SVX Engine cooling "Again & Again"

[SVXRide]

Originally Posted by Boxersix

Sorry I've been out of this thread for awhile Been fighting a chest cold and my computer crashed a few weeks back. Had to wait for a damn recovery/reboot CD from the manufacture


Can someone take/post/send me a picture of the OEM lower SVX radiator hose attached to the rad and pump. A straight on pic from below would be ideal.

I haven't been able to do a single thing here due to the above crap, but I did get the pump and thermo housing form the member here and I'd like to do a little testing before I dig into the next customer project I have scheduled up here.

I can't really go by anything with my WRX as it's not setup like you guys have. Different rad, different frontal area, WRX purge tank, etc, etc. There's absolutely no way I can replicate your cars' running status.


FWIW I have not been able to get this car to overheat, but again my system is different and it's also ~15-30F out here in the winter months.

About time you checked back in

Wish you had posted yesterday! I was under my son's SVX replacing his radiator (you don't even want to ask me why I had to replace the radiator) and could have taken all the pics necessary. I'll see if I can't post up a pic of the lower hose, since you've got the pump and 'stat cover.

Here's a question for you - what's the ID of the outlet on the radiator in your Impreza that has the EG33 in it?

-Bill

[Trevor]

Originally Posted by Nomake Wan

As you are so fond of saying in this thread, you have provided no evidence that you are anything but a person arguing with people whose credentials are not in debate. If you wish to resolve this grave error in my judgement, then it would appear the resolution is simple.

I could comply with your inaccurate sarcasm, but I have no desire to duplicate the several others who triumphantly blow trumpet.

[Boxersix]

Originally Posted by SVXRide

About time you checked back in

Wish you had posted yesterday! I was under my son's SVX replacing his radiator (you don't even want to ask me why I had to replace the radiator) and could have taken all the pics necessary. I'll see if I can't post up a pic of the lower hose, since you've got the pump and 'stat cover.

Here's a question for you - what's the ID of the outlet on the radiator in your Impreza that has the EG33 in it?

-Bill

40mm if i remember correctly. It's a ebay aluminum tank rad, 2" core. Supposed to be an OE fitment. I used an OEM WRX lower rad hose that I had to trim back a tiny bit to make it fit. It's still not 100% perfect as it's a little askew to clear the tubular subframe/crash bar I made for the front of the car. The hose was a tiny loose over the thermo cover on the pump.

I can easily mod OE thermo covers to suit this larger fitment if one so desires. I have yet to see that that particular mod works on a real world car at high loads though. I could test one on my car but again since my setup is quite a bit different the results may not be the same on an SVX. Loading my car up on a dyno at high continuous RPM would generate heat, but my overall cooling system setup and frontal air inlet is drastically different than the SVX. Even my rear radiator fan shroud and fan is different.

[SVXRide]

Originally Posted by Boxersix

40mm if i remember correctly. It's a ebay aluminum tank rad, 2" core. Supposed to be an OE fitment. I used an OEM WRX lower rad hose that I had to trim back a tiny bit to make it fit. It's still not 100% perfect as it's a little askew to clear the tubular subframe/crash bar I made for the front of the car. The hose was a tiny loose over the thermo cover on the pump.

I can easily mod OE thermo covers to suit this larger fitment if one so desires. I have yet to see that that particular mod works on a real world car at high loads though. I could test one on my car but again since my setup is quite a bit different the results may not be the same on an SVX. Loading my car up on a dyno at high continuous RPM would generate heat, but my overall cooling system setup and frontal air inlet is drastically different than the SVX. Even my rear radiator fan shroud and fan is different.

Adam,
Okay, so this is interesting...Stock SVX rad's outlet is 33mm ID, your rad's outlet is 40mm ID, and Tony's modified PWR rad's outlet is 45mm ID. Overheating with the stock outlet size and no overheating with a 40 mm or 45 mm outlet. Huuummmm, could there be something here? The only apparent fly in the ointment here is that your water pump still has a 33 mm ID inlet and the balance of your coolant system "around" the EG33 block is different...oh, never mind
-Bill

[Trevor]

Originally Posted by oab_au

I think that the testing that Tony and Jones have done, has shown that the main problem that has affected Steve and Dan has been found, and rectified. The results are pretty conclusive.

