OK, OK, I know I'm late. As I said last December, "stuff" gets in the way. With that mea culpa, herewith are all the gory details of my wife's Porsche 944 Callaway Turbo.
1983 Porsche 944 Callaway Turbo
By Thomas A. Thompson – August 2019[/b][/b]
General History of the Porsche 944 Model
For a full discussion of the Porsche 944 model’s origins and history, the following links are very useful:
The balance of this monograph describes the history of the specific above-described vehicle.
Production and Delivery
The 944 described above was produced by Dr. Ing. H.C.F. Porsche AG in April 1982 and assembled at the Audi body plant in Neckarsulm, Baden-Wurttemburg, Germany, not far from Stuttgart. Its VIN number indicates that it was the 973rd example of the model run. The author has been told, without verification, that Porsche reserved the first 30 production numbers for its own use, which, if true, would make the car the 943rd produced.
The car had been ordered by a cardiologist then living in Guilderland, New York. The original owner was and is a friend of the car’s current owner and the author. Financing was arranged as a lease through the first titled owner, Essex Leasing, Inc. of Essex, Connecticut. The car arrived at the selling dealer, Route 44 Volkswagen, Inc. dba Porsche/Audi of Avon, CT in mid-May 1982.
A note: The original owner claimed the car had been ordered to be finished in the Porsche color “Guards Red”, with a black full-leather interior. The delivered car was finished in the Porsche color “Light Blue Metallic” (the English name; the German name found on the paint code sticker in the car is “Hellblau Metallisch” – “Sky Blue Metallic”) with an interior described as “Grey/Beige”, featuring light beige carpets and seats upholstered in black/grey Berber cloth with vinyl sides and backs. The seats also feature lower and more comfortable bolsters than the stock vinyl-and-cloth or leather-faced seats. No explanation of the differences between as-ordered and as-delivered has ever been discovered.
Callaway Turbocharger Conversion
The 944 was delivered from the selling dealer directly to Callaway Cars of Old Lyme, CT shortly after arrival. The original owner and Reeves Callaway were previously acquainted through earlier motorsports activities. At the time, Callaway Cars was engaged in two major activities:
1. Development and implementation of aftermarket turbocharger installations for automobiles whose manufacturers did not offer a vehicle so equipped.
2. Development of a new design for a race car engine intended for the American “Indy Car” circuit, the best-known race of which is the Indianapolis 500. This effort was financed through an “R&D Limited Partnership” and resulted in the business having a group of automotive engineers on staff.
The 944 brought to Callaway by the original owner was the first of its kind to be turbocharged by the Callaway firm. As reported in a January 1983 article in “Autoweek” magazine, it presented several challenges which needed to be overcome for a successful result. The stock 944 engine was extremely sophisticated for its time, and not especially well-suited to turbocharging.
First, it relied on a fully electronic engine control system, the Bosch Digital Motor Electronics unit, (Motronic, or DME) which controlled all fuel and ignition activity within the engine. In the Autoweek article, Callaway engineer Terry Eames described the situation this way:
“The problem is that they have mapped out ignition for every conceivable parameter (including engine speed, air temperature, throttle position and lambda sensor) and they have programmed all that into a chip. They (the engines) run extremely well, but they certainly weren’t designed for turbos.”
Second, the stock engine was built with a 9.5:1 compression ratio. That is significantly higher than what is practicable on a turbocharged engine, where pre-ignition detonation is “the major enemy” of a dependable, long-running engine. Engine heat increases due to the higher internal pressures of turbocharging were also an issue.
Solutions to these challenges were found through four major modifications beside the basic turbocharger unit itself:
1. The DME unit was “tweaked” with “a little signal conditioning” according to Terry Eames. Included in this scope were a knock sensor device that retarded spark timing when it sensed detonation inside the engine, and a microprocessor-controlled fifth fuel injector (added to the stock four injectors) fitted ahead of the fuel rail to add cooler fuel to the compressed intake charge which heated as it was compressed.
2. The fuel injectors themselves were replaced with higher-flow injectors as used in Porsche’s 911 Turbo model, which was purpose-designed by the company for higher horsepower and torque.
