Matty ,i just spent an hour on a post for you but lost it when i tried to submit it!!!!!!!
Just a few things this time!!
TUBE THICKNESS:
Its the width of the tube thats important, the wider the tube the more tube to fin contact and thats where th heat tansfer starts taking place.
With a copper/brass core the tubes have to be kept to about 10mm wide because of their strength. alluminium tubes can be made 30mm thick if they have a support in the centre of the tube( Like a gen3 comm core) .
To get this tube/fin contact area in a copper brass core you would have to go to a three row 50mm thick core!!
FRONTAL AREA: The bigger the better with this one(hight by width). if ducting to a radiator, the opening of the ducting can be down to 25% of the size of the core frontal area without loosing efficiency!! This also slows the air before the core causing pressure to build.
CORE THICKNESS: If there is insuficient space for a large radiator a thicker one will have to be used. But realise that a core twice as thick is not twice as efficient because the cooling air has already started heating up half way through the core.
FIN COUNT AND CORE THICKNESS: Fin count is usually measured in fins per inch and this tells us how tightly the fins are stacked together. modern road cars with thin cores have a high fin count to help with efficiency at road speeds.
On race cars it is usual to have a lower fin count and a thicker core. the lower fin count helps air pass throgh the core. if the fin count is too high the air will do its best to go around the core!!
It is also very important to seal the edges of the radiator to the radiator support panel/ducting and block any unessesary holes in the radiator suport panel. This increases the pressure diferential from the front and the back of the radiator assisting flow through the core..
DOUBLE PASS: Converting a radiator to a
double pass unit efectively halves the number of tubes but doubles their length, and another bonus is the water is mixed before the second pass. This modification is worth a 25% increase in efficiency.
Ive done this mod to a couple of race cars enableing us to use smaller and lighter units.
Hope this helps, Simon.