gorge

My new garrett turbo that I'm about to install doesn't require coolant to cool it down and I'm just wondering how it's going to stay cool without it.
Apart from the oil input and drain pipe holes the only opening is about an inch away from where the turbo attaches to the manifold. It's where the exhaust gases pass through before reaching the turbine.
Is this supposed to be used for water injection?
What's required to set the turbo up for this?

Syritis

iTrader: (2)

no it's oil cooled. lots are like that.

the extra hole sounds like it's for and EGT sensor. i bet it has a 1/8 npt thread.

for street driving and 1/4pulls it isn't an issue, for road race it's going to wear out faster then and water cooled one but i wouldn't worry about it.

tips for adding longevity, 1. always let the car return to idling EGT's before shutting the car off. 2. use a turbo blanket, i know that sounds backward, you can't stop the heat from conducting through the turbo but it will reduce the radiant heat around the turbo. or at the least use a stainless steel bowl as a heat shield.

gorge

what does an EGT sensor do? Do I need to have one?
It's a t4 flange garret turbo and the stock oil line drain won't connect to it. Are there aftermarket ones you can buy from somewhere, or do you need to have one made?
Also, what's the best way of plugging the turbo coolant lines? I have an FC.

BLACK MAMBA

iTrader: (58)

Exhaust Gas Temperature sensor, you coulb by lines or make your own steel braided lines,

http://www.atpturbo.com/ is one of the many turbo and components suppliers.

you need to block your water lines.

gorge

Could you provide a link to a line? I just want to buy one already made.
For my T4 manifold to engine gasket, do I just use the mazda FC exhaust manifold gasket, or do I need something different?

arghx

iTrader: (3)

water cooled is better for longevity but on a car that's not consistently daily driven or consistently raced it's less important. Here is a diagram showing heat transfer on an oil-cooled turbo:



list of symbols is attached

gorge

Since heat is transferred to the oil,you'd think this would also decrease engine life.

gorge

also, heat wouldn't be able to radiate away from the turbo if you're using heat wrap etc to protect the engine bay so you either have to let the turbo get damaged or engine mounts etc.

just startn

iTrader: (33)

I dont know if your ready to install this turbo yet. What are your supporting mods?

arghx

iTrader: (3)

Heat is still going to get transferred to the oil whether you have coolant flowing in there or not. Engines have an operating range of acceptable water and oil temps. The heat transfer to the oil (and probably the coolant) is proportional to the mass flow rate of the compressor--the more air the turbo is flowing, the more heat you will generate (duh).

arghx

iTrader: (3)

I have not seen a full analysis of heat transfer on a water-cooled turbo. I suspect though that the water and oil temperatures aren't far apart as they flow out of the bearing housing. Having a water-cooled turbo primarily helps carry away heat when the engine shuts down:



To further improve cooling, some engines have an electric water pump that will stay running when the engine shuts off. BMW N54 engines do this for example:



Like any other engineering decision, oil vs water cooled turbo is a trade off. Oil cooled is simpler, cheaper, and has less failure points. However it allows additional heat to build up on shut down which hurts longevity of the turbo compared to the water-cooled design.

Syritis

iTrader: (2)

I've been racing for two years on one motor and an oil cooled turbo with a turbo blanket and heat wrap.

when the engine is running the parts are moving, the heat is being moved away from the turbo through the oil and exhaust. heat radiating away from the turbo make a small if not negligible difference to the turbo temps. if it sits still while red hot the heat parts tend to fuse together. so i say if you let your EGTs return to idling temps before shutting off the car you have nothing to worry about.