spiderpigcity Posted May 23, 2011 Share Posted May 23, 2011 I was talking to an ex formula 1 technician the other day and he was telling me that watercooled turbos are a myth. he said that they heat the engine up quicker from cold and the water does nothing to keep the turbo any cooler. basically he said dont bother paying the extra for them as the flow needed and diameter of pipe would be huge to actually cool those kind of temperatures. anyone heard of this before? Quote Link to comment Share on other sites More sharing options...
Homer Posted May 23, 2011 Share Posted May 23, 2011 I very much doubt the likes of Garrett would add this if it wasn't required. The water cooling is to cool the dual ball bearing. It's not needed on journal bearing turbo's. To quote Garrett: Garrett ball bearing turbochargers require less oil than journal bearing turbos. Therefore an oil inlet restrictor is recommended if you have oil pressure over about 60 psig. The oil outlet should be plumbed to the oil pan above the oil level (for wet sump systems). Since the oil drain is gravity fed, it is important that the oil outlet points downward, and that the drain tube does not become horizontal or go “uphill” at any point. Following a hot shutdown of a turbocharger, heat soak begins. This means that the heat in the head, exhaust manifold, and turbine housing finds it way to the turbo’s center housing, raising its temperature. These extreme temperatures in the center housing can result in oil coking. To minimize the effects of heat soak-back, water-cooled center housings were introduced. These use coolant from the engine to act as a heat sink after engine shutdown, preventing the oil from coking. The water lines utilize a thermal siphon effect to reduce the peak heat soak-back temperature after engine shut down . The layout of the pipes should minimize peaks and troughs with the (cool) water inlet on the low side. To help this along, it is advantageous to tilt the turbocharger about 25° about the axis of shaft rotation. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 23, 2011 Share Posted May 23, 2011 I very much doubt the likes of Garrett would add this if it wasn't required. The water cooling is to cool the dual ball bearing. It's not needed on journal bearing turbo's. So how come all the std turbos with plain bearings have water cooling? Quote Link to comment Share on other sites More sharing options...
Homer Posted May 23, 2011 Share Posted May 23, 2011 So how come all the std turbos with plain bearings have water cooling? I was responding assuming it was not a question relating to OEM installation - i.e. large single turbo conversion. Longevity would be my guess as to why many OEM applications have them. Quote Link to comment Share on other sites More sharing options...
vertex Posted May 23, 2011 Share Posted May 23, 2011 if manufactures are using water cooled turbo from factory, what harm can it do? maybe he's an ex technician for a reason? Quote Link to comment Share on other sites More sharing options...
aman00123 Posted May 23, 2011 Share Posted May 23, 2011 Well water cooling can't do any harm can it? So it's got to do more good for the turbo than bad Plus imo it's quite obvious to see that any extra cooling, no matter how small, is going help in some way or another Quote Link to comment Share on other sites More sharing options...
spiderpigcity Posted May 23, 2011 Author Share Posted May 23, 2011 (edited) but hotter turbo means more power. Wheres mr beardy? If there is a mr beardy on this forum can you please do the calculations for the flow rate and volume of water/coolant passing the turbo and using 3/8 id hose and let us know how many litres of water at 90 degrees c you would need to make any significant temperature drop in the turbo; and can the stock waterpump and cooling system provide this flow rate etc. I wonder if it is significant. I think Japan had the same problem with their reactors and they had the pacific ocean to cool it. Edited May 23, 2011 by spiderpigcity (see edit history) Quote Link to comment Share on other sites More sharing options...
Scott Posted May 23, 2011 Share Posted May 23, 2011 Hotter turbine means more power, hotter compressor means less power. The more cooling between the turbine and the compressor, the more efficient the turbo. Edit: Japan had the issue because the power to the pumps was shut down, they had to rely on emergency generators. Do you normally talk this much nonsense or have you been on the sauce? Quote Link to comment Share on other sites More sharing options...
spiderpigcity Posted May 23, 2011 Author Share Posted May 23, 2011 Get mr beardy, he will know the answer. I have not been on the sauce, I was taking the p*ss:) Just wondered if anyone could answer the question and give the figures to show us Quote Link to comment Share on other sites More sharing options...
Scott Posted May 23, 2011 Share Posted May 23, 2011 Only beardy I know is beardy man... and he rocks Quote Link to comment Share on other sites More sharing options...
spiderpigcity Posted May 24, 2011 Author Share Posted May 24, 2011 (edited) i found this "Everyone needs to keep in mind that the water cooling does very little for the turbo while it is running. The major benefit occurs after shutting the engine off. When setup properly the water in the turbo boils, the vapor escapes, and cool water refills the turbo. This helps keep the center housing cool and prevents the residual oil from turning to sludge." and this THE reason to have a water cooled turbo is post shutdown cooling. The only way this is going to happen is if you can properly setup a thermal siphon. During operation water cooling does very little. Edited May 24, 2011 by spiderpigcity (see edit history) Quote Link to comment Share on other sites More sharing options...
