cos rush - i think ya car is a dax rush right? well the problem is frontal area and heavy right foot. the rads dax offer for the rush are limited in their ability to dissipate heat from the the engine for the following reasons:

1) small frontal area of radiator (try and find another car with a bhp potential of 350-400 with a tiny rad like the rush!)

2) proximity of the rad to other bits in the engine ie rad is partially covered by chassis rails etc (even worse in mine as its 4wd and the dif is there)

3) poor general airflow through the engine department because there is no where for the air to go from the rad and the i/cooler. dax's scoop thingy is a gimick. duncan cowpers car had large vertical side vents on each side of the car at the rear of the engine bay to help

dax recken that the newer alloy rad is 30% more efficient than the old one. ive got both and not convinced. the new ones are made by dockwray engineering in silverstone.