will show errors from our desired operating A/F points. So why don't the LTFTs cause the complex filters in the ECM to use these LTFT values to move the tune off of the desired performance settings.
Maybe you should go to HP Tuners forum and ask it but I think the method used is right.
The LTFT in effect DO move the tune to the desired settings. So why change the base table then?
Another reason is when the PCM is in open loop, it has to rely on a set of default tables which don't change. They could have two sets of tables, but that would be more complex.
For safety of the engine, the tables are the default tables thus should not change.
Last edited by Mez; May 27, 2009 at 05:04 PM.
