Originally Posted by TBM
Latest little bolt on addition to my Crossflow is an underdrive pulley.

It's a smaller diameter main crank front pulley - supposed benefits are:

1. Alloy, so stronger than the original welding steel (they have a habit of breaking up)
2. Smaller diameter means that the Water Pump and Alternator spin at a lower speed so less strain on them
3. The reduced spin of the ancillaries can possibly relate to an increase in usable bhp due to less draw.
4. Reduced weight of the front pulley will help her spin up a bit quicker (same as the lighter flywheel)

Fan belt is OK on furthest setting, so ordered a shorter one so I get a bit of play. Fitted an alloy water pulley at the same time.

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Interesting. Could this not have an impact by overheating by not circulating the coolant as quickly?

2004 Series 1 Roadster