The clue came with Tony’s pressure testing on his own car. The graph that he produced (post #299) showed that the pressure at the thermostat housing, fell as the rpm went up. That showed the possibility, that because of the temp of the water, and the negative pressure, at the thermostat housing, the coolant could boil.

As John (SVX Commuter) says, and I respect that John has been with pumps long enough to have found all the problems. The boiling starts to build steam or vapour at the centre of the impeller, to implead the flow. This then reduces the flow of coolant through the engine. The engine starts to heat up, and the coolant entering the pump, increases in temperature, so it will boil earlier at the same negative pressure. This is a compounding effect, the more vapour entering the pump, will further reduce the flow through the engine to the result, of the coolant in the block boiling.

The vapour is the result of temp and pressure, and does not leave the pump.. As the vapour rises up the impeller vanes, the pressure increases and the vapour condenses back to water. The pressure in the engine block will remain high, even though the flow is reducing.

The testing that Tony has done with the test rig has shown that when the inlet to the pump is increased, the negative pressure at the pump is reduced, and Steve has proven the theory with an excellent result in the buggy. This is the best testing we could have wished for. Racing in very high temps, and sustained high rpms, the only difference to Dan’s car (besides the car) was a different radiator.

With what we have learned, if Tom uses the modified thermostat housing, Dan will have the same results as Steve. The modified top pipes should be retained to ensure, that with the increased flow that the thermostat mod will allow, there will be even flow through the two sides. Harvey.

The problem involving an SVX cooling system has not yet been found or established and there have not been any conclusive results regardless of conjecture.

As is the illustration shows, pressure was tested at a point within the pump housing and after the pump cap/cover/elbow. Therefore the alleged boiling due to a drop in pressure, must be confined to the pump housing and a point after the radiator outlet and pipe. Therefore increasing the size of radiator and or outlet i.e. that comprising the inlet to the pump, can not alter the situation you describe.

The suggested problem is confined to the pump cover, and as a result this statement is not correct:- ”The testing that Tony has done with the test rig has shown that when the inlet to the pump is increased, the negative pressure at the pump is reduced, and Steve has proven the theory with an excellent result in the buggy.”

Conjecture with reference to a centre outlet is also concluded and this modification given a second thumbs down.

The boiling theory remains to be proven. That in respect of a larger bottom pipe is disproved.

Tom has come to the correct conclusion, and does not intend to make a radiator modification, having due regard in respect of the cost and work involved.

[Dessertrunner]

Bill I think the difference in the heads is not worth worrying about at this point in time. As Tom suggested we need to find a way around the Termostate issue. I want to do it different to Tom by fiting the themostate in the top pipe and being able to turn the coolant return off and on based on temp in the engine.
Tony

[SVXRide]

Originally Posted by Dessertrunner

Bill I think the difference in the heads is not worth worrying about at this point in time. As Tom suggested we need to find a way around the Termostate issue. I want to do it different to Tom by fiting the themostate in the top pipe and being able to turn the coolant return off and on based on temp in the engine.
Tony

Tony,
I think we're in agreement here. My latest posts have been on two points:
1. That the difference you're seeing between the two heads is probably within the error bars of your instrumentation, thus "good enough" to not spend any additional effort looking at , and
2. The outlet on the Radiator in Adams EG33-equipped WRX (which is not showing any signs of overheating) is 40mm ID (sitting square between our 33mm ID stock radiator outlet and your 45mm ID modified PWR radiator outlet).
I do agree that the relocation of the 'stat should be the next course of action. It will be interesting to see how changing the restriction to the "return" line affects the overall system. How is your proposed approach different from what Tom has proposed to do with Dan's car (i.e. add an in-line 'stat to the line feeding the radiator) other than being able to "turn off the return flow (need some help here on how you intend to do this ) ?

