Tri-turbo X5 40d?

[snipez999]

Did I not read this new lump is due out in early 2012? Missus has a Q7 S Line 30d and is due to change next May. She loves he X5 so would be nice (for me too I think!) if the new lump were out by then too - anyone know?

[Rusty]

Did it not state that the 3rd turbo is for the diesel tanker following behind?


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[X5Sport]

Rumours and speculation were certainly rife a couple of years ago, but never more than that (so far at least) and when you look at the performance of the 40d twin-turbo, it's hard to see why it would be needed. Even at 300+ bhp it still has some growing room, but it might be pushing too far for the current 6-cyl unit to have three turbo's.

I was trying to work out the configuration as the plumbing to get three to play nicely might be easier said than done in practice. I suppose they could use the twin-scroll setup for the pair and a conventional smaller, or larger, turbo depending upon running order onto manifolds. The two turbos on the 40d is quite an arrangement with the airflow being directed in different directions depending upon engine speed and throttle demand. Control of inlet and exhaust pressures to keep the through flow going without harmonic pressure standing waves in the system would be kind of interesting on a three way set up.