maf pid

[ahall1]

How do i create a calculated pid to show commanded maf(gms/sec) divided by actual measured gms/sec as a ben factor that i can use to redo B5001(maf table)hertz vs gms/sec.

[Black02SS]

You don't need to. All you need to do is take the BEN PID that is for your wideband and use that. If you need help on this, just let me know what wideband you are using and I will take care of it in the next hour.

[ahall1]

thank you its an Innovate LC-1.

[Black02SS]

I assume you don't need this now that TAquickness got you all covered?

[ahall1]

Yea I'm good to go now,thanks black02ss.

[Black02SS]

Yea I'm good to go now,thanks black02ss.

Anytime, that is what we are here for, to help the community.

[Redline Motorsports]

Hey Black,

I am getting ready to start playing with the MAF a bit more now that my last post turned into quite an information adventure!

Is it possible to elaborate a bit on the best way to create a map for dialing in the MAF?

I am still a bit confused right now with the MAF BEN factor method. I understand that the BEN factor is the percentage you are off from commanded vs. actual but what are the two factors compared and how do you tie that back to the MAF adjustment.

Thanks

Howard

[Black02SS]

Hey Black,

I am getting ready to start playing with the MAF a bit more now that my last post turned into quite an information adventure!

Is it possible to elaborate a bit on the best way to create a map for dialing in the MAF?

I am still a bit confused right now with the MAF BEN factor method. I understand that the BEN factor is the percentage you are off from commanded vs. actual but what are the two factors compared and how do you tie that back to the MAF adjustment.

Thanks

Howard

The MAF Ben factor is applied to the MAF table (B5001) just the same as when you do it to the VE table. I normally will scale the MAF table 5% rich to start out just the same as I do when I start SD. This just ensures the car isn't lean. Some may do it other ways. I then make a map as has been posted. This MAP mimics the MAF table in the tuner. Here it will tell you how far off you are in relation to the commanded AFR, just as you said. So at 5000hz you see a BEN factor of .90, that tells you that it is 10% rich. The goal here is just the same as the VE table, you want to hit as many cells as possible and achieve a BEN factor clost to 1.00

[Redline Motorsports]

Chad,

Thanks. For starters where is that map that was floating around?? I think I understand the reasoning behind the MAF BEN procedure I just wanted to confirm the steps required to get the answers. I guess what confuses me is that with the VE method, comparing commanded to actual makes sense to come up with a "difference" factor. With the MAF you are working with Hrtz vs. AFR ratio I am mentally off. I understand that by changing the scaling you can pull the AFR one way or the other to achieve a desired AFR but just need to see the MAF map I guess.

I also believe I understand that disabling the MAF, doing an SD tune (and getting the AFR on the money), that once you enable the MAF if its off , it will pull the AFR readings off. The purpose of this step is to get the MAF scaled to where the AFR where before you disabled it. Correct??

[Black02SS]

Chad,

Thanks. For starters where is that map that was floating around?? I think I understand the reasoning behind the MAF BEN procedure I just wanted to confirm the steps required to get the answers. I guess what confuses me is that with the VE method, comparing commanded to actual makes sense to come up with a "difference" factor. With the MAF you are working with Hrtz vs. AFR ratio I am mentally off. I understand that by changing the scaling you can pull the AFR one way or the other to achieve a desired AFR but just need to see the MAF map I guess.

I also believe I understand that disabling the MAF, doing an SD tune (and getting the AFR on the money), that once you enable the MAF if its off , it will pull the AFR readings off. The purpose of this step is to get the MAF scaled to where the AFR where before you disabled it. Correct??
Totally correct Howard. The same difference factor from the VE table is applied to the MAF table. If it is off by XX amount, that means you need to tell the MAF you have XXX more/less air at that hrz. I can't remember, are you using a LC1?

[Redline Motorsports]

Totally correct Howard. The same difference factor from the VE table is applied to the MAF table. If it is off by XX amount, that means you need to tell the MAF you have XXX more/less air at that hrz. I can't remember, are you using a LC1?

