Relocating a radiator pros & cons ..

[oldcorollas]

Thanks again guys, i have thought already if i leave the radiator in its place of fitting a thinner radiator as the fans are mounted out front & they are trying to blow air through the condensor & then the big radiator too & i have checked already & i felt that there doesnt seem to be a lot of air exiting the back of the radiator the way it is now with the fans running & if i fit an additional small radiator in the back that will help too, the thing is i'm a bit of a tight ass & the current big radiator is in good nick & i didnt really want to throw out the core & start again, hence fitting it up the back, but its something i will need to weigh up, i even thought of putting the condensor out back but that will definately add up with the plumbing & recharging the system etc ..

As far as lifting the back of the bonnet i think i have heard guys say that around the bottom of the windscreen area is a high pressurre area ?? not 100 % sure i have the facts right there though ..

lifting back of bonnet is fine at low speeds and in traffic.

you have fans blowing through radiator? or through AC core than radiator? is it all sealed up so no blown air can escape?

is there any chance you can put a shrouded fan on the back to pull air through?

a slimline fan with a full shroud, and no air leaks in between fan and radiator, will be a heck of a lot more efficient than a blow through setup.
push vs pull, read a few things saying pull is up to 15% more efficient. pull with shroud will be bestest
you can also offset the fan so it clears motor, as long as there is enough depth (1"?) for shroud to pull air from radiator (can do calcs for shroud spacing from fan cfm)

pics of current setup showing how fans interact with cores, and if there is any sealing/shrouding?

[oldcorollas]

fwiw, Caldina and GT4(?) bonnet scoops have 2 parts.. 1 to direct air to the interwarmer at speed, and a seperate duct to allow engine bay air to escape while stopped

[crownv8]

The problem with the conversion he has done is that there is just no room for anything behind the radiator. There is barely enough room to run a hose between the engine and the radiator. The only way to do it is to move the radiator forward and use the thinnest one possible and he might gain enough room to fit a very thin electric fan. Plus he has the air cond still there which only compounds the issue.

There is no quick fix for his problem. A lot of engine swaps into hilux end up with cooling issues.

[oldcorollas]

fair enough.

here's what i had to do on rolla.
top of rad is moved forward about 50-60mm, bottom is moved forward about 150mm. filler neck is offset backwards.
fan is offset to side to clear waer pump pulley
with a bit more offset to the fan, the shroud could be deeper (but fan is tight against battery where it is, and has ~10-15mm clearance to pulley))
http://i301.photobucket.com/albums/n.../e-bay-top.jpg

yup, thinner rad with better fan and shroud setup will be better cooling.
if pulling air through ALL of radiator, because of shroud, cooling will be better, even with aircon there.
fan on front of the aircon core only will help (ducted to go 100% through air con core)

[TERRA Operative]

Lifting the back of the bonnet can help plus the gaps down the side of the bonnet are increased when you raise the rear allowing air to escape. Yeah there is a high pressure area at the bottom of the windscreen but is it greater than the high pressure at the front of the car???? Correctly positioned bonnet vents will obviously be better but its a lot cheaper to buy four longer bolts and some square tube for packing and drive it to see what difference there is.

The flow will be greatly reduced above 40kph, to the point that very little air will be flowing through the radiator.

How do I know? I've done my own testing and found under bonnet temperatures skyrocketed when the rear of the bonnet was raised. It's great for 4WD rock crawling, terrible for anything else.

[oldcorollas]

true, and is only good for heatsoak, not for flow through radiator.

hmm, there is very little space.. is pretty tight in there
(infotechplus) http://i148.photobucket.com/albums/s...us/bigwad2.jpg
(madmont) http://i183.photobucket.com/albums/x...1/hilux1jz.jpg
(2JZhilux) http://i23.tinypic.com/m99001.jpg

would still be looking to try and get rad forward.. must be some area down the bottom you can get back?


as for original question, it depends on the height the rear radiator is..
the pump sucks from the radiator, and pushes through the motor..
if the secodn rad is at similar height to the outlet from engine, then not much extra pressure is required.
if it is lower, then will be better.. higher will be harder for pump to push, but maybe nto that much.
this is assuming you can the front and rear radiator in series, or just have 1 rad at rear.

plumbing to heater core may not help so much, since the volume of water is low through the small pipes.


other option is to run elec water pump, and second rad in parallel.. ie need some T-junctions.
then flow through secodn rad is only dependent on the elec pumps flow.

rear rad will need fan and lots of it + good shrouding. can7t imagine you will redirect any air of worth from vehicle speed..

[2jzhilux]

Thinking of doing exactly the same thing with mine with the radiator under the back where the spare tyre used to go, will let you know how it goes.
Have you thought about a w2a intercooler?

[lexsmaz]

As has been said i dont like the blow through fan set up either, but there is really no room at all for a rear mounted fan, the water pump snout is about roughly 25mm from the radiator core ..

The thermo's are snug up against the condensor & there is an air gap which you need between the condensor & radiator & it is also sealed off on the sides from letting air escape & i dont want to get rid of the A/C as its a good thing, so really moving the radiator to the back is probably the easiest ? thing to do so long as the pump & air flow to the radiator is good enough & from the feedback it sounds like the pump should hopefully be able to cope, so its just fingers crossed the air flow will be sufficient as it will be sitting up higher than the bottom of the cabin, but with fans & some air ducting i feel it should be ok, time will tell ...

2jzhilux, the intercooler is not a huge one & i think really the condensor & radiator & fan combo lack of room etc is the big issue, when were you thinking of doing your rad move, i'm in no real hurry so would be keen to hear how your's goes .. I was looking at fitting mine just a bit behind the cab, so the flow issue is less of a worry than yours if you are going down the back ..

[oldcorollas]

if all else fails.. water spray onto radiator or aircon cooler, to be used with fan when in traffic?

[lexsmaz]

Thanks again for the input guys & oldcorollas thanks for the pic's my setup is quite similar in frontal room to infotechplus that you put up & due to the condensor & front mount fans i cant move anything more forward, water spray could certainly work, just a bit messy maybe ? ..

[crownv8]

fair enough.

here's what i had to do on rolla.
top of rad is moved forward about 50-60mm, bottom is moved forward about 150mm. filler neck is offset backwards.
fan is offset to side to clear waer pump pulley
with a bit more offset to the fan, the shroud could be deeper (but fan is tight against battery where it is, and has ~10-15mm clearance to pulley))
http://i301.photobucket.com/albums/n.../e-bay-top.jpg

yup, thinner rad with better fan and shroud setup will be better cooling.
if pulling air through ALL of radiator, because of shroud, cooling will be better, even with aircon there.
fan on front of the aircon core only will help (ducted to go 100% through air con core)

That is the sort of work that is usually needed for an inline six in the hilux engine bay.

[jabbatron]

..........

[Hatta1978]

Hi,
Hey lexsmaz, I've seen JZ engines having hydraulic cooling fan, is that the one your using? It's quite thin and uses the power steering pump for hydraulics. Not sure if they sell for conversions, but maybe it's available at you wrecker/ chopshop?
Regards.