GSlender's Track Beeotch!

[gslender]

I'm off to the track on Monday, so I'll let you know how well it goes after then. Hopefully it doesn't vibrate apart into heaps of bits.... !!! G

Did you make it to the track to test out the new airbox?
If so, how did it go?

Airbox was excellent... engine cooling not so much.

I have since made further improvements into how the airbox gets air and installed the bottom air under tray (and subsequently created a hole for the intake duct etc)

I hope to head out again soon and see if the cooling issues are sorted and get my time behind the wheel.

G

[gslender]

I think your options are:
remove thermostat (don't need one and it's a massive restriction)
Coolant reroute
High PSI radiator cap
Single lower radiator hose (I've just ordered a silicon NB one)
and the key one: Get more airflow through the radiator (remove shrouds, add vents in the right spot on the bonnet, seal in the bottom of the engine bay)

Thanks - I've done a few of those so hopefully it will be sorted next time.

1) I've cut-out/drilled the dribble hole and this should help with restriction (but agree removing is my next step).

2) I've got a coolant reroute installed (but think this was my problem as it was going really low, low down on the engine block (as low as the bottom of the alternator) and I believe I had air trapped at the back of the head - so a combination of re-routing my re-route and ensuring zero air is in the system is what I've done here.

3) I've added a top shroud and the lower air tray - both of which will help ensure there is good air flow through the radiator.

So hopefully these will all solve the problem.

G

[sailaholic]

I wouldn't run no thermostat on a road car. I did it while doing a radiator flush and temps got too low.


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[Magpie]

I'm seriously considering switching to an electric water pump set up that way the thermostat can be taken out.

[NitroDann]

Do it. Seriously, its great.

[Magpie]

NitroDann already started the ball rolling especially considering my car is in pieces so taking the water pump/thermostat out and replacing with an electric setup is a good idea. Once done I'll start a thread to let the results be known.

[NitroDann]

Do it, PWM controlled CD EWP is the bomb.

[gslender]

I'm seriously considering switching to an electric water pump set up that way the thermostat can be taken out.

I recall reading an engineering book that stated the thermostat was actually part of the cooling design. Water needs to flow through the head/radiator at a slow/reasonable pace to actually transfer heat. If you race water too fast not enough of the molecules will transfer heat effectively and the cooling system will degrade.

http://www.agcoauto.com/content/news/p2_articleid/191

As such, I'm not 100% sure that removing the thermostat entirely is a good idea - most advice I've had is to gut them and perhaps widen them a little, but removing might actually be counter productive.

Just a thought.

G

[NitroDann]

You want a plate with a hole, say 1/2" in the centre.

[Magpie]

Thanks G, however looking at how the Davies Craig works is that the pump only runs when it needs to, that is if the engine is 'cold' then it will not switch on.

http://www.daviescraig.com.au/Controllers___Switches-list.aspx
For EWP’s: the updated Digital Controller (Part 8020) will manage the operation of the EWP® by varying the speed of the EWP® in response to the temperature of the engine and manage control of your electric engine fan...

Using Thermal Switches with our EWP's will not vary the speed of the pump in response to engine temperature but rather turn the pump on and off at your set temperature

The cars use will also depend upon the temp, if you want economy you will have a higher water temp whereas for power the water temp will be lower. Here is a good explanation http://www.arrowheadradiator.com/14_rules_for_improving_engine_cooling_system_capability_in_high-performance_automobiles.htm

[madjak]

I think cooling works entirely the opposite. The faster the flow (up to a point) the more even the temps across both the engine and radiator. If the flow is slow the temps will rise as the water flows through the engine reducing the temperature difference and reducing transfer. The opposite occurs in the radiator... the water is cooled quickly if the flow is low so by the time it gets to the bottom of the radiator there is less heat transfer resulting in less total heat exchange across the entire radiator.

I figure with no bottle necks, ie no thermostat, the water will flow free and with less turbulence. Gives me better heat transfer and more even cooling across the head. Also removes a point of failure.

On a road car you need some sort of restriction for when you are cruising. Dann's advice of the plate with a hole sounds good. With my smaller radiator I dont seem to have and overcooling issues at cruise but its not something I've really tested.

If you had trapped air in the system it could cause coolant to sit way too long in the head and boil. Filling my system is messy but I hold the top hose vertical, place a bucket under the radiator and quickly pour lots of coolant in until its overflowing cleanly then connect the hoses. Its hard to get all the air out with my setup.

[Geoffro]

Hey what's going on, my name is Geoff Slender from Sydney, we must be related?

[sailaholic]

Davies craig tested the effect of water flowing too quickly and found it to be a myth. However they also found that cooling could be related to flow speed up to a certain point, after which additional water speed had minimal advatnage in cooling.

Its stated here in the FAQ section - http://www.daviescraig.com.au/Electric_ ... ntent.aspx

They had a technical section that had the graphs but i can't find them quickly at the moment.

I have read that people believe that removing the thermostat can cause "overheating" due to the the lack of restriction in the cooling system allowing localised boiling due to either a lower system pressure allwoing boiling at lower temperature. The other theory was that removing the thermostat promotted differernet flow paths to standard again allowing localised hotspots.

The arguement against the system pressure one is that the system pressure provided by the radiator cap should be significantly more then the dynamic pressure provided by the pump and that bumping the system pressure with a higher pressure cap should overcome this.

On the coolant flow path i've got now answers. I emailed Davies Craig about it but never got an answer.

The obvious answer to both of these issues is to run a flow restrictor as mentioned by dan. However the DC pumps flow capability reduces significantly with flow restriction so you have to considered if the restriction is more then the pump can handle. Based on feedback it seems the EWP80 seems to have enough flow even with a restrictor. Though you will notice in the FAQ DC never say to fit one.

[ndragun]

Davies craig tested the effect of water flowing too quickly and found it to be a myth.

The coolant flow thing I was led to believe was only a problem if cavitation occurs. That is - it flows so quickly through all the nooks and crannies in the block that it starts to swirl and bubble in places and so makes less contact with hot stuff. Same thing happens with an outboard motor when it spins too fast - it cavitates and you lose thrust, since it stops actually contacting the water. You'd have to be really pumping the shiz out of it though to get it flowing that fast surely?

[gslender]

Well, I wouldn't be surprised if a mechanical pump could cause cavitation as it sure pumps heaps and heaps of water at high rpm. I think the restriction makes sense. Too many OEMs do it for it not to be needed. Some manufactures actually have a cooling restricter that purposefully changes the flow behaviour. Also, if a larger than pipe diameter thermo helped engine cooling then again, they use it... But they don't and instead restrict the water at the point of the thermo.