Tech Article Title Author Date
An Overview of 5v Engine Technology Audi Magazine Reprint 1997

It all began with a few quick laps in Alabama. Before new technology goes into mass production, it is thoroughly tested. And because Audi is very conscientious about testing, the company went to Talladega, driving 621 miles around the track at an average speed of 206.84 mph. The year was 1986, the car was an Audi 200 quattro, and the powerful engine was a 2.2 liter, five-cylinder turbo with 25 valves and 633 hp. The most important new insight in this high-speed test, aside from the fact that Audi set a new world speed record, was the superior performance of five-valve technology. Despite the excitement of achieving a world record, the big picture must not be ignored. Ten years later, Audi introduced two production models utilizing five-valve technology it its A4 series. It was the first European producer to user this cutting-edge technology, previously reserved for the priciest sports cars, in regular production. The advantages of the fifth valve, in brief: efficient performance and streamlined construction.

The details are key. Five valves per cylinder permit quicker, more efficient firing, because three inlet valves allow for maximum flow - which is determined by the size of the valve disk and the valve's opening stroke. The valve injection improves, so more energy is converted per stroke. Because each valve is smaller, less mass must be moved, which in turn permits increased rpms. With this arrangement, the spark plugs take on a central position; the short distance traveled by the sparks reduces knocking, which results in high compression, economical operation, and top performance.

The advantages of the fifth valve are most apparent in long-stroke engines like those typical of Audi. Long-stroke engines run quietly and develop maximum torque even at lower rpms. The user of five-valve technology improves performance and torque, without an increase in displacement (which would result in both higher weight and energy consumption). Five valves are in perfect ratio to the size of the valve disks and valve stroke, and also allow Audi an optimal design of the combustion chamber.

The irresistible development is currently used in the 1.8 liter turbo-motor with 150hp. Here, the comparatively small exhaust turbo-charger is not used to increase top performance. But to improve torque. The qualities of this engine can be visualized roughly as follows: Normally, the profile of torque curves resembles that of Kilimanjaro; they climb steadily, reach a narrow peak, and then it's downhill again. The torque curve of the new five-valve turbomotor, however, is more comparable to high plateaus of a Tibetan scale. Maximum torque of 210 newtons is reached at 1,750 rpms - that is almost immediately after leaving your parking space, and this power is maintained until 4,600 rpms. This yields impressive results: top speed of 220km/hour and 8.3 seconds from zero to 100 km/hour. In addition, this motor's terrific torque curve subtly teaches the driver to shift sooner, resulting in better fuel economy, which we know is the most efficient way to go without sacrificing the fun of driving. And if you happen to be driving on a German autobahn, you might even get the chance to try out the car's full sporty potential and pump it up to 5,700 rpms.