Did I get the wrong Turbo? (1 Viewer)

[gilghana]

I think the issue with water cooling the turbo on a 1HZ is that the engine coolant actually heats up more with the added job it is expected to do in cooling the turbo... and IIRC the HDJ has a larger radiator which I assume is because it is running a water cooled turbo. I would suspect that like a lot of things Toyo perhaps went for a belt and braces type approach in water coollng the HDJ. Some aftermarket turbo kits that I looked at do water cooloing, some don't. Certainly with my HZJ with the CT26 turbo I have found in very high ambient temps that the cooling system is certainly taking strain! It is not that it overheats, but put it like this there is another engine temp gauge and an EGT gauge on my rig for a reason... A friend who is a CAT Engineer has suggested that if I do fit my ebay Celica A/W aftercooler that I could circulate the added cooling circuit with my 100 liter underbody tank - and also add the turbo into this second cooling system. I will probably not go down this route as the vehicle may end up in colder climes and I don't really want to shower with glycol But it would be interesting to see the effects and get a warm shower at the end of the day!

 

[Ron R]

I find that VERY hard to believe! The day my cooling system is hotter than my turbo in normal operation is the day that I'm going to be VERY concerned about my engine.

I can only agree on that.

The only time my turbo is at or less than 200F (which is about the maximum for the water temperature) is when the engine has been idling or I'm using engine braking down hill. Normal running and it's at a minimum of 600F.

Is that EGT or do you refer to the temp of the turbo body?

 

[Tapage]

Thought AA thinks in the HZ cooling system that aren't designet to manage other heat element as a turbo .. anycase not a big deal.

My personal " feeling " it's the turbo need to be a certain temp to operate well .. maybe due a metal tolerances ..

 

[Dougal]

As far as I've seen it at a friends HDJ80 with FT engine that turbo obviously is watercooled. And the manual as well as the parts list show waterlines for the turbos.

Having a phone call with AAI the day before yesterday inquiring about parts, they stressed to NOT connect the watercirculation. They said the cooling system of the engine would heat up the turbo !
I have no knowledge of the heat strain in a turbohousing, but my guess is that the turbo at the end will run cooler with waterlines connected to the cooling system of the engine.
According the factory install the turbo is fed from the lower radiator hose (connection on the thermostat housing) being the 'coldest' part in the system.
My feeling (and it's just a feeling) is that under slow-moving conditions (climbing steep hills, sanddunes in the desert) and high ambient temps the turbo will operate at lower temps compared to no cooling circuit connected.

So there you go again.....AAI in my eyes is very experienced in adding aftermarket turbo's and I assume their advise is based on years of experience and knowledge. But what about the Toyo engineers do they install unnecessary parts on their engines ?

The water jacket slightly cools the turbine side and can slightly heat the compressor side. Neither are good things.

Your turbine should run as hot as possible for the best efficiency, maybe you've noticed the "turbo beanies" that some people are now running to keep the turbine housing hot.
Your compressor should run as cold as possible for the best efficiency.

As for the toyota engineers putting in un-necessary parts. They'd field a lot more questions if they installed the turbo with open ports and nothing hooked up.
The variable vane turbos on the new toyota diesels do not have water cooling. These are turbos that are specifically designed for diesels and don't cross-over into petrol applications.

 

[cruiser_guy]

I can only agree on that.

Is that EGT or do you refer to the temp of the turbo body?

When I speak of turbo temps it is always EGT's.

The water jacket slightly cools the turbine side and can slightly heat the compressor side. Neither are good things.

As for the toyota engineers putting in un-necessary parts. They'd field a lot more questions if they installed the turbo with open ports and nothing hooked up.

I agree on the temperature desires of the turbo and compressor but sometimes efficiency needs to sacrifice a little for longevity.

As for the ports with nothing connected, the CT26 that's going into the FJ45LV has ports that have been blanked off from the factory on both the Supra and the MR2. Toyota had the option of the water or oil feed (can't remember which) from either side and blanked off the unused side.

 

[Dougal]

I agree on the temperature desires of the turbo and compressor but sometimes efficiency needs to sacrifice a little for longevity.

In many cases yes that's very true (your turbo is really efficient when your EGT's hit 900C).
But a water cooled turbo won't last any longer than one without a water jacket on a diesel.
The big killers of turbos are oil (quality and quantity), debris in the intake air, EGT's out of control and overspeed. None of which are affected by the water jacket. The water jackets only purpose is hot shutdown protection and if you're continually doing hot shutdowns it's not just your turbo that's going to complain.

 

[Ron R]

Still busy gathering parts
So too much time to think about the install.

Talking about watercooling many say it's not necessary or even bad to have it. I agree on Dougals remark about temps. The bigger the temp difference between turbo in and turbo out the more you gain.
But keeping the compressed air as cold as possible (intercooler) is an advantage as well. But I don't want to use an intercooler.
And would the water jacket not act as a shield against the turbo temps towards the compressor part?
The water would keep the area more or less at a temp not higher than cooling water temp which is coming directly from the 'cold' side of the radiator in my setup.

 

[crushers]

it will not keep it as cold as the cooling temp but it might keep the temps down.
want to have fun? once it is installed fire it up and remove the inlet coolant line and see the pressure the coolant is flowing at... (or not flowing at would be a better term)

 

[Dougal]

Still busy gathering parts
So too much time to think about the install.

