Gt3788 guys... a question

[laserjock]

@hesutton @no mufflers @tjsea

What size water lines did you run to your turbo?

Heath I’m pretty sure you tapped your heater hoses. tjsea, I think you pulled your supply from the back of the drivers side head like I did but I don’t remember where you returned it to. no mufflers, I honestly don’t remember where you took your water from.

I’ve spent a lot of time thinking and reading and I’m wondering if my temp issue is a result of overtaxing the water pump. I think I put 5/8 hoses on mine so that may be robbing too much water from the system keeping the turbo nice and cool but making the heads run hotter. I have s feeling the heads are running hot more than the gauge is telling me and it’s not showing up until I downshift to bring the revs up and of course push more water.

I don’t know. Just thinking out loud here. Do any of you guys have water temp issues towing? I’m not interested in solving this the way Heath did (nice solution as it was) but I need to do something. She gets pretty warm going over the mountains with the camper and AC on even though the truck really doesn’t seem to be working that hard.

 

[no mufflers]

i used 5/8'' hose. the way i routed the hoses are from the right head into turbo, out of turbo into heater core, out of core to water pump. it seemed to make the most sense.

i think the warmest it got driving home from VA was maybe 220* but it will stay at 210* for the most part. that was doing 75 mph up the hills and it would drop off in temp fairly quick.

from what i have herd some where is you dont want the water to move to fast because it wont suck up the heat. not sure in your case that the problem is the water flow speed but just throwing that out there.

 

[DrCharles]

from what i have herd some where is you dont want the water to move to fast because it wont suck up the heat. not sure in your case that the problem is the water flow speed but just throwing that out there.

This is pure bull hooey that contradicts every rule of physics! Right up there with "never change ATF, the dirt and crud is the only thing making it work now".

HOWEVER. If the water pump is turning so fast that it cavitates, THEN there will be a problem. Also wastes power to spin the impeller faster than necessary.

 

[79jasper]

This is pure bull hooey that contradicts every rule of physics! Right up there with "never change ATF, the dirt and crud is the only thing making it work now".

HOWEVER. If the water pump is turning so fast that it cavitates, THEN there will be a problem. Also wastes power to spin the impeller faster than necessary.

Right, because you know that as a fact with water cooled turbos?...

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[no mufflers]

This is pure bull hooey that contradicts every rule of physics! Right up there with "never change ATF, the dirt and crud is the only thing making it work now".

HOWEVER. If the water pump is turning so fast that it cavitates, THEN there will be a problem. Also wastes power to spin the impeller faster than necessary.

i mean i have no solid evidence on what i said. i read somewhere that someone ran an engine in a truck with no t-stat and on the freeway it would overheat. a t-stat was put in and the problem went away. the theory was the coolant moved to fast and couldn't cool properly. now i understand this does not apply directly to mikes situation but figured i would share.

if water was slowly flowed through a hot tube wouldn't it absorb the heat better then very quickly just passing through?

 

[laserjock]

Well, it depends on the material and the transport of heat through that material. Aluminum for example is a great conductor of heat which is why it works well for a heat sink. You can cool 1 end and the other end will cool in the hot zone. Stainless is terrible. It takes forever to cool a stainless but once it’s hot because the heat keeps slowly radiating to the surface. Ever get something stainless real warm then cool it with water to touch set it down and a few seconds later pick it up and the surface is hot again? The movement of heat through the medium matters. That all being said, we are talking about all cast iron here (the heat load side anyway). It’s a question of heat in vs heat out. I’m running some water wetter which should help alleviate the surface interaction problems that might be the root of the “flowing too fast” theory (I’ve heard it too). I think it’s one of two things. I think it’s either a water supply problem or a radiator efficiency problem. Water supply could be in two categories. Not enough getting to the radiator or not enough circulating through the engine. I’m not sure where I fall on that yet but tjsea had a great suggestion of bypassing the thermostat with a portion of the water (probably the turbo/heater core/filter circuit). That would conceivably negate water flow to the radiator as a problem. I had considered an orifice in the output of the turbo to push more water through the engine and potentially the oil cooler. Times like this I wish I had an oil temp gauge.

 

[DrCharles]

Right, because you know that as a fact with water cooled turbos?...

