Super AND turbo? -That's not uncommon these days. -Volkswagon does it in tiny engines for cars like the Polo and lupo, I'm pretty sure. -It should be mentioned that we don't get the miniatures over here, where the smallest VW sold is the Golf, which is considered a 'small' car, (unlike Europe, where the 5-door Golf is seen as a perfectly acceptable full-size family vehicle). It's been out for a few years now, but -again- this year, won
international engine of the year. It doesn't KEEP the turbo awake, so there's still a 'kink' in the boost profile, but it does squeeze prodigious numbers from an otherwise tiny lump.
My weekend toy isn't a 930, but instead the 'cup' version of the 951... a little quicker than the 930, but only marginally. Far better balanced however, although air-cooled purists sometimes scoff at them while they're parked (it's hard to scoff from the rear-view mirror, or -more commonly- a hedge!
) . Lag is comparable, but the 'push' from the seatback once it wakes up (above 3200RPM) has to be felt to be appreciated. The slight 'gutlessness' below boost threshold (well, 'slight may be understating it!) makes the boost SO much more stunning by virtue of direct contrast! It's known as the '951S', which has a LARGER hotside on the turbo, resulting in even SLOWER wake-up, but even LARGER payoff at the top end. It runs at full boost for approx 80% pf the track distance at Sebring, and returns 5.5MPG on 105 octane [(R+M)/2].
The Audi motor is direct-injection spark, but they've had to sacrifice one valve per cylinder to make it happen. They grew it from their old 5-valve-per chamber motor (which flowed
wonderfully, incidentally) and they gave the center-top 'nail-hole' over to the injection system.
My last car, I also bolted a blower on, but it was a positive-displacement type; Eaton (magnusson) as opposed to the 'nautilus' (vortech). My cousin has an Eaton on a C5 'Vette, and a colleague has the same vette with the Vortech on. Side-by-side comparison is revealing. The Vortech sound stirs the loins somewhat, and hints at what lurks beneath. At low revs, the torque from the Magnusson is the clear winner, but over 2500RPM, the Vortech blows the twin-screw completely out of the water. Driving style probably dictates which a person may prefer... a low-rev grumbler-potterer will enjoy the Magnusson, a high-rev, neck-wringing-screamer will likely prefer the Vortech. (Not that the 'Vette' is known as 'lacking' in low-grunt anyhow...)
Of course, to get the power out of the same engine block, with the same swept piston volume, the compression ratio has to be reduced, otherwise the amount of boost you can put on is seriouslty limited before detonation occurs (unless you replace the pump gasoline with a
seriously expensive cocktail!) -whether by lifting the head, dropping the pistons, or some other method. This then means that at zero boost, the same volume of gasoline/air mixture gets squeezed rather less, and consequently yields rather less 'puff' after the flash.
With that in mind (and I'm certain I've sung this tune here before) I was really intrigued by SAAB's variable-displacement engine, since SAAB have been selling ONLY turbocharged cars for longer than anyone else I can think of in the US market, (i.e. a range of cars where EVERY engine is turbocharged) they chose to investigate their options. Of course, in the GM buyout 20 years ago, this was 'back-burnered' and the motor never came to fruition. -I understand that this complicates one of the simplest part of the engine equation -the block- and that the added expense is significant, but the improved economy of TRULY shrinking the engine, by both drawing in less air AND reducing the volume of the combustion chambers should be a real step forward.
Saab being sold to Koenigsegg... I still can't get my head around that. -That just sounds like the cart dragging the horse, and that never ends well... but GM would've possibly just killed it otherwise.
The direct-inject spark Audis (which I think at the moment is ALL Audis -here in the US at least- but I'd have to research) are now sold almost exclusively in quattro (4WD with a Haldex controller and computer-intervention for distribution of torque wherever grip is highest) which helps address the grip-limits. If you're going to market yourself as a car which you can have fun in, then you have to start looking for ways to get that grip to the pavement. Combined with the DSG (torque-converter-less automatic) transmission, this means that you really can begin to speed-up the 'jackrabbit' starts, -and although these are (philosophically) the polar opposite of 'green' mentality, the fact that they have already invested that much into the technological side of the motor in the name of efficiency (stuff which Ford is announcing only now) is pretty necessary in (more politically-green) Europe, and Germany especially.
http://en.wikipedia.org/wiki/Audi_S3
Keith