Nic Hahn from Illinois recently became the new owner of a fascinating 1996 Saturn SL2 with only 3,800 miles on the odometer. The vehicle was a former engineering development car for one of General Motors’ main air conditioning parts suppliers, and when Hahn bought the car a few months ago, there was still testing equipment in the engine bay. To learn more, I scoured old news articles and even contacted the manager of the now-defunct Decatur, IL wind tunnel in which the car underwent air conditioning testing for years. Here’s what I learned.
I first caught wind (it’s a bad pun) of this story on the Underappreciated Survivors Facebook page, where Hahn wrote this:
Keen to understand the nearly-mint-condition Saturn’s background, I reached out to Hahn. “So the backstory I got was from a gentleman who works for the company that purchased the wind tunnel [in] Decatur from Ford Motor Company,” the proud Saturn owner told me over Facebook Messenger. “He said that when the company purchased the wind tunnel this vehicle was left there and it was used to set up the dyno for the AC testing,” he continued.
“It was used for a few years after this company bought the wind tunnel and then they put it up internally for a close bid auction and he was high bidder.”
By the time Hahn bought the car last year, traces of its air conditioning development car-background remained in the form of thermocouples (these are basically wires made up of two dissimilar metals that create a voltage that can correspond to a certain temperature) under the hood and on interior vents:
Hahn wasn’t too sure what this Saturn SL2 had been used for back in the day, so I did a bit of research, learning that indeed, this thing had been an engineering development car for an air conditioning company. But based on my research, the wind tunnel that housed the car for many years did not belong to Ford as Hahn initially wrote, but rather, to a company called Zexel.
The Japanese Air Conditioning Company That Made Saturn Compressors In Decatur, Illinois
Zexel was a Japanese automobile parts supplier that set up what would become its U.S. headquarters in Decatur, Illinois back in the late 1980s. Then called Diesel Kiki (the Illinois subsidiary was DK Manufacturing Inc.), Zexel bought the Decatur facility from Borg-Warner in 1987, per Herald and Review’s April 14, 1987 story, which reads, in part:
Decatur’s Borg-Warner Climate Control Systems plant will close by year’s end unless it is sold, a spokesman said Monday...Officials of Japanese owned Diesel Kiki USA had confirmed they were negotiating for the plant.
Diesel Kiki is one of the largest Japanese manufacturers of parts of vehicle air conditioners.
Borg-Warner’s [spokesman] said the company anticipates “phasing out production of the (Decatur) plant during the year. The product has become non-competitive,” due to overseas competition.
The Decatur plant manufacturers reciprocating compressors for vehicle air-conditioning systems. Earlier this year, it sold to Diesel Kiki the rights to manufacture and distribute a newer type of compressor that was developed at the Decatur plant.
In 1990, Diesel Kiki became Zexel, and it was then that the air conditioning manufacturer began producing compressors for GM’s new Saturn division. Herald and Review’s “One Decatur company on its way to Saturn” announced the deal:
In the article, Executive Vice President of Zexel Illinois (as Zexel USA Corp’s Illinois subsidiary was then called, taking over for the name “DK Manufacturing Inc.”) Charles Farley Jr. said the company was providing rotary compressors to both Geo and Saturn, and that Zexel was to be the latter’s sole supplier. That was huge business for the Illinois company, and it’s the main reason proximity to Saturn’s Tennessee plant, Farley said, was such an important factor in Diesel Kiki’s decision to move to Decatur in the first place.
In 1992, Zexel opened its Environmental Research Laboratory in Decatur. That lab, which you can see in this Herald and Review article from the time, included the aforementioned wind tunnel that housed the low-mileage SL2 up until recently. The tunnel had some impressive capabilities. From the story:
The facility is used to test a variety of automobile functions and resistance in an environment as cold as -86 degrees or as warm as 122 degrees. The tunnel also can generate winds of about 99 mph with relative humidity as high as 95 percent.
“What’s the big deal here?” You might ask. Why is a Japanese supplier opening up shop near a Saturn plant, and why does it need its own state-of-the-art lab to help GM develop AC systems? And what’s the deal with that Saturn that apparently took residence in that lab?
