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Author Topic: crazy maf values problem 2.9 Stroker  (Read 566 times)
misuspl
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« on: July 06, 2024, 03:22:49 PM »

I have a problem with the wavy MAF reading, usually 3800rpm 280g/s 3840rpm 320g/s 3880rpm 270g/s 3920 300g/s, sometimes it fluctuates 30/40g but sometimes it even reaches 70g in the 40rpm range.
Logged me7logger, changed ECU, MAF harness, DV, manual boost controller instead of N75, throttle, intake manifold.
Setup:
Stroker 2.9 with K04 RS6 Hybrid
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cherry
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« Reply #1 on: July 06, 2024, 04:24:25 PM »

I can only guess, especially without logs. Maybe surging because of too high boost at too low flow. But you should hear this. Try with less pressure. Which boost pressure do you have and which altitude are you?
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misuspl
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« Reply #2 on: July 06, 2024, 04:45:25 PM »

the boost does not wave, tested on mbc at 1 bar it is the same, the maximum boost is 1.5 bar at the top. I have a 5120hack, so the set pressure was 1240mbar, and the result was +- 1230, the deviations in the boost are so small that it is not the fault.
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misuspl
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« Reply #3 on: July 06, 2024, 04:51:06 PM »

Log
https://docs.google.com/spreadsheets/d/12g11r-bSzhtRHsvkvfoM07Eiei07SCGPssqoj3imvx8/edit?gid=1739520211#gid=1739520211
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cherry
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« Reply #4 on: July 06, 2024, 05:35:49 PM »

Normally you cannot see high frequency surging from logs. I had this problem with TFSI K04-064, MAF is going crazy. Did you connect a mechanical boost gauge or trust in the logs only?
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misuspl
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« Reply #5 on: July 06, 2024, 05:50:12 PM »

I have a boost gauge inside the car, and it matches the logs.
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misuspl
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« Reply #6 on: July 06, 2024, 05:51:18 PM »

I have a boost gauge inside the car, and it matches the logs.

How did you solve the problem in that case?
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cherry
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« Reply #7 on: July 06, 2024, 06:07:37 PM »

I tried a few things with cam angle in past but no luck, so i simply lowered the boost. Check attached log from a CDL engine, there is also no boost deviation in logs, but check MAF values @ 4000 rpm. The log is only a few days old. I could hear the surge from these engines also in few dyno videos.

Is it mechanical boost gauge or electric? There will be a high frequency flutter noise.

To get rid from surge you need more flow or less boost. Do you have any compressor map from these turbos to check if you are in the range?

Edit: Attached also the raw csv, not sure if the xlsx will open correct in all country settings...
« Last Edit: July 06, 2024, 06:10:53 PM by cherry » Logged
misuspl
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« Reply #8 on: July 06, 2024, 06:21:57 PM »

I don't hear any surge in my car
In your log, the flow waves once at 4k rpm, in my case, at such speeds, the variable phase works, but the flow waves all over.
Its electric boost gauge,
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