Porsche 911 Turbo, Masses Of Torque At All Speeds

Porsche’s 911 Turbo has always been a cracking supercar, but the new model goes further in every direction. Not only is power up by 60 bhp to 480 bhp, with much more low-speed torque than before, but the new four-wheel drive system and traction control give greater stability and traction in all conditions.

The Porsche 911 Turbo is a fantastic combination with the usual elegant Porsche looks. This neat supercar gets well under the 4.0 second barrier for 0-60 mph, and has a top speed of 192 mph. Wow!

Based on the 997 version of the 911, the Turbo gets the improved body and suspension that goes with the 997, but just about everything has been developed specially for the car. It even has new aluminum doors.

Subtle changes make the car look different from the old Turbo and the other 911 Carrera cars. At the front, there are two large side air scoops low down, with lamps integrated into them, and the fog lamps outboard.

The side air intakes are revised, and at the rear there is a new split spoiler which extends at speed, twin exhaust pipes of a new shape coming through the lower apron and air outlets at the sides. The wider rear track and fenders, together with the large 19 inch forged aluminum wheels help make the car look very powerful.

The Cd remains a very good 0.31 while the rear spoiler increases down force, and the revised front end results in less lift. A good example that function and form result in elegant lines.

Completely different response to the GT3

Once you drive the Porsche 911 Turbo, you will find a completely different animal from the GT3, which packs a 415 bhp punch, but needs lots of revs to keep it roaring along 5,000 to 8,000 rpm. By contrast, the Turbo will hurtle you forward at about 2,500 rpm, and there is massive power up to 6,000 rpm, where it develops 480 bhp. That’s 133 bhp per liter, a very high specific output.

The 3.6 liter dry-sump engine has a very wide spread of power, with maximum torque of 457 lb ft (520 Nm) all the way from 1,950 to 5,000 rpm. This is the sort of power band you expect on an engine with a modest output, but not one producing 133 bhp per liter!

There’s more to come, in one of the features of the optional Sports Chrono Package. Choose that package and you get an over boost function. If you need extra power for a short time, such as when accelerating hard to overtake in limited space, the turbo system is allowed to give even more boost than the normal 1 bar (14.7 lb per square inch) for 10 seconds, lifting maximum torque to 501 lb ft (680 Nm) a huge amount from a 3.6 liter engine.

What’s more, since there is a new four-wheel drive system which ensures maximum torque is provided where it is needed without wheel spin, this is a very sure-footed car, capable of being driven fast where others need to tread warily owing to the danger of losing grip.

Turbo with variable inlet vanes

What’s the secret? Like many turbo Porsche cars, the new one Porsche 911 has twin turbos, but it is the first high-performance gasoline engine to be equipped with turbos having variable inlet vanes. These have been used on diesels to widen the power range for 10 years or so, but the high temperatures in the exhaust of a very high-performance gasoline engine make their use difficult. Porsche has overcome this problem with the use of special high-temperature materials in the turbine and water cooling.

The inlet vanes can be rotated through a small angle in the housing, so that at low speeds, they provide small, tapered passages for the exhaust gases to go through. The result is that the gases speed up and release enough energy to provide plenty of boost.

At higher speeds, the vanes are moved so that the passages are wider, thus allowing all the gases through without creating back-pressure and reducing flow. In this way, you get the benefit of having two turbos one small and one large in the same unit. That’s how they get the wide range of power.

Faster acceleration with Tiptronic S

All this means that Porsche 911 is not just very quick from 0 to 100 mph and more, but also accelerates very quickly from say, 50-80 mph held in one gear. Actually, if you want the fastest accelerating 911 Turbo get one with the Tiptronic S automatic. It may be only a five-speeder, but because the control is linked to that of the traction and four-wheel drive controls, the car accelerates faster than the manual. This is the first Porsche to do this the Turbo Tiptronic S gets to 60 mph in just 3.6 seconds, compared with 3.8 seconds for the manual box.

Of course, a close-ratio six-speed box is provided for purists - with short-throw shifting and improved synchromesh but it is the Tiptronic S which steals the thunder. Porsche has added two important features. The first prevents the box from shifting downward when you lift off as when you slow down while waiting to overtake. The second actually shifts down a gear when you lift off and put your foot on the brake, as you do when entering a bend. Clever stuff; does some things you would do yourself.

To give you the maximum performance, Porsche has built many other electronic systems into the car. There is a stability control, ABS and brake assist which keeps full brake pressure on in emergency braking PASM, which has two modes of adaptive damper control, and a new traction control for the four-wheel drive.

New four-wheel drive improves stability

In the new four-wheel drive system, there is a multi-plate electro-magnetic clutch in the axle gear system for the front Porsche 911 wheels. This system was chosen over a hydraulic system which would have generated a lot of heat.

The control system measures many things including the cornering rate and acceleration, and then decides how much power to transmit to the front wheels. Of course, if wheel spin is developed at one end, more power is sent to the other end.

The system can transmit up to about 75% of the engine’s torque to the front wheels although wheel spin would set in at around 57%. If a rear wheel start to spin, a massive amount of torque can be sent to the front wheels to keep the car charging forward while remaining stable.

In fact, Porsche says this system is so good, the stability control is hardly needed. For example, at the onset of over steer, more power is sent to the front wheels. If the car starts to under steer, the power sent to the front wheels is reduced, altering the car’s weight distribution, and restoring stable cornering.

Big brakes and low weight

Of course, such a car needs good brakes, and the Porsche 911 Turbo now has 13.78 in (350 mm) discs all round. Six-pot calipers and 42% larger pads improve front braking, while four-pot calipers act on the same size discs at the rear. If you want the ultimate in braking performance, you can opt for ceramic composite discs which are huge 15-inch (380 mm) diameter.

Weight is always a problem with a new model, and Porsche engineers have worked hard to keep the weight down to that of the old model. One innovation is the use of aluminum doors, which reduce weight by 31 lb (14 kg). These are unusual in that the door frames, which include many brackets and the structural members, are thin-wall pressure diecastings. These are clad in aluminum sheet.

The new car weighs 3,495 lb (1,585 kg), which is pretty good for a car with a steel body and four-wheel drive. It is a competitor for the more expensive Ferrari F430 and Lamborghini Gallardo, and the only less costly car that can close is probably the Noble M15.

So here it is; the very latest and hottest turbo, a fast-shifting auto if you want it, a new generation of four-wheel drive, with all the bells and whistles to go with it.