Remember that 1992, when Zexel’s wind tunnel went into operation, was an important time for climate control suppliers, as the U.S. government was mandating that automakers switch from R-12 refrigerant (which had dominated the industry for decades) to R134a by the 1994 model year in order to reduce ozone-depleting chlorofluorocarbons. So Zexel, as I later confirmed with the lab’s former manager, was quite busy.
The wind tunnel-equipped facility was needed not only to test Zexel AC components and systems but also to give automakers “technical support they need to meet the challenges of the 1990s,” per Zexel’s VP of engineering M.R. Butts.
Here’s more from the story about the wind tunnel and the need for suppliers to provide support, especially given the new regulations from the U.S. government:
Butts said much of the automotive research and development burden is shifting from automakers to suppliers, such as Zexel. Zexel tackled replacing chlorofluorocarbons (CFCs) in air-conditioning equipment in the face of U.S. law requiring elimination of CFCs in 1994.
Zexel already has sold a non-CFC system to Volvo for 1993 models and expects to have alternative equipment available for all customers in teh 1994 model year. Major customers are Subaru and Saturn.
Things Start Going South For Zexel And The Town Of Decatur
Things seemed to be going well for Zexel through the 1990s. An October 1998 article from Harold and Review paints a pleasant picture of the Decatur, Illinois-based AC supplier’s operations.
The corporation now has two Central Illinois plants, in Decatur and Arcola, that design and produce compressors, evaporators, condensors, refrigeration systems, automobile navigation systems, and fuel injection systems for Saturn, Volvo, Isuzu, Subaru, Mazda and Nissan.
...the company is renewing its focus on environmental awareness through new technologies as their state-of-the-art Environmental Engineering Laboratory and continually striving to develop the sophisticated systems manufacturers need for new hybrid cars...
But in 1999, after having acquired over a 30 percent stake in Zexel, major German auto supplier Bosch bought half the company, Automotive News wrote at the time. Not long after, French auto supplier Valeo got in on the Zexel action, creating a joint venture with Bosch that changed the Decatur company’s name from Zexel to Zexel Valeo Climate Control Corporation. Shortly thereafter, layoffs began.
It wasn’t long before Zexel walked away from Decatur, Illinois. It was a huge blow for the town, with Herald and Review writing in all bold and all caps the headline: ZEXEL, VALEO TO CLOSE. Harold and Review’s February, 2002 article describes the reasoning for the shutdown:
The market for rotary vane compressors, the specific product produced by Zexel Valeo in Decatur, has been disappearing for the past two years. The company is moving the product to Japan, where a market does exist stronger, [Zexel Valeo chief operating officer] said.
The article also mentions that Zexel lost its Saturn business because GM decided to build compressors in-house. Things get even more depressing in the news story, with the author mentioning that Zexel’s closure was expected to put 220 people out of a job and that it was just another hit for a town whose manufacturing jobs were quickly disappearing:
Zexel is the latest in a list of closures in the past three months that include Bridgestone/Firestone Inc., Crane Pumps and Schnucks. Thousands of manufacturing jobs have been lost in Decatur in the past year.
All the while, though, the Saturn SL2 remained in the facility.
After the plant closed, Valeo bought the full rights to Zexel’s AC operations from Bosch, who apparently became the sole owner of the Decatur property before selling it to some investors who created an industrial park (see Google Streetview image above). The wind tunnel and Saturn SL2 test car were not part of that deal, as Bosch was renting the Environmental Research Laboratory to a company called Air International. Per Herald and Review:
Since Zexel closed in 2002, there have been businesses interested in the space, but the previous owner, Robert Bosch Corp., wasn’t willing to subdivide the property. The only tenant now is Air International, which uses a 10,000-square-foot wind tunnel on the property.
Automotive air conditioning company T/CCI later bought the wind tunnel from Air International and used it all the way up until a few years ago to do many of the same things that Zexel did in the 1990s. T/CCI described the wind tunnels functions in a 2015 press release, saying:
The climatic wind tunnel tests air conditioning cool down, heater warm-up, defrosting, defogging, engine & transmission cooling, road loads, inclines, trailer towing, city traffic simulation, front end airflow, hot or cold soak evaluations and custom test development. Key attributes of the tunnel include temperature control, humidity range, airflow dynamometer, repeat-ability and solar simulation.
