I've seen that explanation but it confuses me a bit. What is the air source that the secondary air pump uses? If it's exterior air, the air shouldn't be considered "warm" as compared to exhaust gas, right? So how would extra exterior air heat up the catalytic converters any more than having just the exhaust gases pass through the converters?
It uses external air, on my M54B25 it is a bit different than on B30 and it has small washable foam filter under top removable cover.
Like in this video:
http://www.youtube.com/watch?v=HgvtCI21Aio
I think the temperature of air does not matter, exhaust gases burn hotter with added air (it is my amateur physicist opinion).
Edit: there is an explanation in this article:
http://blog.bavauto.com/12072/bmw-se...to-diy-obd-ii/
Yes, thank you.
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03 ImolaRot|6sp|Alcantara|Silver Cube|CW|Xenons
Coby Alcantara Knob|CF Diffuser|BMW Performance Kidneys|Umnitza Eyes|RCR|UUC TSE3|GruppeM CF-Kevlar Intake|BC Racing Coils|Spacers|BavSound Stg. 1
BMW/CCA/CT VALLEY
1979 911sc: The Perpetual Project
Ive also recently found out why it's so noisy all of a sudden.... There is a bearing in there that is known for getting dry. This is what is making the noise, however, it is still working properly, just a bit noisier than normal. When the day comes that the pump starts to get fussy I have a real issue, as these pumps are pretty pricy.
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03 ImolaRot|6sp|Alcantara|Silver Cube|CW|Xenons
Coby Alcantara Knob|CF Diffuser|BMW Performance Kidneys|Umnitza Eyes|RCR|UUC TSE3|GruppeM CF-Kevlar Intake|BC Racing Coils|Spacers|BavSound Stg. 1
BMW/CCA/CT VALLEY
1979 911sc: The Perpetual Project