Yes I am using an LC-1 currently. Hopefully today my "high end" WB that is tied into my dyno shows up today. I think it has two 5 volt output signals in which I want to get one sent to the Flashscan.

I think if I saw the map I would better understand what pids are being drawn to each other and compared. I appreciate your patience as sometimes I have to fumble with the understanding which afterwards is a basic thing to do!:bash: . Needless to say I am way further along then I was two months ago!

Thanks Chad

[Black02SS]

Here are some screen shots of a car I did. You will see how the BEN is in the VE table after I have applied it to the MAF table as well.

http://black02ss.dyndns.org/VEBEN.jpg
http://black02ss.dyndns.org/MAFBEN.jpg

[Redline Motorsports]

Isn't that same MAP as used for the VE?? If so once you enable the MAF your original commanded vs actual will be off if the MAF is out of calibration. At that point you now need to bring it back to the correct commanded by recalibrating the MAF scaling. By transfering the BEN factor to the MAF calibration table you are "trimming" the values to adjust for the percentage of error. Correct??

At that point when you determine what your BEN numbers are, how do you cut/paste a x/y map of values into a column of values as noted in the MAF calibration parameter?

[Black02SS]

The MAPs I posted above are just to give you an idea of what it looks like. The VE map isn't used after SD when tuning the MAF, I just showed it as a reference to see what your BEN looks like after you re-enable the MAF and adjust the MAF table. I just grabed this tune Howard as it isn't the final log. I looked but I can't find anymore. :(

[Redline Motorsports]

Chad,

I guess I need to back up for a second. Maybe to clarify the differences between a SD tune and Autotuning. Autotuning uses only the open loop fuel table as a "direct" commanding of fuel. That tied in with the ability to read actual, compare it and change it by a factor is the basic theory. Correct?

The SD tune uses the VE table as the means of getting the PCM to not make LTRIM adjustments to keep the AFR at 14.7 for all but PE mode, which can be adjusted through PE changes and WB readings. Correct?

In the VE SD tune I can see that after you do the tune with the MAF disabled, you would want to go back and get the MAF to agree with where you ended up without it. Correct?

What about when you are auto tuning and you are just getting what you want for AFR because you are directly controling the fueling. :nixweiss:

I happen to have a stock 02 ZO6 in which we just installed a set of Kooks headers and a Vararam intake. I already noticed the LTRIMS at idle are 15 % and the AFR is reading some what lean at cruise rpms/loads. I would think most of the leaness is from the MAF being out of whack from the intake change. I'm sure the VE is fairly close and the motor is already making over 40 RWHP more and 40 RWFT over the stock setup. Now I need to fatten up the fuel a bit on top as its too lean still. This would be a perfect time to get the auto tuning working as the car is only slightly modified. It still leads me to the best approach after I get the car tuned without the MAF.

I'm on a roll!

[Black02SS]

I was going to call you but your website doesn't seem to be working on my end so I couldn't get a number. :lol: I am not quite understanding this question.


What about when you are auto tuning and you are just getting what you want for AFR because you are directly controling the fueling.

[Redline Motorsports]

That would be great.

Its 518-355-8460

Thanks much.

Howard

[Black02SS]

That would be great.

Its 518-355-8460

Thanks much.

Howard

Sorry it took so long, I just tried calling and left a VM.

[joecar]

Can I get a copy of the MAF BEN for LC1, please...?
Thanks,
Joe

[Black02SS]

Here you guys go.

[caver]

The map you create references frequency to airflow in g/second. Essentially what you are doing is telling the ecu what the airflow is for a given frequency,using the ben factor.

I do this on every car I do. 1st I change B0120 to 300 to make sure the pcm is only using the maf,you also need to disable stft, ltft and dfco.

Watch the changes under about 6khz as you can find yourself chasing ridiculous numbers around. Also if you log under 1000rpm it will skew the readings big time.

Final check is to enable ltft and log low rpm light throttle as I find it's real easy to end up being to rich in that range.