Turbo Water Plumbing

[sicrb25]

Hey Guys,

Just installed a new inlet plenum and im looking for another place to plumb the turbo water return (stock turbo RB25DET).

Is it alright to put it here??

[sicrb25]

Noone?

[sicrb25]

Come on someone must know

[discopotato03]

Hi , I'm not quite sure which part your trying to plumb but assume you must mean the top hose that went via the steel line around the back of the head ? Surely there must be some provision on the inlet manifolds plumbing for this return if its designed for an RB25DET ?

Anyhow if not , the idea is to not make the turbo a high spot in its water cooling plumbing , if you do the steam bubbles displace coolant (steam is less dense and lighter than water and it forms a gas trap) so it gets no cooling after hot shut down - bad . You MUST have cooler water rising from below the turbo and the post turbo water rising to a high point in the cooling system otherwise the bubbles can't escape and the turbos coolant system can't thermosyphon when the water pump stops .

Also if you try to get water from the wrong side of the engines thermostat (radiator side) the water pump WILL draw water backwards through the turbo's coolant line because you've effectively added a bypass for the thermostat and so the engine takes longer to warm up from cold . You need to have the water supply and return to the engines coolant from the block and generally the head - but not on the radiators side of the thermostat - not a problem for an RB as the thermostat is on the bottom hose .

I think the simplest thing to do is to tap into the water return manifold on the lower side of your new inlet manifold and place the return there . Basically recreating what Nissan did .

Cheers A .

[sicrb25]

Okay so from what your saying plumbing it there is a no no, i dont really feel like pulling the whole thing apart again to tap into the water line.

Only other place i can think of is here?

[discopotato03]

Its still lower than I'd like it to be . There's no reason you can't go round the front like an RB26 does except there wont be the barbed fitting like they have to connect it to . The inlet manifold really is the best place to do it .

Cheers .

[Craved]

the first pic is the water feed up to the systems bleed valve and throttle connector and if im not mistaken also feeds the water inlet to the std feed line for the turbo via the inlet manifold.

perhaps making a custom hard pipe that sits above the inlet runners that is fed from that first pics water feed, then connects back to the std water lines behind the head.