3. The engine was disassembled. The head and piston tops were machined using a CNC machine to enlarge the combustion chamber dimensions by .100”. The stock cast piston tops were machined across most of their diameter to the depth of the “eyebrow” cuts machined into them at the factory to allow proper valve clearance. The result was to lower the compression ratio, from 9.5:1 to 8.0:1, per the Autoweek article.
4. An air-to-air intercooler was fitted between the compressor side of the turbocharger and the intake ports of the engine to assist in cooling the intake charge.
Another modification involved eliminating the stock exhaust manifold and replacing it with a custom-fabricated mild steel manifold to provide the proper location and strength to hold the IHI turbocharger unit. Aft of the turbo unit, Callaway eliminated the stock exhaust system in favor of a larger 2.5” exhaust pipe feeding out through a custom-fabricated stainless steel resonator.
The tuning process showed that the stock radiator and internal oil cooler were sufficient to handle the increased engine heat, provided that the fuel mixture was enriched as much as the DME system would permit. The thermostatically controlled radiator fans were found to increase their duty cycle due to the higher coolant temperatures. Coupled with the extra fuel injector, this reduced fuel mileage from the stock 25-27 mpg to 18-20 mpg. Some twenty-nine years later, operations in the high-and-hot New Mexico desert would demonstrate a need for greater cooling capacity.
Dynamometer tests were conducted on the engine before re-installation. It was found to produce 285 bhp at 12 psi boost at 5,500 RPM, just shy of doubling the stock engine’s 143 bhp at 5,500 RPM. Torque figures increased dramatically also.
Callaway-brand roundel badges were added to the left rear and the ash tray cover of the car. A rectangular Callaway badge was added on the top of the distributor drive housing at the front of the engine. The cost of the conversion process was approximately $7,850 in 1982 dollars. The car was re-delivered to the original owner in late June 1982.
Callaway Production History
The “944 Callaway Turbo” was offered from May 1982 until Porsche AG announced the European introduction of its own turbocharged 944 model in late 1984. Callaway ceased taking orders for its version at that time. It has been reported to the author (without independent verification) that Callaway modified thirty-eight 944s in total. Also reported, but not verified, is that one of Callaway’s former mechanics completed a thirty-ninth modified car using Callaway parts outside of Callaway’s supervision. (Update 6/14/2020: Reeves Callaway was contacted by an appraiser engaged by the author to value the car for insurance purposes. In his response, Callaway noted that he believed only "7 or 8" 944 Callaway Trubos were built, not the 38 reported years ago to the owner.)
The original owner drove the car from May 1982 through August 1983. His typical mission for the car was daily commuting from his home to his practice office and hospital in Albany, NY. The car was returned to Callaway for service on at least two occasions. The author accompanied the owner on one of those service visits. Along the way, the car acquired the nickname “The Big, Blue Toy.”
In late summer 1983, the original owner decided to sell the car. Although it proved itself a superb open-road sports car, its performance in city traffic was affected by a slight “turbo lag”. In addition, he was anxious that the car wasn’t damaged in parking lot encounters with opening doors, shopping carts and the like.
The current owner, Jane Thompson, and her husband, the author, had earlier expressed interest in acquiring the car should the original owner decide to sell. As a result, the Thompsons became the owners of the car through taking over the existing lease on August 31, 1983. Less than two years later, on July 18,1985 they bought out the balance of the lease and acquired fee simple title to the vehicle. Regrettably, no service records from the original ownership were included in the sale.
A full discussion of services performed on the car is beyond the scope of this monograph. An Excel Spreadsheet summarizing all service during the owner’s possession of the car is available. However, several modifications added after the Callaway Turbo installation are worthy of note. These include:
1. Sound system – In the summer of 1982, the original owner engaged Rich’s Car Tunes of Watertown, MA to replace the stock radio and front speakers with a custom-designed sound system installation. As completed, the system featured a Concorde head unit with AM/FM and cassette tape functions, two Kenwood KAC-901 amplifiers mounted in the rear under-carpet compartments, two 5.25” ADS 325im stereo speakers mounted in the front doors, and two 7” ADS sub-woofers mounted in the rear compartment covers. The head unit was replaced in 2008 with an Alpine CDA-9855 unit with AM/FM, CD and mp3/iPod capabilities.
