MAF Flow sheet input?

[Tried2Live]

I have my car running fairly well now, but I'm wondering if there is a place I can enter my MAF meter's flow sheet to get things calibrated a little better.

Pro-M MAF meters come with a 9 point flow sheet listing the voltages the MAF is reading at whatever Kg/Hr air flow.

Is this something I can do?

[SA]

I have my car running fairly well now, but I'm wondering if there is a place I can enter my MAF meter's flow sheet to get things calibrated a little better.

Pro-M MAF meters come with a 9 point flow sheet listing the voltages the MAF is reading at whatever Kg/Hr air flow.

Is this something I can do?

Go to Setup|Sensors|Mass Air Flow Sensor|0-5V MAF|MAF Sensor Cal Table.

The X-axis is voltage and the Y-axis is percent of full scale.  What you have to do is plot your flow data and do a curve fit that will give you an equation for the curve.  You can use this equation to determine your flow readings at each of the specific voltage breakpoints in our table.  Then just take that data and divide the units out by scaling it from 0-100%.

I've attached an example.  Look at sheet 2 of the attached Excel spreadsheet.

SA

[Tried2Live]

Thanks for the spreadsheet.

I used another program I had to convert from a 9 point curve to a 30 point, plugged it into that spreadsheet, copied those numbers to the chart and was all set.

Took the car for a spin around the block and was very impressed. Drag radials don't hook well in the cold anyways so it was a spin-fest, but the fact that it made power and only popped through the intake once makes me happy.

I can't wait for the wideband now. This thing is way more fun to mess with than the other programs I've used.

[SA]

Great news!  Sounds like you've been around this block a few times   .  

Aside from the sync problem (which was a little unusual), it's always nice to hear from someone who can PLUG this thing in and PLAY with it like you have   .  Congratulations!  Well done.

By the way.  Are you using the distributor wheel with the modified tooth?  I'm wondering if that modification may have contributed somewhat to fixing the problem.  If so, it would be nice to know in case this issue comes up again with someone else's combination.

SA

[Tried2Live]

I modified the wheel a bit, but not much. I'd say 5-10 thousandths at the most. That one tooth is already pretty small, so I didn't want to take it down too much further.

[BLKMGK]

Why modify the wheel?

[SA]

Why modify the wheel?

I suggested it.  It was an effort to help the software out a little and relatively easy to do.  There's definately some variation in the sensor outputs from these distributors.  I've never seen or heard of an issue with a stock 5.0 distributor but he's using the one originally installed on the 351's in trucks.  We've never tested one of those.  

I was also wondering if the same change might help the guys using the MSD distributors (which seem to have even more variation).  I have a special software version in testing right now that may eventually help with the MSD distributors though.

SA

[Tried2Live]

He thought that possibly the narrow tooth wasn't narrow enough, and that the computer may not have been able to tell the difference between it and the others.

I guess the narrow tooth is supposed to tell where #1 cylinder is or something.  

[SA]

He thought that possibly the narrow tooth wasn't narrow enough, and that the computer may not have been able to tell the difference between it and the others.

I guess the narrow tooth is supposed to tell where #1 cylinder is or something.  

The leading edge of the narrow tooth is 10 degrees BTDC of cylinder #1.

SA

[BLKMGK]

Ah okay - Scott that's the SAME distributor used in my Mustang BTW. As you probably know by now it's a pretty common unit and works great. I've heard of at least one Mustang having issues with the MSD unit so variances don't surprise me.

Still deciding what to do with my car or if I ought to go for a turbo Miata.

[SA]

Ah okay - Scott that's the SAME distributor used in my Mustang BTW. As you probably know by now it's a pretty common unit and works great. I've heard of at least one Mustang having issues with the MSD unit so variances don't surprise me.

Still deciding what to do with my car or if I ought to go for a turbo Miata.

Yeah...Mike Sitar used the truck distributor with the EMS on his car until he decided to put one of his 12 tooth wheels on the crank.  Worked fine for a while on his car then he rebuilt the motor and started having some wierd noise issues.  He still has the distributor and pickup but he chopped all but one of the teeth off and is using it as the sync signal now.  I think he enjoyed ditching the TFI module   .
 
SA

[mlowry1260]

SA,

I'm new to the AEM EMS and I'm trying to understand the relationship of maf flow versus % of load the program shows.  I have a meter matched to my 370 cc RC injectors that has much greater flow potential than the stock maf meter.  What makes the % of flow curve look different from the stock curve?  Of course my meter will flow greater volume than the stock 19# maf meter.

Mark

[SA]

SA,

I'm new to the AEM EMS and I'm trying to understand the relationship of maf flow versus % of load the program shows.  I have a meter matched to my 370 cc RC injectors that has much greater flow potential than the stock maf meter.  What makes the % of flow curve look different from the stock curve?  Of course my meter will flow greater volume than the stock 19# maf meter.

Mark

Good question!

Let's see if I can answer it without writing a novel   .  The AEM Pro software allows the user to view calibration data using several different unit conventions.  Because of this, the base calibration curve has voltage breakpoints on the x-axis and % of full scale on the y-axis.  This way, it doesn't matter if your MAF sensor was originally calibrated in lbs/hr, grams/sec, kg/hr or furlongs per fortnight!  

I posted a spreadsheet above that shows how to take a specific calibration curve (in this case for the stock Ford MAF) and turn it into a curve that can be entered in our AEM Pro software.  

Hope that helps.  If you have any more questions, feel free to PM me.

SA

[anoldsman]

What makes the % of flow curve look different from the stock curve? Of course my meter will flow greater volume than the stock 19# maf meter.

I am not sure on yours but here is how I believe that Pro-M recalibrates for a different injector size.  If you look at their 19 lb/hr flow sheet verses their 50 lb/hr flow sheet it is simple ratio increase. 50/19 = 2.6316 and the max flow difference is 99.62/37.86 = 2.6313.  If you multiply the 19 lb/hr flow sheet by 2.6315 it will be extremely close to the 50 lb/hr flow sheet (because of rounding errors).  So just input your flow curve into the AEM and you should be fine because I assume that the flow increase is proportional to the injector flow increase.  I hope that this helps.

Chris

[Paul Fontenot]

I fed my MAF data to the spreadsheet and it gave me an equation (y = 99.115x2 - 196.75x + 151.83). What in the world do I do with this? I'm assuming I use it to convert the KG/Hr data I have but I'm not sure where this goes on that spreadsheet.