* Brand New (not on exchange) Genuine Mini part optimised in house.
* Re-centralised butterfly.( Other companies do not do this part ! …. just the stop screw )
* Re-calibrated stop screw.
* Prevents any boost pressure / power loss when fully closed at full throttle.
* Smooth power without surging.
DID YOU KNOW? Using a stiffer internal spring can cause surging under certain part throttle conditions . This is caused because the S/C is pumping air against both the nearly closed electronic throttle, AND a closed bypass valve (due to stronger spring). A portion of the air then has nowhere to go except backwards through the supercharger rotors !.Hence the ‘yoyo’ or surging effect. The spring needs to be strong enough to hold the butterfly fully shut at just before full throttle. ( But not too much before), and have a smooth action . GTT Bypass valve is guaranteed for use even at 22psi boost !
Fits: Gen 1 Cooper S (also JCW/GP1)