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New 2007 Turbocharged MINI Cooper S engine

Zandvoort, The Netherlands. July 26. Though the exterior appearance of the new for 2007 Mini Cooper and Mini Cooper S haven't changed very much, and the interior changes are small, the engine is completely new in just about every respect. Having seen the engine and driven the car the last week in July at the Zandvoort race track in the Netherlands, let me take you on a guided tour through it.
The first impressions when one sees the engine under the open bonnet of the 2007 MINI Cooper S are that there no longer is a supercharger on top of the engine, the engine is reversed from the previous generation with the exhaust manifold on the front of the engine, and the cold air intake box runs across the back of the engine compartment, rather than on the right hand side as had previously been the case.
The 2007 MINI Cooper S is shown here with the hood open. A is the cold air box, B is the exhaust manifold, and C is the turbocharger.
The overall impression is much more BMW than MINI, with everything looking clean, high-quality, and very inaccessible. But that's the bottom line with this engine. There isn't much mechanically that can be done to tune this engine – no easy pulley swap, no improved cold air box is needed or appropriate, and the move of the intercooler from the cluttered and hot area above the engine to a very efficient location under the engine and directly behind the lower front grille means there won't be any easy improvements to be made by DIYers.
On the other hand, the engine is already producing close to ten more horsepower, and an incredible 20 more pound-feet of torque that come in lower on the rpm curve, in a car that is rumored to be significantly lighter than the 2006 and many owners won't see the need for significant power upgrades.
The cutaway engine on display at the Press Preview (at right) shows more clearly where the important parts are located.
Letter A is the turbocharger, cut away here so that one can see the two separate passageways through which the exhaust flows, with each of the two channels carrying exhaust from two cylinders, which is designed to minimize back pressure and hence reduce the lag that normally accompanies acceleration in a turbocharged engine.
Letter B is the intercooler, which is now under the engine, directly behind the lower front grille, which should make cooling much more efficient, and of course cooling the air being sucked into the engine and pressurized by the turbocharger increases engine horsepower and efficiency.
Letter C is the catalytic converter, now prominent in the front of the engine.
Of course, the problem inherent in this set-up is that for air go get from the cold air box through the turbocharger, then through the intercooler before getting to where it can be forced into the engine, it has to go from back to front, top to bottom, back up to the top, and then from front to back again. If someone set out to make the longest possible passageway, this would be it. Nevertheless, that is a significantly more efficient intercooler, in a much improved location, so the cooling benefits may very well outweight the problems of air flow.
The real test of the engine is on the track. Over the course of about 45 minutes of totally unrestricted use, I learned two things about the engine. First, though there is just the hint of hesitation – attributable to turbo lag, I suppose – from a dead stop, the car quickly takes the bit and really moves.
Second, that torque makes the car very tractable (or trackable). According the the engineers, peak torque of 177 pound feet, over twenty more than in the supercharged engine, is reached at 1600 rpm and is available all the way to 5000 rpm. On the track, even a tight track like this one with lots of elevation changes, that meant that there was absolutely no reason ever to shift out of third gear, even when taking a hair-pin turn at the end of a downhill run that was followed immediately by an uphill pull.
The only thing I sort of missed was the characteristic howl of the supercharger on song.
There's no question that this engine – if it doesn't display any teething problems after its introduction – is going to make new MINI owners quite happy on the track or at the pump, and will make environmentalists just as pleased.
Gary Anderson