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Author Topic: M3.8.X Stage 1 maps & procedure  (Read 9505 times)
marantzvieta
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« Reply #45 on: November 21, 2024, 06:50:17 AM »

I wonder how anyone could get any more with stock turbo. The 180hp variant runs at about 140g/s MAF at full power. See attachment...  Huh Huh Huh

THIS is why i wanted you to post it here. 140g/s for a 180hp tune is low. A healthy 150hp must flow about 130g/s at redline, a healthy 180hp should flow 150g/s at redline. You might have a vacuum or boost leak, maybe a defective component somwhere... this is why you are having underboost issues and not reaching requested loads.

My car has reached 130g/s with 150hp tune, 152g/s with 180hp tune, and now I am flowing 164g/s at 5700rpm and 169g/s at 6300rpm. Which I believe to be the absolute reliable limit to stock k03 turbo.

To estimate power it is said through the internet to use maf reading/0.8 but I consider this calculation too optimistic as 130g/s would translate to 162hp. I use mafreading*1,2 which translates 130g/s to 156hp (more accurate on my perspective). Same for 180hp, do the maths. 169g/s*1,2 is 203hp, which I belive to be accurate when running against similar power/weight cars.

Smoke test your car and make a thorough check. Untill you don't get those values with stock tunes, do not tune any further.

Best regards.
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doktor
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« Reply #46 on: November 21, 2024, 01:22:14 PM »

THIS is why i wanted you to post it here. 140g/s for a 180hp tune is low. A healthy 150hp must flow about 130g/s at redline, a healthy 180hp should flow 150g/s at redline. You might have a vacuum or boost leak, maybe a defective component somwhere... this is why you are having underboost issues and not reaching requested loads.

My car has reached 130g/s with 150hp tune, 152g/s with 180hp tune, and now I am flowing 164g/s at 5700rpm and 169g/s at 6300rpm. Which I believe to be the absolute reliable limit to stock k03 turbo.
Sorry there was some misunderstanding, I was just wondering how any real figures above 180hp would be possible with a stock k03, but then Leonhard pointed out that my compressor map was wrong. I believe the car has the K03 with 2072 compressor which looks much better than the 1870. I did one more log and it seems it works acceptably well. The slight underboost happens between 2.5 and 3.5 krpm for 3rd gear pull. For 4th gear its better, and for 5th gear it is almost perfect. This looks like a job for PID tuning, but I don't even know any other maps except ZSOLLDRN. I think I will just leave it as is...

Edit: About ZSOLLDRN... It says "Boost Control Filter Time Constant for Low Pass". I know what is a time constant of a low pass filter, but low pass where? The feedback loop can contain more lowpass filters... And the values in it (below 100ms) are still much shorter than the duration of the overboost (like a few seconds).

-Jan
« Last Edit: November 22, 2024, 02:21:40 AM by doktor » Logged
doktor
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« Reply #47 on: Yesterday at 06:45:29 AM »

A question about overrun fuelling (I am actually trying to do the opposite to most people - maximize engine braking capability), why do I see around 0.6ms load during overrun? Even several seconds after releasing the throttle, in a wide range of engine speed. Is this some kind of a bug or does it always fuel on overrun?

Also, I noticed the idle regulation starts at quite high rpm, like 1500 (other cars 1000-1200). I only see a relevant value called NDLSO (obere Drehzahlschwelle für digitale Leerlaufstabilisierung - Upper speed threshold for digital idle stabilization) which reads 1200 and does not seem to reflect reality. What are the relevant maps for overrun fuelling and idle regulation?

Thanks
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