I need a smaller water pump pulley.

I have built a couple of 166mm crankshaft pulleys but finally there is not really much space left between water pump pulley and harmonic damper. It works but it is not a long term solution. A worn damper or water pump will kill at least the belt sooner or later.

ASP may sell them but it would be great if someone here could help or knows where to get them.

If not i have to build them.

Thanks

Steven

Berlin Germany.

 

i can get you an asp water pump pulley separately, is that small enough?

 

Hi,

thanks for quick response.

Got the information from ASP: the waterpump pulleys for the 178-185 harmonic dampers from ASP are 100mm (stock size 120,55). Looks too small for my aplication. I probabely go for a custom build pulley (110mm). Not decided yet.

But even with my 166mm crankshaft pulley: a 100mm waterpump is a huge overdrive.
I am wondering how often you 185mm guys are changing waterpumps?

At this stage it makes sense to change to an electric waterpump IMO. Much better efficency and gains a couple of hp`s.

Steven

Berlin Germany

 

I have the 185 pulley and dont know why you have a water pump concern? Why do you think you need a different pulley, I autocross and reach 6000 all the time, no issue. Woody

 

It seems that the stock water pump can handle a lot more rpm. Good news for me.

You asked me about my concern. I have no concern, when the pump can handle 6000 x 185 all the time.. :-)

But here we go, example: i was in a hurry today driven from a to b. About 10-15 minutes 4500-5000 on the german autobahn. Just straight not pushing the pedal max to the limit.

you 185 / 100? = 1,85 x 5000 = 9250
stock 154/ 120 = 1,28 x 5000 = 6416

more than 40% overdrive at the waterpump. A little scary.


Steven

Berlin Germany

 

Not too much thought went into the stock impeller design, so the question is t what rpm does cavitation occur and what is the max speed of the bearing with the side loading that it has?

 

On my vert (192mm crank pulley) the water pump pulley is soooo small the ribs under the pulley had to be cut to accommodate the pulley!
Wonder what it's spinning at!?

 

Hahaha. A turbocharged water pump. 15.000 rpm

 

I have the stock water pulley. ww

 

I have an aluminum 115mm water pump pulley I cut myself. Still plenty of meat left on the sidewall to trim off 2-3mm off the diameter. I ran it for a few weeks and cut a smaller one, but it made about 15 passes at the track and spun true. You can see the belt mark on the pic attached.

 

I hope it is made better than the LET pump pulleys, they failed quickly due to the rads being too small, the bolt faces shattered as well.
CLICK
Another case of the quick buck being more important than part testing, some members forgave the maker for the poor design.
Aluminum is a cheap and easy material to machine, but it is prone to failure much sooner, see the aluminum SC pulleys for more proof.

 

I have an even thinner wall version on the coupe now and it has done around 3K miles with 35 passes and shows no signs of stress anywhere. I did actually go to trade school for machining, not tuning cars.

 

And I'll add that I run a Eurocharged aluminum 65 that (knock on wood) hasn't grenaded under spirited driving for 4 years with me, one with itsky. But I will pull it and inspect with dye since the belt is coming off to rebuild the alternator. Found out the problems with Slagburger's car and mine decided to get jealous. Unless upside is the new job has lifts available.

 

All the aluminum pulleys will fail before the steel ones. The aluminum ones will fail at the groove root close to the bearing edge. The area of the belt in front of the bearing is flexing the pulley over the edge of the bearing.