XSeries-forum

so.. its not 2 turbos, its not a twin-scroll turbo, what exactly is the modern TwinPower Turbo then?

one read here, which has left my head spinning like a turbo!

It’s a twin turbo in both of mine (E71 & F46) but I did notice that it is only the LCI F46 which actually has two hairdryers!

Are you certain that it isn’t a ‘twin scroll’?  Looking at Realoem shows a split exhaust manifold feed to the blower with a wide exhaust turbocharger scroll cage that resembles a twin-scroll.  Single scroll have almost identical stage sizes whereas yours has a ‘standard’ inlet side (charge air) and a wide driven side (exhaust).

https://www.realoem.com/bmw/enUS/showpa ... Id=11_4474

It may be an optical illusion.

This might help though......

https://cdn.bmwblog.com/wp-content/uplo ... _eng_3.jpg

most literature suggests the modern TwinPower units are single turbo based.

the link I sent below reads 'modern BMW TwinPower engines don't necessarily use twin-scroll turbochargers, but they do have a distinct exhaust manifold that catches more exhaust pulses to feed the turbo and thus create more power with less lag'

Updated my reply.....and yes it is confusing.

The pre-LCI F46 (220 Gran Tourer) was a single turbo with that type of exhaust manifold, but now has two turbos as the engines have been de-tuned to get through EU6c/d emissions, and then the second turbo brings the bhp and torque back up again.

Yours could be either just the clever manifold, or a twin-scroll.  Clear as mud really!

A bit like the engine numbering being 630,635,640 but all use a 3-litre engine!  I would expect yours being a 640 it ought to be a twin scroll?

Seems to be, on further reading so far all indicators are that TwinPower nowadays mean twin-scroll.

also the N55 exhaust manifold 'seems' to suggest the airflow being split into 2, for the twin-scroll feed setup