Electric Water Pumps (EWP)

Postby **NitroDann** » Fri Sep 09, 2016 11:02 am

Linear voltage wont get linear flow.

Test with a bucket of water.

madjak · Postby **madjak** » Fri Sep 09, 2016 12:41 pm

Testing with buckets is not that realistic as the pressure and momentum isn't the same as when it's all hooked up. I'd expect the flow rate to be fairly logarithmic... so at 50% PWM I'd guess at close to 80% flow. In terms of tuning, I'd rather the PWM control be linear to the voltage rather than flow anyway. In the end it just numbers on a chart so all that matters is experimenting with the values to get a balancing point.

In the case of my car, it's going to be hard to get any real meaning for anyone else as everything is different. Plus I don't cruise in my car so I'm not worried about over cooling. In my case I need some simple control... so it needs to run at 50% until the temp hits above 90degrees... then rapidly ramp up to 100% to keep the engine below 100. Once I'm in the pits and the rpm's stop, the pump can run at 30% until the engine drops to 50 degrees then turn down to nothing.

I've ordered a thermocouple that I can bolt to the head, so I'll get a direct temp reading from the head itself. This should remove any need to have coolant flowing to get an accurate temp reading and can act as a fail safe if the EWP fails or I loose the coolant.

Postby **NitroDann** » Fri Sep 09, 2016 1:30 pm

For example with the fans, they made a bunch of noise but would barely budge at 96% but were on full blast by 98%.

Dann

madjak · Postby **madjak** » Fri Sep 09, 2016 2:50 pm

You can actually tell how much the EWP is pumping by squeezing the silicon hose from the block to the radiator. @ 50% PWM I can squeeze the tube and feel the water running by but I have the sense that if I tried I could stop the flow. @ 100% PWM that hose is vibrating with the water rushing through it, and feels a lot more solid due to the pressure of the pump. It's definitely moving a torrent of water!

In a couple of weeks I have an entire weekend at the Collie Motorplex. I can get down there on Friday morning and have a few hours testing on the track before competing in a hillclimb sprint on Saturday and then back to the track again on Sunday. I'm already confident that the water speed is sufficient to provide excellent cooling. One thing I need to keep an eye on is that there is far less coolant moving through my engine and radiator than a standard engine due to the diminished size of my radiator and the reduced space in the block due to the grouting. There is maybe only half as much (2.5 - 3L). If there is any air in the system and due to the small reservoir at the top of the radiator, it will be pulled down through the radiator by the pump and pushed back through the engine. It is far easier to bleed than previously as I can run the pump before starting the engine and flush the air bubbles out so I'm not that worried. But still I'll just keep an eye on it on the track weekend.

ED_MX5 · Postby **ED_MX5** » Wed Sep 14, 2016 7:26 pm

About to install mine on Sunday.
A few tips needed to hopefully make my day easier.
Being installed on a 2000 NB vvt still with AC and PS and all that factory stuff in case it makes a difference.
-Can I just cut into the factory hose and use that? Or do I need to make something up? If so angles would be helpful.
- Davies craig mention not to hard mount it. Any opinions or experience with this?
- Is there anything else I need to know about it?

My issue with time is it takes me 2 hours to get to my car atm. So anything to speed up work would be fantastic. As I also need to reinstall all the timing gear. So it's not a whole day of just water pump.
Thanks all.

Ed

madjak · Postby **madjak** » Wed Sep 14, 2016 11:07 pm

My setup isn't a very good reference. My radiator isn't stock so the input and output are at different points. I mounted my EWP to a short (70mm) length of silicon hose clamped to the output. This works pretty well to hold it in position and could be a short length of any spare radiator hose. The AN lines I'm using are also pretty ridgid and when clamped to the chassis also support the pump.

Use cable ties to keep the timing belt from skipping off the cam gears and also do something on the crank to stop the belt skipping teeth.

plohl · Postby **plohl** » Wed Sep 14, 2016 11:46 pm

ED_MX5 wrote:Davies craig mention not to hard mount it. Any opinions or experience with this?

Yes, it broke. I would advise against hard mounting it.

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ED_MX5 · Postby **ED_MX5** » Thu Sep 15, 2016 12:02 am

Haha, point taken.
I won't hard mount it.

3gress · Postby **3gress** » Thu Sep 15, 2016 12:30 am

Finding a shorter belt for the alternator after oem pump pulley removal was a pain, im now using a bosch 4pk735 belt, with a custom tensioner on alternator. Check that the oem hoses will fit the supplied adaptors, maybe grab some generic rad. hose lengths and shapes from the parts store before you go and get some good hose clamps. :DIY:

madjak · Postby **madjak** » Thu Sep 15, 2016 4:18 pm

I just picked up a 695 belt for my suzuki alternator that is mounted on the exhaust size of the engine. I think my engine is now more non-mazda than it is mazda! I think the only stock parts left is the sump, oil pump, crank, block and head. Everything else is after market

I'm also going to make up a small timing belt cover for behind the crank pulley. I've cut the stock one down to fit and pop riveted on some angles to fill the gap either side and in between the belts. Hopefully it will stop any large rocks dropping down onto the crank timing pulley which would be a bad thing.

madjak · Postby **madjak** » Fri Oct 07, 2016 2:12 am

This is pretty cool. K-type bolt on thermocouple at the back of the head. This runs to a adafruit amplifier then to a 5v analog input on my ecu. It gives me temp readings from -250 to 750 degrees and is accurate to around a degree. It also doesnt need coolant flow so it will be ideal to use for engine safety.

Bolt on thermocouple was $10 on ebay
Amp was $30 from adafruit

smy0003 · Postby **smy0003** » Fri Oct 07, 2016 10:12 am

That's pretty awesome. A really elegant solution.

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madjak · Postby **madjak** » Fri Oct 07, 2016 10:29 am

Yeah its great... should be a standard install on any high performance engine. The same setup works for EGT too, except with a bolt in 90 degree sensor. so for $130 you can have 4 x EGT sensors.

madjak · Postby **madjak** » Fri Oct 14, 2016 7:18 pm

Wow... ive finally run my car on the track at full pace. The CTS is hitting a flat 82 degrees whilst the thermocouple on the head is reading under 80. My EWP map is only running the pump at 40% at this point in my map. After the run the fan and EWP run untill coolant drops below 60 degrees which takes around 1 minute.

As a side note, I'm also running my 3D printed wing today and I just dropped over a second off my previous PB. The car is far more settled through the sweepers which is helping. With the EWP the car does feel like it has more power but I'd need it on the dyno to really tell.

Pretty happy with it all... the car feels solid.

smy0003 · Postby **smy0003** » Fri Oct 14, 2016 7:25 pm

madjak wrote:Wow... ive finally run my car on the track at full pace. The CTS is hitting a flat 82 degrees whilst the thermocouple on the head is reading under 80. My EWP map is only running the pump at 40% at this point in my map. After the run the fan and EWP run untill coolant drops below 60 degrees which takes around 1 minute.

That's really impressive, are you going to back off the EWP a bit?
Or is 82deg where you want to be?