Tuning Notes by WeathermanShawn

[redhardsupra]

yes, it's all been solved. have you read any of my stuff? it's all there black on white. solving for VE, calibration of MAF, equivalence and transforming MAF to SD models... and then there's stuff I didn't publish because it's not 'production-grade'

[WeathermanShawn]

yes, it's all been solved. have you read any of my stuff? it's all there black on white. solving for VE, calibration of MAF, equivalence and transforming MAF to SD models... and then there's stuff I didn't publish because it's not 'production-grade'

Marcin, I have read your entire website. I don't see your tuning methods published.

It is a way of tuning using just the MAF and closed-loop tuning. No need to do a SD tune, or the traditional MAF Calibration. The bottom line is that both the MAF and VE Table accurately reflect the Airflow. As long as you have accurate WOT AFR's, and maintain stoich (using the narrowband O2's) and LTFTs, and verify with your wideband..saves a lot of steps, and gets you the proper AFR's required for a good tune.

[redhardsupra]

I absolutely agree that no matter what airflow model you're using, the airflows need to be identical. I will go even further with this statement, and say that they need to agree across the full range of airflows. What makes it difficult to compare them is that MAF is against a completely arbitrary frequency, and SD has the more naturally laid out airflow values, for different RPM/MAP tuples. If you want a wacky visualization, use the RPM/MAP map, use the MAF frequency as the data for it. You should see small groupings of similar frequencies within each cell, just like the corresponding airflows would.

It doesn't really matter which airmass model you start with. They are equivalent. That's what all of the 'three airmass models' writeup was all about. It combines WB data and fuel usage estimation to produce an airmass that you can map on either MAF or VE scales. I've done all kinds of transformation like this, MAF->VE, VE->MAF, fuel->both VE and MAF, wrong fuel mappings to right fuel mappings... basically, the method works.

[WeathermanShawn]

I absolutely agree that no matter what airflow model you're using, the airflows need to be identical. I will go even further with this statement, and say that they need to agree across the full range of airflows. What makes it difficult to compare them is that MAF is against a completely arbitrary frequency, and SD has the more naturally laid out airflow values, for different RPM/MAP tuples. If you want a wacky visualization, use the RPM/MAP map, use the MAF frequency as the data for it. You should see small groupings of similar frequencies within each cell, just like the corresponding airflows would.

It doesn't really matter which airmass model you start with. They are equivalent. That's what all of the 'three airmass models' writeup was all about. It combines WB data and fuel usage estimation to produce an airmass that you can map on either MAF or VE scales. I've done all kinds of transformation like this, MAF->VE, VE->MAF, fuel->both VE and MAF, wrong fuel mappings to right fuel mappings... basically, the method works.

Let me be clear..My approach eliminates many time-consuming steps that are laborious and unnecessary. No SD tuning, and no MAF Calibration using wideband AFR values.

You are using the MAF Airflow to calculate the VE Table. The only use of your wideband is to properly log that your are remaining at stoich AFR in non-PE mode, and to accurately maintain an accurate AFR at WOT (in PE Mode). You are using your LTFT values vs MAF Frequency to address discrepancies in fueling (Airflow).

[5.7ute]

Shawn, if your method can demonstrate fuelling accuracy when running either off the maf or in SD mode it is obviously working. When you get the time it would be good to see a couple of comparison logs to see how well your system works.
Personally I would use STFT only so any correction isnt carried over when entering PE. But not everyone would upgrade to a custom OS to get this function.

[Aloicious]

Yea, I am drastically limited by altitude! I can only hit ~ 82-84 kPa on a good day.

Great read, thanks! My baseline barrometric pressure around here is ~85-86kpa, on a very rare day I could hit 90 for maybe 1-2 cell counts. now that I have the blower I can break through that barrier, but I saw a significant drop in power when I moved from ~500 ft to ~4500 ft.

[WeathermanShawn]

Shawn, if your method can demonstrate fueling accuracy when running either off the maf or in SD mode it is obviously working. When you get the time it would be good to see a couple of comparison logs to see how well your system works.
Personally I would use STFT only so any correction isnt carried over when entering PE. But not everyone would upgrade to a custom OS to get this function.

Thanks Mick:

You have an excellent point about utilizing STFT's in lieu of LTFT's.

I have done logs utilizing both SD and MAF runs. I say virtually no difference. In SD mode, I might have gained ~ a +2 MAP max, vs MAF..and interestedly when I tried a SD closed-loop tune..it was easier to manage the LTrims vs the MAF-closed-loop. But, acceleration-wise and fueling were nearly identical.You simply make a run..log your LTFT's vs MAF Frequency..then cut and paste the LTFT % correction vs MAF Frequency. That gives you a nearly perfect MAF Calibration Table. You then do another log and utilize the EFILive CALC.VE pid and using the EFILive MAP function, you apply the data to a RPM vs MAP Table. You then cut and paste that directly to your VE Table.

Your VE Airflow and MAF Airflow then match perfectly. You then log another run..log your AFR's at Stoich and WOT..and it all works.

The bottom line is that all your Airflow and fueling is nearly perfect.

[mr.prick]

I'm trying to figure out how you are adding LTFTs to the MAF.
You can add them as percentage but paste & add will add them as whole numbers.
I made a calc_pid for paste & multiply.
Are you just adding them by hand with the Adjust: box?

[redhardsupra]

heh, good question: how do you know what units are the trims in? are they percents? are they grams/sec of airflow? are they ms of pulsewidth?

as for the rest: i totally disagree. you cant have ' a simple version for beginners' and then some other set of routines for more advanced users. Nature does not alter its behaviour based on the audience. the hacks at the tuningschool tried that approach, PE hacks for beginners, MAF jacking for the rest sort of approach, and i ripped them a new one for that. their answer was 'well, but it still makes us money so we're right' 'nuff said.

[WeathermanShawn]

heh, good question: how do you know what units are the trims in? are they percents? are they grams/sec of airflow? are they ms of pulsewidth?

as for the rest: i totally disagree. you cant have ' a simple version for beginners' and then some other set of routines for more advanced users. Nature does not alter its behaviour based on the audience. the hacks at the tuningschool tried that approach, PE hacks for beginners, MAF jacking for the rest sort of approach, and i ripped them a new one for that. their answer was 'well, but it still makes us money so we're right' 'nuff said.

Marcin, the LTrims are in percent, but the MAF Frequency is being logged with g/s as its units.

As far as the other comments..I have a hard time understanding your combative style. You are very quick to criticize everything.
I have yet to see you put into plain words a Tuning Tutorial that works. You are knee-deep in theory, but never step up with a plan.

I am offended when you throw out words like 'hack' and so quickly dismiss ideas that you have never really stepped up to publish.Why don't you step up and help, instead of being the perpetual 'house' critic and being continuously offensive in your language and tone.

Give us your technique, and put it on this forum. It takes courage. Lets see you do it..