I called up T/CCI, but the operator told me the facility is no longer in use. To learn more, I reached out to a former Zexel and T/CCI employee who used to manage the wind tunnel. He actually recognized the Saturn!
A Nerdy Discussion With The Wind Tunnel Manager
When I asked if he knew about Hahn’s green Saturn SL2, Richard Ennis replied with an affirmative before telling me about his role as a manager of this wind tunnel during his 14-year term at Zexel between 1987 and 2001. He says he even managed a different wind tunnel for the company prior to this one’s completion.
“Absolutely, I almost bought [the SL2] myself,” he began. “I worked as the Wind Tunnel Manager for 12 years during the period. The plant was closed and the Wind Tunnel sold to a company ‘Air International’ [in 2001]. The car went as part of the deal.”
He continued, discussing how Zexel used the car to calibrate the climatic wind tunnel’s instrumentation and all “process variable parameters.”
“That car was given to us by Saturn to use as a ‘calibration car’ in which after calibration was performed on the tunnel instrumentation OR the tunnel results did not make sense we would pull it in and run our standard tests.”
“We used [the Saturn] to ensure the tunnel calibration was correct. You’d be surprised but we were able to achieve +/- 0.5 deg F repeatability during these tests. The precision was such that we could tweak the expansion valve to vary the suction superheat conditions by ~ 1-2 deg F.”
“Later, the company I work for now bought the Wind Tunnel and we got the calibration car,” Ennis said. That company, by the way, is T/CCI.
Unfortunately, the facility shut down a few years ago.
“The tunnel later had a fire and was closed, that’s when the calibration car went up for auction. Of interest is the development work we did with Saturn to design the AC system with the first variable displacement rotary compressor, it’s still a remarkable design.”
If you’re curious about the variable displacement rotary compressor, read this, though I have to warn you that my discussion with Ennis got quite a bit nerdier from here, so don’t read that variable displacement technical paper if you’re worried it might fill you to your nerdiness capacity.
Let’s go back to the photos showing all the thermocouples.
Ennis walked me through some of the instrumentation. “Underhood the n=2 taps were for both suction and discharge pressure and temperature,” he said. “The vent temperatures are exactly that, to measure the resultant temperature to confirm the AC performance.”
I asked Ennis about the types of testing this car would typically undergo, and guessed that testing the AC system involved some sort of duct-out temperature goals after a certain duration given certain high-ambient conditions (100 F or so).
“Precisely,” he confirmed. “The specifications were based on Harrison Radiator (later Delphi) and the base conditions for the Soak and Cooldown were simply to soak the vehicle under solar lamps to an internal breath temperature of 138 degrees F (I think that was the temperature) and then start the vehicle and AC running up to 31 mph for an hour.”
Breath temperatures, he went on to clarify, just refer to interior/cabin ambient air temperature. He also described the climatic conditions in a bit more detail, saying the ambient temperature was 100 F, relative humidity was 40 percent, and the solar load was 1000 Watts per meter squared.
“Both the vent and breath level thermocouples had requirements for temperature based on time,” he told me. “We also monitored other operating parameters such as top radiator temperature, oil temperature, transmission temperature, fan voltage, engine speed, etc...”
So this Saturn must be in pretty good condition, you would think. And those 3,800 miles were probably almost all miles on the dynamometer, and not actually miles driven on the road, right? “Absolutely,” Ennis told me. “It had zero miles when we got it, we never drove it around but instead had it in the big garage bay outside the tunnel.”
Hahn confirms that the car is immaculate aside from some paint imperfections where straps held the car down during dyno testing. “Before we bought [the car],” he told me “we ran a carfax because the previous owner said he had to jump through a bunch of hoops to get the vehicle titled because it hadn’t been titled before. Carfax showed zero activity before 2019.” Hahn says he will put the car up for sale soon, though he didn’t mention pricing.
It’s a remarkable find and an amazing vehicle with a rich history. And now I have to end this article, because somehow a story about a nice Saturn I saw on Facebook went from “Hey look at this 3,800 miles Saturn” to a history lesson about air conditioning manufacturers in Decatur, Illinois and a nerdy engineering discussion about instrumentation and test regimens with an engineer who actually used this very car in a climatic wind tunnel. My editors are going to kill me.