I'm changing to a watercooled EA82 turbo this weekend (along with other work)... If I hook up the watercooling circuit later, will it harm the turbo to be run with only oil cooling it?

I may have an intercooler hooked up this weekend as well if that helps...

I'm changing to a watercooled EA82 turbo this weekend (along with other work)... If I hook up the watercooling circuit later, will it harm the turbo to be run with only oil cooling it?

I may have an intercooler hooked up this weekend as well if that helps...

 

Intercooling wont help.

 

It would probably be alright if you drive it carefully...... but i would be inclined not to risk it. If you must, i would recommend using a high end synthetic oil.

synthetic oil won't help thats a myth, it won't hurt the turbo much, but i will severly decrease it's lifespan, i strongly reccomendrunning the coolant lines asap but it wont hurt it to do a little driving, but be careful as the turbo will be very prone to overheating,not the engine just the turbo, which will cause the oil in it to burn up and fry the bearings, and leave sludge in the turbo if it was my car i wouldn't do it unless i had to as a last resort.

 

edit: no an intercooler will only help the engine keep cool not the turbo

Watercooled turbos are also cooled by oil ofcourse. Ive been running a watercooled turbo without the water hooked(non subaru) up for some months and it shows no signs of wear. Just let the turbo cool before you shut the car off. It doesnt take long but it will stretch the life of the turbo.

see, that's what I was thinking. The car comes with an oil-cooled turbo, and it can have a water cooling circuit added to it. If there's no difference in the turbo except for the W/C hardware, then ... you see where I was coming from...

Yes synthetic oil will help the turbo. It won't burn up on the bearings as fast as reg oil.

 

No you do not have to run water to the turbo. It is there to keep it from overheating after shut down. So don't shut down the motor with a hot turbo, k? IE don't race down the street, pull in your drive way and cut it off. Its a bigger problem where the turbo is mounted to a large cast irom manifold that will retain and transfer a lot of heat after shut down.

Turbo centre housings are almost identical 84/85 w/the exception of the added water jacket on the ea82s.Same bearings,same everything.Draw your own conclusions.

...It is there to keep it from overheating after shut down...

+1.

 

A couple turbo-manufacturer sites that I have looked over specifically state that the watercooling is there to minimize bearing-oil coking after engine shutdown. They state that the water does little to nothing during engine running, and that the direction of the coolant flow, and flow itself, is unimportant during running. Plumbing needs to have one line physically lower ("after" inflow) and one line physically higher ("after" outflow) so that the turbo can thermosyphon after shutdown.

Thanks everyone. I was thinking it was safe but I feel better getting input from others on this.

Pat, thanks for the tech. I had no idea it was irrelevant while running.

I am possibly going to put a small radiator core inline with the tubro's coolant inlet; I figure it can't hurt anything...

go for it. I;ve run a couple of the RHB-5's from the ea82t on air-cooled VW engine with no problems. Also, these VW engines are only driven with an abusive right foot. The coolant will be better of course and I would hook it up, but if you need this sucker running pronto, go for it!

and I thought Pat's advice was good! thanks!

I'll show up and agree... You dont need to water cool the turbo, just let it idle a bit after you run it... not even hard, just at all... let it sit a bit and if you did drive it hard, let it idle longer... Shorter Turbo life? Pishaw! My 82 Honda is oil cooled only turbo... no turbo troubles there (other then the feed pipe has a slight leak) Get a turbo timer if you are not sure... Water coolings biggest shining achievement is after running cooling, but it does help some during running... like taking your engine's normally 190 degree coolant and ramping that up over 200 degrees! YAY!

awesome. the main reason I want to procrastinate the water cooling circuit is that I want to consider rigging a small radiator inline with the turbo W/C circuit, and integrate it with the scoop I'll be installing soonish for the intercooler I just got.

Let me know what hoodscoop you use and give me a picture or two. I'm still gathering ideas for my hoodscoop on my EA81T.

sure will though it might be a little way out. I'm thinking about a WRX scoop though.