As some of you already know, I put my 2001 XJR on the sale block. Car is absolutely beautiful and reasons for sale are all posted in my Classified ad on this here forum.

In the meantime, a lower pulley conversion caught my eye and I started to think... Usually this type of thinking ends up in parts acquisition...expensive parts acquisition. I'm thinking of performing this mod in case I won't find the buyer for my car and end up keeping it.

The increased diameter lower pulley should give about +5lbs of boost, does not require modifications (except for the pulley swap itself) and should give you about 40-50 hp in the mid to high rpm range.

I was hoping to hear thoughts on such install - ALL opinions welcome. I want to know the negative side of going to the lower pulley as well as experiences of those who've done this swap.

 

If you do the swap, I need your lower pulley......

 

gives you extra punch low down - worth it.

 

I was reading about this exact same conversion two days ago. In depth type report and where he had brought it....maybe worth a search? The first two pullys were faulty.

 

Yes, I read that one too. That's the thread that got them bad ))) thoughts into my head. Except that he went with upper pulley. My only concern is that a larger lower pulley will make the entire belt drive to spin faster thus putting stress on a/c, power steering, water pump, etc.

 

No, they're on a different belt.

 

I know that the super charger is spun via a separate belt, but the accessory pulleys are still spun by the crank pulley even by separate belt. Unless the inner crank pulley diameter is same as stock in which case this alleviates all my worries regarding added stress. Correct?

 

Yes, only the charger pulley is changed. 4 bolt fixing. Best to remove the whole harmonic crank damper to install, and tapping the threads for the bolts helps too.

 

Sean, which bolt holes are you speaking of? Are we talking about the auxiliary belt drive on the crank or through to the harmonic balancer?

 

The S/C pulley bolts to the aux/crank damper, kits supply longer high tensile bolts, it's good form to thread chase as sh*t collects in the back of the threaded holes, can bind the bolt and sheer.

 

Got ya, thanks. If I end up holding onto the XJR, this the mod that I'm definitely going for.