BMW twin turbo V8

charge cooling, reverse flow heads, high pressure direct injection, this is a very interesting engine that will premiere in the X6 soon.

Its still the 4.4-litre V8 but it produces 402bhp at 5500rpm and 442lb ft of torque between 1800 and 4500rpm, it can take the X6, 50i to 62mph in 5.4sec. Due for launch in May 08.

[URL="http://www.autoblog.com/2008/01/21/detroit-2008-bmws-twin-turbo-4-4l-v8/"]Autoblog:[/URL]
[QUOTE]Undoubtedly, the most unique feature of the 4.4L TT is the packaging of the turbochargers in the valley between the cylinder banks.

This is made possible by the swapping of the intake and exhaust ports in the cylinder heads, with the exhaust now exiting towards the middle. This allows the turbochargers to be mounted in the valley with minimal plumbing, which means less bulk, lower weight and better efficiency.

Immediately after exiting the turbochargers, the exhaust gases enter the catalysts. It's important to keep the cats as close as possible, as the exhaust carries heat that is required for the converters' operation.

Packaging the cats in this location underneath the hood must present some interesting insulation challenges!

Instead of expensive variable-vane technology, each turbo makes use of fixed geometry and relatively simple wastegates.

...

Between the compressor outlet and the intake manifolds lie a pair of air-to-water intercoolers, one for each bank. Such an intercooler reduces packaging volume and tract length compared to a top- or front-mounted air-to-air heat exchanger.

Immediately downstream of the intercoolers lie a pair of electronically-controlled throttle bodies.

Below each centrally-located coil-on-plug (COP) assembly resides the direct injector, along with the feed lines and fuel rail. It's presumed that piezoelectric injectors are employed here, which are fast enough to allow several injection events per combustion cycle.

Each fuel rail gets its own fuel-pressure regulator. The operating system of this system is yet unknown, but we're guessing that it's similar to the 200 bar (3000 PSI) that is used in the engine's direct-injection predecessors.

Dished pistons are used to lower the compression ratio, with a compact ring package to reduce crevice volume and frictional losses.

The net effect is a peak of 400 HP, with 450 lb-ft of torque delivered between 1750 and 4500 RPM. In a sport sedan such as the 5 Series, this engine will likely erase fond memories of the musclecar era, and even in portly SUVs such as BMW's X5 and X6, the result should still be rather impressive.[/QUOTE]

If this engine can propel a tank-heavy machine - as the the X6 is - in 5,4 secs from 0 to 60... well, I can't wait to see what it could do under other BMWs bonnets.
Niiice piece of engineering BMW. As always.

This is the engine that will, according to rumors, will propel the next generation Esprit.

Good choice from Lotus, as smart packaging and low weight / compact dimensions was always a Lotus characteristic!!!

Hmmm. I wonder if I can swap out the engine in my M6 for this! What a glorious, glorious thing this is. It's just a shame they put an engine cover on it.

[QUOTE=lightweight;786322]This is the engine that will, according to rumors, will propel the next generation Esprit.

Good choice from Lotus, as smart packaging and low weight / compact dimensions was always a Lotus characteristic!!![/QUOTE]

Not to mentioned the whole twin turbo V8 thing that was going on in the last few models.

[QUOTE=lightweight;786322]This is the engine that will, according to rumors, will propel the next generation Esprit.

Good choice from Lotus, as smart packaging and low weight / compact dimensions was always a Lotus characteristic!!![/QUOTE]

Wonder how heavy it is.

I assume reverse-flow heads refers to the swapping of the intake and exhaust valves? Is that actually hard to do?

[QUOTE=Kitdy;786340]Wonder how heavy it is.[/QUOTE]

It's twin-turbo, so probably quite heavy.

Is the engine related to the M3's engine?

It says that the pistons are dished. I am trying to think of what that means and in my mind I am imagining a hemi engine. Am I close too the mark or out in space?

apperently it averages 18.5mpg in X6 form.

[QUOTE=2ndclasscitizen;786383]I assume reverse-flow heads refers to the swapping of the intake and exhaust valves? Is that actually hard to do?[/QUOTE]


not hard, but its a different idea when you have to consider cooling. they wanted to minimise turbo plumbing and reduce ultimate engine size. it is kinda taller though, oerhaps limiting it to larger bmw vehicles...no 145i maybe:D

[QUOTE=2ndclasscitizen;786383]It's twin-turbo, so probably quite heavy.[/QUOTE]

cant find exact mass just yet, we can expect it to be close to mercs V8 at about 240kg.

[QUOTE=Kitdy;786392]Is the engine related to the M3's engine?[/QUOTE]

i would say no, its based on the regular 4.4 as found in 545i etc.

[QUOTE=mclaren_crazy;786403]It says that the pistons are dished. I am trying to think of what that means and in my mind I am imagining a hemi engine. Am I close too the mark or out in space?[/QUOTE]

the crown dip means that for the same block/bore/stroke as the NA version a simple piston change will decrease the compression ratio to rule out knocking (for those not in the know.) If i am not mistaken a hemispherical combustion chamber minimses surface to volume ratio of combustion chamber reducing heat loss.

what gets me is how they arent using clever piston crown design to maximise the benifits of direct injection. sometimes the piston can help with swirl, fuel spray redirection, circulation etc...

[QUOTE=NicFromLA;786324]Hmmm. I wonder if I can swap out the engine in my M6 for this! What a glorious, glorious thing this is. It's just a shame they put an engine cover on it.[/QUOTE]

No idea why, but engines these days look so abstract. Nothing wrong with that, but have you seen the engine in the Lexus IS-F without the cover? It looks like a tangle of wires!

I know there is a reason for the madness, but seriously. I like to display the engine, a la Audi RS4 or Ferrari F430.

[QUOTE=2ndclasscitizen;786383]I assume reverse-flow heads refers to the swapping of the intake and exhaust valves? Is that actually hard to do?
[/QUOTE]
No harder to do that this! (which probably deserves a thread of its own)
[url=http://www.sae.org/automag/technewsletter/080108Tech/01.htm]Automotive Engineering International Online: SAE Technology Newsletter[/url]

Centre exhaust V8s look so cool
[url=http://www.ultimatecarpage.com/pic.php?imagenum=8&carnum=2850]Brabham BT24 Repco - Ultimatecarpage.com - Images, Specifications and Information[/url]

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