Re: [xj-s] high flow water pump

["Kirbert" <palmk@mailer.gadcomm.net>]

> From:          Juliansean@aol.com
> I think the one thing that is not mentioned very much in this
> discussion is water pump output.  It seems simple to me to put a
> smaller pulley on the water pump and thus increase the flow thru
> the rad precisely when you need it - at low engine rpm.  Does
> anyone have a pump to look at and see if the pulley is removable?

The pulley is press fit onto the shaft.  I'm sure it wouldn't be hard 
to pull it off and press on another, if you can find a smaller one.

I'm not sure it's a good idea.  At redline, that pump is putting out 
a LOT of pressure, and speeding it up may result in even more blown 
hoses than we presently get.

Another idea might be to replace the impellor.  The pressure 
generated at a given RPM is a function of the OD and the OD can't 
really be changed, so you won't get higher pressure -- but you might 
get considerably different flow rates.  The vanes on a centrifugal 
pump impellor can be radial, "forward leaning", or "backward 
leaning", each with its own flow characteristics.  The impellor in 
the Jag water pump is quite unusual for automotive water pumps in 
that it has extremely backward leaning vanes.  An impellor from a 
Chevy water pump will fit in the same pump, but the Chevy impellors 
are much closer to radial vanes.  My *suspicion* is that the Chevy 
impellor will result in better flow at idle, but I can't back that up 
with any data -- despite the fact that I have a Chevy impellor in my 
car.

I have some books on centrifugal pump theory somewhere, maybe I'll 
look it up sometime when I'm not feeling so lazy.

 -- Kirbert      |     If anything is to be accomplished,
                 |     some rules must be broken.
                 |          - Palm's Postulate

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Follow-Ups:

• Re: [xj-s] high flow water pump
• From: John Napoli <jgn@li.net>

References:

• [xj-s] high flow water pump
• From: Juliansean@aol.com

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