NOTORIOUS VR
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« Reply #15 on: March 13, 2013, 08:38:20 AM »
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Maybe a little cheeky yes.. but you do say it often  No doubt you have contributed greatly, but I just find it a little comical that in many threads you end with "not for free" and it's only been apparent to me recently that you do that (as I have been away from the forum for a while and have been reading threads one after another). Take it as you wish, my comment was just a little poke no need to get bent out of shape over it |
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DigiFather
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« Reply #16 on: March 13, 2013, 11:55:50 AM »
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mbwiejska12 you can call to me, and i think you are from poland |
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Creed
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« Reply #17 on: March 13, 2013, 10:56:59 PM »
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So how about placing the MAF on one turbo intake and scaling the MAF accordingly for twins, less piping, less code, no ESP hack, etc..
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mbwiejska12
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« Reply #18 on: March 15, 2013, 04:39:07 PM »
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Is it possible, according to my idea, to transfer the MAF to the MAP sensor behind throttle, in intake manifold? I mean plugging cables from the MAF to the MAP sensor. Then it can be tuned using the map MLHFM (Linearization of MAF voltage)? Can it work?
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prj
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« Reply #19 on: March 15, 2013, 07:25:22 PM »
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Is it possible, according to my idea, to transfer the MAF to the MAP sensor behind throttle, in intake manifold? I mean plugging cables from the MAF to the MAP sensor. Then it can be tuned using the map MLHFM (Linearization of MAF voltage)? Can it work?
No, that is impossible, you need to write custom code. |
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NOTORIOUS VR
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« Reply #20 on: March 17, 2013, 08:18:33 AM »
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Sounds awfully complicated just to remove the MAF.
Why not just run an HPX (or similar) sensor in blowthrough, problem solved and still keep ME7 happy.
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bbernd
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« Reply #21 on: March 20, 2013, 12:52:19 AM »
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Sounds awfully complicated just to remove the MAF.
Why not just run an HPX (or similar) sensor in blowthrough, problem solved and still keep ME7 happy.
what I dont get ist... how does the blowtrough MAF handle the different pressures... I mean how does it recognize if the air blows trough with 1 bar or 2 bar... the airspeed could be the same at different pressures, but the amount of air is f.e. double... ...suck trough maf have always the same pressure to handle... (ok, maybe little pressure drop) |
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CoupedUp
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« Reply #22 on: March 20, 2013, 06:09:42 AM »
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what I dont get ist... how does the blowtrough MAF handle the different pressures... I mean how does it recognize if the air blows trough with 1 bar or 2 bar... the airspeed could be the same at different pressures, but the amount of air is f.e. double...
...suck trough maf have always the same pressure to handle... (ok, maybe little pressure drop)
The air amount isn't double. It's a closed system so what comes in(at the filter) MUST be the same that goes through the MAF, now the velocity, temperature, etc may have changed but those should all keep, roughly the same MAF reading because the convection of the thermister should be the same. I'd be worried about blow-by oil getting on the thermister and going through MAFs. |
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bbernd
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« Reply #23 on: March 20, 2013, 09:12:12 AM »
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The air amount isn't double. It's a closed system so what comes in(at the filter) MUST be the same that goes through the MAF, now the velocity, temperature, etc may have changed but those should all keep, roughly the same MAF reading because the convection of the thermister should be the same. I'd be worried about blow-by oil getting on the thermister and going through MAFs.
I think you didnt get me :-) Let me explain my thoughts twice. An inlet side MAF reads air at nearly atmospheric pressure (so to speak) even at lets say 2 bar pressure absolute after turbo. The air trough the maf is measured by its velocity. The faster the more cooling effect to the sensor. The amount of air is given by cooling effect to the sensor and the diameter of the MAF housing = MAF curve. So you put the same MAF to the pressure side. Sure the amount of air stays the same trough the entire system at the same 2 bar. But now, the MAF sensor is getting air with double density at 2bar. Single density at 1 bar and triple density at 3 bar. How can the MAF sensor handle this, because the velocity of the air maybe the same at different given boost pressures. Is the cooling effect of the air dependent to the air density? Must be I think!? |
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ddillenger
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« Reply #24 on: March 20, 2013, 09:29:49 AM »
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Noone suggested using a stock sensor, in fact the hpx sensor with the included transfer sheet is preferred as it has been calibrated for this use.
