I read somewhere in a sticky that a member actually tuned the MAF tables with a Volt Meter, or DMM. Is this okay to do? I was actually thinking about logging it when I got my LM1. This way I could relate the RPM and AFR from the LM1 logging also the voltage from the Maf then crossing that with the air flow and RPM that datamster tells me. I understand the LM1 is probably faster but I should get close.

Does this sound doable? Otherwise you just have to take shot in the dark at it. If this will work at idle and part throttle through the first three maf tables, will it work in 4,5,and 6? I have not read enough into PE tunning yet.

 

Sorry if I'm being captain obvious here, but couldn't you just log it with some.......logging software?? Tunerpro, winaldl, or ECM852 will allow you to fully log everyone of your sensors.

 

LM1 doesn't have inputs, unless you order the accessories (like auxbox, rpm converter, etc...), unless they've changed recently.
With the ALDL dataloggers that are available, there's not much need for too fancy stuff, for the type of tuning that's common for daily driver cars.

Linking the log files together is a pain. ESPECIALLY SINCE THE LM1 LOGWORKS LOGS SHOW THE WRONG TIME-BASE... Argggh. I should check if they've fixed that yet. Told them about it in December I think. But, it's easy enough to fix in excel.
A good thing to use in excel: copy the LM1 .dif file into a worksheet within the same workbook as your ALDL log. Then, insert a column in your ALDL log. Then fill that column with =lookup(time from ALDL log,time array from LM1 log,AFR array from LM1) (for example: =lookup('ALDL'A1,'LM1'$A$2:$A$3000,'LM1'$B$2:$B$3000). Fill that into the column in your ALDL log. Delete the original time stamp of the LM1 log, and make it go 0; A2+0.15; A3+.15; etc... (double click on bottom right of that cell, and it will automatically fill the column). Delete the original time stamp of the ALDL log, if it's not in a good format, and do a similar fill (0; A2+.09; A3+.09;...), but in whatever time-base it records at. Then graph the data. The LM1 data may be shifted. So, for the LM1 time, change the 0 to move the data left or right. Try to match DFCO areas. If the time base is wrong, change the .15 to .164, or whatever it is to 'spread' the data out to match up DFCO points. With practice, it'll only take you a few minutes each time. If you have excel..... note: could also use HLOOKUP, just follow excel's help menus...

More funnnn with computers!!!

 

I have been using Datamaster, and to my knowledge it does not show voltage outputs for any sensor except the o2 sensor. I could be wrong but I have not stumbled across it. I have not used the software you mention, I do have Tunerpro however, but I thought that was just tuning software.

 

Tunerpo RT datalogs. You should have at least 20 items or so of data in your logs, including the MAF voltage.

 

Thanks! I am off to go look at the details of that software.

 

I guess now that I think about it, how does it benefit me to know the voltage rather then the actual air flow. The air flow in my software is a direct correlation to the maf voltage, so if need be I could always look at the maf tables and get close.

 

Exactly!! Don't worry things will start making more sense as you go along.

 

However now I wonder.....I read an article in one of the stickies about the maf tables needing work if you do something to change the flow characteristic, like taking the screens out. I also read a mustang article about tunning and they mention maf tunning and they said that the maf tables could need some work after adding a cold air intake, or something other then stock.

So what actually changes?? If the voltage is directly correlated to the air flow then how can they be off or need adjusting? I have read very much about changing the maf tables, I am still at a loss as to what exactly to change. Some have mentioned calibration. In tunerpro I believe that the value I can change if the maf tables is air flow.

As I read on.......

 

The screens serve 2 purposes. Mainly, they keep debris from hitting the spider web sized wire. They also effect the turbulence of the air as it passes this wire. The turbulence helps keep a steady reading at low flows. I've never descreened a MAF, so I haven't seen this in person.

If you grind down the heat sink, you'll effectively make the diameter of the tube bigger, which lets more air through the tube without changing the flow through the sample zone in the smaller inner sampling orifice. This makes the airflow vs volts change, requiring a re-cal.

The MAF has built in / inherent air temp compensation, but, if you make a really short duct, and have an air filter there, or perhaps a bend in the tube near the inlet of the MAF, the readings can fluctuate (buffetting), and/or scew (more flow on one side of the MAF). An open ended MAF is bad. It needs a semi-long straight inlet for stable results.

 

So my next question would be should I even worry about that now?

I am still somewhat concerned about the air flow numbers in the table (air flow vs. RPM). I dont believe I am seeing enough flow for my 383. For instance the guy that tuned the car had the max value come in at 3600 RPM's which is different from a stock table. However I believe these are maximums so I dont think I have to worry about it.

I read somewhere though that the fins act as a heat sink, so the MAF may not live very long without them.

 

Those maximums "clamp" the calculated airflow, in the event of a MAF failure. They also limit the airflow used for fuel calculations. Once they're set to 255, there's no more way to command 14.7, and get 14.7 if the engine flows more than that. So, what's done, since the engine is usually at WOT when above 255 g/s, is to use PE fuel to get the desired air fuel ratio (but requires commanding a much richer air fuel ratio). There's no way to get the 165 to read more than 255 g/s with a stock MAF. You can however, put the MAF sensing part of the sensor into a larger tube, and change your injector constant (and then re-change the calculation for the displayed value), and change the calculation for the displayed MAF flow vs Voltage. Then, you'll be commanding X and getting X.

However, resolution is lost in the process (but is still fine, up to a point).

 

I tell people that all the time and none of the MAF users believe me. It is good to hear you say that. They all think it is an 8_bit ECM problem limiting the airflow. The 165 ECM also has an input for a digital MAF so that is an option too, but needs a code mod.

 

This might be getting slightly off topic of this thread, but where should my flow numbers be for a 383. Right now the most air flow i have seen is 218 grams/sec.

 

Should be more than that...

 

218 grams/sec is about 29 lb/min which is about 315 FWHP. I would think your 383ci would be a fair amount higher on airflow.

 

Well I am still running the stock TB. I do however have a ported plenum with siamesed runners, and a TPIS big mouth manifold. I had the heads ported an polished and 2.02 intake and 1.6 exhaust valves put in. The cam is kind of mild.

However I have not yet put headers on the car, that is going to happen this weekend, and the exhaust is fairly restrictive. My thoughts, along with a guy I work with is that those numbers will go up and the car will breath better.

Now, how many CFM's is the stock maf capable of vs. the stock TB. Would it warrant me to get a larger TB?