Automobile Mag: BMW X6 M “Replacing Turbo Lag with Turbo Brag”

Interesting | August 8th, 2009 by 4
bmw n63 engine x6 m

We’ve said our part when it comes to the new BMW X6 M and there is probably no need to repeat it, but…..just in case …

We’ve said our part when it comes to the new BMW X6 M and there is probably no need to repeat it, but…..just in case there are some of you that missed our X6 M test drive, we will repeat it again: “the BMW X6 M is a true Motorsport vehicle and even the purist BMW fans should be proud to have the opportunity to experience something different without fearing that it diminishes the M brand.”

Yes, we’ve said it again. The X6 M really lived up to our expectations and as long as you don’t expect it to be the M3 or M5, you will absolutely enjoy its performance.

But this article is not about what we think and since we’re a BMW blog, we might have that 5% bias sometimes(not all the times). This article is about the new, innovative N63 engine found in the BMW X6 M and which has been closely analyzed and dissected by Automobile Magazine.

bmw n63 engine x6 m 655x305

BMW’s N63 engine–the 400-hp 4.4-liter twin-turbo V-8 used in the X6 and 750i–suffers from turbo lag like every other turbocharged engine in the world. Compared to other turbo engines, that lag is minimal. Compared to normally aspirated engines, though, the engine’s response to the accelerator pedal is less than immediate.

Instant response has long been one of the trademarks of BMW M engines–they’ve historically used individual throttle bodies to minimize the delay between stepping on the gas and waking the beast. So when it came time for M to design its first turbocharged production engine, the S63, BMW’s performance division set about reducing response times to levels we’ve never seen in turbocharged engines.

One step in accomplishing this goal was achieved by devising a turbo-lag-reducing exhaust manifold so clever that BMW has patented it. It works by ensuring that each turbo is given a burst of exhaust gas at even intervals–something that’s normally not possible on a twin-turbo V-8 engine. Here’s why, and a description of how BMW’s manifold works.

First of all, the S63 shares the N63’s reversed cylinder head orientation–both engines have their exhaust ports vent to the inside of the Vee rather than in the traditional direction, which is out to the side of the engine.

Continue reading over at Automobile Magazine