Water cooling on turbos - do u need it?

[ookami]

If there are posts on this can someone please point me in the right direction as when i searched i couldn't find much.

Anyway when my 33 got here from japan it had no water lines connected to the turbo and they were simply blocked off. The turbo is a HKS2835R Pro. My mates R33 also had a GT3037S and it had water lines disconnected too. My car was apparently built by a fairly reparable japanese tuning house so i'm not sure why they would not connect them. Any ideas? What are the pros and cons of connecting them? I was reading on another forum about how the water flowing through them does shorten the life of the turbo, but i'm just not how? surely water flowing through the turbo wouldn't wear away the centre that quick if at all?

[PHATR32]

lol, water flowing through them would be better cause it help cool the bearing, thus reduscing wear.

steve

[ookami]

so why what would be a good explaination as to why they weren't fitted in the first place?

[PHATR32]

maybe the bearing was worn and leaking coolant?

steve

[HYBRID VL]

My T04B duz not have any waterlines just oil lines.

[GTR-Ben]

Most samller ball bearing turbos will have water cooling due to there being less oil flow for cooling because of the restrictor.

Saying this I have seen cars with the water blocked off. Maybe on a drag car or similar they don't see the same heat as they are only going for a few seconds?

I guess it all depends how it's designed and what it's being used for.

It was a lot of extra work running the pipes etc on my car for the water and oil.. but I think it's worth it.. and it looks good too

[discopotato03]

Water has a high thermal mass - it takes a lot of energy to boil it . If the turbos bearing housing can be kept at or below 100deg C the lubricating oil flowing through it will not burn or solidify killing the bearings . This is most likely to happen when the engine is shut down hot , the bearing core hanging off a potentially red hot exhaust manifold and turbine housing can roast any oil present . Contrary to popular belief many OEM water cooled turbos don't have water pumped through them but have one water fitting higher than the other to allow thermosyphoning . It does not take much water volume to maintain a safe temperature in the turbos water jacket for the 3-5 min after shut down that is critical . When I fitted the GT28RS to my old FJ20 I used the blocks drain plug hole for the water inlet and drilled / tapped the head behind the thermostat for the hot water outlet . After shut down you could hear water boiling in the turbo , the bubbles rising up the high pipe , out through the thermostat and rad cap into the overflow recovery bottle . Obviously the boiling water was being replaced by cooler water lower in the cooling system untill the bearing housing got down to or below 100 C . I think all turbo SR's and RB's had factory water cooled turbos so the inlet and outlet should be there . If you can use it because its cheaper than fried turbos .

Can you post pics of the exhaust housing side of your turbo please , I'd like to see what sort of dump pipe pattern the HKS GT Pro housings use .

Thanks A .

[ookami]

yeah i will post pics later on today of the dump pipe when i get a chance to take photo's. It is a strange pattern though. Its the internal wastegate version too.

discopotato03 I see what your saying about the water lines though. I'm guessing my car was previously used as a weekend track car of some sort going by the size turbo (not drag spec is it) and lack of lag and the rubber it had on it (falken azenis) and the larger aftermarket radiator and the alloy coolant surge tanks it has. I still can't understand why they just wouldn't hook them up.

[JCMarshall_Law]

I can think of one reason not to connect the water lines, the cyclic thermal stressing of the turbo housing would surely reduce the life of the turbo. It would not be a problem if the engine always ran at steady state, but they never do, full throtle, fullboost, off boost, high rev, low rev, low trotle, idle, you get the idea.

Water running through the turbo would create huge thermal gradients as the turbo rapidly heats and cools as hot exhaust gasses and cool water flow through the housing. the thermal stressing could posibly lead to cracking of the housing and distortion of the bearing surfaces.

Now that is a reason I have thought of, the engineers who design these things are very clever people and they most certianly thought of these things. I am saying that manufactures of performace parts are usually looking for performance (supprise!!!) rather than reliability. So water cooled turbos obviously work and I think they probably work better in the short run for high performance applications but in the long run realability could be a problem.

Having said all of this I cannot say I have ever seen a turbo fail from causes which can be directly linked to the turbo being watercooled. Just a posibility.

[discopotato03]

Thanks ookami , off topic I know but I need to see one as the T3 flanged GT3037 Pro S probably uses a similar integral gate version of the housing and dump .

I've been told that on race cars the water cooling is sometimes deleted to reduce complexity and long term reliability devices are not needed .

[JCMarshall_Law]

Obviously turbos always see cyclic thermal stressing but water cooling would make the problem much more significant.

[ookami]

thanks guys, i think i'll be connecting them back up once i get my car back. I just can't see a valid reason as to why i should not connect them up. After thinking about it for a while could it possible that the coolant lines were not connected to help keep engine temps down? I mean my car has a larger alloy radiator and 2 coolant surge tanks so it must have run pretty hot to need that? The coolant that was in there was like a aqua colour and burnt the hell out of my skin too

[discopotato03]

Actually Pat it works the other way . The thermal mass of the bearing housing is quite small and with water in it it never gets red hot . With todays iron alloys the heat to the bearing housing is not a problem . Its keeping the oil temperature below the cooking temperature that is the issue .

The exact reason why car manufacturers do it is so that turbo engines can be shut down like any other engine and not have heat related turbo failures . Manufacturers put long waranty periods on new cars and todays drivers don't want to be bothered with tiresome idle down antics . Another thing to think about is todays lean burn engines exhaust gas temperatures are highest in highway cruise mode . Full load and boost EGT's are significantly lower .

[JCMarshall_Law]

Thanks disco, I think your right there, Just trying to think of another reason not to connect water lines.

Stock R33 turbos are not water cooled are they?

[caminperth]

Stock R33 turbos sure are water cooled. Have pulled out a few now.

Interesting thread by the way....

[KamikazeR33]

u dont need them connected... the water cooled turbos are usually only the bb turbos

btw if its not connected im sure there would not be anywhere to connect water to it as they would have done this otherwise

[ookami]

yeah there are still the standard places to connect the water they are just blocked off with bolts, so i'm not sure why.

[discopotato03]

Can we have some pics of your turbos exhaust housing / dump pipe please . Thanks A .

[ookami]

oops .. today forgot. Will get them tonight and post up.

[ookami]

oops .. today forgot.  Will get them tonight and post up.

sorry for the delay