Rb25 Coolant Flow / Hose / Swirl Pot / Header Tank Setup

[robbo_rb180]

could i get opinions on this setup.

about to do it all in speedflow fittings and just want to make sure its right

another rb in s chasis.

red to highest point on radiator -4 hose

blue to bottom of radiator -6 hose

green to overflow -3 hose

is my hose sizing correct for this application?

the top fitting is going on motor side of the radiator as high as possible on the tank, will this be ok?

[frozenwaffles]

hi everyone. how did this end up? did you end up removing the fitting at the back of the block and also the fitting from the side of the thermostat housing?

I want to remove both but im not sure what size bung to use or welch plug? i measured the rear fitting to be 1" NPT.

The whole from the thermostat housing is 18.45mm wide. what welch plug will fit that and where do i get it from?

[Looney_Head]

hi, sorry to drag up an old thread, has anyone had any issues when blocking off the fitting at the back of the block and blocking off the fitting on the back of the thermostat?

i am building an RB30 and have blocked off:

am i going to have issues with water flow when the thermostat is closed?

[DCIEVE]

I ran a line between the two, just tap the thermostat housing.

[czy18e]

Reviving an old thread as I need to understand how to plumb the hosing for my swirl pot on rb2530det. 

None of the pictures are working thanks to photobucket. 

Can someone please post some fresh pics of their set ups or just a plumbing diagram or photo?

thanks for any help. 

[frozenwaffles]

hi, here is all you need to know...

 

i had a swirl pot on my car... it actually caused more problems than it was worth. on my R33 in my drift car, i have no water hoses coming off the block at all besides the one from the side of the thermostat housing that i have linked to the top outlet of the head near the front of the engine. this is my bleed point. turbo is hooked up as normal.

once i read the service manual on the RB25det thoroughly, i found the biggest mistake everyone makes when filling the coolant system in these engines....

you have to fill it extremely slowly. the specified filling speed is no more than 2L/min. this means you must take 5 min to fill it up! trickle speed....but doing this means there are no airlocks!

[czy18e]

Thanks heaps mate. Could you post a couple pics of your drift car set up?

[frozenwaffles]

hi, i will try and do this on the weekend coming up for you...

[burn4005]

 

On 8/8/2017 at 1:52 PM, frozenwaffles said:

hi, i will try and do this on the weekend coming up for you...

Hi Mate, could you elaborate on the "it actually caused more problems than it was worth" statement in your post above?

 

interested to hear what issues you had

[frozenwaffles]

the main issues i had was that i could never get good flow. i always had trouble bleeding it. it was setup correctly.

in the end i put my normal factory bleed point back in, simplified my cooling system and have never looked back.

i will get some pics up soon. sorry, been busy with work and the hi-tec drift all stars series.

[NEO25T]

On 10/04/2013 at 6:39 PM, Dan_J said:

no the bottom of the header tank is connected to the heater joiner near the block

( might be the one that goes to the thermostat or the one right off the block, need a closer look)

and yes the radiator filler neck nipple is connected to the highest point (below the cap) on the H/tank.

i'm not running any coolant on the top half of the intake manifold so no bleed point

pic below for a rough idea of my set up

 

On 10/04/2013 at 8:24 PM, Risking said:

 

Couple of issues with the setup above.

Bottom of header needs to go to the radiator side of the thermostat housing preferably as low was possible

 

Is someone able to explain the difference between running the bottom of the header as per pic compared to the lower radiator hose

[NEO25T]

On 05/08/2017 at 11:06 AM, frozenwaffles said:

hi, here is all you need to know...

At the jamboree today i was having a stickybeak at some of the engine bays and noticed one setup similar to this one.

It had no radiator filler and the 3 points on manifold ran to near the top of header tank and bottom of header to bottom radiator hose.

The difference was it was like a swirl pot too and mounted in top radiator hose.

I still dont understand these setups properly, mainly the lower hose.

[STATUS]

On 8/30/2017 at 7:03 PM, frozenwaffles said:

the main issues i had was that i could never get good flow. i always had trouble bleeding it. it was setup correctly.

in the end i put my normal factory bleed point back in, simplified my cooling system and have never looked back.

i will get some pics up soon. sorry, been busy with work and the hi-tec drift all stars series.

odd, i always have the opposite experience we can often fix issues by fitting them. All our track customers use them, our nascar engines also have them std.

This car was fitted with one 8odd years back and will do 45min plus track sessions flat out anywhere...

