Powerhouse Jaguar XKR / XK8 4.0 V8 Supercharger Lower Pulley Performance 18% (X100)

Regular price £356.00


18.6% performance upgrade lower supercharger drive pulley inc. Crank Damper EXCHANGE with special length drive belt for Jaguar XKR / XK8 4.0 V8 (X100) 1998 - 2002.

These pulleys are CNC machined from high grade billet aluminium. Produced to the highest dimensional tolerances and surface finish to that of any on the market. Our exchange crank dampers have been inspected, modified, blasted and given an OE black painted finish before our pulleys are installed.

Supercharger pulleys are the most proven and best £/Bhp performance enhancement available for supercharged engines. Changing the pulley ratio results in the supercharger working at a higher speed and producing more boost. Because this just directly increases airflow through the car’s existing sensors, the ECU is kept aware of the increased flow and no further alterations or remapping are necessary


Boost & Power gains:

On 4.0 engines, the lower pulley mod yields much better results than the upper pulley. This modification gives an 18.6% supercharger driven speed increase, which equates to about a 3.5psi boost pressure rise. It will make the car feel as though the engine has grown by a litre. These upgrades have been fitted to many cars, result vary but discussion on forums and bar stools confirm about a 60bhp/ftlb gain from this modification. While this is true for the midrange gain the Eaton M112 supercharger loses efficiency at high rpm so actual peak power gain may realistically be about 10-15bhp. Irrespective of the increase tailing off towards redline where engines are least used, this modification gives a HUGE increase in instant grunt and acceleration which really does transform the car. IMPORTANT - if you already have a performance upper pulley, you will need to upgrade your intercooler and intercooler circuit water pump, as inlet air temperatures can rise too high with both pulleys upgraded and risk engine damage unless cooling is addressed.


Sale Includes:

  • 1 x Crank Damper with Uprated Alloy Performance Supercharger Pulley 18.6%
  • 1 x Special length Supercharger belt to suit



Before purchasing first check that you have the correct damper that can be modified. Some models of the 4.0 used a different damper that cannot be modified to use this pulley. Please refer to our images to find which is the correct version. To help, the pulleys we can modify have solid outer pulleys, the incorrect version can be identified by the presence of a rubber band between the pulley and the hub.



Installation is relatively straight forward, the pulley needs pulling off and once off the replacement simply bolts back on. In order to do the install, you will need a few workshop tools including a puller for the crank damper. We advise using a specific puller for the crank pulley. If the pulley does not come off easily please DO NOT lever the crank pulley to remove it. This is a common practice that rarely succeeds, however, bends the pulley which makes it useless on exchange.



We offer two types of exchange for this crank damper.

IMMEDIATE DISPATCH - If you need the damper quickly for the same day job we charge a £250 deposit in addition to the sale which we request by PayPal. This is returnable upon receipt of your exchange crank damper however we do reserve the right to adjust the deposit amount or refuse if the returned damper is in an un-useable condition.
STANDARD DISPATCH - Our typical service is to reserve a stock damper for you, on receipt of your exchange unit we will inspect it for useability and either send the damper out or if the damper is un-useable we will discuss your options.


Part Number




Jaguar XKR / XK8 4.0 V8 (X100) 1998 - 2002.