To ensure that you get the most out of your dyno tuning session there are a few key items to remember.
- Fuel. Your vehicle will consume a healthy amount of gasoline during the tuning process. Be sure to arrive with a full tank of gas.
- General Maintenance. To make certain that you get the most out of your dyno experience it is imperative that you have kept up on your routine scheduled services. You can’t expect your vehicle to operate at it’s peak if parts are worn out. For example, ensure that you have fresh spark plugs and a clean air filter. Safety is also a concern while your vehicle is at KTR. If KTR determines that a worn tire, tie rod end or other mechanical problem puts the safety of a KTR employee or spectator at risk we will postpone your dyno session until these issues are resolved.
- Realistic Goals. Email or bring with you a list of your modifications and expectations. This information will allow the dyno session to run more efficiently and effectively for everyone involved.
Having your vehicle ‘tuned’ on a chassis dyno, can be a great experience.
Yes, if you would like video or still pictures taken, we are more than happy to oblige.
The fact is there is no way of directly measuring power - all types of dynamometer measure torque and then power is calculated from the formula BHP = Torque (ft/lbs) x rpm/5252. This basic equation is the foundation of all engine design, development, and tuning. Two main methods of measuring power are used in the automotive industry - (1) measurement at the crankshaft of the engine or (2) measurement at the driving wheels. Read on to find out more about these two methods.
The majority of rolling roads used to determine power figures in the US are inertia dynamometers. Inertia dynos do not directly measure the force on the dyno rollers to determine power figures. Instead, these systems calculate the force on the rollers using the formula:
F = ma
Where F is force; m is mass; a is acceleration
The mass and system inertia of the dyno rollers is known. In order to calculate the force applied, inertia dynos measure acceleration of the rollers by measuring the increase in current and voltage production when the dyno's eddy-current retarders are used as a power generator instead of a power absorber (as used to hold the dyno load when mapping engines).
Force on the rollers is therefore the roller mass multiplied by the acceleration determined by the voltage output. This force is multiplied by the radius of the roller itself to give torque at the wheels using the following equation:
T = Fr
Where T is torque; F is force; r is radius of application
Power is determined by using the formula:
BHP = Torque (ft/lbs) x RPM/ 5252
This calculation is then used for the power at the wheels measurement. If an ignition pickup on the engine is used, these power figures can be used to plot a power curve. In order to determine power at the flywheel figures, a coast down procedure is used which measures the deceleration of the rollers, and uses this figure as negative acceleration and the F=ma calculation is used again to obtain the power losses through the transmission.
The major problems with these systems occur when changes are made to any of the rotating masses in the system. This includes items such as the clutch, flywheel, or aftermarket wheels. These items do not change the power of the engine (obviously). However they will change the rate of acceleration of the vehicle. Therefore these changes will change the power output measured on an inertia dyno. This is another reason why a number of dyno manufacturers will not guarantee accuracy greater than 5% for their dyno systems.