SVX Engine cooling "Again & Again"

[bazza]

I think a solution has been found. I mentioned here http://www.subaru-svx.net/forum/showthread.php?t=61824 that I found that when I gutted the EG33 water pump and let an electric water pump do the work it all seemed to work rather well.

A mate of mine has made 750 bhp the other day with a turbo EG33 running a rear radiator and an electric water pump (Davies Craig, their biggest unit). Previously with the stock water pump he was bubbling after a single run. Now it will do run after run at ridiculous power and he can drive around the street without an issue. We'll be taking it racing soon for full testing at F1 power spec haha.

So back to the cause - I just think the stock pump flows far to much for the system - I posted a while back that it flows > 300 Litres per minute when I tested it, the flowrate was ridiculous! I also found and posted that the EJ2X was restricted after the pump (far smaller block exits than the EG33) which naturally limited it's flowrate and reduced if not eliminated cavitation. The interesting thing is the electric water pump is less than half that. People may think 130-150L/min may be too little.. but then when it can easily cool a 750 bhp car .... any stocky 200 bhp car will love it also... and then if you look at the engineering - water can only absorb so much energy. When you get above a certain flowrate - you're only removing the same energy and Davies Craig have some very interesting data regarding this on their website. It's rather easy to get a electric water pump into the engine bay - you just need to ensure it's plumbed up correctly - ie heater return is on the suction side etc.

I'll report back with more track testing when we get out there. Hopefully will also put an electric pump on my SVX for some testing if I get some time.

[Dessertrunner]

Have removed

[Tapani]

I wonder what would happen with the waterless Evans coolant..... I was very close to trying it when I had the engine open and replaced the whole cooling system (except the heater core).

********

I was at a track during last weekend. Engine cooling had not issues what so ever (after the HG job). +20C ambient.

When pushing the car "a bit harder " the tranny went into over temp mode after two laps. No light, so the 101C threshold was exceeded, but not the 107C (lamp).

I need an external cooler. Then I can push the car longer to really test the engine cooling.

Tapani

[Dessertrunner]

Have removed

[bazza]

Originally Posted by Dessertrunner

Bazza thinking about your point a bit further right now the air temps are down around 10C which is pretty easy to cool anything. The real test is going to be when the summer comes and you or your friend track the car at 40C or above. Seeing as we are heading into summer it won't be long to find out.

What ever the soluation is it will be great if everyone can finally realize the potential of our engines.
Tony

Was done during that warm spell in Melbourne and then on the dyno for some of it... dyno rooms are usually north of 30'C.

But yes, test will be when it hits the track. The difference between 10'C and 40'C is the amount of air you need to hit the radiator. As seen in V8SC, they simply add restriction to the front of the radiator on cold days and open it up on hot days.

[icingdeath88]

Electric pump + gutted stock WP worked for the EFILogics guys as well. How does one go about "gutting" a water pump?

[Tapani]

How about decreasing the efficiency of the stock pump?

/T

[bazza]

How do you reckon it could be done? Removing 2 blades? Filing out outside?

Nice thing about electric pump is you gain hp. BWM also run many cars with EWP and many new cars will as they move to instant start - ie car is off in traffic a lot so needs an electric pump to keep water flowing.

[Tapani]

Originally Posted by bazza

How do you reckon it could be done? Removing 2 blades? Filing out outside?

Nice thing about electric pump is you gain hp. BWM also run many cars with EWP and many new cars will as they move to instant start - ie car is off in traffic a lot so needs an electric pump to keep water flowing.

Yes - electric pumps do have nice features - and control possibilities are endless.

The pump efficiency has been discussed for a long time. This is post #9:

Tony, trying to apply some crude logic to your previous results.

Engine and therefore pump speed, is a deciding factor according to recorded fact. I have previously mentioned speed of water flow and others have suggested possible impeller cavitation. As far as I am aware this factor has not been properly tested, whereas there is every reason to suspect this as an issue.

Reducing the pump efficiency is not difficult and involves at the worst, only the cost of a used component. The time honoured method is to drill substantial holes through the rotors.

Speak to some old timers who have used the flat head Ford V8 for racing.

You have the fortitude and will find the answer, Trevor.

/Tapani

[Dessertrunner]

Have removed

[bazza]

Originally Posted by Tapani

Yes - electric pumps do have nice features - and control possibilities are endless.

The pump efficiency has been discussed for a long time. This is post #9:

Tony, trying to apply some crude logic to your previous results.

Engine and therefore pump speed, is a deciding factor according to recorded fact. I have previously mentioned speed of water flow and others have suggested possible impeller cavitation. As far as I am aware this factor has not been properly tested, whereas there is every reason to suspect this as an issue.