Talking about watercooling many say it's not necessary or even bad to have it. I agree on Dougals remark about temps. The bigger the temp difference between turbo in and turbo out the more you gain.
But keeping the compressed air as cold as possible (intercooler) is an advantage as well. But I don't want to use an intercooler.
And would the water jacket not act as a shield against the turbo temps towards the compressor part?
The water would keep the area more or less at a temp not higher than cooling water temp which is coming directly from the 'cold' side of the radiator in my setup.

It won't make any difference to your turbo compressor outlet temps.
There's not enough surface area to get any meaningful heat transfer, if there was it would heat the air coming into your turbo compressor, then the turbo would heat the air more as it compresses.

If you need an intercooler, then it's best to get an intercooler. But they aren't strictly necessary until you're over 15psi boost anyway.

 

[Ron R]

want to have fun? once it is installed fire it up and remove the inlet coolant line and see the pressure the coolant is flowing at... (or not flowing at would be a better term)

Have been asking this myself as well. The 'pick-up point' will be just in front of the thermostat. My guess is that there will be pressure from the waterpump here because Toyota uses this point as well. Have never tried to take of the hose thou.
The flow rate through the housing will not be that impressive anyway if you look at the diameter of the piping.

It won't make any difference to your turbo compressor outlet temps.

Don't know or we are talking about the same...
What I tried to express was that the hotter the exhaust gasses enter and the cooler they leave the turbine the more you get out of the gasses in terms of energy. Therefore the flow down of the turbinewheel should be as unristricted as possible.
In this process the temp drop should not be due to cooling effects from the coolingsystem, or at last be minimized as much as possible.

There's not enough surface area to get any meaningful heat transfer, if there was it would heat the air coming into your turbo compressor, then the turbo would heat the air more as it compresses.

If you need an intercooler, then it's best to get an intercooler. But they aren't strictly necessary until you're over 15psi boost anyway.

Yes, agreed, the contact area is not that big and the heat generated by the compression effects will be much more than the transferred heat by the housing. But the waterchannels being present allready, why not use them? Work involved is minimal.

I won't be running over 12 PSI and therefore I was not going to use an intercooler anyway. Firstly I'm not aiming at many horses more and secondly I want to avoid the hassle of installing a cooler.

 

[Dougal]

Don't know or we are talking about the same...
What I tried to express was that the hotter the exhaust gasses enter and the cooler they leave the turbine the more you get out of the gasses in terms of energy. Therefore the flow down of the turbinewheel should be as unristricted as possible.
In this process the temp drop should not be due to cooling effects from the coolingsystem, or at last be minimized as much as possible.

Yes we're in agreement there.

But the waterchannels being present allready, why not use them? Work involved is minimal.

There is potential harm from hooking them up wrong and none from leaving them unattached.
If hooked up wrong it can vapour lock, so it situations of hot shutdownt then restart you're blowing cold water into a housing that's above boiling. The thermal shock can crack the housing.

So if you hook them up, make sure it can thermosiphon with the engine off and not vapour lock.

 

[Ron R]

Yes we're in agreement there.



There is potential harm from hooking them up wrong and none from leaving them unattached.
If hooked up wrong it can vapour lock, so it situations of hot shutdownt then restart you're blowing cold water into a housing that's above boiling. The thermal shock can crack the housing.

So if you hook them up, make sure it can thermosiphon with the engine off and not vapour lock.

*If* I hook them up. Thanks for this info.
If so, I intented to use the original piping. This feeds and drains from below. But there is a blank plate on top of the casing I can use as well to create an exit. Connecting that to the downstream tube from the cabin heater could take care of getting rid of airbubbles because that tube is located higher up than the turbohousing.

 

[UnderPSI]

turbo has no idea what engine they're on, just volume of air going thru it. Water cooling is usually used in front wheel drive cars were the turbo sits behind the engine next to the firewall. Coolant doesn''t vapor lock, there is hardly a chance of the CHRA to retain air.

what model turbo is it? there is no turbine map for that turbine housing on a T25.

 

[Dougal]

turbo has no idea what engine they're on, just volume of air going thru it. Water cooling is usually used in front wheel drive cars were the turbo sits behind the engine next to the firewall. Coolant doesn''t vapor lock, there is hardly a chance of the CHRA to retain air.

what model turbo is it? there is no turbine map for that turbine housing on a T25.

It's not air that vapour locks a turbo housing, it's water vapour (AKA steam).
If your water can't thermosiphon through the housing then the small amount of water in the jacket boils to steam. If the engine is restarted the comparatively cooler water in the pipes rushes in and that's where the thermal shock occurs.

It's not guaranteed to happen, but it can if the conditions are right.

Correct there are no turbine maps for the T25's, only a few compressor maps. Garrett only started making turbine maps available in the last few years, the T series were replaced with the GT series before then.

 

[UnderPSI]

I have never seen a cracked water cooled housing. Turbine maps are avaliable for the 25's, just not that size A/R.

 

[Dougal]

I have never seen a cracked water cooled housing. Turbine maps are avaliable for the 25's, just not that size A/R.

Got a link for the turbine maps?

 

[UnderPSI]

The GT maps is what I use, they're not the same, but damn close.

 

[Dougal]

The GT maps is what I use, they're not the same, but damn close.

They're a completely different wheel. Sure you could use them to get a basic idea, but there's no way it'll be "close".

 

[UnderPSI]

The turbine wheel is close.

 

[Dougal]

The turbine wheel is close.

It might be close in external measurements. But flow modelling has come a long way in the last 20 years. I highly doubt a T25 turbine designed in the late 80's has comparable flow or efficiency to a GT turbine wheel designed recently.

Hey, landcruisers haven't changed much in the last 17 years, the 200 and 80 share the same wheelbase right.