Turbo charging has long been a favoured route for tuners with the 2.0-litre ‘Silvertop’ Ford Zetec engine, as it delivers potentially large power gains as relatively low cost.
However one of the problems of bolting a turbo onto an engine originally designed as a normally aspirated unit is that the original camshafts are optimised for a standard non-turbo motor. Conversely, turbo engines have different cam timing requirements, so if the original cams are retained, ultimate performance will be compromised.
And the Ford Zetec is no exception, so, responding to demand, Belgian based performance valvetrain specialist Cat Cams has produced a set of profiles specifically designed for Zetec turbo use, tested in conjunction with Devil Developments of Littlehampton, Sussex.
Carrying part number 2290114, the profiles are designed with higher lift than the standard Zetec profiles and with greater duration on the inlet profile. On the exhaust side, the duration is reduced slightly to aid turbo spool up, greatly increasing response and mid-range torque.
Technical details on the Cat Cams Ford Zetec turbo profiles are as follows:-
2290114 256/247° - 230/212° - 10.00/8.70 mm
A like for like swap with the standard camshafts, the Cat Cams Ford Zetec turbo profiles are directly compatible with the standard Ford hydraulic valve gear. Back to back dyno testing has shown an 11 bhp improvement in peak power, with gains of up to 25 lb.ft of torque in the mid-range.
As can be seen from the graph, the mid range torque has been transformed. On the run with the new cams the boost pressure had dropped to 7psi (from 9psi on the std cams). If the wastgate had been tweaked to restore the boost pressure we would have expected to see approx 270bhp.
On the final run, with 14PSI of boost, the engine made just under 350bhp. Thats 100bhp more than when it arrived and the owner is very pleased with the results.