What happens at a Rolling Road Test ?

[perksy]

What happens during a rolling road test  

and How much should i be looking to pay for it  

[Blatman]

Your car is placed on to the rolling road and usually strapped down to prevent it climbing out and runing you over!

The RR operator will then hook up various leads and sensors to rake readings from your car to determine the current running conditions. He should then run the car up to 60mph, drop in to neutral and let the car coast almost to a halt. This is the coastdown test and is *vital* in order to help with calculating power at the crank and transmission losses. He will then do a power run to give you the current BHP.

The operator will then run the car up to identify the problems you are there to resolve. He will use the rolling road to apply braking forces to the wheels so that the engine can be run at various throttle loads without having to drive it flat out. The readings taken from the various sensors will help determine what action needs to be taken to improve the way the car runs or to resolve whatever running issue may be present. Once all the work has been completed, another coast down test is done, and then another power run. If all has gone well, you should see an improvement in either the power figure, or at the problem you arrived with should be improved or completely resolved. You should be given a graph of the power and torque readings (called power and torque curves) as well as other data like max rpm used, air temperature and barometric pressure. You are given these readings as the weather conditions can affect the results slightly. A good rolling road will make compensations for weather conditions to calculate "corrected" BHP figures.

Expect to pay between £50 and £80 an hour.

[Mark Stanton]

Be warned - sometimes engines do go bang