2. Also, in the summer of 1982, the front carpet set was replaced due to dye transfers caused by a defective floor mat. The original owner erred in ordering the replacement carpet, obtaining a “champagne” (very light tan, almost but not quite indistinguishable from the original color) replacement. The carpet was installed by Paterek Brothers of Old Chatham, NJ, a nationally known restorer of Porsche and other classic automobiles. Paterek Brothers subsequently replaced the rear carpet set for the same reason, with the same “champagne” color to maintain consistency.
3. Also, in the summer of 1982 the stock wheels (15”x7”, “cookie cutter” design, and associated 215/60HR15 tires) were replaced with BBS “RA” model wheels (16”x7” front and 16”x9” rear, with 205/55VR16 and 225/50VR16 tires). These were in turn replaced in 2009 with Porsche “Sport Classic II” wheels (17”x7” front, and 17”x9” rear, with 225/45VR17 tires front and 255/40VR17 tires rear). A new set of tires was installed in April 2019.
4. In January 1987 the engine was completely rebuilt as the result of a failure of the cylinder #4 compression ring, which scored the alloy engine bore. The rebuild included returning the engine block to Callaway Cars, where it was step-bored and fitted with steel cylinder sleeves. This modification was not performed in the original conversion but became a standard feature of the process following “the first five or ten” conversions, according to Reeves Callaway in a telephone conversation with the author at the time. Also replaced in the rebuild were all wear parts throughout the engine, and the stock pistons. A set of used Porsche 944 Turbo pistons were sourced by the rebuilder, German Auto Haus of Burnt Hills, NY. The heavier, forged pistons were chosen for greater durability than the thinner, cast pistons of the stock engine.
5. In April 2000 the exhaust system was replaced again with an ANSA muffler in place of the resonator, and a newly fabricated stainless-steel exhaust manifold replacing the original Callaway mild steel unit. The turbocharger unit was rebuilt at the same time.
6. In May 2014 an external oil cooler was installed by PMCI of Corrales, NM to provide greater oil cooling capacity in high desert operations.
7. In June 2015 an aftermarket 944 Turbo radiator sourced from Wizard Cooling of Buffalo, NY was installed by PMCI.
The car was first featured in an article in “Autoweek” magazine’s January 1983 issue. A reprint copy is available. “VW & Porsche” magazine featured the car in an article in its March/April 1983 issue. A copy of that article is available also. It was also featured in the September/October 1982 issue of the local newsletter of Hudson-Champlain Region of Porsche Club of America. (Update 6/14/2020: An article on Callaway Porche trubo conversion also appeared in "Car & Driver" magazine's November, 1983 issue.)
The vehicle appeared in local and regional Porsche Club of America events between 1984 and 2010, winning its class on several occasions, including the 25th annual “Zone I Concours” in Saratoga Springs, NY in 2004. Other regional awards include a first in class at “Fiesta New Mexico”, a PCA event held in May 2012 in Santa Fe, and at the “Deutschland in ‘Burque” car show in Albuquerque, NM in June 2012.
The car has also appeared at the national level in several “Porsche Parade” Concours d’Elegance events. The Porsche Parade is the annual national convention of the Porsche Club of America, the world’s largest single-marque sports car club. These appearances include:
1986 – Portland, ME 1994 – Lake Placid, NY
1998 – Mt. Tremblant, QC, Canada 2005 – Hershey, PA
At the 1994 Lake Placid Parade, the car placed fourth in class. At the 2005 Hershey Parade, the car won its class for 944 touring cars with a score of 235 out of a possible 265 points. At the 2014 Monterey Parade, the car placed second in class.
The car has only been driven once on a racetrack. That was at a spring 1988 high-performance driver education event at Lime Rock Park in Lime Rock, CT. The purpose of the appearance was to break in the engine which had been rebuilt the previous winter. The car has also competed in Porsche Parade autocrosses, which are low-speed events typically held at sites other than racetracks.