What is the current heater core recommendation?
- Thread starter Cornbread
- Start date
Well, it's getting cold here in the desert and i can confirm that the brass heater core does NOT match the output of the stock plastic/aluminum design... I am getting about 105-115 degrees out of my vents on a cool desert morning... I did notice that they upped the fin density. The whole point of this brass upgrade was to never do this again, and I am contemplating doing it again, lol. I would say that even if the flow isn't 100 percent looped through the tubes, the convection of the water tank should spread some heat to the fins. apparently stock heat should provide about 130-150 degree air, so its substantial. I know the TJ heat is able to make my feet uncomfortable and sting my face with strong heat, this feels comfortable warm, NOT HOT.
Ill live with it, and give them a call... see where it goes but for now ill be OK.
I haven't seen the gap in the baffle, but it has to be smaller than the cross section of the tubes if the baffle exists at all. I would expect even with the gap, at least half or more of the total flow is still going through the tubes, but that's obviously not enough. I can't believe that they could really not know to expect this result from leaving that gap in the baffle, which makes me wonder if they had some reason to do it intentionally, like the tank can't handle the pressure if 100% of the flow was forced through the tubes.
Ehh, I dont necessarily buy the too much flow thing... remember the pressure is provided by the water pump, what isnt "forced" is bypassed elsewhere in the cooling system or stalled at the pump imeller. I think this heater core was made in a "This Looks Like It Will Work" methodology. Good news is there is less heat in the heater box for summertime.
I would suspect that convection and the thermal mass of all the 200 degree water would be enough to keep the fins nice and hot, so more fins would help. I am not sure the design really requires ALL (as in 100%) the incoming hot water to flow through all the tubes, a slight circulation may be enough. Case and point, stop your jeeps engine and keep the heater and fan on high, it takes a while for that heat to cool down. I think the higher fin count may increase performance of this coil. Ultimately a cross flow core would be optimal, takes on either since but not sure that will package well in our heater box.
I was only musing on what could possibly have led them to hamstring its performance by letting a portion of the flow bypass the heat exchanger, but to be precise, not too much flow - too much pressure. The more you pinch off the flow (such as closing the thermostat and forcing all the flow through a few small tubes) the more pressure is produced.
I don't have a pump curve for the 4.0 water pump so I don't know how high the pressure will go as the flow is choked down. I know worst case will be thermostat closed and high rpm (which moves the curve similarly to a change in impeller diameter demonstrated in the sample above), and I know aftermarket parts manufacturers are pathological in their relentless pursuits of cutting cost, including thinning materials, reducing labor time spent in processes and quality assurance, reducing labor cost by hiring less skilled workers, and all of those things will reduce the life of a pressure-containing part in a way that can be mitigated by reducing the pressure it's subjected to.
Occams razor points to it being intentional for me, because if one single person that knows how heat exchangers work saw that design, it never would have made it out the door. To assume it's just the result of some shooting from the hip requires the assumption that someone willing to put down the capital to open and maintain heat exchanger manufacturing equipment but not willing to hire someone that knows about heat transfer or fluid mechanics, which makes no business sense. In other words, it's easier to assume they knowingly made a cost-cutting choice than that not one single employee of a heat exchanger manufacturer understands the product they produce.
thermal mass has no effect on the steady state heat output, it acts only as a temporary buffer during transient operation. You could have a 100 pound heater core with 8 gallons of coolant in it and if the surface area, flow rates and material is the same, you'll get exactly the same steady state heat output, it'll just take forever to heat up and and cool down.
I am supprised by the posts here for Performance Radiator heater core for a TJ. I have a 2006 TJ and just had a Performance Heater Core installed after my original started to leak. I have been running the heater as it's getting cold in the mornings (New Mexico). It puts out plenty of heat and looks well built . I went to Performance Radiator in town and had it the next day. I went to them because I saw so many other posts that they were good. Not just Jeep but others as well. Anyway, I'm sure not going to change it now.
I have had a Performance Radiator heater core in my LJ for years. It works as intended - plenty of heat in the coldest weather.
As far as I can determine, the primary markets for Performance Radiator are jobbers and repair shops who must warranty parts and labor for their customers. If that is truly the case, I can't imagine that Performance radiator would stay in business if they sold junk and they have been around for a long time.
As far as I can determine, the primary markets for Performance Radiator are jobbers and repair shops who must warranty parts and labor for their customers. If that is truly the case, I can't imagine that Performance radiator would stay in business if they sold junk and they have been around for a long time.
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