Topic: Electric water pump

[mack90]

http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2009544/p-2009544/N-111+200728815+600001656/c-10101

Anyone tried this?  I bet that would free up at least 10 hp if it can be adapted.

[jfrabat]

I dont know about 10HP; while it is true that the water pump will take up some HP, installing an electric one will increase the demapd of Amps, which means that the alternator will rob more power...  In the case of the e-fan, the advantage is that the fan does not need to run when the jeep is rolling at 30mph or more, but that is not the case with the water pump...  I dont know, I'm just not sold on the idea...  Besides, any electrical problems, and you are stock on the trail because you loose your cooling.  I would not try it...

Felipe

[Jeffy]

It's a big 'IF' it will even fit.

[95yjman]

Wow, I've never really heard of that.  I'll stick with what I got though.

[Jeep_Lust]

installing an electric one will increase the demapd of Amps, which means that the alternator will rob more power... 

I have never been sold on the reliability of electric water pumps; they're big in the Hot Rod community. The advantage to the electric drive is that you can setup a vacuum switch to cut the power to the alternator's field coils under WOT. The pump runs off of the battery during that brief time of hard acceleration. The alternator cuts back in when the demand is low and the vacuum comes back up. Honda has some of their cars setup so that the alternator only charges under deceleration, at least as long as the battery is above a certain level.

The vacuum cutout to free up hp under max acceleration will save a couple of hp even without the electric water pump, and you can always wire out the switch if it goes south...

[neale_rs]

The value of electric fans and pumps is due to being to turn them off at times.  According to the laws of physics there is no free lunch.  Using gasoline to turn a motor which then turns a pump is less efficient than just turning the pump directly, assuming same pump pressure/flow, etc.  The more amps the alternator needs to put out, the harder it is for the motor to turn it, no way around it.

[neale_rs]

The value of electric fans and pumps is due to being to turn them off at times.  According to the laws of physics there is no free lunch.  Using gasoline to turn a motor which then turns a pump is less efficient than just turning the pump directly, assuming same pump pressure/flow, etc.  The more amps the alternator needs to put out, the harder it is for the motor to turn it, no way around it.

Second try, bad wording the first time.

The value of electric fans and pumps is due to being able to turn them off at times.  According to the laws of physics there is no free lunch.  Using gasoline to turn a motor which then turns an alternator which then runs a pump is less efficient than just turning the pump directly with the gasoline motor, assuming same pump pressure/flow, etc.  The more amps the alternator needs to put out, the harder it is for the motor to turn it, no way around it.

[Jeep_Lust]

  Using gasoline to turn a motor which then turns an alternator which then runs a pump is less efficient than just turning the pump directly with the gasoline motor, assuming same pump pressure/flow, etc. 

That's assuming that pump drive from the engine is efficient, like 2nd Gen small blocks that run the water pump directly from the camshaft, with no belt drives. V-belts are notoriously high-friction (one of the reasons for the switch to "serpentine" micro-vbelts). Electrical generation and electrical motors are highly efficient, which is why before the days of efficient inverters, electrical motors driving AC generators were used to convert DC to AC.

Of course here you still have the alternator running off of a belt drive.... whether or not it's a V-belt depends on the year.

When I was a kid, I drew up an alternator that ran off of an exhaust-driven turbine, like a turbocharger. Getting the turbine speed down to a realistic speed for an alternator was the problem.

[neale_rs]

Using the exhaust would be the way to go!   

[jfrabat]

Using the exhaust would be the way to go!   

Wouldn't that cause a restriction in the tailpipe?  You need pressure to turn any kind of load...  The difference in the Turbo is that the restriction results in more air coming in, which in turn results in a more powerful explosion that cause an power increase...  But in the case of an alternator, there would be no increase.

[neale_rs]

I'm sure some engineer could find a good design.  Maybe make a wider section and put the turbine there to one side, make the turbine easy to turn and use gear reduction to bring the speed down enough to run the alternator.  Something like that.

[oldjeep]

And some of the nascar guys run it off the driveshaft, but I'm pretty sure i don't want my alternator or water pump down there

[Jeep_Lust]

Wouldn't that cause a restriction in the tailpipe?  You need pressure to turn any kind of load...  The difference in the Turbo is that the restriction results in more air coming in, which in turn results in a more powerful explosion that cause an power increase...  But in the case of an alternator, there would be no increase.

 You compensate for the restriction in flow by using a lower-restriction exhaust behind the turbine, using the turbine asa sort of upstream muffler. And the force that drives turbos is not entirely about pressure. You're also recouping some of the lost heat energy in the exhaust. This is why turbo engines frequently have the feed pipe to the turbo thermally wrapped; to get as much of the heat enegy to the turbo as possible.

[jfrabat]

You're also recouping some of the lost heat energy in the exhaust. This is why turbo engines frequently have the feed pipe to the turbo thermally wrapped; to get as much of the heat enegy to the turbo as possible.

Dont you want the turbo as cold as possible?  As far as I know, the hotter the turbo, the hotter the air coming in will be, and the loss oxygen it will carry... Is this not the reason for the intercooler?

[aw12345]

you want the intake air coming from the turbo going to the engine cooled. on the exhaust side the turbo draws a lot of heat out of the exhaust gas. One of the reasons you can just about run a turbo without a muffler