Rear mounted water "helper" radiator - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

grumpysnapper · 01-14-2022, 08:01 AM

Belts and braces...
Basically, I never want to worry about cooling ever again...no matter what the situation, so I'm adding a small "helper" water radiator inside the rear bumper (in addition to a second oil cooler up front).
Its 280x189x37mm (21 Row) Plate and Fin with a 9" Spal puller fan.
An electric booster pump will feed it (which can run up to 27 litres per min), with both fan and pump triggered whenever the front radiator fans activate.
There is a heap of vacant space in the rear bumper shell, and with the reversing light unit removed, quite a decent sized vent directly into what I would assume is a low pressure zone. (A serious amount of flow exits when the fan is active)
I see it mainly as a helper with cooling down straight after a hard run.
The radiator is mounted and the pump is in place and the electrics are live, so now I'm in the process of running (5/8) hose from front to rear..and back.
There will be wire mesh protecting both sides, and even though it looks vulnerable to rocks etc from under the car, it is surprisingly well protected...sitting up fairly high, and with a large muffler in front (which I am going to wrap to all but stop any radiant heat).
I'm going to be fascinated to see if it works and how it goes (fingers crossed!).

Ashikabi · 01-14-2022, 08:04 AM

Where are you pulling oil from?

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grumpysnapper · 01-14-2022, 08:08 AM

Quote:

Originally Posted by Ashikabi

Where are you pulling oil from?

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Coolant

Ashikabi · 01-14-2022, 08:11 AM

Quote:

Originally Posted by grumpysnapper

Coolant

Oh I saw you say oil cooler and assumed this was that. But I remember you from your other thread now. Why not just get a bigger radiator? That would offer much more cooling than this thing. Not that this won't work, cuz it will. I just don't believe it will work as well

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grumpysnapper · 01-14-2022, 08:20 AM

Quote:

Originally Posted by Ashikabi

Oh I saw you say oil cooler and assumed this was that. But I remember you from your other thread now. Why not just get a bigger radiator? That would offer much more cooling than this thing. Not that this won't work, cuz it will. I just don't believe it will work as well

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Yeah, already have a bigger and more efficient front (PWR) radiator, and I quite like the idea of taking any heat I can away from the engine bay area.

soundman98 · 01-14-2022, 08:58 PM

could also consider running an aluminum hard line for most of the length underneath the body. it's not going to add much cooling, but would add more cooling than a rubber line in the same scenario...

norcalpb · 01-16-2022, 03:27 PM

I dig it, also reminds me of the diff cooler openings on the cup cars.

churchx · 01-16-2022, 05:33 PM

Hmm .. how rad is protected from rocks flying in air intake path and puncturing it? how it's protected from dust or dirt getting by in air intake path and clodging rad up (probably even more of issue with rad fan sucking extra of that when it's operating)?

grumpysnapper · 01-17-2022, 08:20 AM

Quote:

Originally Posted by churchx

Hmm .. how rad is protected from rocks flying in air intake path and puncturing it? how it's protected from dust or dirt getting by in air intake path and clodging rad up (probably even more of issue with rad fan sucking extra of that when it's operating)?

I dont think it will be too much of a worry, it sits up quite high, and is shielded by the muffler.
I'm also going to put some wire mesh in front of it, to make sure.

grumpysnapper · 01-17-2022, 08:35 AM

Passed its first proof of concept test, with flying colours.
No leaks, electrics working properly and the pump is very effective.
Lots of heat!
The 9" fan overlaps the edge of the radiator so there are some heavy plastic shrouds top and bottom to stop the fan drawing air from around the edges.

blsfrs · 01-17-2022, 04:04 PM

Do you run a rear diffuser?

NoHaveMSG · 01-17-2022, 07:22 PM

lol that reverse light is awesome.

Have you ducted your radiator? The front one I mean.

Turdinator · 01-17-2022, 07:28 PM

Where in the cooling circuit are you pulling from and returning to?

86TOYO2k17 · 01-18-2022, 01:06 AM

This is pretty sweet setup.

You could also replace sections of the lines to/from the rear rad with something like this
CK100-8 Single 16 Inch Pass Heat Sink Super Flow Fluid Cooler.

Also if you don’t have already a radiator mister helps a lot. A lot of rally guys use this.

