Tuning MAF

[98WhiteDevil]

Hey guys I'm trying to tune my MAF with EFILive on my 98 Trans Am. I got the VE's in line, now I'm moving on to tuning the MAF. I kept everything the same as when tuning VE's and I plugged in the MAF to read the frequency, but nothing showed up on the table, I set the table up just like the MAF Calibration table.

After this didn't work I then enabled C6002 (P0101, P0102, and P0103) and also changed the MAF Frequency Fails back to their stock values (C2901, C2902, and C2903), but kept everything else the same. I tried logging the MAF frequency but it still didn't work.

I've tried 2 different maps to log this stuff.
1). Map 1: Data (GM.DYNAIR), Column (Value, 1 column), Row (GM.MAFFREQ)
2). Map 2: Data (CALC.BEN_LC11), Column (Value, 1 column), Row (GM.MAFFREQ)

What am I doing wrong. Also if possible, could somebody give me a step by step process of how to tune the MAF, again I have all my VE's in line. I need to know what tables I need to make, what PID's I should select, etc. This would be really helpful as I've been trying to figure this stuff out all day with no success.

Thanks

[jfpilla]

Try logging SAE.MAF.:)

[SSpdDmon]

You don't need to log SAE.MAF. You need to log the GM.MAFFREQ, the BEN for your WBO2 (which requires GM.AFR, EXT.AD1, and your WBO2 calc pid), and then set the column to something like RPM. The labels for the RPM column should be ",8000" exactly (yes, type the comma). The rows should be identicle to the MAF table in the tuning software (copy with labels from tuning software and paste labels into the map builder). The data is your BEN.

[jfpilla]

SD is right. I should have pointed out that GM.MAF will not register info with the MAF 0'd.

[5.7ute]

SSpDmon what do you do with B0120 when tuning the maf ? I lowered the value in this table to 1000rpm so it ran exclusively off the maf without the correction factor from SD.

[SSpdDmon]

I lowered mine too, but only to 1800rpms. That way, only the 400-2000rpm rows in the VE would influence the MAF. Then, I filtered my logs to show only data from 1900rpm on up (assuming a 100rpm hysteresis to be safe).

[98WhiteDevil]

Hey, SSpdDmon, I noticed your from Farmington MI, I'll be living there this summer working with GM High Performance Vehicle Operations. Should be there in about a week.

[SSpdDmon]

Sweet. I'm working out of the Tech Center in Warren (purchasing). We'll have to grab a beer or something sometime. :)

[98WhiteDevil]

After you guys are done tuning, what do you set B0120 to? Do you guys set it back to the stock 4000 value or do you change it?

[98WhiteDevil]

Also, when I dialed in my VE's the car ran fine. Then when I dialed in my MAF, the car ran fine. But when I put the 2 together the car runs like shit. Why does it do this. The car runs fine with either just the VE's, or jus the MAF, doesn't make sense?

[SSpdDmon]

Right now, I'm experimenting with B0120 and have it set at 2600 - well the last time my MAF was active it was. I don't know if there's a clear cut way to determine where this needs to be set. When my dad's C5 came back from Lingenfelter after the Maggie install, they had dropped his B0120 down to 400RPM virtually eliminating the VE. But, then they left the MAF alone and fudged the IFR table to get fueling close. Go figure...

As for why the two don't mesh well together, I'm at a loss. I've noticed this a bit on mine and I'm seriously contemplating going to SD full time. I can't say for certain that's the best thing to do. But, I'm starting to run out of ideas.

[Chalky]

Right now, I'm experimenting with B0120 and have it set at 2600 - well the last time my MAF was active it was. I don't know if there's a clear cut way to determine where this needs to be set. When my dad's C5 came back from Lingenfelter after the Maggie install, they had dropped his B0120 down to 400RPM virtually eliminating the VE. But, then they left the MAF alone and fudged the IFR table to get fueling close. Go figure...

As for why the two don't mesh well together, I'm at a loss. I've noticed this a bit on mine and I'm seriously contemplating going to SD full time. I can't say for certain that's the best thing to do. But, I'm starting to run out of ideas.

Jeff:

When you cut through all the BS, my guess is 99% of all dyno tunes are done this way. Not pretty but it is fast.

[SSpdDmon]

Jeff:

When you cut through all the BS, my guess is 99% of all dyno tunes are done this way. Not pretty but it is fast.
Yeah, I know...

Oddly enough, it's inspiring me to break the paradigm. I have a mental image of what I'm working on right now. If all goes well, I'll be posting up the results. The bitch of it is decel. I've got some PM's going back and forth with Blacky to get their perspective on what I might be missing and what we can't see. In the mean time, I've got my fingers crossed... :)

[Chalky]

Joecar: I thought you had a post in here.

As far as the shortcut tunes, I guess I was just thinking that for the added cost of LPE work, they would have one the extra step.

Jeff: Looking forward to your findings. ANy hints?

[SSpdDmon]

Joecar: I thought you had a post in here.

As far as the shortcut tunes, I guess I was just thinking that for the added cost of LPE work, they would have one the extra step.

