Hello mates.

So i buy this pulley set for my 1990 TT z32 - http://www.ebay.co.uk/itm/390474237408?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 .

When i get them i was really confused becouse every pulley got diffrent size than oryginal one o_O .

Photos - https://picasaweb.google.com/109341889407399430291/Pulleys?authuser=0&feat=directlink .

 

If im right water pump with this pulleys will be moving slower, i think Its not good :/

 

Its ok to install this kit or not realy?

Edited October 22, 201213 yr by Draxan

Hello mates.

So i buy this pulley set for my 1990 TT z32 - http://www.ebay.co.uk/itm/390474237408?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 .

When i get them i was really confused becouse every pulley got diffrent size than oryginal one o_O .

Photos - https://picasaweb.google.com/m/viewer#album/109341889407399430291/5801053806356535025 .

 

If im right water pump with this pulleys will be moving slower, i think Its not good :/

 

Its ok to install this kit or not realy?

 

picasaweb isnt showing the pictures, just linked to the website with "log in" on it.

 

If the water pump wheel is smaller, it will spin faster, if its larger than the OEM one it will spin slower.

https://picasaweb.google.com/m/viewAlbum?uname=109341889407399430291&aid=5801053806356535025&start=0 - and how about this link? Its hard to do that using phone :/

https://picasaweb.google.com/m/viewAlbum?uname=109341889407399430291&aid=5801053806356535025&start=0 - and how about this link? Its hard to do that using phone :/

 

aha, the larger diameter of the water pump wheel, is offsetting the smaller crank sprocket, so you should have the same pump speed, if they have been made well.

But : smaler crank+biger pump=slower pump . Im right?

But : smaler crank+biger pump=slower pump . Im right?

 

the closer you get to the centre of a wheel the faster it spins, so smaller crank + bigger pump = same speed as the bigger wheel is off setting the faster spin speed of the smaller crank

If You are right gears in all bicycle are broken ;) ;)

http://www.temecularodrun.com/ref/rpm_calc.asp :winkiss:

If You are right gears in all bicycle are broken ;) ;)

 

You are going from a large crank pulley (spins slower) to a smaller crank pulley (spins faster), it had less distance to travel, thus spins faster, you are going from a small water pump (spins faster) to a large pulley (spins slower)

 

Tell me how im wrong please?

 

small water pump (faster spin), large crank (slower spin)

 

To

 

Large water pump (slower spin), smaller crank (fast spin)

 

All you are doing is changing the speed of the spin vs the size. its the fundamental workings of gears, so if im wrong, then everyone on the planet who builds gear boxes and bicycles is also wrong.

 

And if you still dont believe me

 

http://www.howstuffworks.com/gears.htm

size of pully does not matter regarding rpm...small or big they each turn at the same speed.What does determine speeds is the "drive or slave" pully size:winkiss:

My understanding would be that with a smaller than standard crank pulley, and larger than standard water pump pulley would actually result in the pump spinning slower. It is not about specific rpm, it is about circumference. The smaller pulley will deliver a certain length of belt per revolution, therefore, when the belt has to rotate the water pump pulley that is in fact bigger, it takes more length of belt for the pump pulley to complete one revolution. Net result would be that the pump pulley would not have completed a full revolution by the time the crank pulley had. Thus resulting in a slower rpm of the pump.

omg confused I am

My understanding would be that with a smaller than standard crank pulley, and larger than standard water pump pulley would actually result in the pump spinning slower. It is not about specific rpm, it is about circumference. The smaller pulley will deliver a certain length of belt per revolution, therefore, when the belt has to rotate the water pump pulley that is in fact bigger, it takes more length of belt for the pump pulley to complete one revolution. Net result would be that the pump pulley would not have completed a full revolution by the time the crank pulley had. Thus resulting in a slower rpm of the pump.

 

you are correct ... it will under drive the water pump ...

 

so to correct the pump speed it needs to have a smaller pulley on pump to match

Ok so i was right, its slow down my water pump (and wiscous fan too), and the same with powersteering pump :/ . Anybody use this set? It should be for 300zx... I wonder how big is a rpm diffrence, its safe or not.

get a flex measure tape . measure the Complete dir of both Old pulleys and new

and i can work out the RPM differents for u

http://www.temecularodrun.com/ref/rpm_calc.asp :winkiss:

 

this calculator and my numbers from photos are not good enough? :)

ok original pully set is driving the Pumps at 950:1 ... all most a 1:1

 

the Alloy pump set is driving at 650:1 its 300rpm slower at 1krpm of the engine

so at hmm 5k rpm its 1500rpm slower? :|

yep 5000rpm Engine speed works out at 3270 Pump speed

hmm i wonder diffrence like this its ok or not. I got bigger radiator but...

I'm not 100% sure what's going on here but to me it looks like this particular "ebay" kit is trying to achieve two things, namely:

 

(1) Underdrive crank pully to reduce drag on the crank, and

(2) Allow the re-use of the standard belts by over-sizing the ancillary pulleys

 

Don't quote me on this but looking at the pictures of the new pulley sizes versus stock pulley sizes it is clear that the crank pulley is SMALLER, which is how it should be. All the other new pulleys appear to be LARGER than the stock pulleys. As I can't really see a mechanical reason for this I can only assume it is done to allow the stock ancillary belts to be reused (ie, smaller crank pully + larger ancillary pulley = roughly the same belt length). As a general rule, always use NEW belts when you change any of the pulleys.

 

I have sold many Unorthodox pulley kits over the years (as well as our own 'DTA-Motorsport' branded lightened pulley kits) I don't think that the above 'ebay' kit will cause any harm to your engine components but critical parts such as the water pump and powersteering pump rotating at a lower rpm will eventually cause undue stress on the components. If you look at an Unorthodox Racing kit you'll find that only the crank pulley is smaller than stock, all the others are the same size. This of course requires shorter belts than stock. This setup does mean the waterpump is rotating slower but it is still within tolerances. However, there are OVERDRIVE waterpump pulleys on the market which will return the rotational speed of the waterpump back to normal.

 

In conclusion, which is relevant to the OP, the kit you have purchased is NOT a normal lightened underdrive pulley kit. I personally don't think installing it will cause any harm to the engine BUT I would seek professional advice from the likes of Jeff/Jaime at ZedWorld to be 100% sure. They know these kits (and cars) inside-out.

 

I hope the above explanation makes some sense.

 

Regards,

 

Dan

ex-trader

Wow! Thank You very much for this answer! I think i just install them and test the diffrence. And i pray hard nothing blow up :P ;)

EDIT :

 

DONT buy this set! Its 4 of them in set, You can use TWO, crank pulley and water pump/fan pulley and thats it...

P.Steering pulley is completly wrong, and alternator pulley is like this -

I looked at these glad I didnt bother now. Get yourself a refund.

is the a reason why the 2 pulleys didn't fit ?

I have the same kit and alternator pulley does not fit, but my power steering seems ok, what is wrong with your power steering pulley,

My power steering belt is to small need a smaller belt...