Stage 2 Maf problems?

[Connor]

So you're saying about the 2.0 MAF in a 2.8 housing, does that mean it's just a pure air flow restriction or the sensor is incapable of reading the airflow?

[tb205gti]

The sendor is not able to messure the flow.

[Connor]

So how does fitting the same element to a bigger housing help? Excuse my ignorance but im trying to get my head round it

[jammapic]

You would recalibrate that sensor to take into account that what it was reading was actually more air

[dr_jekyll]

Another words it would measure more air but at a lower resistance because of the volume increase on the intake pipe

[jammapic]

For example,

If on the stock MAF a certain voltage measured 900 units of airflow, the bigger one might measure 1350 units of airflow.

You just need to re-scale some stuff in the map, and that is then calibrated in.

JP

[Slam Wagon]

Dont see why the 2.2 isnt the better option, ok it cant measure much more but still it measure more. And no faffing with swapping bits over, its just buy a new whole new unit. Then you have to get it mapped in anyway.

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Plus your saying for for a 3" pipe, 80mm is 3.1

[jammapic]

It really doesn't measure that much more.

I think the stock 90 one measures 900 and the 2.2 measures 1050. IIRC.

JP

[pro_steve]

The stock 90 can measure up to 577Kg/hr, the 2.2 MAF can read 774 Kg/hr.

At 5000 RPM, for example, that's a difference of 960 mg/r vs 1290mg/r. Quite a big difference really. And obviously you aren't going to get all of that useable range out of it, but with some clever maths on the linearisation you can maintain smoke control down low and also up high and then get it useable above 900 anyway. If your MAF is broken anyway then it's not too much trouble to change to one of these.

When you use the normal MAF in a 2.8 housing, how are you working out the calibrations other than just the maths for the cross section, you've got boundary layers, the depth at which the sensor is submurged/actually measures the flow etc etc to work out, or does it not need to be that precise?

[dr_jekyll]

Just so you all know new maf solved my issues ? lol


The akward moment when two well known mappers comment on your thread......
[attachment=18848]

[Connor]

3... lol

[jammapic]

No fighting. Every day is a learning day....

[dr_jekyll]

Only abit of banter were all learning here bud

[pro_steve]

haha, there's no need to argue on forums, I was just putting the information out their because I had it in an excel sheet from last week, I'm sure James finds it interesting as do all tuners when we talk numbers etc
And obviously we don't get all of that extra top end range but the linearisations won't be far off and the figures are interesting. In the lower revs the MAF reading can go right up to 1400 if you've got a nice big boost leak.

[tb205gti]

The stock 90 can measure up to 577Kg/hr, the 2.2 MAF can read 774 Kg/hr.

Are you sure about that? Do not take the max flow limiters as gospel.. Ever tried fitting one in a flow bench?

At 5000 RPM, for example, that's a difference of 960 mg/r vs 1290mg/r. Quite a big difference really.

It is not able to measure that much, not the 2.0 nor the 2.2 sensor. They are maxed out before that. Let's just say that they are able to measure that kind of flow - how much power does that give us? Remember we do not want any smoke from it.

And obviously you aren't going to get all of that useable range out of it, but with some clever maths on the linearisation you can maintain smoke control down low and also up high and then get it useable above 900 anyway.

clever math = decalibration ? I know that there are some folks that tend to decalibrate the sensor by 30% - thinking it will give them more headroom. But you can not beat physics. Running decalibrated is always a bad idea.

If your MAF is broken anyway then it's not too much trouble to change to one of these.

True, but the 2.2 sensor will not give you much more (measurable) flow as you think.

When you use the normal MAF in a 2.8 housing, how are you working out the calibrations other than just the maths for the cross section, you've got boundary layers, the depth at which the sensor is submurged/actually measures the flow etc etc to work out, or does it not need to be that precise?

You do not need to be 110% accurate on a diesel since the engine will not die from a miscalibrated sensor - but using a flow bench and some logging on the car (wideband lambda) you can get a 98% match with reality. The rough work is done by using maths, the finetuning is done by using the flow bench. Once you have the first one nailed - you have them all, as long as the sensor position in the housing is the same. Offsetting it will give you a different reading.

Getting the right MAF is critical to be ableto control the smoke properly. it will not give you more power, but it will give you a better burn since you have so much more control.

MAFLess is _very_ rough, the maps needed in order to run MAFLEss have too low resolution. I see no point in running without a maf really.