Rear mount radiator

[tim090]

Im building a 4.5 turbo patrol wana rear mount the radiator. Just have a few questions? I'm using a 19 x 28 inch 3 core radiator with twin 11inch thermos in a shroud to suit. interested in seeing what material and diameter tube people have used to run it back and if you've gone under or through the cab? Also do both feed and return lines need pumps on them? Any info would be good. Cheers

[georgey]

You only need one pump.
Either side will be fine as its pressurising the whole system.
You use exhaust tubing probably 1-2'' in diameter but always use coolant and not water because it will rust.
for the bends get rubber radiator hose.
or you could use rubber the whole way.
It gets hot so run it under the cab out of the way,preferably ontop or even inside your chassis rails.

[DamTriton]

georgey - all wrong.

I would think that 2 x 11" thermos are NOT going to pull enough air. Try 2 x 14" or 16". (Going on Davies Craig for an example a 12" fan pulls 635 cu ft at a pressure of .3" of H2O, a 16" fan does close to 1700 cu ft at the same pressure). I would guess the standard engine driven viscous fan would be about 16" and capable of 2000+ at normal engine speeds. You will need this as you have absolutely no ram air effect in the back.

EWP's are not something you want to fail at full revs in a turboed engine. Be safe and get two, one in each side of the radiator. Once again you will probably NEED the capacity due to the engine configuration you want, at least if one gives way then you have still got some cooling capacity left until you can get out from where you are.

As for coolant tube consider metal as the only option Mandrel bent if possible where needed, but watch out for electrolysis. Avoid rubber except for areas subject to vibrations ie engine-chassis, chassis-radiator. Mount the radiator in rubber mounts to absorb thermal expansion and be sure to earth all metal components (engine, radiator tubes and radiator) to one point on the chassis to reduce electrolysis. Radiator tube inner diameter should ideally be the same as the radiator inlet/outlet to maintain flow rates

[georgey]

i didnt take into the account of engine choice.
ive only done them on smaller engines. 1 was sufficient as the standard pump was still there.

[tim090]

That was the plan to run two pumps one on each side, as for the tubing has anyone used aluminium tube? I know is not the cheapest option but I didn't think it would heat up as much keeping it cooler? Good point about the thermos mite look into what there ratings are, because there won't be much air flow...

[georgey]

id imagine that aluminium would be better but it would be softer and be damaged more easily.
If you could get it up out of the way it would be good

[Tiny]

id imagine that aluminium would be better but it would be softer and be damaged more easily.
If you could get it up out of the way it would be good

more easily damaged than what? and by what? ally is going to be more likely to crack if mounted very rigidly, but with some rubber joints that will be taken care off, any metalic piping is going to better in a heat transfer (added cooling effect) than rubber options and ally is going to be the best in terms of corrosion resistance although some light steel zaust pipe would be cheap as chips and easilly replacable if coorosion set in.

[tim090]

As for it getting damaged, that's why I wanted to see if any ones run the alloy tubing through the cab using rubber bends where needed and wrapping in exhaust wrap or putting a shroud over it?

[Modified Toy]

Why not run a AU Falcon radiator fans are all ready mounted to the radiator with a shroud?

[johnsy86]

just use rubber radiator hoses, just look for ones with the bends u need.

[tim090]

Already have the radiator with a mounting kit and shroud to suit, and the plN wS to run as much of it in tube and only use the bends were needed? Thanks for the input will post pictures soon

[evanstaniland]

I'm afte some help aswell with rear mount radiator setup. I'm planning on keeping the normal engine water pump and putting an electric one on the rear. Which side of the radiator should I be putting the rear water pump? I was lookin at a Davies Craig ewp115 would this be sufficient?

Evan

[DamTriton]

I'm afte some help aswell with rear mount radiator setup. I'm planning on keeping the normal engine water pump and putting an electric one on the rear. Which side of the radiator should I be putting the rear water pump? I was lookin at a Davies Craig ewp115 would this be sufficient?

Evan

What sort of vehicle?
Diesel/petrol?

The length of tube to go from front to back and return is going to affect the maximum rate of flow of coolant. I would be tempted to place the single EWP on the opposite side of the radiator to that of the engine driven pump to increase the pressure difference (= potential coolant flow) across the radiator. I wouldn't be skimping on the size of the pump either as it is not a "conventional" setup with short runs of tubing and a radiator exposed to ram air.

PS update you link to your build up to the new forum pointer as the old "carl.outers" links no longer work.

[evanstaniland]

The engine is a 1uzfe 4l petrol v8.
It's in a cut down bundera

[troopy94]

I'm running a rear mount in my truggy with a commo v6 and am using a davies craig ewp80 aswell as the standard water pump on the motor.It's been working really well now with the electric pump helping when at low crawling speeds the car now actually gets colder at idle instead of heating up due to now having better water circulation. The pump is mounted directly under the bottom outlet on the radiator.

