log MAF hz and dynamic airflow ?

[RunnWS7]

When logging MAF (hz and dynamic airflow) do the VE table have to be perfect or can i log LTFT and adjust the VE meanwhile i am collecting MAF info.

[jimmyblue]

MAF Hz "is what it is", an absolute sensor output.
It doesn't care about anything but actual airflow.

But what is your purpose?

[RunnWS7]

I want to start logging dynamic airflow and MAF hz for MAF calculations (i was going to try redhardsupra´s spreadsheet), And i was wondering if i can monitor and adjust my VE table at the same time? ???

[RunnWS7]

Anyone? and do you really have to be in SD to log info for MAF calibrations?

[02sierraz71]

Anyone? and do you really have to be in SD to log info for MAF calibrations?

i used several sheets and it sent all my trims -10. You need to have the maf enabled to tune maf table because you can use the trims and maf hz. The trims you see in SD are a direct result of the ve table and have nothing to do with the maf table.

Log maf hz and trims with the maf enabled. The pull up your log and scan the graph with the cursor you will notice the cursor in the histogram will jump around wherever the cursor is in a ftc that is out of whack note the maf hz in the pid and try and get the range for that particular cell. Then go into the maf table and correct accordingly. For example if the trim is -10 and the hz for that cell are 3500-4500 then get the closest cells in the maf table and multiply by .90 of course you want to use your judgment this will take time and you shouldnt end up with a lumpy graph.
I like disabling the ltft and tuning on stft takes alot less time and if you get them within 4% your long terms will look great whenever you reenbale them.
No one seems to use this method and it is by far the simplest and most effective in my experience.

[redhardsupra]

actually you don't have to be in SD for MAF calibration, I did some experiments and it they yielded the same result.

HOWEVER, you better have your FULL VE table tuned in before going to do the MAF calibration, since MAF calibration is basically matching it to the VE table.

[02sierraz71]

actually you don't have to be in SD for MAF calibration, I did some experiments and it they yielded the same result.

HOWEVER, you better have your FULL VE table tuned in before going to do the MAF calibration, since MAF calibration is basically matching it to the VE table.

Right on

that ve better be slick as a babys butt provides alot better resolution when you renable to maf it cut my 02 oscillations way down so they are more concentrated on stoich afr

Ive found the best way to really get the ve table very very close is to only use stft and disable the ltft's you have to get a good average with the stft because they will jump all over like kids at a mcdonalds play room

[RunnWS7]

Thanks for helping a newbie

Let me see if i got it right...

1. Get the VE table tuned in perfect (in SD)
2. Log MAF hz and Dynamic air (MAF enabled)
3. Put in the info in Redhardsupra´s spreadsheet. (automafv25)
4. update my MAF airflow vs. frequency with new numbers from the spreadsheet.

Is this right? How many hours of logging do i need to get the MAF calibrated...

Thanks again guys.

[02sierraz71]

The sheet didnt work for me I hope it does for you it doesnt take as long as my method. Dont forget to reset trims after only major changes to the ve or maf and if you have to use my method and have questions let me know
good luck

[redhardsupra]

http://www.allmod.net/hpt/MAFwriteup...libration2.cfg is a config file that will let you do fuel trims and maf stuff at the same time.

02sierra: what's wrong? what didn't work? i know it's not the easiest spreadsheet, but there's just a lot of stuff that don't like to get automated. aim me or email me or something, we'll get it figured out, i've done dozens of cars with it, there's no reason why it shouldn't work with yours.

[RunnWS7]

http://www.allmod.net/hpt/MAFwriteup1/MAFCalibration2.cfg is a config file that will let you do fuel trims and maf stuff at the same time.

02sierra: what's wrong? what didn't work? i know it's not the easiest spreadsheet, but there's just a lot of stuff that don't like to get automated. aim me or email me or something, we'll get it figured out, i've done dozens of cars with it, there's no reason why it shouldn't work with yours.

Thanks Redhardsupra... But i still have to do my VE first, and then log info for tuning the MAF right?

