Tech Feature: Derale’s Hyper-Cool Remote Trans Cooler
Housed within an automatic racing transmission are a lot of intricate moving parts. These are put through a strenuous workout under load, keeping the engine’s RPM within it’s operating range and transmitting power from the engine to the drive wheels. In a racing environment, even one that only lasts for seven or eight seconds, the transmission is working incredibly hard to push tons of power, torque, and weight from a dig down the race track. As such, high-performing, albeit compact and robust, transmission coolers are paramount.
During the off season, we put a new transmission into our Project BlownZ Camaro, and to handle the chore of keeping it within a healthy operating temperature range, we opted to pair it with a new cooler from one of the industry leaders, Derale Performance, and their Hyper-Cool Remote Fluid Cooler, which is designed just for this type of hard use.
For those unfamiliar with Derale Performance, the company has been a part of the automotive industry since the 1940′s, and during the six-plus decades that they’ve been in business, they’ve solidified themselves as a top manufacturer of all things cooling. This includes everything from cooling pans to fans and fan controllers, fluid coolers, oil filtration products, and other parts and accessories. Applications span from race cars to street rods, street cars, heavy-duty trucks, and virtually anything automotive with a cooling need.
Today, we’re going to take a closer look at the design and advantages of Derale’s Hyper-Cool unit and show you why it’s remote mounting and stacked plate design are perfect for our racing application. We’ll also give you a brief walk-through of the installation process.
The Hyper-Cool Unit At A Glance
Derale’s Hyper-Cool Remote Cooler (Part No. 13960) is, just as the name implies, a high performance transmission cooler that is capable of being mounted remotely anywhere on the vehicle where there is space for it. We’ll get into the reasons why this is important shortly.
…because the stacked plate allows for more volume, it’s more rigid, it’s stronger, lighter, and wider, flows better, and has a tighter fin-pitch. – Troy Wood
The Hyper-Cool is a complete kit that includes a 25-plate, stacked plate cooler and 500 cfm reversible fan, with all of the fittings, hoses, and components required to mount and operate it. The unit, measuring 10 inches by 13 inches, is available with either -6 or -8AN inlet and outlet fittings — this one in particular bearing the -6 fittings and 10 feet of matching sized Goodyear high-temperature rubber hoses. It also includes a 180-degree Fahrenheit in-line thermostat, as well.
“The Hyper-Cool is an excellent choice for a vehicle like BlownZ because it’s a racing, heavy-duty unit that’s based on the 25-row stacked plate cooler with embossed turbulators inside, it’s completely oven-brazed, all aluminum, and is very, very sturdy. It’s actually tested to 300 psi. When we heard about the project [BlownZ], we didn’t really want to go with a plate and fin-style cooler, because the stacked plate allows for more volume, it’s more rigid, it’s stronger, lighter, and wider, flows better, and has a tighter fin-pitch, meaning it has more heat transferability because there’s more surface area there to pass through versus plate and fin.”
On Derale’s remote mount coolers, the shroud and the mounting bracket are one unit, allowing it to serve two purposes. First, it pulls the air through the most efficiently through the cooler so you’re not losing anything around the fins that aren’t shrouded. And the bracket stand has enough standoff, or leg, on the bottom of the cooler to allow the air to pass through so the fan can pull the air from the bottom. This means the unit can literally be mounted on any surface. It can be a solid surface that doesn’t need to be louvered.
The Hyper-Cool, while a great unit for racing applications, is described by Wood as more of a severe duty transmission cooler, suitable for a range of uses that are severe. It can also be used on manual transmissions, but because you don’t generally see the temperatures in a manual as you do an automatic, Wood likens it to being a bit overkill for such a combination.
Unlike in a more conventional tube and fin-style heat exchanger where aluminum tubes are fitted inside of a metal stack of fins, a stacked plate design features a stack of plates in which hot and cold streams of fluid counterflow through alternating plates. Stacked plate cooler are often very compact and offer exceptional heat transfer with a very well controlled pressure drop. Their design also lends them to being much more durable than tube and fin.
