Author Topic: Water pump pulley mod (Read 2568 times)

VentoTD · « **on:** October 22, 2006, 05:58:36 am »

Since first i started tuning i always thought that good cooling was essential. It all started when my ac compressor went to the next life. I needed to make some changes in the drive belt assembly to get it working without ac. I happend to look at a tdi and copied that to my aaz. Now it was very easy to mod the old pulley to new type but with smaller diameter as shown in picture. This pulley should give me 90% more revs on my water pump. That is a big increase. But the pump should be able to handle it since it's the same pump used on almost all vw gasser engines. Hopefully theres enough traction so the belt dont slip.

burn_your_money · « **Reply #1 on:** October 22, 2006, 06:05:55 am »

How much shorter do you think the life expectancy will be of the pump?

QuickTD · « **Reply #2 on:** October 22, 2006, 08:26:30 am »

Quote

He found that the smallest wp pullies actually had the least head pressure due to the higher revs causing cavitation at the pump.

I was thinking the same thing.

VentoTD · « **Reply #3 on:** October 22, 2006, 08:55:16 am »

Yes dudes i thought of that also... Since im changing timing belts and stuff much to often i dont mind shorter life on water pump. Cavitation surely occurs but im not sure that it does on low reving diesels. Gti gassers run up to 7000rpms with same pump. Anyway im not even sure aazas need better water cooling, but i had to check it out. Dont you guys get crazy ideas sometimes that gets stuck in the head...?

burn_your_money · « **Reply #4 on:** October 22, 2006, 09:07:39 am »

I too get crazy ideas... I had thought of the same thing you did, but then I figured my car never overheats unless something is wrong, so there must be ample cooling

HarryMann · « **Reply #5 on:** October 22, 2006, 10:26:18 am »

Tis would have been taken care of in the original design, the fact that diesels don't rev so high, but 4.5/6.5 (7000 is pushing it!) = 70%

90% more revs ? Thats a reduction, unless you mean by 900%. If the drive wheel is 90% the diameter then the gearing change is 1/.9 = 1.111 or 11%

or do you mean its going 1.9 times as fast.