DIY electric water pump - on the cheap

[dirtydave]

I guess it depends on the car but how much power would a water pump use? Would this mod make a huge jump in mpg? Has any production car used an electric water pump?

[MetroMPG]

Apparently they've gotten over their reluctance: the latest Fit hybrid (& Accord, presumably) have beltless engines (e-motor on the water pump too).

Toyota's hybrid engines are all beltless too.

[Daox]

Ah yes, that brings up another benefit of the electric water pump... heat in winter with the engine off.

[oil pan 4]

Oh no not a chain drive.

The best thing about the electric coolant pump is being able to warm the engine up really fast with out burning any fuel.

http://ecomodder.com/forum/showthrea...mer-23893.html

[serialk11r]

A mod for GM LSx (I think? some American V8) I've seen is an electric pump that uses the stock pump housing and impeller but replaces the pulley with an electric motor bolted to the housing. It is definitely over 100 bucks, but I imagine you can replicate that kind of thing with less money. A better impeller would save a little energy but would never pay for itself. I've never actually had my hands on a stock water pump so I have no idea how easy this is to do though.

I think the Insight having a belt driven pump was to ultimately save on costs? Nowadays electric water pumps are very common, even on non-hybrids. BMWs have them as standard, Porsches have them as standard, etc. You get better cooling because there's less cavitation, better cooling when at low rpm, and you save energy under most situations.

[jeff88]

Daox, is there room to direct drive the pump if you have a physically smaller motor?

If the pump you have is overkill, would a smaller pump be better? (Whether it's direct drive or belt drive.) I'm thinking something like a garage door opener or a gate opener.

Can you source a new(ish) motor from a Toyota hybrid from maybe a JY for cheap?

Can you modify an electric A/C compressor to drive the water pump or even be the pump itself?

Just throwing ideas out, maybe something will stick...

[Daox]

I have yet to see how the motor will physically fit and attach to the engine. I just know there is plenty of room without a power steering pump and A/C compressor in there. I'm sure there are any number of different motors that would work. As for now, I'm planning on using what I have on hand. This might not work for others looking to do the same type of mod.

serialk11r brings up the interesting topic of cavitation. This leads me to something I've been trying to figure out without a ton of success. The real question is, how fast should we spin the pump? Obviously, its based off of many factors which only complicates things. Mostly, we want it to spin just fast enough to avoid is hot spots occuring and causing ignition problems. Sadly, the Tercel doesn't have a knock sensor, so I can't use that as an arduino input. I'm not sure how difficult or accurate it would be to add one though... Suggestions here are quite welcome as well.

[jeff88]

Is there a way to measure how fast the pump is currently spinning... maybe with an adjustable strobe light? At that point you could size a motor properly.

Is the Tercel engine available for any other models that happened to have the knock sensor? Does JDM or other international versions come with the knock sensor? Actually come to think of it, does it even need to be from the same engine?, I know nothing about knock sensor operation.

[nemo]

Originally Posted by jeff88

Is there a way to measure how fast the pump is currently spinning... maybe with an adjustable strobe light? At that point you could size a motor properly.

It's simply a ratio of the circumference of the drive pulley and the water pump pulley. The speed varies with RPMs, idle would minimum and red line max.

[oil pan 4]

Vehicle water pumps use cavitation to limit flow so that delta pressure doesn't kill the thermostat. I had this problem with my suburban, it killed 2 or 3 thermostats before I got it fixed.

That scooter motor should spin 2600rpm at with 24 volts. On 12 volts, around half that.