you to clean aluminium

[PeterCrespin]

Marek covered it all except I assume the reduction is in HC not NOx levels. NOx is formed at high combsution temps, hydrocarbons are left over in unburnt fuel - ergo the air pump is presumably an HC during start-up reducer system.

Whoever told yo the system saps lots of power obviously hasn't read this thread....

I repeat - the air pump only operates brifly at start-up. Doubtless a few joules are used up pumping the air, but unless you do dragstrip runs on a stone cold engine you're never going to need much power any time the system is working. The system will not be operating during any normal driving.

Since non-air pump engines often have a jockey pulley there instead (IIRC) you aren't even going to save yourself a belt by tossing the sytem, it's purely a cosmetic thing when getting rid of the junk. Strictly-speaking, part of me feels bad about jetissoning equipment designed to cut pollution. But this sort of kit was fitted due to the driving habits of Californians in the LA Basin, who often would rather take a car than walk a quarter mile to the paper shop. Since I only start V12s (or my current V8 for that matter) if I intend to get it fully warm, I think my HC emissions are pretty low in comparison to the smog drivers.

There are other aspects of the emissions spec such as timing control and lower compression ratio that do rob power somewhat . But realistically, nobody running even a smog-equipped V12 E-type on the road is going to be short of power.

[Rui]

They go through the inlet manifolds to the exhaust ports. Air is injected on the outlet ports therefore not changing the mixture in any way.
Rui Meneses
S3 1973