Adam,
I flipped back into the thread and took another look at the pics your posted of your EG33 in its WRX "home". Could you post up a simple diagram detailing the set up of the coolant system you're running? There is definitely more going on than what one can see in the pictures!

Cheers,
Bill

[Dessertrunner]

Bill a number of cars use a thermostate that when closed lets coolant flow back to the pump with out going through the radiator. When the engine gets hot it open and force all coolant throught the radiator. Thats the sort of set up I want as engine can do with all the coolant going through the radiator when hot.

After what I found on the water pump only I did a set up on the engine just changing the thermo cap and have no radiator in stead had the 45mm clear pipe. At that point there was no air and all was perfect then I put the new PWR the one with the 42mm ID (need to keep it all correct) and found that there was some air only above 4,000 rpm. As a result of this I decided that I needed to move the inlet to the centre.
Tony

[Nomake Wan]

Originally Posted by Trevor

I could comply with your inaccurate sarcasm, but I have no desire to duplicate the several others who triumphantly blow trumpet.

Were my sarcasm inaccurate, there would have been degrees on your wall rather than trumpets in your hall.

[Boxersix]

Originally Posted by SVXRide

Adam,
I flipped back into the thread and took another look at the pics your posted of your EG33 in its WRX "home". Could you post up a simple diagram detailing the set up of the coolant system you're running? There is definitely more going on than what one can see in the pictures!

Cheers,
Bill

Yessir, crude but to the point:




WRX purge tank is the highest point in the system. Small line off the upper right-side rad tank(left side of the picture) is the bleed back to the purge tank, found OEM on the WRX and Sti.

Throttle body cooling passage has been bypassed, thus not shown as being plumbed in.

I plugged the ports at the back of the head as the one line ran too close to the steering shaft and was more of a liability for rupture than was worth having.

Stock crossover, stock thermo housing. Single 1600CFM slim fan mounted on fully sealed rear radiator fan shroud(my own) with bypass flaps. Front also has fully ducted radiator shrouding. Far from OEM. No lost air going around the radiator core at either side.

The line from the heater core goes to the top port of the purge tank, return line comes from the bottom of the tank. Any air in the system stays in that purge tank until it's bled off through the cap down to the system reservoir.

[Trevor]

Originally Posted by Nomake Wan

Were my sarcasm inaccurate, there would have been degrees on your wall rather than trumpets in your hall.

Others are treating this as a social thread, so that I might as well l join in.

There are certificates in my drawer, which I am content to leave in store.

[Dessertrunner]

Boxersix are you sure that the heater core goes from the pump not to the pump as the current SVX return ports on the pump are into the suction. I look forward to see you pump testing results.
Tony

[TomsSVX]

Bill, you have the water direction from the pump... Both aux ports on the water pump are inlets that feed the back of the thermostat

Tom

[Dessertrunner]

Boxer here are the photos of the water pump etc on a standard SVX (my wifes).
Tony

[shotgunslade]

I guess all will be revealed when I take it to Watkins Glen May 1. If it boils over, we'll be back in the shop to enlarge he water pump inlet to 45 mm and install a transition immediately out of the radiator outlet from 35mm to 45mm. I think another issue will be to insure that the entire overflow tank connection is flooded, so that when the engine cools down, it only draws in water, rather than air. I know that my connection hose, early in my track career was leaky, so I needed to check coolant level in the radiator, rather than in the overflow tank, including running the car at idle with the cap off for a minute or so, in order to purge air bubbles from the system.

One variable that is hovering out there, but which will be eliminated in my car is the possiblity of head gasket leakage. When he rebuilt my motor, Tom found some slight evidence of leakage. It may only have been occurring under extreme use, and thus may not have shown up in the sniffer test I had that probably was done while idling.

We also know that head gasket leakage was not an issue in Jack Laverty's car, but may be a factor in any abused machine that has not had a recent top-end rebuild.