electric water pump for my eg33
 

I know there is a huge thread on overheating which I read a lot when building my eg33 for a mid engine project. The changes I made were to move the thermostat from the inlet to the return side of the engine water system and increased the inlet fitting to 1.75" and am running 1.75 inlet hose to the radiator which is in the front of the car(about an 8' run). The return to the radiator is all 1.5".
With 180* thermostat, the engine runs for about 4 min and then overheats with an airlock in the engine. I have bled the system several different ways with the same result. I even hooked up the garden hose and forced water to the pump. I have pressure tested the system-there are no leaks.
Seems to me the waterpump can not suck water in the volume it needs because of the distance to the radiator and that what is needed is an electric pump at the radiator to push the inlet water to the engine water pump. I guess the flow would need to be at least 30 g/min.
Has anyone done this and did it solve any problems? What capacity pump was used?
Do you guys think this would solve the problem.
Mike

Re: electric water pump for my eg33
 

With the thermostat in the top hose, there is no flow to heat it up to open. The pump is just circulating the water around the two bypasses, but not flowing it across the thermostat.

Harvey.

Re: electric water pump for my eg33
 

Yes, make sure with the thermostat in the upper hose that 1. it is close to the engine, not out by the radiator and 2. drill 2 1/8th inch holes in the thermostat plate to allow some flow even when it is closed to allow air to pass and to allow the hot water to reach the core and open it.

Re: electric water pump for my eg33
 

When I welded in the inline thermostat housing, I plumbed a T just before the thermostat for a bleeder valve and a circulation hose that is connected to one of the circulation outlets on the pump. That allows me to bleed out the air and should also give me the circulation needed to open the thermostat. I should have taken a picture. Drilling the hole makes sense.
Thanks for the input.
Mike

Re: electric water pump for my eg33
 

Yea I should have taken a picture when I did mine. But I just put 2 small 1/8th inch holes in the flat plate of the thermostat. 1 on each side of the main central bulk just to allow flow to pass over the copper core. It still keeps a good restriction in the line so the pump pulls through the other bypass lines before it opens up allowing the coolant to circulate around the engine properly.

Re: electric water pump for my eg33
 

Dumb question, but would you need a thermostat with an electric pump? Only run the pump when water temperature gets to x degrees?

Thermostats exist because you can't stop a mechanical pump running?

Re: electric water pump for my eg33
 

The coolant still needs to be flowing at all times, to prevent hot spots, and so the engine can warm up evenly, etc. In the factory configuration, when the coolant isn't flowing through the radiator, it's flowing through the various bypass lines. The T-stat really just changes the path of least resistance from the bypass lines to the radiator, but the coolant is still always flowing when the T-stat is "closed". It's just limited to flowing through the bypass lines, which keeps it from getting cooled down by the rad, until it warms up enough to open the T-stat.

That said, you can certainly adjust the speed of the pump to flow slower when the cooling demands are not so much, and higher when they are. But I don't think you would want it to ever fully stop.

Re: electric water pump for my eg33
 

An update on the cooling issues with my mid engine project.
Early on, if I used a Tstat, I couldn't get the system to flow so I took the Tstat out. The system flowed but when I ran up the revs, the rad return pressure was so high it blew the coolant past the cap and overflowed the exp tank so the system needs the restriction of the Tstat. You guys already know that. With the rad 8' ahead of the engine, I decided to install a booster pump at the rad outflow rated at 40gpm. This got the system flowing with the Tstat installed. I originally wired it to run all the time but I am getting water in the oil so I suspect that the coolant pressure within the engine is quite high especially when I run the revs up. I now have the pump wired to come on with the first fan which is 185f with a 180f Tstat. Water is still getting in the oil so I suspect a head gasket job. Could it be anything else?
One other odd thing. Within the first 5 miles of a drive, the temp spikes up to 210+ and then returns to 190. This will happen a couple of times and then the temp settles down to 185 and stays there even if I hammer it . When I get back to the shop, the coolant in the rad is always about a quart low. The level in the exp tank doesn't seem to change. If I fill the rad and go out for another drive, the same thing happens.
I am running a single pass rad and drilled two holes in the Tstat.
Thanks for any feedback.
Mike

Re: electric water pump for my eg33
 

For what it's worth, I have a buddy running an EG33'd impreza. For his swap he is using a radiator mounted where his back seats were. He's cut holes in his trunk and has an electric fan to blow air through the radiator.

He does not have an additional pump, and doesn't have overheating issues. So I believe the stock water pump should be enough to flow that far.

http://i144.photobucket.com/albums/r...383A3B3229.jpg
http://i144.photobucket.com/albums/r...68E833E629.jpg
http://i144.photobucket.com/albums/r...ss_2012039.jpg

Re: electric water pump for my eg33
 

I have to agree with BRZCory,

http://www.precisionchassisworks.com...che-911sc.html

Re: electric water pump for my eg33
 

I did some testing with my turbo eg33 a while back and with the radiator in the boot and enough air flow it would definetely work. I was using a Davies Craig water pump. I gutted the stock pump when testing.

Re: electric water pump for my eg33
 

Bazza,

What size pump did you use?

Re: electric water pump for my eg33
 

Used a Davies Craig EWP - 130 IIRC.