Engine Dynamometer
Our in house engine dyno is an essential tool in our R & D department. At Korman, it doesn't make any additional horsepower until the dyno says so!
While engine dynos have several advantages over chassis dynos, the primary benefit is accuracy and repeatability. For each dyno run, we measure not overall room temperature, but temperature and humidity of the air flowing directly into the engine intake, as well as barometric pressure, oil temperature, oil pressure, water temperature, fuel pressure, etc. Our dyno readings are then fed into a computer program which applies standardized S.A.E. correction factors for variations in temperature, humidity, and barometric pressure. These controls allows us to attain repeatability accuracy of about 1%.
Chassis dynos feature easy access, but have a few drawbacks which are inherent to the design. (READ: take chassis dyno figures with a grain of salt, not just absolute numbers, but comparisons as well) Chassis dyno operators must estimate to adjust for these variables.
Tire expansion/rolling resistance-As tires heat up over the course of a run, the increasing temperature and pressure cause the tire to expand and the rolling resistance and diameter to change. There is also a varying amount of tire slippage. It is difficult to estimate these effects on power at the dyno rollers.
Driveline Temperature-As operating temperatures rise, coefficients of friction change in the differential, transmission, etc. As with tire expansion, these changes are difficult to accurately adjust for.
Intake Air Temperature-Very few chassis dyno installations are configured to accurately control and measure intake air temperature and humidity. A fifteen degree variation in air temp and fifteen percent change in humidity will produce a 2.5% variation in engine output. On an E36 M3 engine, that's 6 horsepower.
Having Your Engine Dyno Tuned
Our engines are based on designs tested and proven on our dyno. It is not necessary to dyno subsequent engines of the same design. However, there are some advantages to having your engine dyno tuned.
A dyno tuned engine is fully run in before testing under load. You are not only assured of precise tuning for maximum performance, but your engine is delivered ready for immediate high performance use. You have no further break-in period.
Korman Autowork's dyno tuning procedures include a lengthy run-in time. During this break-in period the cylinder head is retorqued, valves re-adjusted, compression tested, oil pressure monitored, and temperatures closely controlled. Then under close observation, engine speed and load are gradually increased until the engine is ready for full load testing. One more cycle of adjustment and compression tests and we begin power runs. Customers are provided a detailed dyno chart showing engine specifications and horsepower and torque curves. Each dyno chart is certified by Ray Korman.
