It seems that most of the guys out there are using the radiators from companies that specialize in computer cooling. I bought a heater core from pep boys for $22. I figure most just don't want to modify them. Which are more efficient?
I also noticed that guys on forums are very specific about their suggestions, ie. '76 chevy pickup w/out ac. Is there something special about these heater cores, or do they just meet certain specs? I made sure that it is all copper and is 8"x6"x2". Should I have gone bigger?
Where the heater core is designed to get heat out of the loop it is still fairly restrictive in how much heat it will transmit and how well water flows through it. And they are usually made using brass tubing and fins.
Radiators designed for computers like the ones from Thermochill are designed to perform the best for the amount of space that is available. And the Thermochill ones are made out of high quality copper.
But if you already have a decent radiator core give it a shot. Just remember that you might need a couple decent fans to push air through it.
I have used heatercores in the past and have had great results. To be honest, they are actually quite unrestrictive in my experience. It usually takes almost nothing to even blow air through them.
The main problems most people encounter are these:
Barbs- either they are odd sizes or need to be cut and resoldered/epoxied with the correct ID tubing size...not a big deal, but increases the DIY factor.
Unfinished- they are usually that ugly brass/copper color, spray paint fixes this nicely
Mounting options- they don't have those nice holes for screws for fans and shrouds. You can get creative by using plexiglass and drilling holes for fans and mounts that way. I think they work really well, but their size is often rather oddball compared to 80mm, 92mm, 120mm or even 140mm fans and mounts.
86 Chevette- little bigger than a 1x120mm, but thicker
78 Bonneville- kind of in the neighborhood of 2x120mm
I would say that you might see a little better performance due to increased surface area, but it might be relative to your specific setup and flow. It all depends if the work you are willing to put in is worth the savings and look. Remember, a heater core is cheap to begin with, but you have to pay for additional parts for mounting, barbs, etc. Is it worth the hidden cost by the time its said and done?
You can go with something like this. I have one similar to this mounted as a passive on the side of my case. Just saw off (carefully) the barbs, I think 1/2" tubing fits right over. There are mount holes; just drill and run you some screws through. I have mine offset with 1/4" spacers made from little PVC tubing. Works well.
heater cores are all about the same. only changes are size and angle of inlet outlet pipes... they are mostly made of copper and can handle an impressive rate of flow (almost equal to a garden hose). they also transmit heat like you would not believe ... with some pipes and maybe a lil fish pond motor you could easily put together a water cooled system. without some serious craftsmanship it will however look like you pieced together parts from a fish tank and a car.
the heater core will be more restrictive, but as long as your using a pump with a high head pressure it won't be a problem. Themraltake's radiators are basically heater cores, but usually built with smaller pipes.
In terms of design, a traditional radiator is blocked off at 50% of its overall width. water can flow through half of the core all at once. The heater core is a constant loop and water has to be pushed through the entire thing before it comes out the other side.
If you look at the chart, a 90 degree turn with water is like adding 2.5ft of pipe, the heater core consists of dozens of 180 degree turns. A d5 pump will stop moving water when the pressure gets around 8.0, wich usually won't be a problem.
However, say for example the xspc h20 750 pump stops at 4.5.
The heater core tho has more copper surface contact than a traditional radiator and is usually more efficient.