ls1_lover

I would appreciate the advice. 2002 stock SS. Except for the SLP Loudmouth 1 cat back it is bone stock. I am adding a pair of Texas Speed headers. I have HPTuners software. I dont have the wide band 02 unfortunately. So I will just go off the short and long term fuel trims to make my adjustments. However this is the question. Is there math equation I can do to make the change on the entire table at once? Is there an logarithm to apply to adjust all the numbers at once across the board a certain percentage that increments a little bit each time all the way up to WOT? That would be a hell of a lot easier than having to adjust each and every cell one at a time. Am I in the wrong place here?

ls1_lover

Oh, let me add that right now the car runs great with the tune I have. Is there a formula I can apply to the VE table to make it all adjust perfectly for these new headers so I dont have to go in and fiddle with each and every cell? Thanks.

ScottyBG

This would be better put in the PCM and tuning section, however I'll tell you what I know here. There is no simple formula to adjust your VE table. In some areas it may need increased, and in some areas it may need decreased. Considering what you need to do, you don't need a wide band to tune what you have. It is a pretty minor adjustment, that's why your car runs fine with the current tune. It only needs very minor adjustment to get it right on. You can easily use your long term fuel trims to correct your VE table. This is assuming you MAF meter is tuned correctly currently, and its tune doesn't need modification.

You will need to go into your scanner and set up a histogram to match your VE table, same kPa labels on the rows, and the same RPM labels on the columns. Plot LTFT on this table.

Next you will need to go in and disable your MAF meter by setting the fail to zero. So your running in SD mode, and the MAF is not changing the fueling, it is being driven directly by the VE table. Remember your original setting as you will need to put it back in to enable the MAF once your done tuning your VE table.

After this is done, go in and start data logging on this table, remember to go in under controls and clear out your long term fuel trims at the start, so it only uses fresh data.

Drive the car around and populate your histogram in as many cells as you reasonably can, usually you can hit most of them up to about 4K rpm. No real need to run WoT here, but as long as you don't see huge positive fuel trims your should be ok to push the throttle considerably, in order to populate close to the bottom area of the graph. I wouldn't worry about the area above 4k rpm, the MAF will be the major source of data for fueling calculations above 4k.

After you have you chart pretty much populated, copy it, and paste it onto your VE table in the editor, using paste - multiply by %. After this change look at the table and compare it to what you had. Normally I do a little hand smoothing of the table here to handle the cells that are not hit. After this write the calibration, and repeat the process. If you've done well with it, you should have all of your LTFTs be under 3%. Normally your good here, if you have a cell or 2 off a little, you can usually just tweak them up or down a point by hand afterwards.

If you happy with the results go back in and turn your MAF back by resetting the fail frequency to the original setting.

This is a quick overview of what you need to do. I didn't make it a check list, you may want do find and read some other information and have a full understanding of what needs to be done here. I believe this to be correct, and in good faith, however I take no responsibility for this information. Tune at your own risk.

Best of luck with it.

ls1_lover

Thanks for the reply ScottyG. I really appreciate it. I am going to break down what you wrote here and work on it. I have to figure out how to do step one..

You will need to go into your scanner and set up a histogram to match your VE table

I am a newbie as you can tell..

ScottyBG

Are you using Version 3.4? If so I think it may already have a graph set up for what you need? After version 3.0 they call them graphs, instead of histograms.

Practically what you are doing my logging this graph is determining where it is rich and where it is lean. If you have the columns and rows matching your VE table you determine exactly which cell is rich and which one is lean, and apply that change to your VE table.