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Re: Share your MAF Calibration
Posted: June 20th, 2012, 4:40 am
by summerblink
Ok, now I get it, thanks.
Is there some tricks one needs to know when adding the MAF cal values to a tune?
I'm trying to add MAF g/s Smooth -line from your excel in VT to the Base 93US_98EU Octane High Load tune's MAF calibration 1 in edit mode, but for some reason the
values are not pasting to the chart. I just get empty red boxes there.
Maybe it's just an Excel version thingy or something in formatting etc?
Re: Share your MAF Calibration
Posted: June 20th, 2012, 8:05 pm
by Steve @ VersaTune
Select all 129 values in excel, copy to clipboard, click on first cell of table in VersaTuner and paste. That should be it.
It just occurred to me that there may be a unit mismatch. The values in my .xls are in grams/second. Make sure that your VersaTuner is set to Metric units or convert them in excel to lb/min if you prefer to use Imperial units.
Re: Share your MAF Calibration
Posted: October 2nd, 2012, 5:27 pm
by Pinni
mituc wrote:Ok, guys, in my search for smoothness I found the ultimate trick.
As you all know the MAF g/s readyngs, commanded versus actual AFR readings, and so on, are delayed or at least not perfectly in sync because of various reasons:
- OBD scan delay;
- takes a while before the actually metered air produces any AFR effect on the lambda sensors in the exhaust;
- sensor voltage variation delay;
- possibly others.
After spending good hours to smooth every new MAF cal I was generating based on the decently high amount of logs I'm taking with every occasion when I need to do this it occurred to me that I need a higher resolution graph. So I imported the MAF V and the MAF g/s from the MAF cal into an Excel sheet and I generated a graph with the MAF V on the X axis and MAF g/s on Y.
Oh man, the graph was full of bumps, twists, sudden increases followed by almost constant and small climbs, and so on! It was looking awful, no wonder that I had to adjust my MAF cal all the time and never got it perfect!
Then I used a trends function, average every 2-3 cells should work fine. I smoothed the values based on that until I've got it smoothed. I also used the new linear interpolation feature in Versatuner to generate a trend of multipliers to make sure the newly generated MAF cal matches some specific transition points that were in the middle of 0 AFR variations or 0 LTFT's for a long time.
I have no tool to smooth my MAF cal somehow else, this is how I worked on it. This isn't a template that you can work on as I did a lot of manual work, there's nothing really automated. If you have a Cobb SRI you can try this MAF cal (the "MAF g/s smooth" values represented by a blue line on the graph).
Mituc, the smooth calibration in that table, does that relate to the Cobb SRI that is around the same housing size as the stock, or a 3" SRI? Also the smooth Cal in that spreadsheet what temps was that particular version calibrated at?
When I first flashed the smooth maf cal and started up I saw STFT as high as -14 but I am at sea level and temps around 20C ATM, having said that the temps this month or next will see 40C+.
I also have to commend you on the time you've put into the Cal. I wish I had the time to invest in smoothing out my Cal to that level.
Regards
Mathew.
Re: Share your MAF Calibration
Posted: October 3rd, 2012, 3:17 am
by mituc
STFT's are for short term adjusting and you may see them varying a bit more than the LTFT's do, especially in those moments when the A/C compressor kicks in or there's a sudden greater need of electric power which will make the alternator put some strain on the engine as well. So no matter what MAF calibration you're running, just give it a few good miles/kilometers (120-150 miles/200-250km) of mixed driving conditions and see where your LTFT's are after that. The STFT's are about immediate fuel mix adjustment and the LTFT's are calculated based on some averages (well, it's actually polynomial interpolation but you can approximate that with an average of each point).
The MAF cal I posted was done at around +4C ambient temps and probably the winter mix of the gas also played some role, now I'm basically running the same MAF cal scaled down with 5%. the gas I'm using should contain no more than 5% ethanol (so E5).
Re: Share your MAF Calibration
Posted: October 3rd, 2012, 10:19 am
by Steve @ VersaTune
In addition to driving at varied loads, make sure you go through a few start up, warm up, run, shutdown, cool off cycles before you start your MAF cal process.
Re: Share your MAF Calibration
Posted: October 3rd, 2012, 5:18 pm
by Pinni
Ok, cool. I drive around 150km a day and I flashed that Cal. about 4 days ago so hopefully the LTFT's should have well and truly settled now. Also I'm assuming the large differences in ambient temps will make a diff to the calibration considering were now approaching 35 degrees C. I'll do a couple of logs today and see how it's come up.
Re: Share your MAF Calibration
Posted: October 4th, 2012, 2:47 am
by mituc
Just watch your LTFT's and scale the MAF CAL down accordingly. My maf cal is now topping up at about 405g/s
Re: Share your MAF Calibration
Posted: October 28th, 2012, 7:53 am
by mituc
Ok, here is my new MAF CAL. Most probably it will be spot on for any 3/6MPS car in Europe that has a Cobb SRI, possibly on other regions as well because the pump gas is not that different.
Since now with the new turbo my MAF voltage goes up around 4.72-4.74V this MAF cal is accurate at least up until 345g/s.
Enjoy!
Re: Share your MAF Calibration
Posted: March 28th, 2013, 1:06 pm
by mrQQ
what about CP-E CAI, anyone got one?
Re: Share your MAF Calibration
Posted: March 28th, 2013, 1:52 pm
by mituc
If you don't find anyone that can share one with you just start with a CS or better Cobb MAF cal (the Cobb SRI may be a bit larger than CS) and see where you are. The CP-E has a slightly larger MAF housing diameter but as far as I know the difference between stock and Cobb/CS is higher than between Cobb/CS and CP-E.