stacked plate OTW exchangers, the OEM and Spectra are very different designs. Why? From fewer/larger rows in the core to concentric vs. Assuming Honda optimizes thermal management much better than they accomplished fluid isolation in the Denso, it is highly likely aftermarket replacements are (to some degree) inferior heat management assemblies. Having stated that, there is no direct information available on the OTW inside the model 2830 for the RL. Because the ports seen in the new OSC rad are aluminum, I assume the OTW exchanger inside is stacked plate. Follow the images in the link above and you'll see that copper/brass ports connect to concentric OTW exchangers, aluminum ports connect to stacked plates in 100% of the images provided. Based on images in OSC marketing materials seen here: URL it appears the presence of aluminum trans fluid ports visible from the outside indicates stacked plates inside. Flow resistance isn't accidental and (likely) includes all elements of thermal management, including materials, fluid chemistry, flow rate, 'dwell' or duration of the fluid in the chamber, ETC. The OEM stacked plate design introduces significant trans fluid flow resistance which is not duplicated in the Spectra (and other) concentric designs. The Spectra (and others) - where the OTW exchanger is discretely attached to the bottom tank - is a far superior method for keeping trans fluid isolated from engine coolant. And they are so small, any gunk in the trans fluid is definitely going to lodged in here.Īfter close physical inspection of a new OSC rad & reviewing available info from their web site, tearing down the OEM and Spectra rads, and observing the construction of other replacement rads in the aftermarket, these are my conclusions: It occurs to me fluid passing thru these channels must have some pretty intense pressure behind them. Each passage looks to contain a wild staggered array of U channels. What I thought I was seeing thru a jewelers loop turned out to be even more complex that imagined. These images were taken with an inexpensive AVEN USB microscope. So that was off the table.īefore leaving for the office this AM, a thought bubble appeared over my head: 'cross cut the tube port!' That way there would be a clear view into unaltered passages. After speaking to my pal with the water jet about cutting a cross section, it was determined turbulence would damage/distort the tiny veins inside the passages. I really wanted a better idea of whats going on inside there, but cutting was distorting the surface and interior of the channels. Last night I was looking into the OEM OTW cross section and was seeing variations in the fluid passages that seemed odd. Taken this inspection as far as tools and imagination allow.

OK, the end of the geek rope has been reached. And this distinction is not trivial considering the gravity of SMOD catastrophes. For fluids to mix in this design, the failure mechanism would involve two points of failure, which statistically speaking is much less likely than the single point of failure in the OEM design.

The clamping of port to heat exchanger is a male/female flare, similar to plumbing in home/industrial construction.

The clamping of heat exchanger to tank is discrete from fluid passages. The aftermarket appears to have solved that issue by separating tasks. The 'problem' with this design is when a port fails at one task, it fails at both allowing incompatible fluids to mix, causing potentially serious damage to the transmission. The other is to serve as clamping mechanism holding the exchanger to the tank. One is to isolate engine coolant from trans fluid.

The OEM design relies on the trans fluid ports serve two purposes. The first stand out between OEM and aftermarket designs is the mechanical attachment of the heat exchanger to the lower tank. This comparison focuses on the trans fluid heat exchanger and observations of general construction of OEM vs. Out of box impressions of the OSC in this thread: įirst tear down of the OEM Denso in this thread: īy now, most everyone is aware of the dreaded SMOD. The new OSC to be installed in the 06 in the near future. Thanks to forum member Carsmak for the OEM and Spectra donations. A tear down of the OEM Denso & aftermarket Spectra radiators, New OSC included.

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