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"GM High Tech", March 1, 2013

SUPER CHILLER

CAN AN AIR-CONDITIONED INTERCOOLER REALLY CHILL YOUR SUPERCHARGED AIR TEMPS?

BY JUSTIN CESLER

PHOTOGRAPHY BY JUSTIN CESLER

Heat is the enemy. It’s been the enemy since the very first internal combustion engine fired up well over 150 years ago, and will continue to be the enemy for, well, forever. This isn’t an engineering obstacle; it’s a fact of life and, unfortunately, not something a bunch of car guys are going to “fix” just because it would help us run faster at the track. As temperature rises (assuming pressure and volume stay the same, which we are going to do) density drops, which reduces overall power production. Remember, the more air molecules (volume and density) you can stuff in the cylinder, the more fuel you can add and the more power you can produce. If the Ideal Gas Law wasn’t bad enough, hotter air also increases the likelihood of pre-detonation within the combustion chamber (AKA knock), which left unchecked, will turn shiny new pistons into paperweights before you can even lift out of the throttle.

Now, on a naturally aspirated engine, heat is normally just a function of the outside air temperature, assuming you don’t have any major air intake tract restrictions or a ridiculously hot engine bay. The hotter the day, the less dense the air, and the less power you make. But, on a forced induction application, thermal management is a much more complicated issue. For starters, compressing air heats it. Yeah, read it again, it sucks. Compressing air will always heat it up, which means we need a way to cool it before jamming it into the combustion chamber. Luckily, hot rodders invented intercooling, which transfers heat out of the pressurized air, cooling it, and increasing its density in the process. These intercoolers work in a variety of ways, such as air-to-air, air-to-water, and even chemically, but they all rely on a transfer of heat to work properly. You’ve seen this at the track before, with turbocharged and supercharged drag racers stuffing tanks full of water and ice, which circulate through the intercooler to transfer heat away from the compressed air and into the water. This method is great, but for us street guys, it’s just not feasible to carry around 200-pounds of ice in the trunk that we can refill every time we want to smash on the loud pedal.

But, what if there was a way to introduce cold, almost freezing air into the system without ice. What if there was some system on a car that could use refrigerant to condition the intercooler coolant taking it from ambient temperatures to something much colder. Maybe you’ve used something like this before? I believe it would be called air conditioning (A/C), and we’re thinking that most cars come equipped with it. Now, instead of running the A/C in the cabin to cool your little behind and chill the cabin air, what if there was a way to divert that chilled charge to an “air-to-water” intercooler, and chill your charged air instead to decrease intercooler coolant temperatures. Would it drop incoming air temperatures enough to make a difference? Well, there is only one way to find out...

1 The heart of the RX Performance A/C assisted air-to-water intercooler Super Chiller system is this heat exchanger unit, which flows intercooler coolant and refrigerant through itself to pull heat away from the coolant mixture. RX sends the unit with all of the fittings installed for a simple hookup.

2 The RX heat exchanger intercepts refrigerant from the factory installed air conditioning system, and this manifold will need to be spliced in line between the condenser and evaporator. The solenoid controls flow into the cabin and can be engaged in “competition mode” to allow racers to run the A/C system without dripping water onto the track.

3 The RX Super Chiller is basically a universal system, but the RX team certainly has its sights set on the fifth-gen Camaro crowd, whether users are running an aftermarket blower on an SS or a stock unit on a ZL1. For our testing, we hooked up with Howard Tanner of Redline Motorsports, who volunteered his ZLR prototype car for testing.

4 Obviously, the Redline ZLR isn’t a stock ZL1, but with additional boost, a lumpy camshaft, a Redline cold air intake system, and additional intercooler coolant capacity, it would certainly be a great test for the RX Super Chiller. The provided instructions suggest mounting the heat exchanger on the front bumper crash bar, but Howard Tanner and Jay Healy preferred to hide the assembly in the front fender well.