Jeff: Looking forward to your findings. ANy hints?
http://www.ls1tech.com/forums/showthread.php?p=7406040#post7406040

[joecar]

Joecar: I thought you had a post in here.
I was editing it and I accidentally deleted it... :bash: ...big fingers, small keyboard buttons, I was looking down, but I was hitting the wrong keys, ALT/CTRL/SHIFT/TAB are all in the wrong places...:muahaha:

I had to remember what I typed, but this is close:

The tuning shop has a choice:
- do it very quickly for $X (time is money),
- do it thoroughly for $X*2 (charge 2x more, takes 4x as long),

We all know that everyone is looking for a "good" deal, and $X seems to be a "better" deal than $X*2, so the tuning shop offers the $X tune; if they offered the $X*2 tune, not many people would buy it because it costs twice as much (and it takes all day, ties up the dyno when several $X tunes could be done in that time); the shop has bills to pay and mouths to feed.

Same reason offshore-made crankshafts are able to easily sell.

[Chalky]

http://www.ls1tech.com/forums/showthread.php?p=7406040#post7406040

I just browsed that thread and now I have a headache. Regardless, I like your ideas.

[SSpdDmon]

I just browsed that thread and now I have a headache. Regardless, I like your ideas.
The hint you were looking for was in the post I referenced.... :lol:


Right now, I'm working on the IFR table based on the stock MAF curve (B0120 set to 1rpm).

[Chalky]

Just curious but what about cars that are being sold today without MAF's. Are they dependant on VE tables and other related IAT tables and calculations, for example, to achieve proper AFR?

Is the MAF preferable to the VE tables for tuning if you had to choose one?

Why does GM set up the VE as primary lookup up to what, 4000 RPM?

Just trying to understand the logic. No doubt sees the benefit of the MAF and can justify the costs so far. Just wondering if everyone will one day go MAFless.

[SSpdDmon]

Just curious but what about cars that are being sold today without MAF's. Are they dependant on VE tables and other related IAT tables and calculations, for example, to achieve proper AFR? :nixweiss: Beats me...

Is the MAF preferable to the VE tables for tuning if you had to choose one? Now that I have relocated my IAT, I haven't spent much time in SD. Prior to that, VE seemed to have more AFR variance than MAF. Personally, I believe the MAF is great for on-throttle airflow scenarios. Much less than 2~3% throttle and VE (if dialed in appropriately) will probably show more accurate fueling. In talking with Paul, the PCM will revert to the VE under certain situations. I have requested that we get some visibility to this when we're logging. Yes, we can always raise/lower the threshold for tuning the MAF and all. But, why waiste time trying to tune the MAF in areas it's not being used before you return the threshold (B0120) to where you want it? That and I think it would be a 'nice to have'...GM must have put it there for a reason, right?

Why does GM set up the VE as primary lookup up to what, 4000 RPM? Probably because of observed driving habits. How often are you above 4,000rpm and not full throttle?

Just trying to understand the logic. No doubt sees the benefit of the MAF and can justify the costs so far. Just wondering if everyone will one day go MAFless. Aren't we all. I don't plan on going MAF-less though. If anything, I'll go VE-less. :lol: Ideally, I want it all to work well together.


:cheers:

[Chalky]

How did you go about dialing in IFRs? I know how to adjust them when using VE. Just not sure how to go about adjusting IFR without VE.

Also wonder if anyone else has any copies of any top tier tuner tun files laying around? i would love to see them. I know Tordne has a library but I am not sure where all of the tun's originated.

This is a great thread along with the other links. It has rekindled my interest in working on my car again. (Now where did I put the RR?)

[SSpdDmon]

With a stock MAF curve and a screened MAF (preferably stock), you set the B0120 threshold to 1rpm so it's a pure MAF tune. Then, log MANVAC and your BENs. You need to apply the inverse of your BEN to the IFR table to control fueing. So, if you're 1% lean (BEN=1.01), you would multiply that cell by .99 to richen it up via the IFR table. Being creative with the filters will help you dial it in (ie RPM>2200, TPS>4%, no transitional throttle, no decel, etc.).

Then, you go back to SD with the new IFR table and dial in your VE. That's my current experiment at least. Eliminates having to fuss with the MAF table too much, which should be accurate for stock MAF sensors according to the 'experts'.

[joecar]

Just curious but what about cars that are being sold today without MAF's. Are they dependant on VE tables and other related IAT tables and calculations, for example, to achieve proper AFR?

Is the MAF preferable to the VE tables for tuning if you had to choose one?

Why does GM set up the VE as primary lookup up to what, 4000 RPM?

Just trying to understand the logic. No doubt sees the benefit of the MAF and can justify the costs so far. Just wondering if everyone will one day go MAFless.There's been discussion about MAF dynamics on ls1tech.com some time back...
basically, below [GM determined] 4000 RPM the airflow is too transitional so GM decided to use a combination of VE and MAF; above 4000 RPM the airflow behaves well and so GM used pure MAF.

There are cars that came with SD from the factory...
using MAP and RPM as indexes, the PCM/ECM looks up "normalized" airmass in a table ("g*K/kPa") and applies this in a calculation involving IAT, MAP, RPM (and a few others) to arrive at cylinder airmass... same as we cause to happen when we disable our MAF... and then the calculated airmass and commanded AFR are put thru another calculation to get fuelmass and then IPW.

I find MAF is a little harder to dial in compared to VE... requires better filtering of transitions... it gets a little kinkier after applying BEN, whereas VE tends to stay smoother... filtering and/or smoother transitions during driving is the key.

[Chalky]

joecar:

Have a link to the LS1Tech thread? Hard to find anyhting with their search feature.

[joecar]

joecar:

Have a link to the LS1Tech thread? Hard to find anyhting with their search feature.I'm trying to locate it, their search engine is broken...