Hutt Firm Tunes Fast 4 Wheel Drives

When Japanese car-makers brought their super-quick four-wheel-drive cars to New Zealand for a road trial recently, they relied on an innovative new test kit developed in the Hutt Valley to tune their speedsters.

The device is a 4WD dynamometer, developed by International Dynamometers Ltd in Alicetown, Lower Hutt. Technology New Zealand – which invests in innovative products, processes and services – helped the company to make the dynamometer smaller and to build the electronics and controllers.

The dynamometer measures torque – the force needed to drive the wheels – and the horsepower the engine supplies to the wheels. From the two it reads in seconds what is going on inside the engine.

Computer data then helps engineers tune the vehicle to run better. It shrinks what used to be hours of work to a few minutes – cutting garage workshop time and costs to the customer.

The technology helped a Japanese Nissan R34 Skyline 4WD reach an estimated 348km/h on a closed road test near Golden Springs, in the Bay of Plenty, recently. The vehicle showed 1017 horse-power on the Dynapack 8000 4WD machine, delighting Japanese engineers and confirming the vehicle setup.

The dynamometers are very much home-grown. Many of the parts are made at the company's premises, and the dynamometers are assembled there.

"We did about $2.6 million in exports last year," director Alan Sheridan says.
Static dynamometers have been around for some time.

"The obvious example is the 'rolling road' – rollers sunk into the workshop floor and which require a high capital cost to set up and a lot of training to operate," International Dynamometers engineer Tony Devos says.

Simply put, rolling roads measure engine performance under road conditions. They are not as precisely accurate as the Dynapack, he says. The tyre on the rollers, the possibility of wheel-spins, tyre and engine temperatures from long runs – all can add to a distorted picture of what's happening in the engine.

Mr Sheridan says his company has power absorbers, called pods, that can be bolted straight on to the wheel hubs. "It bypasses the rolling road, and the power goes straight to the wheel," he says.

So when the vehicle is put into gear and the engine revved for a few seconds, the pods absorb the power and torque and set up a resistance, giving the wheels something to push against. This enables the engine's performance to be read better on a computer screen.

"It's so precise that it can hold wheel accuracy to one rpm," Mr Devos says.
The dynamometers are portable, simple to work, and are being used in small workshops, as well as by some big overseas motor-racing companies.

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