Independent testing conducted by one of the UK’s leading automotive test and development centres has confirmed that the use of advanced flame-sprayed ceramic coatings can reduce heat transfer by up 26.7 per cent, leading to a surface temperature reduction at the exhaust manifold (which collects the exhaust gases from multiple cylinders into one pipe) of up to 136°C. The technology, developed by specialist coating company Zircotec, offers not only benefits to performance and classic car owners but also to engineers working on new vehicles who struggle to successfully package the increasing number of heat-sensitive components in a restricted space.

Developed first by the nuclear energy industry and used effectively by Formula One and other race teams, the rigorous testing was instigated to demonstrate the effectiveness of the coating on road cars. The firm is already supplying the coating to several OEMs, including Koenigsegg and is, in addition developing applications for improving catalyst light-off times (the time taken by the catalytic converter to reach the optimum operating temperature) and the performance of diesel particulate filters, which require exhaust gas temperatures to remain high.

The tests used a 2002 Range Rover V8 gasoline engine fitted with two sets of manifolds; one standard, the other with the zirconia-based coating. The manifolds were encapsulated to simulate under-bonnet airflow conditions. Testing was conducted on an engine dynamometer, simulating different driving conditions and road speeds.

The results clearly demonstrate that the Zircotec-coated exhaust manifold transmits much less heat to its surroundings than the uncoated standard part. The Zircotec manifold reduced heat transfer at all the different loads and simulated road speeds of 35mph and 70mph. Notably, for harsher applications, the highest gains were achieved when the loads and speeds were at their highest.

In addition to the thermal barrier properties (which prevents heat from being exchanged), the Zircotec coating is more durable than traditional wrap, is easily packaged and provides a fit-and-forget solution for a host of vehicles. Components can be sent directly to Zircotec where they are cleaned and prepared before being coated. The Zircotec process can coat most metals and a recent innovation also allows carbon fibre composites to be coated.