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Merc1 · **Re: Live NAIAS pictures: BMW X6 Revealed -** 01-15-2008, 02:42 AM

BMW had a glass-entombed display of the key hardware comprising the twin-turbo gasoline V8 that will power the 2009 X6. There are some unique details in the layout of the turbos that caught my eye as I wandered onto their stand.

Look carefully. The turbos are located between the cylinder banks, and the exhaust manifolds that feed them likewise take residence in the "vee" of the engine.

Every other modern gasoline vee engine (V8, V6, etc.) routes the exhaust out the other side of each cylinder bank and uses the space in the vee for the intake and fuel system hardware.

Why the reversal? Packaging. The turbos and associated exhaust hardware would normally occupy more real estate elsewhere in the engine bay.

Furthermore, turbocharged engines can generally get away with intake manifolding of less internal volume than those found on normally aspirated engines. BMW took full advantage of the packaging implications of this by switching the location of the intake and exhaust manifolds.

(The black plastic on the outside of the engine in the picture above is the intake manifold for one of the banks of cylinders. Sorry for the glare on the glass; it was unavoidable.)

By locating the small intake manifolds on the outside on the engine, and the comparatively large turbos and exhaust manifolds on the inside, the entire engine package ends up more compact than it would be otherwise. -- Jason Kavanagh, Engineering Editor, Inside Line

Straightline - 2008 Detroit Auto Show: Details on Turbo V8 in 2009 X6

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