We're used to spending a lot of money on power-adders, but do they really add power? One way to find out is to strap your ride onto a dyno at a dynamometer facility and see how quickly the engine can spin the rollers. Often this is costly and cumbersome. A new alternative is Nology's Laptop Dyno software. The system is quite simple: The OBD-II interface cable and interface box, which are included in the kit, plug into your OBD-II diagnostics port on one end and your laptop on the other. (If you don't have this port, you're pretty much assed-out.) The software requires simple calibration before you make your first runs. In addition to horsepower, this software can measure acceleration and pull up, and clear check engine lights or diagnostic trouble codes (DTCs).
To understand how this software measures horsepower, you should understand how it's done on a dyno. Typical inertial dynos have a computer that measures the time it takes a car to accelerate rollers or drums of a specific weight to red line. Horsepower and torque curves are then calculated from data gathered by sensors monitoring the drums' acceleration.
Nology's software can calculate your horsepower based on the time it takes to accelerate to red line in either second or third gear. The software takes many vehicle-specific details into consideration, and also employs the industry standard SAE J1349 correction factor for horsepower and torque. Ambient conditions such as altitude, temperature, barometric pressure and relative humidity affect engine output. Therefore, dynos taken at the beach and the mountains cannot be compared without applying a correction factor. The correction factor converts any horsepower or torque figure into a comparable format that recalculates the horsepower using the following parameters: zero feet above sea level, 77 degrees Fahrenheit, 29.235 inches of barometric pressure and no humidity.
The software layout is pretty straightforward, with vehicle and performance stats on the right column and software navigation buttons on the left. Before you test your power and acceleration, here are some key elements to remember: A closed track is the ideal test environment. If you don't have access to one, the road should be level, straight, unobstructed and, obviously, unpatrolled. You'll need to know some critical geographic and meteorological information about your testing area, such as elevation, barometric pressure and temperature. Once you've entered this information, you'll need to do a little homework to determine the coefficient of drag, frontal area (in square feet) and gross vehicle weight with you and a passenger. The Internet is a great resource for this information. After you've entered this data, you'll be ready to calibrate and subsequently make your first pass.
The calibration process is simple. You need to enter your wheel and tire size into the gear-ratio calculator. After holding a steady speed in your gear of choice, the calculator will tell you what your overall gear ratio is for that gear. Simply enter this information in the appropriate blanks, and you're ready to make a pass.