question about coolant plumbing
 

hey guys, before I make a hole into the upper radiator, I just wanted to double check whether the following would work.

I think the coolant nipple on the driver side of the rear iron is supposed to be output going to the heater core. I don't have heater anymore, so I had capped off. I plan on using this coolant outlet to cool the turbo core and return the coolant to the upper chamber of the radiator.

would this work? thanks!

why don't you use the stock coolant feed/ return nipples that originally fed the twins? its closer to where the turbo will be, and I would think is a more appropriate diameter.

Ideally it would run to a low pressure port on the pump inlet.
This would promote better flow past the hottest part of the cooling system.... the spark plugs.

The downside would be introducing hot water beyond the radiator so some type of small radiator would be required.
Maybe an aluminum trombone like the power steering cooler.

where is the stock return location from the turbo? I can't see it in the diagram..

Top middle labeled "from turbos to wp"

It is on the water pump return (cool side/from radiator) forward of the OMP
Yellow Arrow,
Barry

Attachment 623230

^the yellow arrow above is the return line from the heater, not the turbo.

the return would be the lower of the two hoses in the above pic with the orange sleeving over it.

thanks for the replies. I see it but the reason why I couldn't see it earlier was because of my up pipe going to the single turbo. no way I could run a rubber hose in there.. it'll melt in a few seconds :lol:

Would my diagram work though? My concern is I don't want to shunt too much coolant away from the engine. From the rear housing it's 5/8" which I reduced to AN-6 (3/8") ID hose going to the turbo. From the turbo, I have it dumping directly into the top chamber of the radiator.

Yes that is the heater line.

And yes it lowers the water temp when you turn your heater on in an emergency of overheating.
Unfortunately it works counterproductively to the season... wide open heater flow in winter.
And no flow in summer..... thus the suggestion for a separate cooler
(this is actually a secret cooling trick from a respected race engine builder).
Barry

thanks for the replies. My question was whether I could use the heater outlet from the rear iron to cool down the turbo. I have 2 concerns. #1 is the coolant coming from rear iron going to be too hot to cool turbo effectively? #2 is it going to shunt too much coolant from the exhaust/intake port side?

better yet, is anyone using heater outlet to cool turbo without issues?

If you used the heater inlet hose for the turbo cooling inlet where will the turbo water-out go to?

Normally the turbo sets up a heat siphon when it is shut down (and a slight flow continues).

The worst condition would be capping the heater inlet hose... slowing flow past the spark-plugs.

Mazda wants the inlet/exhaust side of the engine to run hotter but not the spark-plug/combustion side.

Attachment 623200

my turbo-out will go directly into the top chamber of the radiator (welded AN-6 bung) right next to the main hose dumping coolant from the engine into the radiator.

my concern is whether it would heat the coolant too much after having gone through the engine already (mazda seems to inject cold side coolant into the twin turbos) and whether it will circulate fine. I'm thinking the engine may like this setup better because it'll only increase flow through the spark side of the engine while decreasing slow on the exhaust/intake side.

the heat siphon is set up correctly. the low side is the coolant inlet to the turbo and the high side is the coolant outlet.

if your going to weld a bung onto the radiator inlet side for the coolant return, why don't you also weld one onto the outlet side as well for the feed?
with the setup your looking to run you will have long turbo coolant hoses anyway, may we well use coolant that has at least been cooled

if I just welded up a bung before the pump, the coolant would just sit there with no flow.

yea your right, didnt think about that :blush:

thanks barry for the diagram. I just saw it.

it's odd that the stock plumbing dumps hot coolant from turbo right before it goes into the engine to cool the engine! I have it dumping directly into the radiator instead. I'll take some pictures tomorrow.