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Turbo Coolant return - why not to the upper hose to radiator??

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Turbo Coolant return - why not to the upper hose to radiator??

 
Old 12-20-2018, 03:04 PM
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Question Turbo Coolant return - why not to the upper hose to radiator??

Finally putting back together my 94, which (at the last minute) I am now changing over to a bottom mount EFR 6258-G.. which means mixing manifold is in the way. Engine has the Supermiata reroute which I installed when it was the T3 but hasn't been run yet. Now that I am looking the options to solve the mixing manifold issue, I'm scratching my head over something that seems obvious to me but maybe I'm a moron...??

Every reroute sketch I see around here and whenever someone asks where to connect turbo water lines, people say/diagram shows pull 'cold' water from thermo housing/block and dump 'hot' back into mixing manifold right before the water pump.. right?

Why are we dumping hot water there, why not send it into the upper radiator hose to go through the radiator first? Because that location is a PITA to route to and far away? Just seems like we are putting the hottest water directly into the engine instead of running it through the radiator first.

So, am I stupid and looking at this wrong or would that be the be place to connect it to dump the most heat? I ask because it wouldn't take barely any effort to stuff it into a point just before the radiator since I already have the long reroute hose there, but I can't say as I see anyone ever suggest that which makes me question my understanding on this item.
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Old 12-20-2018, 04:09 PM
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because the radiator hose will be under pressure and unlikely to accept your turbo water return. A bit of a vacuum at the mixer..I think .
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Old 12-20-2018, 04:10 PM
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Because during warmup, this would allow coolant to bypass the thermostat.

And no, the pressure at the upper radiator hose is not significantly higher than at the lower or the mixing manifold. The radiator presents hardly any restriction at all as compared to the thermostat.
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Old 12-20-2018, 08:13 PM
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Originally Posted by Joe Perez View Post
Because during warmup, this would allow coolant to bypass the thermostat.
Thanks Joe.. so longer warmup... anyone have an idea what that means in real terms of time? Twice as long, 4 times as long? The -4AN is a 1/4" ID hose.. comparing to the diameter of the thermostat, seems like it wouldn't be some huge time increase, but I could be wrong...

But, using that same argument of 1/4" ID isn't big and therefore doesn't carry a lot of water, I guess you aren't technically putting THAT much heated water directly into the engine, right? -4AN is 1/4" ID which is 0.04908738521 square inches of area, 1.25" ID radiator hose is 1.227184630 square inches, so it's 4% of the capacity (assuming it's just simple math).. seems fairly inconsequential. Guess it just don't matter if that's the case.
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Old 12-20-2018, 08:24 PM
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Originally Posted by Wallyman View Post
Thanks Joe.. so longer warmup... anyone have an idea what that means in real terms of time?
The question which you have asked is one which I interpret as "Ok, so it's clearly a bad idea. But just HOW bad is it?"

While I respect the maths involved, this is a situation in which the known and proven drawbacks outweigh the hypothetical advantages by a large margin, presupposing that this car will be driven on the street.
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Old 12-21-2018, 07:48 AM
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Originally Posted by Joe Perez View Post
The question which you have asked is one which I interpret as "Ok, so it's clearly a bad idea. But just HOW bad is it?"

While I respect the maths involved, this is a situation in which the known and proven drawbacks outweigh the hypothetical advantages by a large margin, presupposing that this car will be driven on the street.
Not really that, it was more "ok, it has a known drawback, but is the potential gains worth the additional PITA of a longer warmup". Yes, 95% street car, so it is a definitive "nope". Never hurts to ask... well, except here, sometimes it REALLY hurts.. but that's ok too. I appreciate you taking the time to answer and not ripping my face off in the process!.

Taking this thread sideways, I'm off to the pick-n-pull yard to try and find one of those steel Kia mixing manifolds that crowder found so I can get that issue resolved. I'm one of those "can weld steel but not aluminum" types, so hopefully I can find one this morning to play with. Curious that the only made from scratch one I have seen around here is the pretty billet piece from Bandit, I would have expected some simple (and cheap) steel flanged creations from this crowd. The EFR arrived last night, so I'm geeked to get moving on this.
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Old 12-21-2018, 08:15 AM
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A little tough to see, but i just drilled an tapped my mix manifold, 1/4 NPT. easy.
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Old 12-21-2018, 08:20 AM
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Old 12-21-2018, 12:33 PM
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Originally Posted by ryansmoneypit View Post
Looks nice! Unfortunately, I'm going bottom mount EFR and pretty sure that won't fit (I'll know when I get the Hellfab mani in February). I did manage to find the Kia steel mixing manifold PN 0K30C15160A off an '03 Rio today (score! $4.85 well spent!) and I'm almost thinking it might work unmodified? (the same one Crowder pointed out) It's tight to the block and drops low... we shall see. I found some -4an weld on male fittings, so I can tack that onto it for the turbo return. If it clears everything as is, then just need a lower hose. If not, I can hack and weld it to whatever shape I need. I also grabbed the heater core return line off the same car, it's long (wraps around the back of the head) and has a secondary nipple on it so maybe I can even incorporate that in modifed trim? I'll post back once I have it mocked up so others can see another low cost option. The part is like $23 new, so it's not a huge investment to go this way if someone wanted to give it a go. Plus steel = easy welding for hacks like me.
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Old 01-09-2019, 12:51 AM
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Default Question about the cooling of the turbo

These are some great pics and great info. Thank you guys for being good enough to show and explain. I have a question about this that goes right in line with the question. I plan on running forged internals and big boost (2854 or 2860) with E-85 on about 11:1 compression, using the 1.6L (lets leave the engine size alone for now and focus on the question, I havenít started the actual build yet so I can still go with a 1.8 if I find one for under $1,800 nearby). The coolant routing and size have me worried I will not be doing enough to properly cool the turbo. 1/4Ē ID seems small, no matter how high the flow rate is. Could I go bigger, or run a secondary cooler before the water goes into the turbo? I also plan on running an oil line cooler after the turbo before it returns to the block (it seems really dumb to throw super hot oil into the bottom end of an engine and demand high performance out of it). Is there any problem in doing any of this? Obviously a large intercooler is going to help out a lot, and I have seen some awesome explanations and pics of heat shields on this forum to help protect the engine and brake lines and stuff from heat. Isnít it just as important to try and keep the entire turbo as cool as possible? If anyone has any tips or suggestions, I would be happy to hear them out. Thank you in advance.
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Old 01-09-2019, 08:02 AM
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Follow the instructions from the turbo manufacturer for proper size lines, oil and coolant. They know what they are doing.

Oil is in the turbo for a second or two, not a big deal. The heat generated in those few seconds is nothing in comparison to the amount of heat being imparted by the engine block.

dont overthink this.
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