I wouldnt use a car radiator... unless you are using a big *** pump... a good way to compare pumps is by the head/volume ratio. the more parts you plan on putting into your system, the more head you will need. each water block, each section of tubing and radiator that you put in your system will use more of the head. to be safe, i would calculate each section of tubing as length, say you have 1 full meter of hosing all together (say.3 reservior->pump, .1 pump->radiator, .2 radiator->cpu, .1 cpu->gpu, .3 gpu->reservior. each waterblock (cpu and gpu) lets say is .3m head (.6 m togther). (i am not sure exactly how much head each block requires, this is just a guess) the radiator is probably about .5 m so all togther u will need 2.1m of head +20% (saftey factor) means u will need ~2.5m of head.
I would definitely recommend a radiator w/ active convection (fans) on it. a reservior is probably only nessisary if you are using <.5" tubing...but i would still recommend it. if ur system is running on 3/8 or 1/4" tubing, that is not alot of volume of water to hold all the heat, esp if u r doing your gpu!
Another note on reserviors, if you are using antifreeze (aka ethlene glycole mixture) it does not hold as much heat as pure water so you will need more of it to hold the same amount of heat. antifreeze does however release heat in the radiator better... so it kind of evens out....
to know if you have enough cooling capacity (numerically), that is kind of tough to do for the layperson. i spent a few years studying thermodynamics, convection, etc and the best advice i can give you is always multiply what you think you need by a factor of safety!!! convection cooling can be tricky.
remember also that the smaller the OD of the tubing, the more fluid friction there will be, therefore you will need more head to push it up the tube. also, the larger the od, the heavier the load is to pump so you will need more head. if you use antifreeze, it is more viscous than water and will be hard to pump, you will need more head. basiclly, if you want to design a system yourself, you will need a fluid dynamics book... pressure head is a function of wall smoothness, viscosity, OD, and velocity.
p.s. this is all from memory, so dont bash too hard if i forgot something! all that about calculating the head, it was estimates! i did not take fluid properties, velocity, or OD into consideration!
I would definitely recommend a radiator w/ active convection (fans) on it. a reservior is probably only nessisary if you are using <.5" tubing...but i would still recommend it. if ur system is running on 3/8 or 1/4" tubing, that is not alot of volume of water to hold all the heat, esp if u r doing your gpu!
Another note on reserviors, if you are using antifreeze (aka ethlene glycole mixture) it does not hold as much heat as pure water so you will need more of it to hold the same amount of heat. antifreeze does however release heat in the radiator better... so it kind of evens out....
to know if you have enough cooling capacity (numerically), that is kind of tough to do for the layperson. i spent a few years studying thermodynamics, convection, etc and the best advice i can give you is always multiply what you think you need by a factor of safety!!! convection cooling can be tricky.
remember also that the smaller the OD of the tubing, the more fluid friction there will be, therefore you will need more head to push it up the tube. also, the larger the od, the heavier the load is to pump so you will need more head. if you use antifreeze, it is more viscous than water and will be hard to pump, you will need more head. basiclly, if you want to design a system yourself, you will need a fluid dynamics book... pressure head is a function of wall smoothness, viscosity, OD, and velocity.
p.s. this is all from memory, so dont bash too hard if i forgot something! all that about calculating the head, it was estimates! i did not take fluid properties, velocity, or OD into consideration!