Justin
What you have been stating is very much a contradiction so I am asking for some details. I am not making judgment what was said but rather looking for the facts so I can decide if this is going to meet my requirements. I am not interested in drama or repeated statements. A basic specification regarding detailed tube and fin sizing would be appreciated. Thus, I would not need to ask questions.
The close mesh core (low pressure drop) is nothing more than a finer pitch radiator from the standard core. Please stop implying that it is something else and confusing people further! The OEM radiator is a finer pitch core at about 6.8 mm with 50 tubes so the purposed design (close mesh core) is almost the same pitch to the OEM radiator. It is certainly understandable why they are recommending this design, and for me, doesn’t require further explanation. The addition cost is justified due to 30% increase in materials required just to be clear.
The assumption that the air flow may be restricted is valid but it’s an assumption and has defiantly gone on a tangent. You have an OEM radiator so you know what the available air flow/restriction area. It is not going to be difficult to transfer the information over to a new design since we don’t have a fan curve. You also have coolant flow rate and OEM radiator that can be used to get the total coolant cross section which can be applied to the new design. We have enough information to create a design but it may be on the conservative side with good engineering judgment unless someone wants to invest further time and effort into this.
The comments from the engineer are just that, and he did not answer the question, but instead stated obvious information regarding heat flux, pressure drop and that dimpled tube was a possible option to meet coolant velocity but you seem to not understand this?
For others, if you on the fence about upgrading the radiator and hoping some other company can do it you will be disappointed. PWR is the only company that has specific technology and available material sizes to enhance thermal performance for at these low volumes. One of the reasons for this is that the OEM radiator is actually a fairly good unit for high production so improving up on this is not that easy of a job.
Some basic design info that is easy to understand:
http://www.arrowheadradiator.com/14_...utomobiles.htm
Quote:
Originally Posted by Justin@ADVAN Performance
Hi Orb,
I do not think it's too much to ask, that you put a little faith in the engineering expertise & design knowledge of PWR.
Which is why given the volume limitations of the rad' and the requirement of a cross-flow core in lieu of the AT heat exchanger, they are insisting on using their "Close Mesh Core Configuration" to ensure their efficiency goals are meet.
Also do not be concerned about the radiator becoming "laminar" due to a lack of coolant turbulence, as they will be utilising a "dimple tube" in their design revision if they deem it necessary, following calculations of the coolant volume flow rate.
Below is a quote from one of their engineers, in response to your concerns regarding coolant volume flow rate and a possible lack of coolant turbulence.
"Our tubes are by no means ordinary or basic in design and we have features in the tubes that keep the coolant turbulent to ensure maximum cooling is achieved, as at the end of the day you are trying to give the coolant enough time in the radiator for sufficient heat transfer but also trying to make sure that the engine has a sufficient supply of coolant."
There is no doubt in my mind that "at speed" on the racetrack, the Advan/PWR AT rad' with the "Close Mesh Core" will perform very well indeed.
What they are unsure of is how well it will transfer heat at low air speeds, in stop-go traffic.
They have not tested the flow rate of the BMW OE thermatic fan, I do not know the maximum CFM rating of the fan, nor does PWR.
That being said Peter has had a good look at the fan unit previously, in his opinion the assembly is quite large and "should" be up to the task of pulling an adequate quantity of air through the core at low vehicle speeds, to maintain reasonable water temps.
As I mentioned previously this is something we would have to verify.
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