Coolant plumbing...
Turbo Mini Forums

Hi all.

Quick question about the best plumbing arrangement for a water cooled turbo.

I know which way it needs to go through the turbo, but where have you guys found it best to plumb the water out of and then back into the engine cooling system?

A plus engine, side rad. No heater. No heated inlet manifold. No engine coolant plumbing done at all yet. Can weld and fabricate if reqd....

Pics would be nice, but a description will do.

Thanks
Jamie

mine goes from heater take off to the turbo, then out of turbo in to heater matrix in the car, then back out of there in to the normal heater plumbing on the lower radiator hose.

"Tuning should be a compromise between what is possible and what is necessary"

10)Thou shalt always quest for more power

[quote=jamie@thefatgarage,2nd Feb, 2011]

I know which way it needs to go through the turbo,[quote]

is there a set way then??

I have started posting on Instagram also my name on there is turbomk1golf

Nothing is impossible it just costs more and takes longer.

Yes there is a set way...

http://www.turbobygarrett.com/turbobygarre...ptimization.pdf

In at the bottom, out at the top. It means less heat soak when the engine is off. Explained in the PDF above.

I set mine up like minij, but after taking advice and reading the PDF above, it is going to be changed !.

Received advice is to take the water from a hole tapped into the block near number 4 cylinder and return it direct to the rad. top tank, which I shall now do.

As far as the 20 degree tilt is concerned I am going to rely on the slight angle made by the mounting of the turbo on the manifold as rotating the core to achieve 20 degrees will make the oil drain more difficult for me, and depart from its ideal angle downwards.I diont think it matters a scrap which direction you flow the water through the turbo as long as it is maintained.

Any other views, please ?.

Schrödinger's cat - so which one am I ???

I have expressed myself badly and misled you.

What I was trying to say was that it did not matter which connection was made to the turbo first,front or back, and I fully understand the thermosyphon need.

If you re-read my post with this in mind you may now be able to understand what I was saying -I will feed from the back of the block to the water port on the side of the turbo nearest to the block,which, because the turbo is at a slight angle to the block, will be lower than the port on the outside of the turbo,the outlet, leading back up to the rad header tank.

I really must try to express myself more succinctly in future !

Apologies David,

I did read it rather superficially when I saw "I don't think it matters a scrap which direction.........". etc.

So long as you have a thermo-siphon once the pump has stopped, you should be OK. Others may disagree but most OEM setups I've seen use the thermo-siphon principle for a shutdown engine.

Edited by Rod S on 2nd Feb, 2011.

Schrödinger's cat - so which one am I ???

I have started posting on Instagram also my name on there is turbomk1golf

Nothing is impossible it just costs more and takes longer.

should you put the water in to the rad through the bottom aswell then?

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

Hot water always goes in the top on rads... without exception I think... I'm sure someone will correct that if it wrong :)

Certainly not seen a car where it doesn't..

Reading this I believe I have mine plumbed the wrong way round too,and may have led you to doing the same,David,sorry.......I have an electric cooling fan with a timer,meaning it stays on for 10 minutes after shutdown and certainly increases the thermosyphon effect as the water in the radiator is cooled.

'Where does the engine go?'

My original system was done out of a need to get something in there and I always had some misgivings. I remember you pointing out,Steve, that it would be disastrous if the heater valve had been turned off, which I had thought myself,

I,m pretty sure your pump and timer will take care of any shutdown turbo cooling issues.,

Just been out and re-made the turbo water plumbing.There is a convenient drain plug at the back of the block,tapped half inch UNF.The Saab banjo bolt that I am using is 14mmx1.5 so it was 2 minutes work to drill out and re-tap to suit. The pipe to the back of the turbo is then only about 8 inches long and took 10 minutes to solder up.
I was able to re-use the other pipe that I had made and now just need to solder the return in to the header tank - another day !

Hi mate, i was thinking of doing that as its nice and close to the turbo, but is there much flow from that drain plug?

simon.

I have started posting on Instagram also my name on there is turbomk1golf

Nothing is impossible it just costs more and takes longer.

I,m guessing the flow will be as good as anywhere and am advised its a higher pressure area (dont understand that, but so what )
I will be totally stripping the block to rebuild, removing core plugs and cleaning out the water jacket, so its got the best chance. I reckon if you are not doing this you should do your best to flush the block with that drain plug out at least.

I think pressure is constant in the whole cooling system, so that sounds a bit like pub talk to me. It's like saying tyre pressure is greater nearer the valve!

well, pressure must be different either side of the pump othewise the water would stay still.

Yes, I grant you that immediately either side of the pump there may be a very small pressure difference. But as near as f##k is to swearing, everywhere else it will be the same.. water doesn't compress well.. as you will find if your cylinder ever gets filled with it.

In fact due to it's lack of compressibility I'm really not sure there will be a difference either side of the pump, it's a mechanical moving of liquid, not like an air compressor.

well theres enough pressure to jet water about 10ft through a pin hole in the heater valve at idle.

according to Vizard the std pump can make about 60 psi against the thermostat at full rpm, although that does sound unlikely to me, but i would expect 10-20 psi.

It's not a question of what Vizard said or what he meant on that occasion, only he can answer that. It's a question of physics. Anyway, I'll leave it there as I know I'm right, and you know how far stuff shoots at the idle from an unknown hole size and what Vizard said once. I have beer that needs drinking!

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

The compressibility of the liquid is entirely relevant if a pressure difference is observed. In your scenario what creates the higher pressure, or as I like to call it more stuff in a smaller place? Does the water pump make liquid somehow? Or has the water now decided to become temporarily compressible? It's one or the other...

By the way, we are talking in theory and not taking into account gasses in and out of solution at differing pressure.. not that I'm about to get into that massive can 'o' worms

Back to the beer... which goes "psst" when I open the can...

so in a brake system when you have your foot lightly on the brake and heavily on the brake there is the same volume of uncompressible fluid, are you telling me that the force on the brake piston remains the same? ofcourse not, its the force exterted on the fluid by somehting else that creates the pressure in the fluid, not the compressibility of the fluid. ergo the compressibility is irrelevant :)

now the cooling system is not 100% rigid, nor does it have only 100% fluid in it. this leeway allows for the pump to impart a force on the working liquid.

pressure by defenition is force / area, doesnt matter whether the pressure comes from compression of the working fluid, or some other force behind the fluild, its still pressure :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Schrödinger's cat - so which one am I ???