It`s adaptive. The calibration is stored in non-volatile memory. The reason it`s advantages to get the VE tables preconfigured is less updating to achieve proper AFR.
That setsthe cells that you are missing and notupdating during operation.

 

My understanding of AFV is that it is a fixed calculation that is an average amount of what had to be adjusted during closed loop operation - not cell by cell. If it were cell by cell and you had a large amount of closed loop feedback then theoritically you could just ride your bike and it would eventually self-tune itself. I also understood that AFV is used in closed loop as well as open loop as the base before calculating a new VE number.

Am I off here?

 

The only way to ensure you have the correct VE values and hence that will determine that the AFR ratios you enter are the correct values is to set the AFR to a constant accross all cells, say 13.8 : 1, then using an exhaust sniffer adjust the VE tables until the sniffer confirms you have achieved the 13.8 : 1. You may then adjust the AFR tables as you wish and the values will be correct. If you dont calibrate the VE tables in this way you have no way of knowing if the AFR values you enter are correct. For example if the VE is way off you could enter a value of 13 : 1 in a cell but the real AFR would be 15 : 1.

Unless you have a setup way outside the canned maps I wouldnt worry too much, in fact you can use this VE to cheat the AFR and maintain the use of the O2 sensors. So you can retain the cell values of 14.6 : 1, and max out the CLB tables which will actually give a trueAFR of about 14.1 :1. If you need it a little richer increase the VE in the areas you need which will trick the ecm into thinking you are pulling in more air than you really are which has the effect of making things a little richer.

WB

 

Damn. This site software sucks and doesn't actually keep track of what threads were read on any visit, so checking in on one forum kills the new-post-tracking ability for all the others if you don't check them too in the same session. And I was just about done getting caught up again when I saw this one...

The ECM learns and stores an AFV for each cylinder. Just two of them. Whenever it's time to make an injector-timing calculation, it looks in the appropriate VE table cell, gets the factor, and hits that with the AFV for the cylinder, then proceeds.

I suspect you're seeing the variations as a result of either temperature changes, barometric pressure changes, or engine load changes. But primarily as a result of the AFV having been altered by being in a different VE table cell before coming back to the same one again. This would indicate (to me) that the VE cells are not calibrated correctly to start with. You really need to get it on a dyno with gas analysis to set them. To have the system work the best it's really necessary to have the relationships between all the various cells be correct. If they are, the AFV shouldn't jump around like that.

The ECM knows it needs to reset the AFV whenever it's in closed loop and the O2 sensor voltage output isn't at the expected value. It's a very dynamic process, not something that happens only occasionally.

That will only have benefit in the closed loop areas unless the relationships between all the cells was very carefully established on a dyno with gas analysis. And if that were done, well, what's the point?

What it sounds to me like you're doing is essentially the same thing as the guys with a new DTT or TMAX making the thing chase its tail all around by trying to make manual adjustments early and often.

 

The DTT/WEGO IID works with wide-band O2 sensors and has no need for VE or VE New tables. It updates AFR with O2 readings. Hence Auto-Learn Mode.
It works very well. Just smooth the cells that have not been updated during operation withing that parameter mode and your done. It`s a real K.I.S.S. method setup.

 

From what I can tell, it has nearly the same amount of data tables as the Delphi. It merely uses them differently.

 

http://www.daytona-twintec.com/downl...structions.pdf

 

Thanks for the link. I thought I'd downloaded all their manuals but didn't have that one. Looking through it I find 17 tables mentioned. The SERT manual specifically says in one place there are 11 adjustable tables in its system.
I didn't scour both manuals but a quick jaunt through them uncovers the following lists.

DTT manual:
Alpha-N Table
AFR Table
Front Cylinder Trim Table
BLM Table
TPS Transfer Function Table
Delta TPS Fuel Multiplier Table
IAC Based TPS Adder Table
ET Based Priming Fuel Table
ET Based Cranking Fuel Table
Time Based AFR Cold Start Enrichment Table
ET Based AFR Cold Start Enrichment Table
Time Based Fuel Cold Start Enrichment Table
ET Based Front and Rear Cylinder Cold Start Enrichment Table
ET Based Idle RPM Table
ET Based IAC Position Table
ET Based IAC Start Adder Table
Time Based IAC Start Adder Table
----
17 tables

SERT manual: "There are a total of 11 Tables."
Air-Fuel Ratio
VE Front Cyl.
VE Rear Cyl.
Spark Advance Front
Spark Advance Rear
Warmup Enrichment
Cranking Fuel
Idle RPM
IAC Warmup Steps
ECM Tuning Constants
Acceleration Enrichment (AE) / Deceleration Enleanment (DE)
----
11 tables (12 if those last two are separate)

But I don't see mention of the CLB there, so yet another?

 

This is what I did on my 03 RK using a Twin Scan II +. Set all AFR's to 13.8 and then set the VE's. Worked out very well for me. And it makes sense to set the VE's first so then you can alter your AFR's and know they will be what you want.

 

The DTTDOES NOT haveVE or VE New tables like I mentioned earlier....It an ALPHA N system. Works great for me and it`s a simple straight forward application. You adjust what you need and know it`s within spec without a dyno. You can watch real-time data and monitor both AFR andO2 sensors.
You adjust the AFR table directly with the desired AFR number. This system will readjust the table with the auto learn within a certain limit. If it`s outside the threshold limit it will set the cell red/blue to indicate maximum adjustment has bee reached. The system work best if you add extra fuel and let it lean the tables out from there. I added 20% across the board like the manual suggested and it worked perfect.