Alloy Radiators

[highflyer]

I have a 3 inch copper rad fitted on my car and would like to replace it with an alloy one, but have been told that the alloy one has to be 2 inches and this will perform better because it is thiner and the air will pass through quicker thus keeping the water cooler but which way have you guys gone with the alloy ones please.
The car will be running 600 bhp max thanks.

[V8Dom]

Russ

ive have 5 row rad on mine, which is an upgrade of the factory 4 row....

ive not heard 2 inch rad is better than 3 before ... the more water you can get in a rad and the more air arround it the better...

try radtec, they are in cannock and have a chat with them...great guys and very helpfull..

Radtec Racing Radiators Ltd,
Hawks Green Lane,
Cannock,
Staffordshire,
WS11 7LH

Dom

[Steve_D]

If you get someone to make you one don't forget the rad is already about as high as it can come (mine actually rubs on the underside of the clip) so any increase in thickness will need to be lost by either moving the mounts down or changing the angle.

Steve

[ezakimak]

What do the F1 boys do I can’t remember.

They either make the radiator bigger so that it holds more water and the air passes through really quickly so that it is not producing drag
Or
The make the radiator really small, with dense or closely spaced fins so that the air has to pass through it really slowly and having more time to absorb the heat. They then make the aperture in the body work smaller so that it doesn’t produce as much drag on the car.

Just can’t remember which one it is?

[GTR-TT]

Bigger area alows thinner core. Since the air warms up during its way thru the radiator it's most effective in the first layer and then it gradually gets less effective during it's way thru the rad.

If you can't have a big area, like in the Ultima, you have to make it thicker. Taking away on thickness to have it more effective is just a bad sales pitch to sell a lesser product. Aluminium is't a very good material for rads at all. It's light but not as effective as a more conductive core.

I would suggest that you find that weight saving on the other end of the car instead...

[738 driver]

Alloy rads can be made to work but real effective ones, for a confined installation are hard to find and usually very expensive.

20 years ago I saw tightly spaced, aerofoil shaped cooler pipes used in an alloy rad, for a high speed application. The basic 'venturi principle' being employed in its design. This was further developed with stator type vanes, automatically adjustable relative to the machines airflow/ride angle.
The rads worked very well, unfortunately their designer/builder is long retired.

[ezakimak]

the ability of the rad to pass air through it will have a corresponding effect, however small, on the amount of front down force. I have a friend who works of one of the race teams in the V8 supercar series in Australia (V8 powered sedans). He said that in order to get front down force they try and bank as much air up on the front splitter azs they can.

obviously a rad that allows air to flow through it easily is going to allow more air through and less front down force. either type AL or CU material could be used its how its used that maters in this case.

[GTWayne]

^^^Fair point but remember that the orientation of the rad is not upright as in a sedan and splitters are not standard on these cars anyhow so the above point is not really relevant here.
To answer your question Russ, I have a slim Pace ali radiator and it works fine with my meagre 650 bhp. Don't forget that the fitment of a slightly narrower core rads means there is a little more room for uprated fans and as the car will only ever experience very hot running whilst below 30 mph (unless you have a problem of extreme proportions), this may well be advantageous
I have 11" fans as opposed to 10's and have also used the extra available depth option made available by the slimmer rad for a more powerful motor. The combo performs faultlessly.

[andygtt]

highflyer said:

I have a 3 inch copper rad fitted on my car and would like to replace it with an alloy one, but have been told that the alloy one has to be 2 inches and this will perform better because it is thiner and the air will pass through quicker thus keeping the water cooler but which way have you guys gone with the alloy ones please.
The car will be running 600 bhp max thanks.

this is only correct when the car is moving.... but in my experience my canam only ever got close to overheating when sitting in trafic on hot days, a thiner alloy rad is going to be much less efficient than your existing one in these circumstances and would definatelly overheat IMO... but you could slap some huge fans on there to get the air flowing... sounds like this is what Wayne has done.

[ricola]

It isn't so clear cut.
Copper is a better conductor than ally, but then the copper rads are brazed/soldered together and those joints have worse conductivity to the fins than an ally rad. Personally I'd go with an ally one as they don't corrode so quickly and are lighter..

[highflyer]

Bloody Hell, now I am really confused, the ally rad I am having made is actually just under 3" and I think a 4 core industrial ? sod it will contact Radtech now and see what they come up with. Thanks Guys.

[GTRCLIVE]

Pace recomended there 65mm 2 core ally rad for an Ultima, and its under half the wieght of the normal copper/tin 5 core. The GTW has an elecrtic water pump so is not realy a great comparison, but that said is was keeping a 7.2L old school SBC cool....

I will be ordering my Rad's from Pace but they are quite a bit bigger.

[andygtt]

Nothing wrong with alloy rads... mine are 2 core but I have 2 of them to cool my V12.