Cooling...

randall977 · 17-06-08, 09:22 AM

My 200 5T runs pretty hot. I don't think there's a problem with it - but it has a tiny auxillary oil cooler for the turbo and just generates alot of heat when driven. All of the later turbos had intercoolers - my questions are; Can I fit an intercooler - is it for water or oil and where does it go? Could I add a second water radiator (there is no room for a larger one)? Should I just run it hot (the fan only kicks in the a car park etc after it's got hot)?

Also... I adapted the plate under the oil cooling rad so it has a scoop - the oil temp seemed to stay down so is it just the water I need to keep an eye on?

AlanB · 17-06-08, 10:09 AM

Hi Randall,

Intercooler cools the inlet charge after the turbo, so shouldn't make a lot of diffence to the heat of the turbo. Are the gauges showing hot, or does it just seem hot??

When I first got a 200 Turbo, I couldn't believe how hot the underbonnet temperature was..... or how quickly it got there. Three cars and ten years later, they are all like that! If the gauges are OK, I would try to compare it with another turbo, although I guess it will likely need to be a later model.

I don't know if your car will be the same, but my cars (KG and 1B) have a complex fan arrangement. They have the biggest fan motor I have ever seen running at one of three auto controlled speeds. The circuit for switching the fan on when parked is largely seperate from the systems which run the fan when driving or idling; one switched by air temp, one by water, so you may need to check that the fan is starting when the engine is on; The fact it runs in the carpark does not guarantee that!
My fan will run at the slow speed at all times when the engine is running unless the aircon is switched "Off". It regularly ramps up to the high speeds in slow traffic.

If yours is like mine, I wish you the best of luck; there is a LOT of wiring in there! LOL.

AlanB

randall977 · 17-06-08, 11:25 AM

Thanks Alan, very useful!

Octanejunkie · 17-06-08, 12:56 PM

There are all sorts of wraps and coatings available these days to help with under bonnet temperatures, all with mixed results. PPC magazine featured a coating system a couple of months back (name escapes me) which apparently works very well.
If you are in any doubt about your cars cooling, it would be wise to have the radiator checked professionally for flow and pressure.
You may be able to find a bigger suitable radiator in a scrap yard from another vehicle (if you have the time and inclination that is

).
A thermostat that opens a few degrees earlier will get the coolant flowing quicker and at lower temperatures.....
There is a product available called "water wetter", which you add to the coolant and works very well indeed. I put some in a Sierra turbo cooling system a few years ago and it dropped the water temperature a fair bit.
Fitting an intercooler will not drop temperatures under the bonnet so to speak, rather cools the air pumped from the turbo to the throttle body. Fitting an intercooler should net you a good few extra ponies too. Might i suggest the compact unit from a Rover 600TI

. Intercoolers are usually mounted alongside the radiator where the maximum cool air flow can be achieved. No fluids run through them.
There is a device called a charge cooler where liquid enters the equasion, but normally this sort of thing is for higjhly tuned stuff.
Failing that, theres always water injection

randall977 · 17-06-08, 02:45 PM

I do like the sound of the intercooler - so I could strap this to the front of my normal radiator? What do I connect it to? SOrry to be a bit clueless on this one.

Octanejunkie · 17-06-08, 05:57 PM

Well you wouldn't strap it to the front of your radiator, that would impede air flow to the cooling system.
The ideal place would be somewhere next to the radiator or somewhere else at the front of the car. Many people fit them under the front bumper or just in behind the grille somewhere.
It looks just like a little radiator.
One end comes from the turbo. This will be the large hose that presumably currently runs from the turbo to the inlet manifold on your car.
That hose would go into one end of the intercooler, then at the other end another hose goes out and back onto the inlet manifold, capiche?
You are effectivly T'ing into the existing intake system.
Its purpose is to cool the incoming charge of hot air from the turbo to the engine and make it denser, therefore cramming more air into the combustion process and making more power.
If you intend to fit an intercooler, the priciest and trickiest bit will be getting the hoses routed properly. You really need to use silicon hoses for this and they can be pretty dear.
The intercooler itself can be picked up for peanuts.
Although a fiddly job, it would be the best bang for buck mod to make. A conservative estimate would be around 20hp extra.

ChrisG · 17-06-08, 07:28 PM

Dialynx used to do a new aluminium rad for the Ur, a four core unit iirc and it means the Aux rad can be removed and still better cooling.

randall977 · 20-06-08, 08:17 AM

Sooooo...I think I may try and aquire a Saab 9/3 intercooler as it appears to be the right size and has the 'in' and 'out' at the same end (which would make it easy to connect into the turbo outlet). I do wonder how much difference the intercooler will practically make to the engine running temperature - I assume quite a bit as the engine will recieve cooled rather than very hot air???