Reducing the pump efficiency is not difficult and involves at the worst, only the cost of a used component. The time honoured method is to drill substantial holes through the rotors.

Speak to some old timers who have used the flat head Ford V8 for racing.

You have the fortitude and will find the answer, Trevor.

/Tapani

Given Trevor's original idea was along the right track - I wouldn't be surprised if drilling holes in the rotors helps. Personally I wouldn't do it because the entire water pump IMO is a problem and it gets worse the more I think about. So for me it needs to be gutted and something else do the work.

A good thing about the electric pump is you don't need a thermostat - the electronic controller does the work. So you can be flowing at max flowrate at idle and even when the engine is shut down. Issue is the electric pumps have a very specific life time. I think it's 75,000 kms for BMW units... but something to be mindful of.

Also doing some more research - Mazda (RX8) and Honda (S2000) water pumps seem to also suffer cavitation issues and time attack guys swap them out for EWP's!

[Huskymaniac]

Ever hear of a bypass using a pressure relief valve? Oh yeah, I already mentioned this.....

[Tapani]

Originally Posted by bazza

A good thing about the electric pump is you don't need a thermostat - the electronic controller does the work.

I may have emailed this to you Bazza a while ago, but it's interesting reading for all. There's plenty more around.

http://etd.lib.clemson.edu/documents...emson-1042.pdf

/T

[Dessertrunner]

Originally Posted by bazza

Given Trevor's original idea was along the right track - I wouldn't be surprised if drilling holes in the rotors helps. Personally I wouldn't do it because the entire water pump IMO is a problem and it gets worse the more I think about. So for me it needs to be gutted and something else do the work.

A good thing about the electric pump is you don't need a thermostat - the electronic controller does the work. So you can be flowing at max flowrate at idle and even when the engine is shut down. Issue is the electric pumps have a very specific life time. I think it's 75,000 kms for BMW units... but something to be mindful of.

Also doing some more research - Mazda (RX8) and Honda (S2000) water pumps seem to also suffer cavitation issues and time attack guys swap them out for EWP's!

Steve from Jones racing wanted to drill the impeler but could not do it, the thing is cast and brakes up, so there is not point about talking about some thing that we can't do.

Also the link to the artical on quick read says he used a 3/4hp electric pump. Were the hell are you going to get a alternator to run that.

I have decided that I am not contributing to this forum for a while as I am sick of the indirect attacks.

Tony

[bazza]

Originally Posted by Huskymaniac

Ever hear of a bypass using a pressure relief valve? Oh yeah, I already mentioned this.....

I reckon give it a go. Personally I wouldn't as it's complicated and I think the sole issue remains, that being a huge pump, far too big for the purpose of cooling the EG33.

Originally Posted by Tapani

I may have emailed this to you Bazza a while ago, but it's interesting reading for all. There's plenty more around.

http://etd.lib.clemson.edu/documents...emson-1042.pdf /T

That is some epic reading - certainly very in depth.

Originally Posted by Dessertrunner

Steve from Jones racing wanted to drill the impeler but could not do it, the thing is cast and brakes up, so there is not point about talking about some thing that we can't do.

Also the link to the artical on quick read says he used a 3/4hp electric pump. Were the hell are you going to get a alternator to run that.

I have decided that I am not contributing to this forum for a while as I am sick of the indirect attacks.

Tony

Not sure what pump he was trying to use but the new Davies Craig 150L/min runs at 185W max. So far has proven good enough to cool 1000 bhp but we'll how it goes on the track. I reckon, worst case is he'll simply have to increase the size of the radiator and ensure adequate flow.

http://www.daviescraig.com.au/Images...ecs%202009.pdf

The Davies Craig as I mentioned is only 185W flat out. You said Steve's was 3/4 hp or 500W.

P=VI or P/V=I
500W / 12V = 41A

Stock alternator will handle that and if not the newer alternators are rated at well over 100A.

Not sure about Steve's impeller but if there's a will, there's a way, probably best to start with a brand new unit as the older ones tend to be brittle. I was once told I couldn't TIG weld up a cast turbo exhaust housing... took a while but got there.

However I think if the pump is the issue then get rid of it. I'm starting to think the bigger inlet, pressure valves, bigger radiators, cross flow radiators, better flow, special coolant, different caps are all band-aid fixes and the major issue remains - the pump is simply too big. So from my point of view for both my street SVX and EG33 race motor, it's simple... gut it and use something far more suitable - ie electric water pump or a smaller mechanical pump - although you really want to reduce complexity so either have to be really well thought out. A major thing you'd want is safety as EWP have less life - so for my setup I'd simply have the engine shut down above 110'C.