I think my radiator is too big.....?

[sprint95m]

I have had a Saab 9-3 2 litre turbo radiator on my 1850 for a few years now. 500x350x42
http://www.carcooling.co.uk/products/Ra ... 17-84.html

With an 88 degree thermostat the temp gauge would read half (irrespective of ambient temperature).


Now I have converted to a Davies, Craig EWP and controller.
This requires removal of both the mechanical water pump and thermostat.
On driving the car now the temperature gauge doesn't reach 1/3, which the controller shows is under 75 degrees. If stationary the temp will rise until
the electric cooling fan comes on. (There is heat from the heater.)
I use Evans Powercool 180 waterless coolant.

On a positive note, the engine is way more responsive. This being more noticeable since it has a lower rotating weight,
because being an early 1850 it has the lighter flywheel and further more has a lightweight Saab clutch cover (at 5kg almost 3kg less than the Triumph version)


I am thinking that the radiator is too big. Its capacity is over 50% greater than a standard 1850 radiator.
Looking at listings I see that Saab actually offer this radiator in three different thicknesses, 42, 32 and 18mm.
Now I am wondering if I may be better off with the 18mm version?


Any thoughts please?





As an experiment, tomorrow I am going I am going to try blanking of half the radiator to see if that makes any difference.



thanks,


Ian.

[Galileo]

I was under the impression that the EWP controller monitors the temperature and sets the flow volume accordingly to mimic the thermostat? If that's the case is the controller working/set correctly?

Still, either way I wouldn't buy another radiator but just blank off the one I have, but then I'm 'careful' with my money!

[soe8m]

In theory it shouldn't matter if you have the std setup or an electric water pump. The coolant does circulate inside the engine and when reaching 88 degrees thermostat value it starts circulating through the rad. Maybe it's not plumped in ok and does already go through the rad? It should not make a difference in temp covering the rad when temp is below thermostat opening temp.

Jeroen

[Carledo]

This has got to be a first for us, an overcooled slant!

Seriously though, I have 3 Saab rads here (besides the one in the Carledo) 1 new and 2 good used, I will have a measure up and see if I have a thinner one you can try, if successful, i'll swap it for your thick one!

Steve

[GTS290N]

I used to keep a piece of cardboard in GTS290N back in 1983, this blanked off half the radiator during short runs in winter.
I'll sell you a piece, I never did patent it!

[Karlos]

I have a Saab 9-3 rad on my 1850 too, along with an 88deg thermostat. It all works nicely at the moment, previously with the 82deg thermostat in winter time the car was cold inside and never got above 1/3 on the gauge. With the 88deg thermostat it stays just under 1/2 that is the 90deg mark on the gauge. If I push the engine hard it will get close to the 1/2 90deg mark but never over and when cruising at around 50 mph it never drops below a needles width under the 90deg mark.

With the EWP does it circulate coolant around the engine and then divert to the rad at a specific temp? In a similar way that the thermostat controls the flow through the rad?
Or
Does the EWP regulate a permanent flow around the engine and radiator but varies the flow rate according to the temperature within the engine itself?

[Mad Mart]

It does the latter, if you have the optional controller & temp sender connected.

[sprint95m]

Blanked off the offside portion of the radiator and it makes it only small difference,
the temperature goes to just over 75 degrees.


A standard 1850 has a coolant capacity of 5.4 litres, of which the radiator is 1.2 litres (22.2% of total).
The Saab radiator is over 1.8 litres so (with the Volvo header tank) the total is now over 6 litres (rad is now about 29%).

With the Davies,Craig controller the set temp. is 85 degrees. As the engine warms up, the controller sets the EWP to pulse
10s/30s off until 65 degrees (20 below the set point) and then 10s/10s until 85 degrees.
Should it go above the set point, the controller will switch on both the EWP and fan until the temp drops to 80 degrees, then the 10s/10s pulsing
will resume.


I am thinking that during the warm up period too much cooled coolant is coming into the engine but haven't decided what to do,
may change to a Ford Focus radiator like THIS ONE, there would be room for an oil cooler if necessary?



thanks,


Ian.

[shaunroche]

I'm not sure yet how the EWP operates but didn't you mention that the fan comes on at 75 degrees? Isn't it the fan that's set too low then and is over cooling?

Just thinking, with the engine running, irrelevant of the size of cooling pack nothing is being cooled when the car is stationary with no fan or EWP on so will reach the temp the cooling is set to come on at?

I think the EWP pulses at the start to stop any hotpots forming but will only start to circulate at the correct flow rate and then put the fan on when the figure it is set at is reached.

If it's supposed to come on at 80 odd degrees why's the fan coming on at 75 or is it set to come on higher but is coming on prematurely?

Only asking as I have a similar set up to you as you know so am wondering....I will not be using evans waterless though.

