The stock item weighs in at around 7 pounds .The GTT item weighs just one pound! The benefits are similar to those experienced with lighter flywheels: i.e. better throttle response and free revving. However both unit cost and fitting costs/time are considerably less than those associated with lightweight flywheels.
Our design features 6 spokes (to achieve the required strength) a separate steel sleeve to achieve the correct interference fit onto the crankshaft nose, and a bolt on pulley wheel. As we’ve said before, an interference fit between an aluminium pulley and a steel shaft is poor engineering practice. This is due to the different expansion rates and also risk of ‘picking up’, a process where the alloy welds itself to the steel shaft when you remove it .
This causes a lot of damage to the alloy part and makes a mess on the steel shaft too. Our pulley is HARD anodised to eliminate corrosion and minimize pulley wear. No other pulley gives you these important design features. The largest diameter +4% version gives the equivalent ‘gearing change’ to the supercharger of ‘-4%’. This means they are best suited to Standard, JCW or cars running a -15% SC pulley. And of course you get the quick spin up too! The above versions are intended for cars running standard rev limit only. GTT design is proven since 2004, some cars having covered 100,000 miles since fitting. V2 features damping patches for reduced resonance.
If your stock crank pulley is ageing and starting to deform causing it to make that ‘cha cha cha’ sound under load and dropping belts, then upgrading to GTT pulley is the cure, and gives much improved engine response.
Sizes available are: – 0% +1% +2% +3% +4%
Please telephone for advice on best size for your car.
Note: Designed for use for standard maximum engine rpm (rev limiter) only. i.e. 7000 rpm
(Badge for illustration purpose only)
Fits: Gen 1 Cooper S (also JCW / GP1)