Hey everyone. So I have a 98 xjr and I want to upgrade my lower pulley. I been doing a lot of research and I have found the only place they sell them is in the uk. Is there any place here in the US that makes them?

 

Don't do the lower.

The upper will give you +3 lbs with MUCH less drama or risk

 

[QUOTE=WaterDragon;701199]Don't do the lower.

The upper will give you +3 lbs with MUCH less drama or risk[/QUOTE
There is two upper ones. Which one do you mean

 

Jaguar XJR XKR s Type supercharger Lower Pulley Upgrade Export Only No Exch | eBay

 

cut

 

Upper pulley



Advantages:

• Half the price of the lower pulley kit.
• Longevity of a stainless steel pulley – other suppliers use cheap mild steel or aluminium.
• No need to access under the car, or for special tool to remove the crank pulley.
• Best option on 4.2l applications which already have larger lower pulleys.

Disadvantages:

• Acetylene gear required to heat the pulley on fitment.
• Modification/material removal from supercharger snout required.
• Less outright grip available to the belt.*

*Some other pulleys are made in aluminium which gives grip problems when hot – our steel pulleys do not.



Lower pulley



Advantages:

• No modification required to the supercharger.
• No fitting cost if done at the same time as camchain tensioner replacement.
• Increased belt grip area.
• Easily transferred to another car.
• Best option on 4.0l applications.

Disadvantages:

• Twice the price of the upper pulley.
• Requires return of your existing crank pulley.
• Only adds 5% to 4.2l cars.
• Need to access under the car to lock the gearbox and a special tool to remove crank pulley.

Taken from Powerhouse UK

 

[QUOTE=losbadxjr;701269]
There is only one upper. It is the pulley located on the supercharger itself. You will have to grind down the dimension of the snout of the supercharger to get the small amount of clearance needed to fit the pulley. Only buy a steel upper, not an aluminum, because the aluminum will have belt slippage.

The smaller option of a +1.5lb upper pulley's improvement may not be noticed much, but does not require grinding down the snout of the supercharger.



So you can go with a +1.5 lb or +3 lb upper, not both as there is only one upper pulley on the s/c

 

I think the lower is easier - bolt on....no grinding or filing of the supercharger potentially wrecking it, cooking the nose bearings, putting it on off centre and throwing belts etc etc....

You can fit both upper and lower, but along with these mods, uprating all the cooling circuit hoses is a must as added heat and strain to the system will find a weak point fast. Blown hoses and head gaskets are potential issues.

It's recommended these mods are only fitted to healthy engines. They're sporty enough in standard tune - if it's down on power there's usually a reason so if this is the case make sure everything is in good fettle before adding any go faster bits.

Along with both pulleys a larger surface area intercooler rad is good add, not thicker like the mod houses sell, although a slight boost in thickness will aid capacity. I found a Nissan 4x4 rad was perfect.
Or, just go buy Avos twin screw kit and be done.

 

The 3# puller is on the right and the stock pulley is on the left. The other picture shows how much material you need to remove from the snout to get the 3# pulley to fit

 

Wow thanks guys. And thanks for the pic's. I will be doing the upper pulley then after I do my coolant flush and supercharger oil changed.

 

Any specific rad or would any nissan 4x4 rad work?

 

I do wish I'd kept the info, it's too long ago for me to remember the exact rad I used - it was just pot luck at a breakers, a pile of rads and a tape measure.