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Re: S40 Driving Electric Water Pump using AUX2 PWM

Posted: Tue Apr 10, 2018 3:02 am
by SMR
Thanks Alex - missed that; I'll give it a go.

Re: S40 Driving Electric Water Pump using AUX2 PWM

Posted: Sun Apr 15, 2018 2:33 pm
by SMR
Hi All,

Test option works a treat - thanks Alex.

We ran the car at Doune Hillclimb this weekend; the PWM control appeared to work, and tweaking the duty cycles so it rapidly ramped up from 30 to 90% around the target temp (70 degrees C) did improve the engine heat-up.

So, one question - any idea if i can get the pump to continue running after the engine is stopped to continue to circulate the coolant and avoid heat soak?

In the paddock, I can plug in the laptop and run the pump in test mode to do this, but I would really like something to deal with the top/holding paddock after a run.

Cheers
Steve

Re: S40 Driving Electric Water Pump using AUX2 PWM

Posted: Sun Jul 01, 2018 6:17 am
by Inspired_dave
Also interested in knowing if anyone has wired in an override for water pumps and fans so they keep running when the engine is switched off.

SMR did you have any luck with this?

Re: S40 Driving Electric Water Pump using AUX2 PWM

Posted: Sun Jul 01, 2018 7:33 am
by SMR
I ended up removing the solid state relay and PWM control of the water pump, and wired it to be on whenever the car is powered up. I also fitted an external power connector so I can plug in a pit battery to run the pump and cool it down when the engine is off.

Steve

Re: S40 Driving Electric Water Pump using AUX2 PWM

Posted: Sun Jul 01, 2018 10:34 am
by Inspired_dave
Thanks Steve. That sounds similar to the setup I have now with my old P8 ecu.

How come you stopped using the PWM/SSR setup? It sounds ideal to have that level of control over how the pump reacts the water temp.

Re: S40 Driving Electric Water Pump using AUX2 PWM

Posted: Sun Jul 01, 2018 2:23 pm
by SMR
We use an external engine preheater anyway, so the car is pretty much up to temp when going to the line - being able to circulate the coolant after a run was deemed more important than the fine control offered by the SSR/PWM method which was pretty much up to 95% duty cycle most of the time anyway.

If we didn't use the pre-heater I would probably have left the SSR/PWM control in place as it does help with warm-up.

Re: S40 Driving Electric Water Pump using AUX2 PWM

Posted: Mon Jul 02, 2018 2:45 am
by Inspired_dave
Ah ok, makes sense then with the preheater. Running the coolant and fans after a run would be my priority too in fairness (I'm doing sprints with the odd hill like yourselves).

I'll see if I can work out a suitable way to bypass the PWM/SSR to keep things cooling after the engine is off, failing that I'll be doing away with the PWM/SSR and just going back to something that doesn't involve the ECU at all.