5 A simple aluminum bracket was fabricated to hold the heat exchanger in place, secured to the inner fender by two bolts. Two large screw clamps (provided in the kit) hold the actual heat exchanger to the bracket. If you’re planning to attach it to your front crash bar, you would simply use the two screw clamps.

6 For a quick and simple installation on a fifth-gen Camaro, RX provides cut-to-length hoses that run from the Chiller heat exchanger to the factory air-to-water heat exchanger. Jay connected both coolant hoses to the Chiller assembly and ran them into the engine bay for the time being.

7 To control coolant flow to and from the heat exchanger, the RX kit uses a simple 4-way manifold. The top left port grabs coolant from the pump, while the two ports on the right side of the manifold flow to and from the heat exchanger. The lower left port sends coolant to the RX Super Chiller and is controlled by a vacuum solenoid.

8 Hooking up the coolant lines in the correct orientation is critical and can be a little confusing when you first get started. From underneath the ZL1, you can see the factory heat exchanger coolant lines (unplugged, left and right), which will attach to the RX manifold. The new lines (provided in the kit) will send coolant to the RX Super Chiller.

9 With the coolant side of the install complete, it was time for Jay Healy to begin hooking up the refrigerant side of the Super Chiller, which will help drop our intercooler coolant temperatures substantially. RX did its homework here, and provides clearly marked OE-style hoses and fittings to get the job done quickly and safely.

10 Before you get started with this step, make sure you have a competent A/C shop properly evacuate the system and save the refridgerant, as you will need to refill it later. Once that’s done, you can remove the 10mm bolt that holds the low side coupler to the evaporator fitting.

11 With the coupler unbolted (right) it was time to slide the Super Chiller low-side line in place (left). This piece simply slides between the existing coupler and the fitting, and clamps back in place using a longer bolt. Make sure you get a good seal here or you’re going to have a leak.

12 The high-side line needs to have a section removed to allow for the Super Chiller high side adapter to splice in place. Using the adapter as a guide, Jay marked both ends of the high-side line and cut them out using the proper pipe cutter. This can be tricky, as you have very little room to work, but with the right tools and/or a lot of patience, anyone can get this done correctly.

13 Once cut and de-burred, the high-side adapter was installed. As previously mentioned, this adapter is used to flow refrigerant through the Super Chiller and includes a solenoid that can stop flow to the cabin for racers looking to run the A/C without dripping water on the track.

14 The Super Chiller already has all of the correct fittings installed, so all Redline needed to do was hook up the high- and low-side lines and tighten everything down. RX marked these lines on each end, which made this step a breeze.

15 And just like that, the inner fender liner popped back in place and the entire system was hidden from view. Not that anyone needs to hide such a cool device, but it’s nice not having the heat exchanger cluttering up the engine bay or hanging under the front bumper.

16 Inside, it was time for a little wiring, with the competition switch mounting under the left side of the dashboard, right along side the door panel. RX pre-formed the aluminum bracket, and the switch comes pre-wired as well. An LED light lets Howard know when the system is on, and a single wire runs through the firewall to the solenoid relay for activation.

17 Finally, it was time to put the engine bay back in order, refill the A/C and intercooler systems, and test the RX Super Chiller out. To do that, we fired up the ZL1 with the Super Chiller of, drove around the parking lot, and then let the Camaro idle while monitoring IATs and intercooler coolant temperatures.

18 After 10-minutes of warm up time, our air-to-water coolant temperatures were running a consistent 111.6 degrees. This hot water wasn’t doing much to cool the 124-degree ambient temps, as we were reading 108 degree charge temps...

19 Howard turned on the RX Super Chiller and let the car idle in the “staging lanes” for 10 minutes. The results speak for themselves. With the Super Chiller on, intercooler coolant temperatures dropped to 75.1 degrees (-36.5 degrees), and charge temps followed, dropping to 84 degrees from 108. That’s a 24-degree drop in a few minutes and would really pull any and all heatsoak out of the blower. In short, it works!

SOURCES

Redline Motorsports

954/703-5560

www.redline-motorsports.net

RX Performance Products

941/721-1826

www.revextreme.com

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