[soe8m]

As I said before when all is plumbed in ok the size of the rad is not an issue under the 88 degree's. After this 88 degrees temp the thermostat opens and does the coolant start circulating through the radiator. All under the 88 degrees it is only engine internal circulation through the little bypass tube. Check the thermostat or how the whole system is circulating.

Jeroen

[shaunroche]

As I said before when all is plumbed in ok the size of the rad is not an issue under the 88 degree's. After this 88 degrees temp the thermostat opens and does the coolant start circulating through the radiator. All under the 88 degrees it is only engine internal circulation through the little bypass tube. Check the thermostat or how the whole system is circulating.

Jeroen

There is no thermostat is there? It's a totally free system pumping around the engine and cooling pack in one go.....

....Now I have converted to a Davies Craig EWP and controller.....this requires removal of both the mechanical water pump and thermostat..... Ian.

[Karlos]

Should the thermostat definitely be removed? I'll have exactly the same problem if I take out my thermostat-as will anyone else using the internal mechanical driven pump.

[shaunroche]

Should the thermostat definitely be removed? I'll have exactly the same problem if I take out my thermostat-as will anyone else using the internal mechanical driven pump.

Yes. It causes a restriction to the flow which is regulated by the electric pump.

http://daviescraig.com.au/product/ewp80 ... water-pump

[gmsclassics]

I have a very similar setup to yours Ian on my race car, exceptions being my alloy, 60% bigger radiator is from a Porsche 944 Turbo, coolant is water plus inhibitor and I have a 2L custom made header tank where the washer bottle is. My pump is the 115l/m version with the same controller. My coolant capacity is up from a standard 5.4L to about 7.2L. With this setup I can run at 7000rpm in 32degree C ambient temperature and the coolant temp gauge only reads 95C. When pump is running full time the entire coolant capacity is theoretically circulating 16 times per minute. Difficult to conceive of a more efficient system. The bonus for me is having the ability for both pump and fan to run on after the engine is stopped for up to a couple of minutes to cool everything down nice and evenly.

The system design necessitates the thermostat removal and blocking off the return to the mechnaical pump housing (with pump removed). This means coolant circulates the entire system right from start up, so it will take longer to get to operating temperature when on the move. This is mitigated by the fan operating for 10 seconds, shutting down for 30 and continuing this cycle until temperature reaches that set minus 20C, it then runs 10sec on, 10sec off until set minus 5C. Above that the pump then runs continuously but speed is varied by increasing the voltage from 6v to 12v by the time set speed is reached. Radiator fan is switched on at set plus 3C. The temperature set should therefore be the maximum that you want the system to run at, NOT the temperature you want it to run at normally.

From that it would seem sensible during colder ambient temperatures to have the set temperature at the high end, maybe 95 or even 100 and experiment with that. This will produce less circulating coolant (pump on 10/30 cycle until 75/80C) and should enable a higher working temperature to be achieved. That Evans coolant has a lower heat transfer than water so suits what you are trying to achieve, yet you will never boil it so can't do any harm. By experimenting, you can later find a suitable set point for the summer months as the controller will always tell you the precise actual temperature in the top hose exiting the engine.

I remember as a child seeing 1950s cars routinely fitted with radiator blinds in winter, I think they only fell out of favour as newer cars had inaccessible radiators. In your part of the world, I would happily try blanking out 50% or more. I would strongly suggest waiting until you've driven through the hottest part of summer, sitting in traffic jam before considering a smaller radiator. Some reserve cooling capacity will always come in handy. With an 88C thermostat in your previous mechanical pump setup, I suspect in winter the thermostat was only letting a small proportion of the coolant into the radiator and low ambient temperatures would cool it down very quickly. Cooling systems are designed to cope with the highest ambient temperatures so will be super effiicent in low temperatures.

Within reason the lower the running temperature the more power, the higher, the better fuel economy. I've never used a 88C thermostat in a road Sprint, only 82C and even 77C, so I wouldn't be worried if you end up with engine temperatures in this range.

I would be very interested to hear how you get on.

Geoff

[tony g]

I have the same issue with my set up. My rad is a fiesta rad. I have the ewp with controller and a trip in the cold mornings i see the same "under 75 deg" as you are (flashing 75). " 2 weeks ago I took a thermostat and cut the guts out of it to leave just the ring, to act as a flow restrictor. This helped a little and heater was a bit warmer.
I have considered putting a full stat back in and using the bypass for when the stat is closed. On the DC website instructions it gets a little confusing re the stats as it starts by saying remove as you dont need it but there are sections that talk of "if" running a stat do this and that.
Restricting the flow out of the engine (stat housing or top hose) seems in theory what we need but getting it wrong could be costly. I have considered making a clamp to clamp the hose for testing and remove quickly if needed, that way we could regulate the flow via the clamp and work out the area of pipe that works best.
I'll watch to see what you come up with

Tony