 

[burn4005]

I also use one and it's been great. Mostly masks coolant air leak issues I think as it's a continuous air bleed. When you turn the car off and it cools down it sucks air in through fittings/hose connections and causes the cooling system to work sub optimally. After fitting mine I've had zero engine temp issues when up it for extended periods.

Having it well bled with no leaks would have given same result but this setup gives reliable cooling system performance.

[DiscardTheWeak]

On 2/24/2018 at 6:59 AM, NEO25T said:

 

Is someone able to explain the difference between running the bottom of the header as per pic compared to the lower radiator hose

I too am installing an expansion tank on my RB26 engine, and am interested to the answer to question this member asked as well. What is the difference in plumbing the bottom of the tank to the fitting behind the thermostat and the lower hose/tank of the radiator? Essentially, which side of the thermosat do you plumb to? My thoughts are that if you want flow through the tank at all times you would want to bypass the thermostat and plumb it to the fitting behind the thermostat housing, no? Thanks everyone 

[burn4005]

if you want it to bleed effectively when cold, then yes plumbing in behind thermostat will provide circulation at all times, but once the engine is hot and the thermostat opens, it'll circulate then and that's when you really want your cooling system to be working properly.

where i circled in red is where you'd plumb it instead of lower rad hose:

 

putting it in lower rad hose, it means you have to wait for it to get hot before you can bleed the system after a coolant change, but that's also the case if you're doing it with half a coke bottle jammed in the radiator and its only once in a blue moon, so not a big deal so i put it in the rad hose.

if you wan't to be technical about it, yes ideally it should be plumbed back in behind the thermostat. but the main reason for using a seperator other than as a bleed assistant is to evacuate any vapour/steam from the head or block, which only happens when it's hot.

when i first installed mine with clear hoses nothing much happened until the engine hit 70ish degrees, then a heap of bubbles started coming through to the separator when the thermostat opened.

Edited August 20, 2018 by burn4005

[DiscardTheWeak]

On 8/19/2018 at 8:48 PM, burn4005 said:

if you want it to bleed effectively when cold, then yes plumbing in behind thermostat will provide circulation at all times, but once the engine is hot and the thermostat opens, it'll circulate then and that's when you really want your cooling system to be working properly.

where i circled in red is where you'd plumb it instead of lower rad hose:

 

putting it in lower rad hose, it means you have to wait for it to get hot before you can bleed the system after a coolant change, but that's also the case if you're doing it with half a coke bottle jammed in the radiator and its only once in a blue moon, so not a big deal so i put it in the rad hose.

if you wan't to be technical about it, yes ideally it should be plumbed back in behind the thermostat. but the main reason for using a seperator other than as a bleed assistant is to evacuate any vapour/steam from the head or block, which only happens when it's hot.

when i first installed mine with clear hoses nothing much happened until the engine hit 70ish degrees, then a heap of bubbles started coming through to the separator when the thermostat opened.

Thank you, I think that is the route I will take. I have redone so much under the plenum, including that fitting behind the thermostat, that plumbing it back there will not be any harder than using the lower rad hose. I am using a radium auto expansion tank, which has an integrated swirl section, its the same idea as the Greddy unit, but machined. 

What size hose are you guys using for the bottom of the tank? From what I have seen in pictures , the Greddy swirl unit has a small hose coming from the bottom. 

[BlackBox]

Im also after some advice on my cooling setup,

I am running a plazmaman Intake manifold and throttle body, and also a Haltec IACV so i dont have any coolant lines running to those.
I have the turbo coolant returning to the back of the intake runners (Orange cable tie)
And i was going to cut the nipples of the top of the runners and tap and plug those (Blue/Yellow, Yellow/Yellow)
And also Plug next to the thermostat housing.

Does this sound alright or am i going to have stagnant flow and airpockets in the intake runners?
The other option is for a swirl pot, but in the strive for simplicity and aesthetics i would rather not install one unless needed.

Cheers,

[frozenwaffles]

you cannot get rid of the outlet on top of the runners. this is the primary bleed point of the entire system! you need a bleed screw in your line coming off the system and this should connect to the small pipe that comes out of the side of the thermostat.

the biggest thing most people do not know about filling an RB25 is that it's meant to take 10 min to fill the system. as in you need to make sure the fluid flows in so slowly that it takes 10 minutes. this way there are no chances for the air to 'lock' anywhere and not allow water to fill a certain section.

[BlackBox]

So do i tap a thread in the top of the runners and install bleed screws or maybe a swirl pot is the easier option?