3S Water Pump Cavitation

[strx7]

Has anyone had issues with 3S water pumps cavitating with continued high rpm usage? I'm starting to wonder if I am having this issue. Have a healthy sized twin pass alloy radiator in the corolla. and on the track, the water temp slowly gets higher and higher.

[sergei]

Has anyone had issues with 3S water pumps cavitating with continued high rpm usage? I'm starting to wonder if I am having this issue. Have a healthy sized twin pass alloy radiator in the corolla. and on the track, the water temp slowly gets higher and higher.

I did on ST205 on the track, but I believe I found the problem at the end: non-oem pressure cap no sealing properly, thus there was not enough pressure to keep the radiator hose from collapsing (water pump inlet).

[85AW20v]

A few years ago a guy from Wanganui, Paul Tulloch, had the same problem in a supercharged SW20 rally car he built up. I pretty sure he solved it by using an electric waterpump. He owns Wanganui Exhaust and Performance Centre 06 345 3228 if you want to get hold of him.

[pureadrenalin]

I have this problem (overheating with long high power runs)

I have (had) both mechanical pump, and electric "booster" pump that would turn on above 80-85 deg, would over heat.
Tried running just mechanical pump, would over heat.
Tried running just the electric pump, would over heat.

Both with and without the thermostat in.

Starting to think things are a little darker than I had hoped

[sergei]

I have this problem (overheating with long high power runs)

I have (had) both mechanical pump, and electric "booster" pump that would turn on above 80-85 deg, would over heat.
Tried running just mechanical pump, would over heat.
Tried running just the electric pump, would over heat.

Both with and without the thermostat in.

Starting to think things are a little darker than I had hoped

Blocked radiator? MAGN1Titus?

[strx7]

I have this problem (overheating with long high power runs)

I have (had) both mechanical pump, and electric "booster" pump that would turn on above 80-85 deg, would over heat.
Tried running just mechanical pump, would over heat.
Tried running just the electric pump, would over heat.

Both with and without the thermostat in.

Starting to think things are a little darker than I had hoped

what power are you making? what is your radiator?

[pureadrenalin]

Standard MR2 turbo radiator.
Radiator has been checked, and is fine.

Making 215rwkw on local Dyno dynamics.

(side note, if I compare the power of my old car with basic mods that made 160kw on this particular dyno to others around the country that were making over 200kw with roughly the same mods or worse, this car should be around 250rwkw on other "look at my power curve" dynos)

[atmosports]

Another thing that can cause cavitation is running too much anti-freeze/inhibitor in the cooling system, seen that before.

Could you swap the water pump pulley & run it slightly slower or backcut the waterpump impellor etc.

Back in the 2L touring cars days, I remember the 3s engines being a bitch for overheating if you didn't bleed all the air out of the cooling system, so might pay to make sure the cap is the highest point in the system.

[strx7]

cap is definitly at the highest point. i'm tempted to ditch the thermostat. The antifreeze one I had thought of. I know it sucks compared to water as far as descent cooling properties go. tempted to stick in water and a couple of bottles of water wetter (for its inhibiter properties)

[atmosports]

I sued to use some Elf stuff, can't remember what it was called, came in 4 or 5L containers, was basically de-ionised water with some corrosion inhibitors in it, worked real well on Lotus Twin Cams, lately I've been using the Miller's Oil version of water wetter, seems to be a lil better but you can't get it from BNT etc like the redline stuff. If you ditch the themostat & don't run some form of restriction it should run cold as, as the water generally flows to fast

[fangsport]

If you ditch the themostat & don't run some form of restriction it should run cold as, as the water generally flows to fast

won't it cause the engine too eventually run too hot?? when Keith (NA Drifter) used my rally car for D1NZ at Timaru, it wasn't thermostatically controlled and eventually got so hot it was off the gauge!!, due to the fact the thermostat is only open for a small percentage of time to regulate the engine to optimum temperature??

[strx7]

with my car running on the spot and the fan turned off my car comes up to full temp (90ish) turn the fan on and the temp comes back down to 60 (i have a few holes drilled in the thermostat to aid bleeding the system. Once i have been out on the track, and come back into the pits and idle it to cool down, i can only get the temp down to 80-85

[pureadrenalin]

If you ditch the themostat & don't run some form of restriction it should run cold as, as the water generally flows to fast

Correct, kinda.

This is why the pump I run (without a thermostat) has a controller.
It runs on for 5 sec (at 6 volts) off for 15 sec till you are within 20 deg C of your set temp. From that point it starts increasing the time on Vs time off. When you hit your set temp it increases the voltage to 12V and runs constantly.
This pump and controller:
http://www.daviescraig.com.au/Electric_Water_Pumps-EWP115_Alloy___Controller_Combo__12V____PART_No_8050-details.aspx

[fuel]

with my car running on the spot and the fan turned off my car comes up to full temp (90ish) turn the fan on and the temp comes back down to 60 (i have a few holes drilled in the thermostat to aid bleeding the system. Once i have been out on the track, and come back into the pits and idle it to cool down, i can only get the temp down to 80-85

Does the temp go any higher than 90 on the track?

[fivebob]

Is it possible that the pump is running to fast and not giving the water sufficient time to cool in the radiator?

If removing the anti-freeze helps, and it should because in improves heat capacity of the system in both the heating and cooling sides. Then you could consider if you can add additional capacity to the system, bigger end tanks perhaps.

[fivebob]

One other thing to look at is that the 3S is essentially an oil cooled engine, under continous high load the oil heats up significantly and this places additional load on the cooling system if the stock water -> oil system is still in place.

[allencr]

Once i have been out on the track, and come back into the pits and idle it to cool down, i can only get the temp down to 80-85

Lotta heat built up in the oil, aluminum & cast iron that will take quite a while to dissipate.
Cavitation creates bubbles through out the system that don't transfer heat very well, the reduction in flow isn't really a problem.
All that old tired BS about 'flowing too fast to cool' if the thermostat is removed is an old wives tale that just refuses to die. There are times when a restriction in the cooling system increases pressure between it & the pump to stop the surface bubbles coming from around really hot exhaust ports. Higher pressure cap does the same thing. The usual Toyota thermostat position at the pump inlet isn't one of those times that would make the myth seem true.
Also forget all the 'magic' stuff that is supposed to work better then plain water, if it does, its only in a lab & barely measurable.
I think either the radiator is too small, all the bubbles that are always present in a cooling system under heavy loads aren't moving easily through the MR2's convoluted system or the air flow through it isn't good.
let the belt slip just enough to slow down the pump at high rpm
Good luck.

[strx7]

with my car running on the spot and the fan turned off my car comes up to full temp (90ish) turn the fan on and the temp comes back down to 60 (i have a few holes drilled in the thermostat to aid bleeding the system. Once i have been out on the track, and come back into the pits and idle it to cool down, i can only get the temp down to 80-85

Does the temp go any higher than 90 on the track?

yip, 105-110 and that is measured where there water goes back into the motor

[strx7]

One other thing to look at is that the 3S is essentially an oil cooled engine, under continous high load the oil heats up significantly and this places additional load on the cooling system if the stock water -> oil system is still in place.

its running an external air cooled oil cooler. may look at an oil temp guage though

[pureadrenalin]

let the belt slip just enough to slow down the pump at high rpm
Good luck.

LOL, water pump is run of the timing belt. Don't want any slip there!

its running an external air cooled oil cooler. may look at an oil temp guage though

Do this, it will scare you.