BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

[cjforumadmin]

http://www.bangshift.com/blog/BangShift-Tech-How-much-horsepower-does-a-mechanical-water-pump-really-take-to-spin.html

[Tazracing]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?


also what about fans, solid, flex and clutch(drag ingauged and not)

I know, but not everyone runs an electric fan

[Buzzy]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

WOW!!! What a great topic!! This has always been a big question. How much power do you lose and is it worth the money going electric. I'll keep watching!

[C1BAD66]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

You guys already figured it out!

Street car; go with whatever mechanical pump gets the cooling job done.

[Drag] racecar; the ability to pump (and cool with electric fan(s)) between rounds, especially in a hot-lap situation, is the way to go.

[mlcraven]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

[Drag] racecar; the ability to pump (and cool with electric fan(s)) between rounds, especially in a hot-lap situation, is the way to go.

I'll keep that in mind if I ever get past the first round on consecutive weekends

[BangShiftChad]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

Taz,

Fan testing is much harder than you might think. Other publications have tested fans on engines on the dyno, but they haven't done it right in all cases I have seen. In order to properly test it you would need to fashion a radiator, shroud, and fan combo that was appropriate for the engine/fan combo. I know this is possible, and am working on it actually, but it isn't just bolting on a fan and spinning it unfortunately. As weird as it sounds, it is probably MUCH easier to do this testing in a car.

We don't care about easy though. Just want to get the answers.

[98ciHemi]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

One test I would like to see is how much power the alternator draws under load, but also under normal running condition and when the field to it is switched off and it is just idling along under no load.

[Tazracing]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

Taz,

Fan testing is much harder than you might think. Other publications have tested fans on engines on the dyno, but they haven't done it right in all cases I have seen. In order to properly test it you would need to fashion a radiator, shroud, and fan combo that was appropriate for the engine/fan combo. I know this is possible, and am working on it actually, but it isn't just bolting on a fan and spinning it unfortunately. As weird as it sounds, it is probably MUCH easier to do this testing in a car.

We don't care about easy though. Just want to get the answers.

never said it be easy.. nothing in life worth doing is..
On the alt test.. your gonna do full load.. is that full alt output.. or normal amp load a race car or street car would see durring a run..
as a full load isn't really what the engine will see during a run..
maybe on an old 43 amp alt. lol

[mrocketscience]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

With my car, changing to an electric pump cut .10 to .15 off my ET. Pretty worth while, I'd say.

[Russell]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

Was the electric water pump run off an alt.? I have always wanted to know if you put and additional load on a alt. how much if any HP it takes to turn it. Also would like to know if it takes more power to turn a 130 amp alt. than a 65 amp. alt. If I have to up grade the alt to run an electric fan and pump are you still HP ahead?

From my personal experance I removed the clutch fan (ran with no fan) for a few runs at Maxton. I was able to pick up 2.6 mph I would guess its worth 8-10 HP. Even with the front end blocked off it did not get too hot durring the run. Driving back to the start line added a lot of heat to engine.

[realsteelfreak]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

While looking through Jegs I noticed that they have electric water pumps and then they have water pumps driven by a belt and motor. The later one they claim saves as much as 20hp. Is there a difference in the two ? was both tested?

How much HP does the alternator cost when not under full load compared to full load?

Does moving the alt. to the rearend housing help save HP by taking it off the engine and let the driveline do the work?

Just questions, because the next build I do the Alt will go on the R/E just for the cool factor.

[Freiburger]

Re: BangShift Tech: How much horsepower does a mechanical water pump really take to spin?

The dyno is not a pressurized system and does not have a restriction on the outlet (ie, thermostat). Did you add a restriction? What was the pulley ratio?