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
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nyet
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« Reply #25 on: March 20, 2013, 09:40:35 AM »
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Is the cooling effect of the air dependent to the air density? Must be I think!?
Yes. Absolutely dependent on the air density. Doesn't matter where you put the MAF, 5v max is 5v max |
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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catbed
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« Reply #26 on: March 20, 2013, 10:04:38 AM »
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I think you didnt get me :-)
Let me explain my thoughts twice.
An inlet side MAF reads air at nearly atmospheric pressure (so to speak) even at lets say 2 bar pressure absolute after turbo. The air trough the maf is measured by its velocity. The faster the more cooling effect to the sensor. The amount of air is given by cooling effect to the sensor and the diameter of the MAF housing = MAF curve.
So you put the same MAF to the pressure side. Sure the amount of air stays the same trough the entire system at the same 2 bar. But now, the MAF sensor is getting air with double density at 2bar. Single density at 1 bar and triple density at 3 bar. How can the MAF sensor handle this, because the velocity of the air maybe the same at different given boost pressures. Is the cooling effect of the air dependent to the air density? Must be I think!?
You have to think though, the air may be double the density due to compressing it, but it is not necessarily the same conditions as ambient air. Meaning when air is compressed, it heats up. Hotter air = less dense. The nature of a hot wire MAF takes into account the air density and temperature. |
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« Last Edit: March 20, 2013, 10:07:32 AM by catbed »
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bbernd
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« Reply #27 on: March 20, 2013, 11:23:11 AM »
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Doesn't matter where you put the MAF, 5v max is 5v max
No question - clear as water  Yes. Absolutely dependent on the air density.
Doesn't matter where you put the MAF, 5v max is 5v max
So from all these points (the following is strongly theoretical): If I put two identical MAF with identical diameter in the car. One on the inlet side and the other on the pressure side, they both will show the same values across the rev/boost range? |
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CoupedUp
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« Reply #28 on: March 20, 2013, 11:31:13 AM »
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I think you didnt get me :-)
Let me explain my thoughts twice.
An inlet side MAF reads air at nearly atmospheric pressure (so to speak) even at lets say 2 bar pressure absolute after turbo. The air trough the maf is measured by its velocity. The faster the more cooling effect to the sensor. The amount of air is given by cooling effect to the sensor and the diameter of the MAF housing = MAF curve.
So you put the same MAF to the pressure side. Sure the amount of air stays the same trough the entire system at the same 2 bar. But now, the MAF sensor is getting air with double density at 2bar. Single density at 1 bar and triple density at 3 bar. How can the MAF sensor handle this, because the velocity of the air maybe the same at different given boost pressures. Is the cooling effect of the air dependent to the air density? Must be I think!?
Ah, sorry I was thinking you were saying it wouldn't work. Yes, you're right. The pressure increase brings more mass(higher density) into the equation which gives the air more potential to take heat away from the thermistor. Your convective coefficient for heat transfer goes up with more density. The MAF sensor should definitely come after the intercooler to battle with less tuning changes. I'm not sure if there would be enough delta(T), pre-intercooler, to get a good resolution out of the MAF. bbax(response 2) - I don't think it will be 100% the same because you'll be flowing air that is slightly warmer than ambient, given that you have a decent intercooler setup. Also, "straightness" of flow comes into account with a blow-through MAF too. You wont want any turns shortly before and after(although not as critical). |
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« Last Edit: March 20, 2013, 11:33:05 AM by CoupedUp »
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bbernd
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« Reply #29 on: March 20, 2013, 11:55:57 AM »
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Ah, sorry I was thinking you were saying it wouldn't work...
thank you for understanding me  I wasn't the questions if it does make sense with stock sensor, or doubt it will work... it was only to clear my last questions about functional working... btt thx |
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