whats your view - there on ebay and i think they are a smaller diameter than std. - but what about the 7 -9bhp gain claim?

 

Your accesories create drag on the engine as speed increases etc, the light weight ones reduce this drag on the engine so theoretically i dont see why they would not work. I have CFM crank and water pump pulleys on mine. Make sure you get a new water pump pully that is larger otherwise you will underdrive your waterpump with just a smaller crank pully which is not good. There are 2 down sides, your lights may dim when the car is idleing and the lightweight crank pully removes the dynamic harmanisor that is on the standard pully, this is a rubber bush which allows a bit of flex in the crank, without this some say it can put the oil pump at risk as the flex can shatter the oil pump gears

 

I had an alloy under drive pulley fitted

 

It will not give your engine more power. Only lower reciprocating weight / rejuice point of inertia.
I would spend the money elsewhere. You should be careful what you buy off "ebay".

 

The big balancer pulley is there for a reason , it take removes vibration from the rotating mass of the crank this is what kills oil pump gears and it doesnt matter if you put steel gears in there eaither it will do the same.

 

Incorrect. If they pulleys are a smaller diameter as the original poster states he suspects, then (also as mentioned) they will under drive ancillaries thus freeing up more power at the flywheel.

 

so basically they are just for show - next question - what camshaft adjustable pulleys are best to go for - obx, kent - what are best?

 

dont no if ur sorted now but when i checked people said most of the cam pulleys (kent, obx are same) but it depends if u want braggin rites! I went for OBX as got them good price brand new and they av dun job fine.

Did u go for the underdrive pulleys (crank and water pump pulleys). Iv seen CFM do a 2 piece set (link below)

http://focus.c-f-m.com/cfm2pcaluminu...csvtst170.aspx

Wot do people think? Any gud? Iv got full exhaust/induction/cams and pulleys on my 1.8 mk1 focus and just wanted make sure i got it all sorted before i get her mapped!

Thanks