Quick Tour of the Performance Centre

Overview of the Facilities

The core of our performance centre is the Sun RAM XII rolling road dynamometer. The rollers are the key part of the rolling road. The car is placed into these and carefully strapped down.

The rollers apply a backward force on the vehicle, putting it under load and therefore simulating typical driving conditions.

This force is set by the operator and the dynamometer measures the power of the vehicle at different speeds and throttle settings.

Alongside the rolling road is the Sun Diagnostic machine. This measures various aspects of the engine and provides the operator with information about how the engine is performing (e.g. misfires under load).

This includes a exhaust gas analyser to measure the contents of the emissions. With the aid of the Sun Diagnostic machine, the operator can determine how best to tune the engine.

John has a number of other specialist tools (or toys) including a laser thermometer to accurately measure the engine temperature. We use this to help us keep the engine at a controlled temperature, which is vital when tuning the engine and protecting it from damage.

Having the rolling road also allows us to do advanced diagnostics to determine the intermittent faults that only occur when the car is under load. By loading up the vehicle with it attached to the diagnostic system, we have a unique ability to study the engine's behaviour.

From all of this information, John can work out what needs to be done to improve the vehicle's performance and advise on what needs to be changed or upgraded.

How we make accurate measurements

To help with all of the measurements, we have been developing special computer programmes that work with the rolling road to provide very accurate power measurement.

We also have a digital barometer and temperature sensor that measure atmospheric pressure to 0.001 mm/Hg and temperature to 0.1 ^oC, which allows us to calculate effects of pressure and temperature on horsepower (bhp). Such changes can make in excess of 10% difference in BHP!

Our main computer is connected to the rolling road, and takes readings of the speed and power. The programme calibrates the vehicle by calculating the rpm at a particular speed. This information is recorded along with vehicle details and used for further result calculations.

The programme then instructs the operator to run the vehicle at certain speeds, and hold the vehicle at a point (and no longer than necessary) to accurately measure the power. Results are not recorded until the power, rpm and speed have settled for a few seconds but are then instantly recorded to ensure no unnecessary loading of the vehicle. However, we have to let the measurement settle (according to manufacturer suggested best practice) to ensure that only accurate measurements of power and rpm are recorded. This in turn allows us to calculate accurate torque figures.

The maximum power is also constantly monitored and measured along with the rpm. All the results are then stored to the database along with barometric pressure and air temperature for later analysis and comparison with previously recorded runs.

We are now working on a version of the programme that constantly monitors the vehicle speed and power as it gradually accelerates over a given rpm range. This should provide an even greater degree of accuracy across the power curve, but it has to be carefully done to ensure the vehicle doesn't accelerate too quickly, as this introduces inaccuracies in measured power.

How we perform a rolling road session

Before a vehicle is put on the rolling road, it is first thoroughly checked. We check cylinder pressures, oil and water levels, tyres and tyre pressures. We also visually and audially check the vehicle to make sure it looks and sounds OK.

The vehicle is then placed on the rolling road and strap it down, and our powerful 3-phase cooling fan positioned as close to the engine and its radiator as possible. We then run it up on partial power to check mixtures, engine temperatures and vehicle stability.

Once we're happy that the engine and vehicle is in good condition, we run it under load and measure the power at certain speeds, keeping careful watch on engine temperature and emissions.

We follow carefully designed procedures to ensure the safety of your vehicle at all times. The result is an exhiliarating experience together with confidence that the performance of your vehicle has been accurately and safely measured.