VAC Race underdrive pulleys - do they work ?

[alexk]

I am trying to get a bit of extra speed from the CSL without causing any issues and the underdrive pulley mod always seemed to make sense.

The idea is simple.
Underdrive the water pump and the power steering pump.
Less rpms on both water pump and power steering pump.
Engine cooling should not be affected as the water will have more time to cool down in the radiator and the tuners claim there is temperature decrease in the power steering circuit.

I ordered a set of VAC Ultralight pulleys from Martin (trackm3).
VAC (as other tuners) claim 8hp gain throughout the powerband.
They come with the longer belt.

Here are the photos

The new VAC pulleys. Excellent build quality.


The OEM pulleys. Also made from aluminium.


VAC water pump pulley. 137mm diameter. Weight 214g



OEM water pump pulley. 116mm diameter. Weight 211g



VAC power steering pulley. 147mm diameter. Weight 304g.




OEM power steering pulley. 121mm diameter. Weight 153g.