As we’ve already hit on, one of the primary reasons that remote coolers are desirable is to get the cooler away from the nose of the car where it’s fighting for incoming air, or where it may not fit at all depending on the vehicle. But beyond that, it’s also important because, by mounting the cooler elsewhere, you’re able to get the cooler itself and the lines carrying the transmission fluid away from the heat source of the engine bay and the transmission. This is where the fan and the performance of the cooler become pertinent, although the flow of the fan itself is a lesser part of the equation.
“In a remote cooler, the fan cfm is really not a huge issue. In other words, all the fan is really doing is providing the air supply so you don’t have the cooler up in front of the vehicle where it’s fighting for clean air and hindering air getting through to the actual cooling system. This is why the remote cooler is so popular with drag racers where you want to get everything out of the way in the front of the car.”
Wood continued, “People always get locked into the cfm numbers like it’s the air equivalent of horsepower numbers, when that’s really not accurate. To have a fan pull through a stacked-plate cooler, you’re going to need a little stronger fan than a tube and fin cooler, because the fins are further apart in a tube and fin, so there’s going to be less static pressure created for that fan to have to draw through. We put the largest fan on our units that we can.”
As you’ll see below, we’ve mounted the Hyper-Cool on the underside of the race car behind the rear end housing in BlownZ. In our discussions with Wood, he pointed out why this is a good choice of locations.
The further the fluid travels, the more it allows it cool and obviously, you’re also adding some capacity by having that distance, so it’s a win-win situation. – Troy Wood
“What you’re doing is getting it away from the heat source. The further the fluid travels, the more it allows it cool and obviously, you’re also adding some capacity by having that distance, so it’s a win-win situation. You don’t want to run it too far because you may run into pressure issues, but by the same token, it does help to get it away from the ambient heat. Anything you can do to remove heat from the engine bay is a good thing.”
Thanks to the design of the Hyper-Cool unit that allows it to operate while mounted to a flat, unvented or un-louvered surface, such as the underside of the race car or on the floor, finding a place to mount it is less involved than once might expect. And because we’d already made some provisions on the undercarriage of BlownZ for a previous installation, it was even more of a breeze in our situation.
The Hyper-Cool cooler has four holes, one in each of the four corners, for mounting the unit. This can generally be a rigid surface or, for added peace of mind, to a fabricated “frame” welded to the body of the car or the chassis to give it a sturdier base. In the case of BlownZ, the guys in the shop had already fabricated a square, one-inch bracket welded framerail to framerail underneath the car, aft of the rear end housing, to bolt the battery and other components to through the floor of the car. To accomplish this, we used our trusty and powerful Lincoln Electric POWER MIG 256 welder that, thanks to its impressive features, makes project like this one a breeze and welds precise and solid. This bracket just so happened to have the same width dimensions of the Hyper-Cool. This allowed us to weld four bolts to the frame, slip the fan over the bolts, and put the locking nuts on it.
Beyond the fact that we had a perfect mounting bracket in the rear of the car, our primary reason for placing the cooler there was to get it out of the way and for weight distribution purposes. Plus, the added length of the lines gave us some extra fluid capacity (roughly an extra 3/4 to one full quart), which in turns means better cooling performance because the distance the fluid must travel gives it extra time in the line to cool before reaching the Hyper-Cool and returning to the transmission.
To lay out the Goodyear hoses, we then connected the inlet and outlets hoses to the fittings on the cooler, then routed them inside the wheel-well above the axles and four-link bracket and then back down the framerail to the transmission. The lines are routed using metal hose clamps strapped to the floor of the car. Once the lines were at the transmission inlet and outlet ports, we could then cut the hoses to size. This, of course, can be done either direction and can even be mocked up with an air hose or something similar in the shop before making the cut.
Our Hyper-Cool unit has performed admirably in our first few trips to the track, delivering just what we were looking for in a transmission cooler. Even in the hot sun of Las Vegas, where temperatures soar to 100 degrees and above, we haven’t seen the fluid temperature creep any higher than 120 degrees. At the end of the day, what Derale has produced here is a lightweight, compact, high-performing cooler that will stand up to some rather harsh conditions at a price point that won’t bust the wallet.