[Just Add Boost]

I bought the Essy serpentine WP pulley to put on the bird. It is a lot lighter than the steel stocker.
I did notice it is 5" diameter versus 6" on the stock pulley.
I think the stock crank pulley and stock WP pulley are the same diameter so putting this pulley on will effectively overdrive the water pump.

A couple of thoughts:
Would the increased pump speed/load negate the benefit of the lighter mass of the new pulley?

Would the increased pump speed lead to pump cavitation at high engine speeds? (8000 engine rpm would be 9600 WP rpm)This will be the Essy WP as the pulley hole is too big for a stocker.

I'm sure there would be a cooling benefit at lower engine rpm as the pump would be turning faster than engine rpm but is that a good tradeoff for more power loss up top?

Essy has a 2.9" serpentine crank pulley but that takes things way too far in the other direction making everything turn too slow IMO, especially for a street driven setup that needs reasonable WP and alternator rpm at low engine speeds.

Thoughts?

[Area 47]

the only thing i can see by overdriving it, is a heat issue in the coolant. moving it "too fast" to effectively collect the heat and move it to the radiator. ran into a similar issue with larger "higher volume" intercooler pumps in my experimentation time with the cobalts. Time is a key equation ot it all. I have the same pump with the essy v drive setup, but had it modified for the heater core line.

i may be way off on this.

[TurboRay]

Originally posted by Area 47:


Moving (the coolant) "too fast" (may not) effectively collect the heat and move it to the radiator.


I may be way off on this.

I'm pretty sure that that's an old "wive's tale", Bryan. Within reasonable high/low rpm limits, I THINK the "dwell time" vs the number of "cycles/passes" thru the radiator & engine pretty much balance out. Someone with more knowledge of thermodynamics would need to verify, however (Don Haulsee?).

My only concern with overdriving the w/pump 20% (9600 vs 8000) would be the increased chance of cavitation, as Chris suggested. However, the curved impellers of the Essy pump make that far less likely. <font color=blue>HERE</font> is a link to Stewart Components' "Tech Tips" that has a lot of good info on cooling systems do's and don't's. :dunno: <font color=navy>

[stott]

Originally posted by Area 47:
moving it "too fast" to effectively collect the heat and move it to the radiator. ran into a similar issue with larger "higher volume" intercooler pumps in my experimentation time with the cobalts. Time is a key equation ot it all.

I'd love to dive more into that, because I've heard that theory before and to me it really sounds wrong. The rate of cooling should correlate with mass-flow of the coolant. More speed by itself isn't enough information, but more flow, which is what a higher rated water pump produces, should absolutely cool more because it will literally flow more mass of coolant through the system.

Who wants to go down this rabbit hole?!

[Just Add Boost]

[/qb][/QUOTE]
As a "side note".....I'm not convinced that the slight weight reduction of using an aluminum vs steel w/p pulley will make any noticeable/significant improvement in performance (but.....I was wrong once before, lol). :dunno: <font color=navy> [/QB][/QUOTE]

Just by guessing, the factory steel double pulley is every bit of 3-4 pounds whereas the Essy pulley might weigh 1/2 pound.
Main reason I got it was the Essy pulley looks so much better than the stocker

[Bob_Myers]

I have run the Esslinger aluminum pulley (smaller than stock) on a stock water pump for 2 seasons, and it is now on one of their billet pumps. No issues detected at all.

Regarding the water "too fast", the reference for discussion is running without a thermostat, and the issues that causes.

If you are running a thermostat, you effectively have a restrictor. I am running one of the "Speedway" housings with no thermostat, but a 5/8" hole restrictor. Car comes up to temperature fine, and holds at 180 with my fan.

[Area 47]

Originally posted by stott:

Originally posted by Area 47:
[b] moving it "too fast" to effectively collect the heat and move it to the radiator. ran into a similar issue with larger "higher volume" intercooler pumps in my experimentation time with the cobalts. Time is a key equation ot it all.

I'd love to dive more into that, because I've heard that theory before and to me it really sounds wrong. The rate of cooling should correlate with mass-flow of the coolant. More speed by itself isn't enough information, but more flow, which is what a higher rated water pump produces, should absolutely cool more because it will literally flow more mass of coolant through the system.

Who wants to go down this rabbit hole?! [/b]

to mix what you stated and bob stated together comes into play as a whole. My dealings were with the intercooler pump {bosch unit used in damn near everything supercharged} versus a larger test option say a rise in iat's after the intercooler than before the pump change. I'm still in jackstand land.

[Just Add Boost]

Originally posted by Bob_Myers:
I have run the Esslinger aluminum pulley (smaller than stock) on a stock water pump for 2 seasons, and it is now on one of their billet pumps. No issues detected at all.

Bob, the Essy pulley worked with a stock pump? The hole in my Essy pulley is too big for my stock pump but fits perfectly on my Essy pump.

[Bob_Myers]

On a stock pump ...

http://i1192.photobucket.com/albums/aa32...xgvjrv.jpg

On Esslinger billet pump

http://i1192.photobucket.com/albums/aa32...pt6byz.jpg

Sorry no better picture on stock pump

[TurboRay]

Looks like Bob used a steel sleeve on the stock pump, Chris. :dunno: <font color=navy>