So obviously, VolksarU has been very embarrassing, especially when I found out that I had taken people's word for things that I should have checked on first. Some of this goes back to the parsimony: Why should I spend my time doing something first when others have already preceded me and my contributions to the craft can be refinements, rather than wholesale invention?
After having run aground in September with the Sirocco radiators, I was forced into this kind of retrenchment. I already have more into the project than the vehicle is worth. Yeah. So what. If you want to get rich, pick a different hobby. Instead of crying too long in my suds, I took the information that DW in Connecticut captured with his successful underbelly design and started considering my own state of affairs: The very best solution is available is just conveniently on the other side of the Atlantic Ocean: Fellows Speed Shop in Birmingham, England, UK.
So I got in touch and dropped a simple query: How much? For air intake, chassis strengtheners, custom radiator and scoop, mounts, and (gulp) shipping. The number I got back caused my mouth to go dry: $1400 give or take, depending on the exchange rate and the banking fees to convert USD to GBP. This might not sound like much, but consider: If everything arrives in one piece (and that's no guarantee) and I hook everything up, dump in 4 gallons of coolant, fire up the engine and the radiator springs a leak, then what? Ask for another one? RMA the first one back in exchange for another that may or may not work? Is Fellows going to eat the shipping both ways across the Atlantic? Let's not be silly.
That is a very high risk / high reward opportunity to buy your way to success. I was frustrated enough to ring them for a price, but not nervy enough to put all of my eggs in that basket. So back to DIY land: What radiator will fit the space between the midship cross member and the major rear cross member, and also fit between the longitudinal frame rails to be held up out of harms way in the same manner that the fellows design is? At the same time, the core surface should as large as possible within the space, given less than ideal orientation relative to the direction of travel. Maximum radiant surface.
So I measured every which way and then went shopping.
Modern factory radiators were out. Too much plastic and epoxy and other things that don't take well to being nicked or sprayed by gravel. This radiator, even protected from major damage by the frame rails, is going to have to be tough.
Vintage style brass and copper radiators are out because they're heavy and have too many serious compromises, U.S. Radiator notes that "The thermal conductivity or heat transfer rate of copper is 92% versus aluminum which is only 49%. However, the copper fins are bonded to the coolant tubes using lead solder which is very inefficient [not to mention toxic] and slows the heat transfer rate to just slightly better than that of aluminum." So in short, your average brass/copper radiator will weigh much more than aluminum, fail to transfer heat any better, and is assembled of toxic components. Um..no.
So this left me in the realm of high performance aluminum radiators. Prices can take off for the sky here, or have historically. That's one of the reasons I was happy and surprised to find Champion Cooling of Lake Elsinore, California. They build all-aluminum radiators for the high performance market and do so at a reasonable price. They've got a fantastic reputation for customer service, and the country is dotted with their dealers, including domestic online dealers. Their radiators are assembled by TIG welding and furnace brazing which gives them a leg up over the competition.
Because I need minimum vertical thickness to fit above the frame rails, I can't use a radiator that has a very thick core. I've only got an absolute ceiling height of 6.125" to stack the radiator and the fans, so only a two row, 1.75" thickness core. Also take into account that the core is halfway between the front and rear (or in this laid down orientation, top and bottom) faces of the tanks, that leave marginal space for dual 12" fans which are 12.75" thick at the central hub motor. Total it all up...and that's less than an inch of vertical clearance left for wiggle room and air output.
So that alone confined me to two row radiators. I found myself with an embarrassment of riches, as Champion Cooling makes hundreds of specialty radiator models in two, three, and four row designs. Just narrowing myself to two row radiators, I had to sort through the specifications of 270 radiators and applications to find the unit with the maximum core area that would also fit in the space. This past weekend, I narrowed it down to eight, and by evening, I had it down to one.
The heir-apparent is the DPI 281 model, which was a workhorse designed for Chevrolet applications from the 1950s through the 1960s, and was found in models as diverse as the Corvette, Chevelle, Impala and Bel Air. This is a design that is going to be available for a long, long time. All of the right attributes were there to be the winner: designed for heat dissipation for about 400HP, or three times the output of my Subaru EJ22 (123HP.) The design has wide brackets TIG welded to the radiator frame, top and bottom tanks (that when laid down, will become 'front and rear tanks.') There is one major hangup, though.
The one attribute that is critical is the the coolant inlet/outlet. In a traditional installation, the inlet/outlet is on the back face of the radiator, toward the engine. By contrast, this radiator will be laying down and vertical space is at a premium. No matter what, I've got to have a radiator where the inlet/outlet fittings are mounted inline (not perpendicular) with the radiator core. So even though I've found my radiator (and purchased it, today) it will still require modification to go into the space.
Yes, it's going to get the fittings removed and relocated to the 'front and rear.' No, I won't be the one doing it. TIG welding isn't the point-n-shoot that MIG welding has become. TIG is fussy, specialty work. I've already got a quote from a TIG weldor for about the same price as the radiator itself to fuss with the inlet/outlet pair and move them according to my requirements. At the neighborhood of $350 for radiator and customization, it is a much more cost effective to modify an existing radiator than having Northern or Griffen or Wizard perform a custom build for me. About 3 times less expensive.
The characteristic that charmed me to this product are the wide flanges (28") and the comfortable fit of 3/4" on each side of the core body, which will ride above the level of the frame rails, well protected by the flanges. Instead of requiring me to add support pins to the ends of the tanks for a suspension mount like Fellows does, the brackets can bolt to the bottom of the frame rails and be very secure. This design also gives me another warm fuzzy that the Fellows design did not: The Fellows custom radiator has the scoop bolted to the radiator body itself. I'm sure that's wonderfully secure, but what happens when you cream a hard-headed raccoon at 70mph? Probably tear the scoop right off, and mangle the radiator badly enough that it bleeds out all over the road. Then what happens? Have Fellows ship a new one? Please. (I'll grant that this isn't likely to happen, and there haven't been any reports from the UK of that happening, but still...)
My notion is that the scoop should be firmly secure to the frame...with shear bolts. A shear pin or bolt is a safety device designed to snap off in the case of a mechanical overload, preventing other, more expensive parts from being damaged. As a mechanical sacrificial part, it is analogous to an electric fuse. If I clock Rocky Raccoon in the brain-pan, I'll lose the scoop, the bolts shearing away. But because the scoop can break-away, you lose it and preserve the radiator, a much more valuable component. You can limp out of Death Valley running your fans full blast without your scoop. You can't without your radiator. In the best case scenario, you pull over, walk back 100 yards, brush the busted bits of raccoon off the scoop and remount it when you hit the next town with new shear bolts.
Using the wide flanges on the DPI 281 radiator, the flanges can connect to the frame rails with 8.8 hardness galvanised steel bolts. But *also* using those wide flanges allows me to mount the scoop to it with the shear bolts. Everybody wins, and a 12 gauge steel scoop will be able to take a good shot without folding up like origami if it happens to hit something soft.
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