Removing the water pump... yes? no?

[diamondlarry]

Originally Posted by Matt Timion

two options:

1) leave the gear in place for the water pump, but remove the blades. The gear will still spin.
2) Remove the gear all together and get a bigger timing belt tensioner.

My Saturn's water pump is driven off of the serpentine belt. However, when I replaced my water pump recently(same time as head swap), the drag seemed extremely minimal. I'm not sure there would be much gain for me to use an electric pump. This doesn't mean it wouldn't for someone else though.

[JanGeo]

Water pump could be powered by a fan blade at higher speeds if you let the air flow through the radiator - sort of the reverse of the old days when the belt turned the water pump and fan and pulled the air through the radiator. You need a free wheeling water pump with electric drive or electric clutch and belt drive since a belt may outlast an electric motor... maybe a slotless free spinning electric motor driving the water pump and fan - may as well do both at the same time.

[Bunger]

The do this on drag hondas... suppose to free up some power, so it must increase FE a bit... doubt it would be worth the cost though.

[SVOboy]

Bunger, I saw crx-nation in the signature of someone on h-t and was like, another new forum, eh, I didn't realize it was yours!

Anyway, what's the cost like on said drag hondas?

[Sludgy]

You can buy electric water pumps for small block Chevy's from a number of places. Most are advertised "for racing purposes only".

Water pumps use a lot of HP at high rpms, but much less at cruising speed. So they help performance more than fuel economy.

[DirtyOldTown]

A lot of people do it on older V8 drag cars but I'm not sure how they'd last on the road. A good friend of mine (and the best mechanic I've ever met, by a long shot) has that setup on his '67 Comet. He loves it for the track but he said on the road it starts to heat up after a while. The benefit to him is that he just turns it of when he makes a pass and then turns it back on while returning to the pits. If you left it off on a cold start it'd probably make the car warm up pretty quick but I'd be nervous about hot spots, like you said JanGeo. As far as the timing belt, it'd probably be best to leave the old pump in place and just get rid of the fins - less risky for the valvetrain in case the belt jumps or breaks.

[Sludgy]

A water pump is a convenience for designers and manufacturers. A well-designed thermosiphon, or an ebullient cooling system could eliminate this pump.

[MetroMPG]

If I had more room under the hood, I'd probably have rigged an electric motor to drive my water pump by now. Though I doubt the savings would approach the 10% savings I recorded from not running the alternator (@70 km/h).

It's surprising how long the car takes to warm up if you're a regular codfisher though. I drove about a 6 km round trip recently from a cold start, 80F ambient, with the engine off about 50% of the distance. The temp gauge was just rising towards "warm" when I got home.

Good thing too, since my inner tube water pump belt had popped off when I left the house, and was sitting on the driveway the whole time

EDIT: can we estimate this? How could we figure out what the energy requirement is for running a pump at various engine speeds? We could start by looking at the energy requirement spec'd for the electric racing pump, but it likely applies to a V8 application (higher displacement pump than most of us are running).

[Matt Timion]

Originally Posted by MetroMPG

EDIT: can we estimate this? How could we figure out what the energy requirement is for running a pump at various engine speeds? We could start by looking at the energy requirement spec'd for the electric racing pump, but it likely applies to a V8 application (higher displacement pump than most of us are running).

Odds are this can be done for smaller pumps too, consindering Bunger said that Honda Racers use it. A lot of racers use 1.5L or 1.6L engines.

[95metro]

With a clutch-driven water pump, would the idle-dip before the idle speed sensor kicks in be some indicator of the energy drain on the engine?