Because I have had engineering classes in physics and thermodynamics. Heat transfer in fluids doesn't care if it's water cooling a turbo cartridge or coolant passing through a radiator!

 

[79jasper]

For you other two, here's some real information. Not just blabbing out.
https://www.turbobygarrett.com/turbobygarrett/oil_water_plumbing

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[DrCharles]

That link has plenty of useful information, NONE of which contradicts what I said, or even mentions that myth of "coolant moving too fast". Nor are you apparently able to refute my assertion, so instead you resort to ad hominem attack (aka "blabbing out"). Nice straw man though, 79jasper. Pick up a thermodynamics text sometime.

 

[DrCharles]

Also I bet you didn't read this (which is linked on the Garrett link you provided):

https://www.turbobygarrett.com/turb...iles/Garrett_White_Paper_01_Water_Cooling.pdf

Which does mention that insufficient flow can cause overheating of the bearing. And again says absolutely nothing about that crap about too much flow. Because it's a myth. Which was the issue raised and to which I replied.

I will now leave you to have the last smug retort that isn't based on fact.

 

[hesutton]

Enough with the ******* contest please.

Anyway..........


I also used 5/8 hose. I used a "Y" barbed hose fitting for the inlet and outlet. Both set up in parallel with the heater core hoses. Did not have any temperature (coolant) increase with addition of the GT3788R. May have cooler average temp than before.... as my EGT's are lower with the Moose turbo than with the Banks. That and the Rodney Red radiator have keep the 'ol 6.9 cool under pressure.

Heath

 

[BrianX128]

I have no relevant turbo to be part of this conversation, but if the turbo is heating up the water too much and "heat soaking" the engine when it returns, could you possibly run a longer heater hose to a coolant filter for example and then route it back into the engine?

Reason I mention this, is I'm still amazed how much my oil cools in my truck through external routing. I had originally put my oil temp gauge where the previous owner had it in the pan. I had a leftover gauge and thought it would be neat to see what my oil temp was going through my baldwin bypass filter and was surprised to see 30-40 degree lower temps but figured it was because of the restrictor I put in the bypass so I moved that second gauge when I installed my giant remote mounted main oil filter (one of those ELF-7405 monstrosities), the filter mount I ordered had a 1/8npt port already in it so I moved the second gauge there on the exit side of the filter and even there the temp was 20-30 degrees less just having some time away from the engine and that was full flow.

Maybe by the time the water would cycle through the heater core and get heated in the turbo and then cool down going through some hose and a small coolant filter it would be back to normal enough that it wouldn't "soak" extra heat at lower rpms?

Just a random thought.

 

[Thewespaul]

Mike, maybe put a temp sensor inline after the turbo and see if your heat spike originates there, and then the rest of the coolant starts to spike, bringing up the temp on your gauge threaded into the head or if it’s vice versa.

 

[laserjock]

I doubt it’s heat load from the turbo. Higher egts are actually giving me lower water temps.

[emoji21]

So my choice is currently high egts in overdrive with lower water temps or 4th gear with higher rpm, more boost and lower egts but high water temps. It’s quite the quandary.

 

[79jasper]

That's a odd one for sure. Maybe you do need to spin the water pump faster. Lol
"The effect of the mass flow rate at constant velocity on the convective heat transfer coefficient of an incompressible fluid in a turbulent flow regime is presented with the help of dimensional analysis. The heat transfer coefficient decreases by ˜10% with a threefold increase in the mass flow rate under these conditions, based on the commonly used Dittus-Boelter correlation for estimation of the heat transfer coefficient. On the other hand, an increase in the heat transfer coefficient is observed if the area is maintained constant. Doubling the mass flow rate will result in a 92% increase in the heat transfer coefficient. However, there is a concomitant increase in the pressure drop, proportional to the mass flow rate raised to 0.95. The pressure drop is predicted to decrease for the constant velocity case with an inverse dependence on the mass flow rate. The pressure drop considerations may be critical in certain situations (elevation of boiling point in case of a boiling heat transfer medium), and any benefit derived from the higher heat transfer coefficient may be lost because of the higher pressure drop across the heat exchanger in the constant area case."

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