[chimpboy]

Use steel or alloy pipe as much as possible with rubber bends where necessary. Much more durable and better for shedding heat as well. Try and position the radiator so that road speed = airflow through it, even with a little scoop or whatever if necessary.

I would have thought that the engine driven water pump would be enough, I would leave that in and if it turns out that it struggles, add an electric pump inline somewhere. Realistically it's a custom job so you just have to try it and allow for a possible need to upgrade/modify anyway.

The biggest single electric fan you can find is the go, unless your radiator is really rectangular such that two big fans are the go. Two small fans are not as good as one big fan. There is some info in the auto elec section of this site that might help with comparing the CFM ratings of different fans, it is just one brand but it gives you an idea of whether you should go for, say 2x14" fans or 1x16" fan. Forget the two 11" fans. Or at least, if you try them, be prepared to have to replace them with something bigger.

Actually here's an idea that might be worth a go, with the rad size you've specified you could have two 16" fans, one on the front of the rad and one on the back, but positioned so that they only overlap slightly in the centre (when viewed from above). I have never seen this done but I think it would work very well. With 16" fans you can keep getting gruntier and gruntier fans if you need to, there are some really powerful ones although they are very noisy.

In terms of fan control, I would want two-stage control ie half speed and full speed, since a rear-mounted rad is not getting much air flow from your roadspeed.

be sure to earth all metal components (engine, radiator tubes and radiator) to one point on the chassis to reduce electrolysis

I might be under a misconception here... I thought it would be better to leave the dissimilar metals isolated, not earthed. Including any pipes etc... basically anything metal that's in direct contact with the coolant, where possible, would be best electrically isolated. Is that wrong?

[DamTriton]

be sure to earth all metal components (engine, radiator tubes and radiator) to one point on the chassis to reduce electrolysis

I might be under a misconception here... I thought it would be better to leave the dissimilar metals isolated, not earthed. Including any pipes etc... basically anything metal that's in direct contact with the coolant, where possible, would be best electrically isolated. Is that wrong?

Ionised water (rust, etc) is enough to act as an electrolyte and precipitate electrolysis of dissimilar metals. Earthing them all to a single point shorts out any circulating electrical currents. Common procedure in aircraft maintenance for the same reason.

[chimpboy]

Ionised water (rust, etc) is enough to act as an electrolyte and precipitate electrolysis of dissimilar metals. Earthing them all to a single point shorts out any circulating electrical currents. Common procedure in aircraft maintenance for the same reason.

Not arguing (because I think I may have this mixed up in my mind)... why then are radiators carefully isolated rather than being earthed?

[NICK]

The engine is a 1uzfe 4l petrol v8.

I have the same engine. what effects does this style of water pump have on a rear mount radiator set up give the pump is timing belt driven?

NICK

[DamTriton]

Ionised water (rust, etc) is enough to act as an electrolyte and precipitate electrolysis of dissimilar metals. Earthing them all to a single point shorts out any circulating electrical currents. Common procedure in aircraft maintenance for the same reason.

Not arguing (because I think I may have this mixed up in my mind)... why then are radiators carefully isolated rather than being earthed?

They are rubber mounted for mechanical isolation. They don't take too kindly to torsional loads where the core meets the tanks. Even my Kia has an electrical wire from the radiator to the body of the vehicle in an attempt to limit corrosion/electrolysis.

[evanstaniland]

The engine is a 1uzfe 4l petrol v8.

I have the same engine. what effects does this style of water pump have on a rear mount radiator set up give the pump is timing belt driven?

NICK

Got no idea I'm gona put an electric water pump on the bottom outlet on the tray and hope the 2 will keep it cool!

[GQ4.8coilcab]

you can run it through the cab but there was an incident at cliff hanger were a hose come off and the navi suffered 3rd degree burns

[evanstaniland]

you can run it through the cab but there was an incident at cliff hanger were a hose come off and the navi suffered 3rd degree burns

im planning on running mine thru the cab but having a shroud around the pipes!!

Evan

[DamTriton]

you can run it through the cab but there was an incident at cliff hanger were a hose come off and the navi suffered 3rd degree burns

im planning on running mine thru the cab but having a shroud around the pipes!!

Evan

Shroud meets 1000 litres of super heated high pressure steam.........

http://www.youtube.com/watch?v=ekEHfihiNz4" onclick="window.open(this.href);return false;
(IIRC the temp only got to 135 C) 1 litre of water = 100 litres of steam, water at 110 C under pressure will turn completely to steam at normal air pressure. (granted only a small portion of the volume of this example)

It would want to be welded over the floor totally and vented under the vehicle, Ie in the cabin space but physically outside the vehicle.


Safety first....

[stuee]

In regard to fan size, a well fitted shroud is the most important aspect. The for EL-AU twin thermo's are hard to go past in terms of bang for buck with an excellent shroud design to boot.

If you want to go aftermarket something like this is a good bet:
http://www.spalusa.com/store/main.aspx? ... m=30102052" onclick="window.open(this.href);return false;

Will work far more effectively than 16" fans attached to the face of the radiator with no shrouding.