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Getting more air...

I have a slight problem with my tuning

I do not get enough air at higher revs.

Enigne is a 2.0L, turbo boost is 2779,4 mBar, but I only get a MAF reading of 1188mg/r at 4.000 rpm. That is only enough air to 86mm^3 diesel - or roughly 180BHp :/
Turbo is TF035 VNT 3. gen from BMW 320d 177BHp.

Now what can be the reason for the low MAF reading?
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It could be. Also weak VE or turbo.

Do you know intake valve/throat diameter, valve lift, duration angle?
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Btw how about boost temperature?

Btw2. It's ~570lg/h - near of the end of your MAF range
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Originally Posted by yan.ko View Post
Btw how about boost temperature?

Btw2. It's ~570lg/h - near of the end of your MAF range
this is my MAf scaling:
http://2200kbhn.dk/log/MAF_scale.JPG

You say I'm running on the edge of it ?

I do not know data for valves, nor the cam
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Ha! That one you sent me in PM ended a bit sooner :-)
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I think yan.ko might be right about your MAF.
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(Post Link) post #7 of 10 Old 02-06-12 Thread Starter
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Originally Posted by yan.ko View Post
Ha! That one you sent me in PM ended a bit sooner :-)
Yes it did, it ended at 4.8V, now I have extended it to 5.0V.

TribesMan: So the problem is not that I do not get enough air through, but since the MAF is on it's limits I'm being held back by that? (Actual MAF value is higher, but sensor not being able to see that?)
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Yes thats what I think is limiting you.
BTW, you extended the axis of the MAF linearisation map? There is no point in doing that, you cant extend the measuring range of MAF by that.

Well you can make a test. A simple log file. Engine speed, air quantity (mg/inj), and MAF voltage.

Then make an acceleration in 4th gear or higher from 2000 to red line. Then you will probably see two things. One is that MAF hits a "plateau" at lets say 4.8V, from certain RPM this voltage will be constant (limit of the MAF). And then you can then calculate from mg/inj into kg/h. And you will probably see that airflow does not reach above ~570kg/h.
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(Post Link) post #9 of 10 Old 03-06-12 Thread Starter
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Quote:
Originally Posted by TribesMan View Post
Yes thats what I think is limiting you.
BTW, you extended the axis of the MAF linearisation map? There is no point in doing that, you cant extend the measuring range of MAF by that.
Naturally I cannot extend the physical limits of the MAF, but what I can change is the span within the physical limits that the ecu will use as plausible values. On my SW everything above 4.8V is considered an inplausible reading. On others (same HW) the plausibility is 5.0v. So I have extended the plausible limit a bit. But I'm still within the physical limits of the MAF. I extended the MAF voltage axis, raised the maximum plausible MAF readings, upper voltage + healing constant.


Quote:
Originally Posted by TribesMan View Post
Well you can make a test. A simple log file. Engine speed, air quantity (mg/inj), and MAF voltage.

Then make an acceleration in 4th gear or higher from 2000 to red line. Then you will probably see two things. One is that MAF hits a "plateau" at lets say 4.8V, from certain RPM this voltage will be constant (limit of the MAF). And then you can then calculate from mg/inj into kg/h. And you will probably see that airflow does not reach above ~570kg/h.
Yes, I need to make that log, but I need to make readings of the voltages manually, the ecu does not log the raw voltage. :/
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(Post Link) post #10 of 10 Old 02-07-12 Thread Starter
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Quote:
Originally Posted by yan.ko View Post
Btw how about boost temperature?

Btw2. It's ~570lg/h - near of the end of your MAF range
HAH! Found what I believe is a single value limiting the maximum airflow to... 570kg/h, despite the sensor being able to see mor than this. I have just tried changing it to 600 to see if i get higher values in my logs. If I do, I need to find out what the limit is exactly, or I need to change the MAF for the one from a 2.8 JTD. (By the looks of it, it is a 1000kg/h sensor..)
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