Here is a excerpt of an interview with Andreas Prueninger who leads the GT team at Porsche:
Andreas Preuninger: "So, this is the motor -- like on almost every Porsche there's not so much to be seen because it's a Flat Six boxer motor and it lies pretty much hidden... but when you drive it, when you feel it, when you hear it -- that's what it can do best."
AP: "We have a 3.8-litre here -- we enlarged the displacement by 200cc on that car, adding a lot of torque to the engine, adding a lot of bite on lower and middle revolutions... You notice the difference right from the start, because there's so much more torque available between 1500 and 4000rpms -- that's the range you use the car normally in 90% of all street-going traffic -- that's where the car has a lot more bite than its predecessor. It's a lot more torquey, you end up being one gear higher always than in the last car."
AP: "The sound hasn't changed so much... a bit more volume in the sound -- I'm afraid it's got a little bit louder, when the exhaust flaps are open -- but I think our target group will accept that."
AP: "We increased the diameter of the pistons, so the stroke stays the same -- we have 102.7mm of bore, instead of 100mm in the old car and that adds up, on the same stroke, to 200cc more. So we can use the same crank and we just differentiated the rods... titanium rods. Even though the the piston is a lot bigger in diameter, it weighs less than the 100mm piston on the old car -- so we even found some weight despite increasing the diameter of the piston."
AP: "It is still the GT1-based engine with eight bearing points and seven oil suction pumps and a full dry-sump system, like in a race-car. So this is almost a race engine and it's up to any task on the race track."
Chris Harris: So the question I have to ask is why no DFI?
AP: "We wanted to stick with the GT1 motorsport block -- we need it for for homologation, because this is the block we race with and this is a homologation car and it needs the same block as well."
AP: "This car is really set up for race track use and that's why we intend to keep it for one more generation or maybe for even more, because customers love this engine... it has lots of character and the GT3 is all about emotion and character and this is what this engine can do best..."
AP: "We are absolutely sure that performance wise and for durability, this is the best choice for a GT car..."
Porsche 991 GT3 / RS engine preview...
A preview of the 2012 Porsche 991 GT3 / RS engine specification...
The Porsche 991 GT3 features a four-litre six-cylinder boxer engine delivering 480 hp (353 kW). In developing the 991 GT3, the emphasis was placed on increased performance, driveability and handling. A six-speed sequential gearbox transmits the power to the rear axle.
The development of the Porsche 991 GT3 is based on the Porsche 911 GT3 R racing car, using the extra-wide body and chassis. Thanks to a 0.2-litre increase in engine capacity, the 991 GT3 delivers 30 hp more than the previous GT3 RS model.
PREVIEW OF NEXT GT3:
Porsche 991 GT3 / RS engine specification:
Porsche GT1-derived motorsport engine
Six-cylinder boxer configuration, water-cooled
3996cc naturally aspirated flat-six
Four-valve technology
Dry sump lubrication
Stroke: 80.4 mm
Bore: 102.7 mm
Max. power: 353 kW (480 hp)
Required fuel quality: 98 octane, unleaded
Multi-point fuel injection (sequential)
Bosch MS 4.0 electronic engine management
E-Gas with 'throttle-blip' function
Race exhaust system with pre and final silencer
Twin-branched muffler with centered exhaust pipes