VersaTune User Forum

Hi Guys - I'm after some advice please

I think my MAF calibration is ok now, but I'm not sure what to do with the 2 WOT logs I was advised to make

I know I'm supposed to be the comparing the actual equivelance ratio with the desired equivelance ratio but then what?

totally lost

any help would be greatly appreciated

Subtract actual equivalence ratio from desired equivalence ratio, and add 1 to the difference. Then find out the maf voltage at that point, go to maf table 1, and multiply the difference at that maf voltage.

E.g:

At maf voltage 3.5v, actual equivalence ratio is 0.8 and desired equivalence ratio is 0.7, then difference is 0.1. Adding 1 to it yields 1.1. So go to maf table 1, find the cell for 3.5v or closest, and multiply the g/s value in that cell by 1.1.
Don't forget to copy all values from maf table 1 to maf table 2 after u finish calibrating.

If u have not logged maf voltage, then you can use the maf g/s values... But u should preferably log and use maf voltage to do the calibrations.

ok thanks for that mate - much clearer

I got it into my head that there was a separate table in the tune editor for the WOT data

well I don't appear to have logged the voltage so I think I'll do the logs again just to be on the safe side

Col

yup.. maf voltage is better than g/s airflow values, because u can aggravate the afr leanness or richness accidentally when using g/s values. so if your tune is lean by 1% at 200g/s cell value, then we cannot be sure that subtracting 1% from the table will not aggravate the leanness.. hence the voltages are more accurate.

Log several WOT pulls, not just one. The results you get in one log may be altered by various factors.
Then you can simply use de Excel sheet from the MAF CAL thread here: http://www.versatune.net/forum/viewtopic.php?f=5&t=126 and calculate the multiplication factor as an average rather than just one set of values. Just to make an idea, for my MAF cal I used data gathered in about 25Km of driving (normally driving, town driving, sometimes with the cruise control on, and also WOT in 3rd to 6th). In the end my MAF cal was perfect, next day, same weather conditions, the LTFT's were around 0 - so that's the advantage of using several data sets (I wrote my own application to process that huge amount of logging, but using that excel sheet with 4 values for each MAF voltage will work very very well).

mituc wrote:I wrote my own application to process that huge amount of logging, but using that excel sheet with 4 values for each MAF voltage will work very very well

being a non computer person, it would be great if there some facility within the Versatuner software to do the MAF cal automatically

i.e. warm the car up, start the program and follow the instructions - after the required number of runs the MAF table is automatically populated and you are then able to reflash

or is that just not possible?

I want it to make me a brew and walk the dogs as well please!!

surely it would only be a few steps more than the cars' ecu is taking anyway...

but like I say... I ain't a computer person

Col wrote: i.e. warm the car up, start the program and follow the instructions - after the required number of runs the MAF table is automatically populated and you are then able to reflash

or is that just not possible?

It should be possible, yes. My application can send a .csv file into your browser with the new MAF cal. I'll try to write a CGI script to do that and put it on some web server so that everybody can use it. You may still need to change manually a few values to smooth the curve but that's another story, most of the hard work is done automatically.

skiptownmcat wrote:I want it to make me a brew and walk the dogs as well please!!

That can't do. But it can smooth your dogs and replace them with some cats and also give you the possibility to choose between a Scottish cat or a high-flow cat - your choice!

thank you Mituc - that will be very useful