Can someone share with me his Mass Air Flow (HFM) from different turbos and boost?

What i just already have is with durametric datalog

K24 oem 1,1 bar max hfm 1366
K24 /20G 1,58 bar max hfm 1900
997 tt VTG flashed 1,3bar 1450 hfm

what i am looking for is some cfm values from k24/18G with boost 1,1 /1,2 or 1,3 bar or other turbos (bone stock too)

 

Wanted to bring this back up as I've done some logs as well. It would appear that the stock 996tt MAF is maxing in the 1366 area as I can crank boost with no change in this value between 1.0 and 1.3 bar. Thoughts?

 

The ECU limits to 1366. You need a flash to change that.

 

It's a flashed 16g setup. If max MAF voltage corresponds to ~1366 and the MAF tube diameter is fixed, how a flash will fix that?

I noticed both of our VEs took a dump after about 5500 rpm, was your MAF sitting at 1366 as well? It looks like all the other cars in that thread were running non-stock MAFs (except for the 997 which has 2).

 

I am not an engine tuner - I don't even play one on TV. The following is my understanding of the issue, and may not be correct.

The limit of 1366 (in my logs, I have seen 1377 a couple of times, but mostly 1366) is programmed into the ECU as a limit. That doesn't mean that is the maximum value that can be measured by the maf, but instead the maximum value that is allowed by the ECU. That could be changed in software.

However, the issue is that you have to have enough fueling to be able to handle the additional air flow without creating an overly lean condition. That is one of the reasons that the limit is imposed. If you have upgraded the fuel system, e.g., with injectors and fuel pump, then you could handle more air, and a tuner could remap the ECU accordingly.

Jon

 

yep, seeing the exact same thing! The flashed X50 in the VE thread also had the same values

thanks for the input, I do have 62 lb injectors. I will "max" the MAF at 1 bar but at 1.3 bar with the MAF still reading the same, the AFRs (and timing) are still spot on and the car is 1.5s quicker 60-130. I'll check with Tony about it but I have a hunch the VE's for stock MAF 996tts dont mean much. I seem to remember reading somewhere that the MAF isnt really used at WOT...

 

Resurrection for more people's input

 

Do not rely on MAF figures above 4000rpm on WOT. Basically the DME will put in a value on a mapped car since it then uses temps, pressure etc.

This is why sometimes you will see high figures on stage 1 stuff, against stage 2 and so on.

It is a shame, because it could be useful in other calculations.

 

So, is there any way of logging the amount of air flow?

 

Blind calibration is what we call with mafs that are pegged to the max... the blow thru reads 2.5 times that...

 

I was interested to hear if there's anything which indicates how much air my engine is flowing

I guess this way isn't the right way

 

997tt, tuned 63.5 mm vtg, 1.3 bar, 1655 kg/h.

 

But when pegged at 2.5 times that, durametric still only shows 1366kg/h right?

 

no..... on our blow thru maf it will read higher...

 

a better measurement system at high airflow with a blown thru and a different maf....stock maf with stock diameter and very high airflow is blind?

greater maf housing diameter is the reasons for this or a another maf (or both)

can you build a adaption from a existing ecu file with stock maf to a blown thru ore do you need a complete new calibration