ChrisG · 20-06-08, 08:34 AM

every little helps !
10 degrees here 5 there etc and it all adds up. As octanejunkie says, bet it's close to 20 bhp.
You only need to see the rolling road figures for some vehicles and how they loose loads by the time run three or four takes place..... everything just heats up as the airflow is so restricted, even when there are big fans running onto the front of the cars

Octanejunkie · 20-06-08, 12:39 PM

If you don't want to go to the trouble of wrapping or coating exhaust components, you could always try making some heat shields.
Get a sheet of ali which is an excellent conductor of heat and see if you can bend/cut yourself out something to shield the turbo and or exhaust manifold (ali is soft). You could use existing bolts to hold it on. The aluminum will absorb the heat and help prevent it rising and spreading it around the engine bay. I made a few of these up for a Rover 600 ti i used to have and it worked really well.
The intercooler won't reduce under bonnet temperatures, only the intake temperature. Its a performance/efficiancy device rather than a cooling device.
If your temperature gauge is reading hot, a good back flush out of the cooling system is probably in order. Silt builds up in the lower parts of the system over time gradually reducing it efficiancy.
Favourite places for it to settle are:
In the engine block. In extreme cases (if back flushing is unsucessful) removing the core plugs and jabbing some wire around inside to disturb the silt, then flushing out with a hose may be required. This is not expensive, core plugs are dirt cheap, but it is labour intensive.

In the bottom of the radiator. Removing the radiator and flushing it both ways with a hose will be needed. Also, you can plug the bottom of the radiator and fill it with a caustic soda solution overnight. It may be easier in the long run though to fit a new/recon radiator though.

I had a BMW once that kept blowing head gaskets. I took the rad out and flushed it all out and it seemed ok. It wasn't though. It was only flowing at 30% and causing the engine to overheat....
Again, look at the thermostat and test it in a saucepan on the stove. It may be sticking or not opening all the way...

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17-06-08, 10:09 AM	#2
AlanB Grown up member Join Date: May 2008 Location: Lanarkshire, Scotland Posts: 103	Hi Randall, Intercooler cools the inlet charge after the turbo, so shouldn't make a lot of diffence to the heat of the turbo. Are the gauges showing hot, or does it just seem hot?? When I first got a 200 Turbo, I couldn't believe how hot the underbonnet temperature was..... or how quickly it got there. Three cars and ten years later, they are all like that! If the gauges are OK, I would try to compare it with another turbo, although I guess it will likely need to be a later model. I don't know if your car will be the same, but my cars (KG and 1B) have a complex fan arrangement. They have the biggest fan motor I have ever seen running at one of three auto controlled speeds. The circuit for switching the fan on when parked is largely seperate from the systems which run the fan when driving or idling; one switched by air temp, one by water, so you may need to check that the fan is starting when the engine is on; The fact it runs in the carpark does not guarantee that! My fan will run at the slow speed at all times when the engine is running unless the aircon is switched "Off". It regularly ramps up to the high speeds in slow traffic. If yours is like mine, I wish you the best of luck; there is a LOT of wiring in there! LOL. AlanB

17-06-08, 11:25 AM	#3
randall977 Mr Typ 43! Classic Audi Club Member Join Date: Sep 2007 Location: Oxfordshire Posts: 838	Thanks Alan, very useful!

17-06-08, 12:56 PM	#4
Octanejunkie Grown up member Join Date: Apr 2008 Location: Clevedon, North Somerset Posts: 293	There are all sorts of wraps and coatings available these days to help with under bonnet temperatures, all with mixed results. PPC magazine featured a coating system a couple of months back (name escapes me) which apparently works very well. If you are in any doubt about your cars cooling, it would be wise to have the radiator checked professionally for flow and pressure. You may be able to find a bigger suitable radiator in a scrap yard from another vehicle (if you have the time and inclination that is ). A thermostat that opens a few degrees earlier will get the coolant flowing quicker and at lower temperatures..... There is a product available called "water wetter", which you add to the coolant and works very well indeed. I put some in a Sierra turbo cooling system a few years ago and it dropped the water temperature a fair bit. Fitting an intercooler will not drop temperatures under the bonnet so to speak, rather cools the air pumped from the turbo to the throttle body. Fitting an intercooler should net you a good few extra ponies too. Might i suggest the compact unit from a Rover 600TI . Intercoolers are usually mounted alongside the radiator where the maximum cool air flow can be achieved. No fluids run through them. There is a device called a charge cooler where liquid enters the equasion, but normally this sort of thing is for higjhly tuned stuff. Failing that, theres always water injection

17-06-08, 02:45 PM	#5
randall977 Mr Typ 43! Classic Audi Club Member Join Date: Sep 2007 Location: Oxfordshire Posts: 838	I do like the sound of the intercooler - so I could strap this to the front of my normal radiator? What do I connect it to? SOrry to be a bit clueless on this one.

