Tuning for headers - B4105 question

[WeathermanShawn]

I usually add the average LTFTBEN to frequencies down to 1500 Hz. Even though you have no logged data, if from some reason you go to higher elevation or your Idle Rpm drops you will hit some of those lower frequencies.

I.E., I keep the same MAF slope..in your case I believe it was +10% LTFT average. Note, when you get your wideband up and running, you will have to switch to the AFRBEN for PE Mode and WOT. In PE mode, you are no longer in closed-loop. It is in essence a form of open-loop. If you get stuck on that, just let us know.

When you get your LTFTBENS ironed out and can log DYNAIRTMP.DMA, it will be a cinch to complete your CALC.VE Table.

Let us know how it goes..Good luck!

[derekf]

Even if I "validate PIDs" before I start monitoring/logging, DYNAIRTMP_DMA isn't considered a "valid PID". Is that maybe something that isn't in 19980100? Is there an alterate PID I could use?

[WeathermanShawn]

Its possible that it is not in that OS.

I'll look up an alternative reference..I'll get back to you..

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I would PM Joecar or do a 'shout-out'. I am not sure why 98's are not supported..

Basically, it will take a Calculated PID that uses a blend of the ECT & IAT or the use of a 'Look-up' Table to replace DYNAIRTMP. I have been plodding along attempting to develop an alternative charge temperature method..I just need to do more work on it.

Hope that helps...

[joecar]

Yes, DYNAIRTMP_DMA may not be defined for 1980x000 OS's...

use the method that Shawn shows, you use the (x,y) values from your IAT/ECT blend table B4901...

Also see posts #17 and 29 here: showthread.php?13217-some-invalidated-pids&p=117959&viewfull=1#post117959

[derekf]

I don't have DYNAIRTMP_DMA to compare against to make sure that the values are comparable, but I'm guessing that I replace GM.DYNAIRTMP_DMA.C in the Calc.VE_Table calculated PID with this new CALC.DYNAIRTMP -- or are there additional changes that are needed to the Calc.VE_Table PID?

[WeathermanShawn]

I believe it should.

I will say it may not be a 'perfect' replacement for the DYNAIRTMP.DMA PID. Sometimes the 'Look-Up Table' method has an interpolation problem at the lowest Airflow Value. I also suffered a 'lag' in the value when I logged it. But, I did it via laptop. BBL may not suffer the same issue.

If you are good with Statistical Analysis, you might be able to mathematically display a factor based on the following (see attachment). The Charge Temperature Factor follows a progression from Low-Airflow to High. So, you could use the 'old' CALC.VE formula and apply a correction factor after the fact.

Thats what I have been working on..

[derekf]

I don't know that this is right, I must have done something wrong in here - the values I'm seeing in the CALC.VE_Table after a somewhat long log range from about 55 to 82, and it seems more like they should be roughly 1.0 give or take to do the "multiply with labels".

derekf_30Jul10.efi

[joecar]

CALC.VE_Table calculates the actual VE (or rather the normalized cylinder airmass)... it is not a multiplier, but the actual VE.

CALC.VE_Table has units of either [%] or [g*K/kPa].

In the tunetool options set the VE units to either of [%] or [g*K/kPa], and then in the scantool use the same units for CALC.VE_Table.

[derekf]

Ok - so this would replace the values I already have?

For example - 20kPa @ 1600 rpm would become 61.9 instead of the existing 49.67?

[joecar]

Yes it replaces existing values.