01-14-2022, 08:01 AM	#1
grumpysnapper Senior Member Join Date: Jan 2020 Drives: BRZ Location: Brisbane, Australia Posts: 294 Thanks: 250 Thanked 473 Times in 173 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	Rear mounted water "helper" radiator Belts and braces... Basically, I never want to worry about cooling ever again...no matter what the situation, so I'm adding a small "helper" water radiator inside the rear bumper (in addition to a second oil cooler up front). Its 280x189x37mm (21 Row) Plate and Fin with a 9" Spal puller fan. An electric booster pump will feed it (which can run up to 27 litres per min), with both fan and pump triggered whenever the front radiator fans activate. There is a heap of vacant space in the rear bumper shell, and with the reversing light unit removed, quite a decent sized vent directly into what I would assume is a low pressure zone. (A serious amount of flow exits when the fan is active) I see it mainly as a helper with cooling down straight after a hard run. The radiator is mounted and the pump is in place and the electrics are live, so now I'm in the process of running (5/8) hose from front to rear..and back. There will be wire mesh protecting both sides, and even though it looks vulnerable to rocks etc from under the car, it is surprisingly well protected...sitting up fairly high, and with a large muffler in front (which I am going to wrap to all but stop any radiant heat). I'm going to be fascinated to see if it works and how it goes (fingers crossed!). Attached Images Last edited by grumpysnapper; 01-14-2022 at 08:27 AM.

01-14-2022, 08:58 PM	#6
soundman98 idealized boredom Join Date: Sep 2013 Drives: '14 Ranger, '18 Tacoma 4Dr LB Location: chicago-ish Posts: 8,969 Thanks: 26,728 Thanked 10,614 Times in 5,323 Posts Mentioned: 84 Post(s) Tagged: 0 Thread(s)	could also consider running an aluminum hard line for most of the length underneath the body. it's not going to add much cooling, but would add more cooling than a rubber line in the same scenario... __________________ "The time you enjoy wasting is not wasted time"

01-17-2022, 08:35 AM	#10
grumpysnapper Senior Member Join Date: Jan 2020 Drives: BRZ Location: Brisbane, Australia Posts: 294 Thanks: 250 Thanked 473 Times in 173 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	Passed its first proof of concept test, with flying colours. No leaks, electrics working properly and the pump is very effective. Lots of heat! The 9" fan overlaps the edge of the radiator so there are some heavy plastic shrouds top and bottom to stop the fan drawing air from around the edges. Attached Images

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01-14-2022, 08:04 AM	#2
Ashikabi Senior Member Join Date: Aug 2014 Drives: 2013 FR-S Location: Northwest Iowa Posts: 7,322 Thanks: 454 Thanked 4,513 Times in 2,931 Posts Mentioned: 59 Post(s) Tagged: 5 Thread(s)	Where are you pulling oil from? Sent from my ONEPLUS A5010 using Tapatalk

01-16-2022, 03:27 PM	#7
norcalpb Senior Member Join Date: Oct 2013 Drives: '13 DGM BRZ Limted Location: SF Bay Area Posts: 1,924 Thanks: 871 Thanked 633 Times in 446 Posts Mentioned: 13 Post(s) Tagged: 0 Thread(s)	I dig it, also reminds me of the diff cooler openings on the cup cars.

01-16-2022, 05:33 PM	#8
churchx Senior Member Join Date: Mar 2015 Drives: 2014 GT86 Location: Latvia, Riga Posts: 4,241 Thanks: 666 Thanked 2,010 Times in 1,387 Posts Mentioned: 51 Post(s) Tagged: 1 Thread(s)	Hmm .. how rad is protected from rocks flying in air intake path and puncturing it? how it's protected from dust or dirt getting by in air intake path and clodging rad up (probably even more of issue with rad fan sucking extra of that when it's operating)?

01-17-2022, 04:04 PM	#11
blsfrs Senior Member Join Date: Dec 2018 Drives: 2013 frs base Location: central Virginia Posts: 360 Thanks: 313 Thanked 181 Times in 111 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	Do you run a rear diffuser?

01-18-2022, 01:06 AM	#14
86TOYO2k17 Senior Member Join Date: Jan 2018 Drives: 2017 toyota 86 Location: PNW Posts: 2,102 Thanks: 333 Thanked 1,166 Times in 768 Posts Mentioned: 15 Post(s) Tagged: 0 Thread(s)	This is pretty sweet setup. You could also replace sections of the lines to/from the rear rad with something like this CK100-8 Single 16 Inch Pass Heat Sink Super Flow Fluid Cooler. Also if you don’t have already a radiator mister helps a lot. A lot of rally guys use this.

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