17-06-08, 05:57 PM	#6
Octanejunkie Grown up member Join Date: Apr 2008 Location: Clevedon, North Somerset Posts: 293	Well you wouldn't strap it to the front of your radiator, that would impede air flow to the cooling system. The ideal place would be somewhere next to the radiator or somewhere else at the front of the car. Many people fit them under the front bumper or just in behind the grille somewhere. It looks just like a little radiator. One end comes from the turbo. This will be the large hose that presumably currently runs from the turbo to the inlet manifold on your car. That hose would go into one end of the intercooler, then at the other end another hose goes out and back onto the inlet manifold, capiche? You are effectivly T'ing into the existing intake system. Its purpose is to cool the incoming charge of hot air from the turbo to the engine and make it denser, therefore cramming more air into the combustion process and making more power. If you intend to fit an intercooler, the priciest and trickiest bit will be getting the hoses routed properly. You really need to use silicon hoses for this and they can be pretty dear. The intercooler itself can be picked up for peanuts. Although a fiddly job, it would be the best bang for buck mod to make. A conservative estimate would be around 20hp extra.

17-06-08, 07:28 PM	#7
ChrisG Senior Member Classic Audi Club Member Join Date: Dec 2007 Location: Bracknell, Berks. Posts: 1,465	Dialynx used to do a new aluminium rad for the Ur, a four core unit iirc and it means the Aux rad can be removed and still better cooling.

20-06-08, 08:17 AM	#8
randall977 Mr Typ 43! Classic Audi Club Member Join Date: Sep 2007 Location: Oxfordshire Posts: 838	Sooooo...I think I may try and aquire a Saab 9/3 intercooler as it appears to be the right size and has the 'in' and 'out' at the same end (which would make it easy to connect into the turbo outlet). I do wonder how much difference the intercooler will practically make to the engine running temperature - I assume quite a bit as the engine will recieve cooled rather than very hot air???

20-06-08, 08:34 AM	#9
ChrisG Senior Member Classic Audi Club Member Join Date: Dec 2007 Location: Bracknell, Berks. Posts: 1,465	every little helps ! 10 degrees here 5 there etc and it all adds up. As octanejunkie says, bet it's close to 20 bhp. You only need to see the rolling road figures for some vehicles and how they loose loads by the time run three or four takes place..... everything just heats up as the airflow is so restricted, even when there are big fans running onto the front of the cars

20-06-08, 12:39 PM	#10
Octanejunkie Grown up member Join Date: Apr 2008 Location: Clevedon, North Somerset Posts: 293	If you don't want to go to the trouble of wrapping or coating exhaust components, you could always try making some heat shields. Get a sheet of ali which is an excellent conductor of heat and see if you can bend/cut yourself out something to shield the turbo and or exhaust manifold (ali is soft). You could use existing bolts to hold it on. The aluminum will absorb the heat and help prevent it rising and spreading it around the engine bay. I made a few of these up for a Rover 600 ti i used to have and it worked really well. The intercooler won't reduce under bonnet temperatures, only the intake temperature. Its a performance/efficiancy device rather than a cooling device. If your temperature gauge is reading hot, a good back flush out of the cooling system is probably in order. Silt builds up in the lower parts of the system over time gradually reducing it efficiancy. Favourite places for it to settle are: In the engine block. In extreme cases (if back flushing is unsucessful) removing the core plugs and jabbing some wire around inside to disturb the silt, then flushing out with a hose may be required. This is not expensive, core plugs are dirt cheap, but it is labour intensive. In the bottom of the radiator. Removing the radiator and flushing it both ways with a hose will be needed. Also, you can plug the bottom of the radiator and fill it with a caustic soda solution overnight. It may be easier in the long run though to fit a new/recon radiator though. I had a BMW once that kept blowing head gaskets. I took the rad out and flushed it all out and it seemed ok. It wasn't though. It was only flowing at 30% and causing the engine to overheat.... Again, look at the thermostat and test it in a saucepan on the stove. It may be sticking or not opening all the way...