Supersprint has been designing and manufacturing high-quality performance exhaust systems in Mantova, Italy, since 1955. Its current line of aftermarket applications takes in over 30 manufacturers from Europe, Asia and North America. With this experience, the company has gained a great deal of expertise in full exhaust performance evaluations, ensuring additional power, quality sound and TV-approved status for all its street products. Small wonder why Supersprint is also the choice of many high-end European tuners for R&D consulting and the manufacturer of exclusive private label exhaust systems.

Supersprint gave us full access to technical personnel and 'top secret' areas. We'll begin with the preliminary testing sequence done for each OEM exhaust system evaluation. An Audi RS4 FSI V8 was in the R&D facility at the time of our visit and a new BMW E92 M3 arrived a couple of weeks later, so we will use these two machines as our real data examples.

In order to comply with TV noise restrictions for street-legal vehicles, Supersprint begins by gathering baseline data on the stock vehicle using standard TV methods. There are two parts: the first is the sound level of a stationary vehicle with the revs held constant at 75 percent of the maximum rpm; the second test is measured with the vehicle in motion; starting at 30 mph (second gear for a five-speed, third gear for a six-speed, or D for an auto), the vehicle is accelerated at full throttle for 65 feet. For each section, the microphone is set 25 feet from the center of the road and the motion tests are run in both directions. When the exhaust development prototype is complete, these tests are repeated to ensure the new exhaust is no more than 1dB louder than the OEM item, as per the TV standard for aftermarket exhausts (see the table at the bottom of the opposite page).

For a full evaluation of the OEM system's baseline performance characteristics, Supersprint selects three or four locations for exhaust pressure and temperature measurements. If the given system is a true dual exhaust, then only one side is used for testing. For the Audi RS4 and E92 M3, Supersprint selected four locations: primary cats, secondary cats, resonator and rear muffler. Two threaded fittings were welded in place at each location to attach Supersprint's proprietary pressure and temperature measuring equipment during dyno testing, and to cap the fittings during the later prototype road testing.

The subject vehicle is then moved to Supersprint's in-house Maha LPS3000 four-wheel chassis dynamometer. The high-tech, German-made Maha is renowned for scrupulously honest methods of power calculation. Baseline pressure and temperature figures are collected along with power and torque data during two types of dyno tests: a fixed-load test where the vehicle is slowly brought up to its top gear and cruised at 60 mph for about 90 seconds per run, and a full-load test (the regular dyno pull we all know and love) where the vehicle is run full throttle from about 2000 rpm to redline in its closest gear to direct drive (1:1, gear ratio to final drive ratio). Both tests are run three or four times for statistical consistency. At the same time, Supersprint also logs various other data through the OBD-II port, such as the air/fuel ratio (Lambda), ignition timing, intake temperature, throttle opening, etc.

By Doug Neilson
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