Originally Posted by
Doby
alex it clearly says bmw use chain!It was just saying how the cams were connected to the crank some cars belt others chain.
Your right - I miss read that, its not exactly clearly written when you start to decribe a specific system and and instantly start by stating the bleeding obvoius about generic systems LOL
But its still not correct.
With double-VANOS, the opening period of the intake valves are extended by 12 degrees with an increase in valve lift by 0.9 mm.
Its more like 60 degrees (in total they are saying 12+15)\and the is no change in valve lift at all - that is the what the ValveTronic system achieves.
The advantage of double-VANOS is that the system controls the flow of hot exhaust gases into the intake manifold individually for all operating conditions. This is referred to as "internal" exhaust gas re-circulation, allowing very fine dosage of the amount of exhaust gas recycled.
Internal EGR is achieved by not allowing all the exhaust gas to escape. The exh gas does not get into the manifold. If you consider M engines typically have individual TBs and so allowing EGR into the inlet manifold would cause a few issues.
Other than that its accurate enough
But its still probably not what Cheeky Dog is asking - as I suspect he's asking why his E46 M3 is rattleing!
They do suffer with VANOS rattle and its not a cheap fix - cira £1000 in parts alone!
Alex