[VYSSWagon]

You can only use Dynamic Airflows where the engine is in a steady state when rescaling your MAF.

I set up an algorithym that only ised values where the MAP had been constant for 4 scans. It shredded a lot of data but the data I lost was wrong in any case.

I also adopted a system similar to VE tuning. Whilst running in SD mode log dynamic airflow, MAF airflow and MAF frequency. I would only use "steady state" data as I said above and I would scale my MAF table by 50% of the average error for each cell.

e.g.

Freq. MAF Dynamic
5000 41.67 g/s 45.25 g/s

Error = (45.25/41.67)-1 = 8.6%

I would then adjust up my MAF table value at 5000 hz by 4.3%. So just as with your VE tuning, you creep up on the answer and don't overshoot.

Took me about 6-7 passes to get most of it right. Below 3,500 hz and above 8,000 hz were the hardest, due to limited data and took a lot longer. Above 9,500 hz, you start to get into the "terminal velocity" range of your intake system.

[02sierraz71]

You can only use Dynamic Airflows where the engine is in a steady state when rescaling your MAF.

I set up an algorithym that only ised values where the MAP had been constant for 4 scans. It shredded a lot of data but the data I lost was wrong in any case.

I also adopted a system similar to VE tuning. Whilst running in SD mode log dynamic airflow, MAF airflow and MAF frequency. I would only use "steady state" data as I said above and I would scale my MAF table by 50% of the average error for each cell.

e.g.

Freq. MAF Dynamic
5000 41.67 g/s 45.25 g/s

Error = (45.25/41.67)-1 = 8.6%

I would then adjust up my MAF table value at 5000 hz by 4.3%. So just as with your VE tuning, you creep up on the answer and don't overshoot.

Took me about 6-7 passes to get most of it right. Below 3,500 hz and above 8,000 hz were the hardest, due to limited data and took a lot longer. Above 9,500 hz, you start to get into the "terminal velocity" range of your intake system.

What is the reasoning for doing it this way? Why is the math setup that way?

[VYSSWagon]

Lets start at the begining

You disable your MAF and log your STFTs and LTFTs and fix your VE table. So now in SD mode your engine knows how much air it is getting. (That is the whole point of fixing your VE table, get the right amount of fuel metered, to give the perfect AFR).

So SD mode is sorted. Now for the MAF. Dynamic Airflow is calculated from your VE table (which we have just fixed). So Dynamic airflow can be considered to be 100% correct. Now you just use Dynamic airflow to fix you MAF table.

Problem is MAF airflow and Dynamic airflow are ONLY equal when MAP is constant. (i.e. airflow into the engine equals airflow into the manifold). Inlet system turbulence is also an issue, particularly at high RPMs nearing terminal velocity. I read a really good analogy that compared an inlet manifold to a sponge and a MAF pipe to a garden hose (I think it was on this forum). This is a very difficult concept to understand, but it explained it really simply.

The reason I decided to use the 1/2 factor again is that I found that I was constantly overshooting. There are always differences between the two airflows, only 1/2% to 1%, but that is the difference between a 12.5:1 AFR and 12.8:1 AFR.

[S2H]

you can also try my sheet..

http://www.audiohelix.com/hptuners/M...-Worksheet.xls

use MAF HZ and LTFT/STFT...
I only used the LTFT... and My MAF is dead on....I tuned it in with my spreadsheet..I went out on tour for 9 weeks..came home and it was still dead on....my dad even drove the car a couple of times while I was out to give it a run or two...
all 0's and -1's...same as when I left...

[Main_One]

Whew, 13 MB soundengineer. Glad I've got a cable modem!

I definitely think I've got a problem when going into steady-state mode at mid-power/RPM ranges. Hopefully this will help!

M1

[S2H]

I still prefer the wideband method when possible...but I didnt have a wideband hapening when I built that sheet...sorry for the size...
now in 2.0 I just made histograms and let the software do the work
I also use Red's dynamic airflow concept too...but usually I use It while finishing up my SD...it gets me really close and then I fine tune with mine...

and of course..IF I can use a wdeband...its always correct when done using AFR error %