German Car Forum

abdulkerim88 · 12-20-2007, 09:09 AM

I have some pictures from the new bmw V8 bi turbo engine.
But isnt it weird that the turbos are on the top like a supercharger.
Is this type of turbocharging ever been installed on an other car before?

Just_me · 12-20-2007, 09:11 AM

here is a quote from the BMW pressrelease on the X6:

"For this is the first eight-cylinder gasoline engine in the world to feature its turbocharger in the V-section between the two rows of cylinders."

Tarek · 12-20-2007, 09:22 AM

I wonder why they opted for that position,and that postion will require some extra room betwwen the engine and the hood,will we see a hood bulge in models equipped with that engine?

klier · 12-20-2007, 09:30 AM

Quote:

Originally Posted by atuv

I wonder why they opted for that position,and that postion will require some extra room betwwen the engine and the hood,will we see a hood bulge in models equipped with that engine?

No I don't think so. The engine will sit low enough for a normal hood.

martinbo · 12-22-2007, 04:14 AM

Hmph. How 'bout that...

Monster · 12-22-2007, 05:43 AM

Very very interesting indeed. I suppose the engine bay doesn't have enough space to fit in the turbo and intercooler package in the normal layout.

When I saw the photos of the turbo engine, I thought "it looks a bit strange to have the intercoolers placed this high" It never came to my mind that the turbo might be located on top fo the engine.

Because everything is so tightly packed together, there won't be as much "head loss" because the pipes are shorter, so the engine will be more efficient. Just a guess.

martinbo · 12-22-2007, 07:28 AM

The key area of innovation for me is the swapping around of the inlet and exhaust ports. This is very unique, I can't ever recall a V-configuration engine where the exhaust manifolds are located centrally with the inlet systems being located on the outside of the cylinder banks - regardless of forced induction or not.

I'd like to understand the heat soak implications from locating to turbos so closely together. In fact, despite its unique configuration, I don't can't see any logical reason to locate the induction and exhaust systems in such a fashion other than for reasons of engine bay packaging.

All I can say is, after a hard drive, don't go touching the hood.

Sidenote; I think the xDrive50i and xDrive35i nomenclature is stunningly daft.

Monster · 12-22-2007, 07:52 AM

Quote:

Originally Posted by martinbo

I'd like to understand the heat soak implications from locating to turbos so closely together. In fact, despite its unique configuration, I don't can't see any logical reason to locate the induction and exhaust systems in such a fashion other than for reasons of engine bay packaging.

Also, the exhaust gas going to the turbine will be extremely hot, hotter than usual because the exhaust pipe is shorter than normal, so the gas won't have that much time to cool.

I guess placing the turbos on top will get more cool air flow than placing it packed within the engine bay. This might resolve the heat soak issue.

EnI · 12-22-2007, 12:37 PM

BMW explanation:

Quote:

Displacing 4.4 liters, the new V8 engine with Twin Turbo technology and direct gasoline injection (High Precision Injection) develops maximum output of 400 hp throughout a broad range of engine speed from 5,500–6,400 rpm. Engine torque reaches its peak of 450 lb-ft throughout an unusually large speed range from 1,800–4,500 rpm. The spontaneous, intense and long-lasting thrust generated in this way is the result of Twin Turbo technology already featured on BMW’s most powerful straight-six combined with High Precision Injection. The cooling effect of direct fuel injection also ensures a compression ratio quite unusual on a turbocharged engine, helping to give the engine an even higher level of all-round efficiency.

The position of the turbochargers and catalytic converters in the V-section between the two rows of cylinders is likewise an innovation in technology allowing particularly compact engine dimensions and at the same time requiring new configuration of the intake and exhaust ducts. This means shorter intake and exhaust manifolds and larger cross-sections significantly reducing pressure losses on both the intake and exhaust side.

In its power and performance characteristics, therefore, the engine is comparable to a significantly larger normal-aspirated engine while offering the advantage of much lower weight and reduced package size.

Not only are the dimensions and weight of the new V8 unusually modest, but the fuel consumption is also exceptionally low for an engine of this caliber.

S'Pimp · 12-22-2007, 02:06 PM

^^
marketing speech

EnI · 12-22-2007, 02:49 PM

Quote:

Originally Posted by S'Pimp

^^
marketing speech

In general, yes. But I wanted to point out technical aspects.

More will be said at NAIAS, and then featured on bmw-web.tv

S'Pimp · 12-22-2007, 04:51 PM

nitty-gritty

abdulkerim88 · 12-22-2007, 06:23 PM

Great pictures.
They have just changed the inlet an exhaust port.
the inlet is at the black box and the exhaust is in the middle.
because before the black box there is a intercooler.

Sunny · 12-22-2007, 07:13 PM

The very short path from the exhaust ports to the turbos should help reduce lag.

EnI · 12-22-2007, 07:28 PM

OMG, those two exhaust manifolds are almost touching each other. I'm really interested how the cooling problem is solved.

I suppose enormous heat is developed right under the engine cover - which is made of plastic, btw. I just hope the plastic is heat-resistant.

These engine & engine bay must have hell of a cooling system to manage all that heat.

PS: now the "secret" of the engine in new 7er (from the spy pic) can be revealed: it's a twin-turbo 4.4L V8 with turbochargers and catalytic converters positioned in the V-section between the two rows of cylinders, and with a new configuration of the intake and exhaust ducts.

S'Pimp · 12-23-2007, 05:28 AM

abdulkerim88 · 12-23-2007, 06:07 AM

i think that the turbos under the hood are cooler then the normal ones.
because the wind wil get in from the front from the car and will get out from the whipers.
I made a photo to explain it.

Ultimate Car Guy · 12-23-2007, 06:55 AM

Quote:

Originally Posted by EnI

I'm really interested how the cooling problem is solved.

These engine & engine bay must have hell of a cooling system to manage all that heat.

This could be 1 of the reasons why future BMWs will have massive grille's like those shown on Concept CS.

EnI · 12-23-2007, 08:09 AM

Quote:

Originally Posted by Ultimate Car Guy

This could be 1 of the reasons why future BMWs will have massive grille's like those shown on Concept CS.

S'Pimp · 12-23-2007, 08:10 AM

Quote:

Originally Posted by abdulkerim88

i think that the turbos under the hood are cooler then the normal ones.
because the wind wil get in from the front from the car and will get out from the whipers.

not really

but of course, efficient aerodynamics ( airflow )

S'Pimp · 12-23-2007, 08:19 AM

Quote:

Originally Posted by EnI

I suppose enormous heat is developed right under the engine cover - which is made of plastic, btw. I just hope the plastic is heat-resistant.

These engine & engine bay must have hell of a cooling system to manage all that heat.

most pieces of the airbox are made of Mg

S'Pimp · 12-23-2007, 08:43 AM

Compare with V8, n.a., 4,8l :

EnI · 12-23-2007, 08:54 AM

Quote:

Originally Posted by S'Pimp

most pieces of the airbox are made of Mg

Are you sure? That would be strange since Mg (although lighter) is worse thermal conductor than Al. Are you sure it isn't (brushed?) Al?
Yet I really hope it isn't just a galvanized plastic.

Monster · 12-23-2007, 08:58 AM

Humm I think the airbox is still made from plastic. You can see 2 little vents on the engine cover, but that alone isn't really enough to let much cooler air pass through.

S'Pimp · 12-23-2007, 09:01 AM

can also be

maybe two-piece; only upper part in Mg - lower in Al
cause its no plastic, till the pipes and small things

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BMW X6 4.4 V8 Bi-turbo Engine