Supercharger Pulley Install

[k-huevo]

One of the most cost effective modifications that can be performed on the MCS is to replace the OEM supercharger pulley with a smaller one. Overdriving the supercharger creates higher levels of boost earlier in the power-band which promotes improved acceleration. The OEM pulley is an interference/press fit; this requires a special puller for removal to avoid mangling the shaft. The replacement pulley I recommend is a two piece collet style, slip fit, available from a variety of manufacturers. This style of pulley has proven itself in ease of installation and reliability. The installation process doesn’t require advanced skills and the only out of the ordinary tools needed are the pulley clamp and belt tension release. There is more than one way to perform this install, here is my method.

Tools needed:
Pulley clamp and puller
Allen hex socket for the new pulley (4mm on an Alta)
Sockets – 8mm, 10mm, 13mm, 16mm, 18mm
Ratchets
Phillips & Flathead screwdrivers
T-30 Torx
Belt tension release tool & strap locking tool (allen wrench or OEM)
Torque wrenches – in-lb with 10 to 80 range minimum, ft-lb with 7 to 74 range minimum.
Ramps
Hydraulic jacks X 2

Drive the MINI up on ramps and place chucks behind the rear wheels.


Open the bonnet and remove the dip stick, unbolt the chassis to engine bracket ground strap (13mm), unclip the upper hoses on that side and unscrew the routing clip on early models (10mm), disconnect the upper vent hose on the fuel tank vent valve, and bend the retaining tab to allow removal of the valve, position the valve up and out of the way.


Remove tension from the belt using the OEM leverage tool and lock the strap stop. Isaac (Ike) demonstrates.


Working from underneath the vehicle, remove the power steering fan (it is removed in this photo) with a 13mm socket. Check the operation of the fan blades for smooth spinning. The fan blades on Ike’s MINI wouldn’t turn, and once freed it had a gritty feel.


Loosen the splash shield bolts (10mm).


Unfasten the screws (Phillips).


Remove the lower vibration mount bracket’s bolts (16mm), both from the oil pan bracket and the subframe, so the “dog bone” moves freely.


From under the bonnet, remove the intercooler cover (T-30 Torx), and air box cover. Place a flat blade screw driver blade in the end of the clamp around the outlet hose and twist to unfasten. The self tapping bolts in the cover are 8mm.


Remove the inlet snorkel.


Open the boot and disconnect the battery.


Take the cover off the ECU connectors located to the right of the air box, unfasten the connectors. Pull rearward on the sliding locks to release; do not attempt to pull the connectors up without unlocking. Re-installation is in reverse, place the connector over the pins and slide/push the locks inward to secure.


Remove the lower air box portion with the ECU included (10mm).


Unscrew the coolant hose hanger from the front of the intake manifold (10mm).


For early models, remove the bolt from the upper engine vibration damper’s pitch control bracket at the chassis mount; next, remove the bolt from the engine bracket mount (16mm).



Remove the 18mm nut from the hydraulic engine mount (early model shown).


A late model vehicle will only have the hydraulic engine mount nut, no braces.


Place a jack under the gear box for support.


To allow clearance for the transmission mount’s bolt, the throttle body connector may need disconnecting. For some builds it is not necessary. Remove the transmission mount bolt (16mm).



Place a jack under the oil pan; depending on the lift range of the jack, a thick shim may be needed.


Bend the heat shield, located under the coolant expansion tank, upwards.


Isaac demonstrates operating both jacks at once while observing engine movement; the gear box side is lowered and the oil pan side is lifted. The reality is more like, lower the transmission, look for contact under the vehicle, lower some more, look for contact, raise the other side, look for contact up top, etc.


With the engine raised enough to access the tensioner bolts, remove the rearmost bolt (16mm), the lower bolt (10mm), loosen but leave in place the upper 10mm bolt, remove the tensioner pulley arm pivot bolt (16mm) on the supercharger; after the arm is unbolted, unscrew the final 10mm and remove the entire tensioner assembly.


Remove the original supercharger pulley. There are few different style clamps and pullers available. In this photo I’m using the Alta V1 puller without the handle and an impact wrench to turn the extractor bolt. To protect the end of the supercharger shaft, screw in the grounding strap bolt. With this bolt in place there was a fitment issue with the V1 puller and attached handle, that’s why the impact was used instead of handle and ratchet.


For removing the JCW pulley on the GP shown in this photo, I used a standard size pulley aluminum clamp machined by holdenontoit, and milled to accommodate the 11% smaller JCW pulley, a bolt grip puller is attached for extraction. Kar (simplekid15) shows us how it’s done using a ratchet.


After the original pulley is removed, clean the supercharger shaft, new pulley & hub, with brake cleaner or acetone. Slide the hub collet all the way to the bearing protector and slide the pulley over it. Screw the attaching screws (4mm allen head on an Alta pulley) in finger tight. Before starting the install be sure you have all the hardware; sometimes fastener parts are missing. Torque the bolts in the tightening sequence and torque value specified by the manufacturer. For an Alta V1 it is in-lbs, moving in an X pattern, torque sequentially, tighten the first round at 10, then 30, 60, and the final round at 80 in-lbs.


Reattach the tensioner assembly starting with the rearmost 16mm bolt, the bottom 10mm, and loose fit the top 10mm; 33 ft-lb for the tensioner’s 16mm and 7 ft-lb for the 10mm. When screwing in the tensioner arm pivot bolt, leverage the arm so there are no side loads on the bolt which may cause cross-threading.



Carefully re-align the engine & transmission and torque all fasteners to MINI spec. The nut on the hydraulic mount is 50 ft-lb, all chassis bolts and mounts are 74 ft-lb, power steering fan 14 ft-lb.

[Ike]

Thanks again for your help, Keith. The car is absolutely transformed. I wanted to live with the car a little before I posted my impressions, but this is definitely a worthwhile mod and I can't imagine the car without this extra kick in the pants. (<--two thumbs up)