When performance car specialist Litchfield Imports wanted to make the ultimate Subaru Impreza, it turned to the best in the business. That included Harwell-based thermal management experts Zircotec.
Litchfield's Impreza Type 25 is based on the already quick Japanese-only Spec C car but features a more powerful, 2.5 litre engine co-developed with Cosworth. This produces 415bhp, rather than around 300 on the 'standard' car but it also generates more heat.
This can be a problem because of the way Subaru engine bays are laid out, says managing director Iain Litchfield. “The engine doesn't like heat. The intercooler sits on top of the engine, rather than down at the front by the radiator. This is fine when you're driving along but if you sit in traffic it doesn’t get the air flow.” |
An intercooler is a heat exchanger that cools the air compressed by the turbo before it enters the engine. Cooler air is more dense, so packs more oxygen into the cylinder, producing more power. However, the intercooler's effectiveness is determined by the difference in temperature between air passing through it and the air around it. This is complicated still further because the up-pipe that brings hot exhaust gases to power the turbo and the down-pipe that takes them away again are both routed directly beneath the intercooler. To resolve this, Litchfield, having heard about its work on World Rally Championship cars, turned to Zircotec.
Its solution was to plasma-spray a zirconia-based, heat-shielding ceramic coating on both the up and down-pipes on the Type 25. This prevents the exhausts transferring heat across to the intercooler, helping it work efficiently so the car responds in a predictable way |
