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
chavis10 says:
07:29 AM, 01/14/08
GM's new 4.5L diesel will have a similar design as well
vvk says:
07:38 AM, 01/14/08
Amazing. I wonder how they handle heat dissipation issues. Those turbos get red hot.
felonious says:
08:57 AM, 01/14/08
That's one tall engine setup! Unfortunate that it will only fit into a truck or SUV in that configuration.
Regarding the glare on the glass, you can use a polarized filter to get rid of that in the future.
ateixeira says:
11:05 AM, 01/14/08
Totally agree about the heat. Especially with an engine cover, you gotta wonder how they'll get rid of all the heat produced in that area.
SubyTrojan says:
12:52 PM, 01/14/08
Great blog entry, Jay!
I was wondering the same thing, vvk.
iskch says:
02:30 PM, 01/14/08
Awesome concept by BMW. We'll see more use of turbo charge engines.
estreka says:
02:53 PM, 01/14/08
It's a positive that the exhaust is atop the engine (since heat rises, engine temps should remain cooler). But heat still rises. The hood is going to need a heat shield to keep the paint from cracking.
Do they have specs?
hondacura4 says:
04:59 PM, 01/14/08
"That's one tall engine setup! Unfortunate that it will only fit into a truck or SUV in that configuration."
I believe this TT V8 will eventually replace the normally aspirated 4.8L unit found in the 550i, X5 4.8i and the next generation 750i.
jr1m90 says:
05:17 PM, 01/14/08
Who says it needs a stinkin' engine cover?