Homer Posted May 24, 2011 Share Posted May 24, 2011 You're either trolling or haven't grasped your own question. I'm going with the former. You keep saying "turbo" while at the same time referencing water cooling. The water cooling is ONLY for the bearing, it has no effect on anything else in the assembly. Water cooling is required to help longevity, it doesn't make any difference to power or spool characteristics Quote Link to comment Share on other sites More sharing options...
bobapple Posted May 24, 2011 Share Posted May 24, 2011 Right sorry to butt in, but I am going to, to try learn something . I understand the water is their for the bearing longevity but are you not putting quite hot fluid into something that is already quite hot does this not further the heat temps? And if it did is that extra temp pushed more to the hotside for effficiency?. Sorry if that makes no sense. Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 24, 2011 Share Posted May 24, 2011 the turbo can get silly hot like white hot and manifolds can glow so the hot water would help cool it , it helps cool the engine doesnt it! Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted May 24, 2011 Share Posted May 24, 2011 Right sorry to butt in, but I am going to, to try learn something . I understand the water is their for the bearing longevity but are you not putting quite hot fluid into something that is already quite hot does this not further the heat temps? And if it did is that extra temp pushed more to the hotside for effficiency?. Sorry if that makes no sense. No because the engine coolant would be a good couple of hundred degrees cooler than the core of the turbo, and with it being pumped round it will be taking heat away Quote Link to comment Share on other sites More sharing options...
Thorin Posted May 24, 2011 Share Posted May 24, 2011 Quick someone go get beardy man! Bizarre. Quote Link to comment Share on other sites More sharing options...
bobapple Posted May 24, 2011 Share Posted May 24, 2011 Thank you, sorry if it seemed a silly question as said still learning. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 24, 2011 Share Posted May 24, 2011 Was writing a long winded beardy answer to all this, when i hit the wrong key! I'm i mad:diablo: Quote Link to comment Share on other sites More sharing options...
spiderpigcity Posted May 24, 2011 Author Share Posted May 24, 2011 here is another scenario for you, if the centre of the shaft had lots of cool liquid running around it and the end of the shaft in the ehaust housing is white hot wouldnt that shatter or crack the shaft? Ive seen it happen on the film Alien 3 where the alien explodes! Quote Link to comment Share on other sites More sharing options...
stevie_b Posted May 24, 2011 Share Posted May 24, 2011 Wheres mr beardy? He's behind you. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted May 24, 2011 Share Posted May 24, 2011 here is another scenario for you, if the centre of the shaft had lots of cool liquid running around it and the end of the shaft in the ehaust housing is white hot wouldnt that shatter or crack the shaft? Ive seen it happen on the film Alien 3 where the alien explodes! It doesnt run round the shaft otherwise you would have an oil system full or coolant It runs through channels in the core of the turbo. And youre right, if you were to run cool liquid round it would crack, luckily the coolant is around 100 degrees so thermal shock is avoided Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 24, 2011 Share Posted May 24, 2011 here is another scenario for you, if the centre of the shaft had lots of cool liquid running around it and the end of the shaft in the ehaust housing is white hot wouldnt that shatter or crack the shaft? Ive seen it happen on the film Alien 3 where the alien explodes! This is why you warm up engines Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 24, 2011 Share Posted May 24, 2011 OK second try, Do turbos actually need to be water cooled, and what does it actually achieve? Well IMO and looking at the whole thing logically, its been stated that all plain bearings need to be water cooled, well i don't think so, as all PB turbos use an unrestricted oil feed which provides a fair degree of cooling due to the amount of oil flowing through them, i am inclined to think that most manufactures add water cooling, as a failsafe, and because most factory setups are based on small turbos fitted closely to the engine block, and so has a very hard time dispersing heat. Now the other thing that been stated says that the time a turbo most needs water cooling is when the engine is shut off, to prevent the oil being cooked and forming coke, well IMO i don't think this actually works, because the only cooling that can be provided is through liquid convection, as the water pump is no longer running, and due to the sizing of most pipework is not going to be that beneficial, especially if the engine is regularly shut off after a lot of turbo use (yes i know its not good practise, but it does happen as not everybody is clued up!) Do BB turbos need water cooling, well as the oil flow is somewhat restricted in most, i would have to say yes, as it takes over where the oil flow on conventional PB turbos leaves off, and between the two it gets just about adequate cooling. Also be interested to know peoples opinions on the purpose of restricting the oil flow/pressure on BB turbos, i am inclined to believe its due to over oiling a BB will actually undermine the purpose of fitting BBs IE to theoretically reduce spool up time and overcome inertia, however as PB turbos actually run on a film of oil anyway, so why arnt they just as quick at spooling, i am inclined to think that set up and sized properly PB turbos can be just as quick, but that getting into another can of worms;) Like many i have run big PB turbos fed with oil only, very successfully, with no heat issues, OK it usually necessitates the use of an external oil cooler but thats to be expected as it a bigger area of metal to add heat to the oil. Be interested to know out of all those who have run a big BB water cooled turbo, how many have needed to use a bigger rad? and i don't mean just for the sake of changing it. Its also been stated that water cooling a turbo is only for the bearing and has no other use, well i would dispute this, as any liquid flowing through the turbo core, be it oil or water is going to carry heat away from it, and therefore have an overall cooling affect, i think the most amusing comment was, "Everyone needs to keep in mind that the water cooling does very little for the turbo while it is running. The major benefit occurs after shutting the engine off. When setup properly the water in the turbo boils, the vapor escapes, and cool water refills the turbo. This helps keep the center housing cool and prevents the residual oil from turning to sludge.";) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 24, 2011 Share Posted May 24, 2011 (edited) Here you go, this should answer everything, and from a horse's mouth http://www.turbobygarrett.com/turbobygarrett/images/tech_center/Garrett_White_Paper_01_Water_Cooling.pdf Edited May 24, 2011 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 24, 2011 Share Posted May 24, 2011 so there you have it water cooled will last you longer as long as you have the outlet higher then the inlet. Quote Link to comment Share on other sites More sharing options...
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