Is the VE reported for the cylinders in the SEST logs the value read from the VE tables? Is the VE new the value it's actually using based upon feedback off the O2 sensors? Along the same lines is the AFR desired and spark advance the values from the tables or do the tables just provide the ECM a starting value it then adjusts?

 

The AFR table is what your requesting the ECM to give you (it's&nbsp\\;the value&nbsp\\;your asking for) but if the VE tables are off the AFR values mean nothing. The VE tables are set for the configuration listed in the canned map....if you didn't use those parts in the build the VE tables are off.&nbsp\\; The New VE is a reading&nbsp\\;from the Adaptive Fuel Values that see the requested AFR in the table reads the VE table and says 'HEY, there is no way he can get 13.5 AFR with the set VE tables so I will alter the VE table and try to achieve what he wants....lol....how's that for an explaination....lol&nbsp\\;

 

If you think of the VE table as a new name and&nbsp\\;this gets easier to&nbsp\\;grasp. Think of the system as you set the entire AFR table to 13.5 and VE table (call it the AFR calibration table) to calibrate the the AFR table to a flat 13.5 AFR at evert point you can get the motor to on the dyno.&nbsp\\; The engine size / injector size table is really an accross the board AFR calibration constant.&nbsp\\;&nbsp\\;If the entire table say was getting too many cells to close to say 115 you can increase the engine displacement number up 10% and move every one of the&nbsp\\;VE numbers down 10%&nbsp\\;and poof you are back to tuning.
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If you want more general reading on the subject tru Googleing tuning an Alpha-N EFI engine.&nbsp\\; This is really closer to behaving like alpha-n than it is speed density system.
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Hope this helps
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AW

 

OK let's start with the basic stuff

VE is what the ECM is calculating from the VE table and using to start with

VE New is the corrected VE value the ECM uses from the combination of the VE table and the learned information from the O2 sensors

AFR is what the ECM is issuing from calculating the various AFR tables . It may not be what you are really getting out the pipes!

Spark Advance is what the ECM is issuing from calculating the various spark tables&nbsp\\;

 

It helps a lot knowing the values are from the tables. One thing I'm seeing it looks like there's a time differance between the engine speed and ve being logged. Idling at 1k it seems rather random as to whether I get the above or below ve value relative to the logged rpms. So it was hard to tell if it was&nbsp\\;just the rpms were differant when the ve was read or if there was something more going on.
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Professionally I specialize in performance tuning large scale computer systems. This seemed a way to combine two interests. So I'm trying to learn. I would really prefer to make small changes to the current calibration like maybe get rid of the ping I'm getting on the front cylinder. Regretably the SERT doesn't come with the stock calibration and, as near as I can tell, it won't read the calibration off the bike. It seems to get a base calibration to play with I'm going to have to change the a/c.&nbsp\\;Right now I wouldn't learn much from changing the air cleaner. So I'm looking to the differance in the calibration as a guide to understand just what it does beyond simply improves air flow. Like in what ranges does it have the biggest impact on ve and how big an impact.

 

Does the Delphi maintain discreet values for VE New and subsequently use them or are they really just informational representations of the tabled VE values as modified-in-use by the AFV?

Are there various values of AFV maintained per cylinder, or just one (each) [sort of the same question as the first]?

Does the AFV, once modified as necessary during closed-loop, also then pertain to open-loop operation?

 

Glen
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Here is back to back logging of the SERT&nbsp\\;totally stock and then with the o2s disconnected.&nbsp\\; With the o2s disconnected, I get VE and VENew reported as the same number so it appears that the VENew is only looking at the o2s.&nbsp\\; It is possible that the code&nbsp\\;is programed&nbsp\\;to ignore the&nbsp\\;all adaptive learned numbers, if the o2s are not on line, but the coders are not talking.&nbsp\\;
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http://www.ncs-stl.com/sert/o2s_vs_none.jpg
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AW

 

Given that the learned values are so monumental as to what your ECU is doing to your tune... I wonder what the Harley engineers were thinking when they desidded to hide that stuff from you in the data feeds coming off the SERT.
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AW

 

So calibrating the ve tables you basically try to get the ve and ve new values to match? You set the afr table to a constant value so as to eliminate any guess work as to the targeted afr? I gather a dyno can step the rpms by varying the drag on the rear wheel. The calibration list for my bike for the ac ranges from 500 rpms to 6500 and 0.0 throttle to 100.0%. Can you actually get down to 500 rpms at 100% throttle or up to 6500 rpms at 0% on a dyno? Do you run every column stopping in each cell or just test a subset of throttle positions and rpms? If read it takes 50-100 runs for a dyno tune, about how many of those would be for calibrating the ve tables?

 

LilBudyWizer
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You are catching on quick...&nbsp\\; asking all the correct questions.&nbsp\\; I will let the dyno guys answer the procedure as I don't tend to tune with a $30,000 dyno.&nbsp\\; I tend to use million doller roads and a laptop.&nbsp\\; I never ride on a dyno anyway.&nbsp\\; My wife gets board and the exhaust burns her eyes.
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AW