The basis of the R53 reduction pulley is to increase horsepower with a lighter, more compact unit. A main factor with Cooper S drivers is finding ways to augment their boost levels. Often, it can take the installation of many expensive parts to get desired results. Using an R53 pulley is an affordable alternative to overhauling an entire system. Instead, it is a replacement for the larger, heavier pulley that holds back everything your turbo engine is capable of. Even if you do not plan on taking your car to the track, this upgrade will still make a difference. R53 reduction pulleys help your car experience greater boost even during residential driving.
It has to do with rotational mass. The more of it there is, the more it slows things down. Alta reduction pulleys are light and compact, allowing the supercharger to increase rotational speed. This process causes a bump ranging from 3 to 5 PSI. With the rise in PSI comes extra boosting capability, allowing the Alta reduction pulley to offer between 15% and 20% more horses and torque. The estimated rise in horsepower does not take into account other modifications. For instance, if you have an Alta reduction pulley installed along with aftermarket exhaust parts and a CAI (cold air intake), that number can climb even higher.
You have a choice. Alta reduction pulleys come available in two sizes – 15% and 17%. Considered the more common size, 15% pulleys generate approximately 12-17 more horsepower in the wheels (WHP). Drivers whom are either more in tune with performance needs or take their cars out on the track may prefer the 17% option. This Alta supercharger pulley offers about 5 solid PSI and can contribute over 20 WHP. What it does more than anything is assist in escalating boost at lower RPMs. The Alta supercharger pulley keeps acceleration smoother and more responsive, even at cruising speeds within the city confines.
Included in each kit are the part, the hub, screws, washers, and an Allen wrench. Installation involves removing the factory part and inserting the Alta supercharger hub onto the shaft. Total installation time varies between 2 and 3 hours, depending on skill level. Once in place the supercharger reduction pulley does not require changes to ECU settings or a tune.