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Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Tue Apr 01, 2008 7:30 pm
by mudhunt
Hey ive turboed my gq and i used a subaru rs water air intercooler what has everyone else done? I want to know if it was a good move or if i should put a scoop in and go top mount air air????
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sat Aug 02, 2008 5:04 pm
by doby
Was thinking of puting the same subaru water to air intercooler kit on my GQ. From what I understand the water to air coolers are mutch more effective for off road use than than a front or top mount. this is because you dont get enough air flow through the front / top mount when at low speed, where as the water to air coolers are always working due to the warter constently being pumped through, even when the truck is stationreary. You will get mutch cooler and dencer air with much less pressure drop and turbo lag than a front mount. If going for the top mount air to air it would pay to put a heat sheild under it and a bonnet scoop above. I will be going with a water to air cooler, bit more work to fit than a top / front mount but much for 4x4ing. Hope this helps.
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sat Aug 02, 2008 5:30 pm
by tweake
looking at doing similar, just not to sure if the Subaru IC will flow enough.
anyone know what boost the Subaru originally ran?
mudhunt- what boost are you running and how much drop are you getting across the intercooler ?
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sat Aug 02, 2008 7:33 pm
by gary_in_nz
i would love to do this aswell, i just wanna know where the water side of it gets plumbed up to??
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sun Aug 03, 2008 12:08 pm
by doby
The water to air intercooler uses an electric pump and a small radeator witch can be mounted any where, plenty of room between the a/c radeator and the front grill in a GQ. All this dose is circulate the water through the intercooler to the radeator and back round. They are much easer to instal because you only need to run 2x 1" water hose insted of 3" intercooler tubeing. A small thermo fan mounted on the radeator will help keep inlet temps low at low speed. Every one seems to use electric pumps, is there any reasion you cant use a small belt driven or PTO type pump?
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sun Aug 03, 2008 1:05 pm
by monstr
Hi Mate i assume your talking about the water pump,I used a Subaru one as they are cheap and fairly easy to get hold of ,the one on the truck has done a couple of years now and if it craps out its only a 2 min job to throw my spare on ,never really thought about a belt drive or one of the PTO as this was the easyest option ,Steve
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sun Aug 03, 2008 1:46 pm
by tweake
you could run a mechanical pump but it would be advisable to run a thermostat on it so it doesn't get to cold. electric pumps are just easier as you can setup different control system, ie thermostat so it only runs when motor is warmed up, switchable/variable speed so its not running flat out all the time. in cold weather/at cruise it can probably be turned off completely.
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sun Aug 03, 2008 1:51 pm
by doby
Fear enough. Next question, I have disconected my air con and am useing the pump as an air compresser now. I still havent removed the ac radeator yet, would I be able to convert this into my water radeator for the intercoolre. All you would need to do is plumb it to the intercooler with a pump in the line. Dont know much about ac systems, Would this work?
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sun Aug 03, 2008 3:12 pm
by tweake
provided there is no restriction in the aircon rad then i can't see why not, it should be big enough.
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Sun Aug 03, 2008 3:41 pm
by monstr
Was going to do that myself but ended up useing the Subaru one instead ,we just modified it a bit putting in a filler cap ..Steve
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Mon Aug 04, 2008 2:29 pm
by darinz
There isn't really any need for a mechanical pump as the required flow isn't that high. ie it will be under about 10 litre per min. The Subaru pump is 2 speed and I think the high speed is only about 10l/m. I'm running a pump that is only rated at 7l/m at present (due to the other pump dying and this was all I could get). I will be running one with about 20l/m and the flow required for mine is a lot more than a TD42.
And colder the better as far as the coolant goes. The turbo will be heating the air so you want to cool it as much as possible. I've mounted the radiator on the deck of my truck but it is quite a bit bigger than a subbie one. ie it has twin fans and is out of a 2 litre car.

You can see the top half of the rad above the spare tyre.
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Mon Aug 04, 2008 3:39 pm
by mudhunt
what core did you use darinz? is it custom or barrell etc
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Mon Aug 04, 2008 4:43 pm
by darinz
PWR 6x10 barrell
Re: Intercooler options for a gq (4.2 diesel just been turboed)
Posted: Mon Aug 04, 2008 9:54 pm
by red_dog
this isnt rod fletcher by any chance ? captain qa?