Paxton-McCulloch Supercharger History - Part II
Paxton / McCulloch Supercharger History – Part II
The Paxton VS57
The concept of a cheap, bolt on aftermarket supercharger for the general public was never dropped by Bob McCulloch and extensive research was carried out by Paxton Engineering (who changed fairly quickly to Paxton Products) to produce a system which would deliver a significant amount of boost at low engine rpm without subsequent high impeller speeds at high engine rpm. The system was required to have the service requirements of the automobiles it was to be fitted on, and should to be quiet in operation and retailed at low cost. Manufacturing and installation requirements specified that one supercharger model could be fitted to a variety of vehicles, and that lubrication was internal to minimize contamination.
The VS57 was the result of over $700,000 being spent in research and development in an effort to meet these requirements, and was made possible by the elaborate multi-section magnesium die casting production methods developed by Gerald Robechaud. The VS57 was first produced in 1951 in limited numbers, and was extensively road tested in California for two years before being marketed to the public in 1953. The VS57 was driven using a V shaped belt and used a unique Variable Speed (VS) drive pulley in conjunction with an idler arm to generate high boost at low engine rpm. The flanges of the supercharger pulley were designed to have a variable separation, which was used cleverly in conjunction with input shaft speed multiplication via a planetary ball drive, to vary the impeller speed across the engine rpm range. At low engine rpm belt tension separates the flanges of the input shaft pulley and drives the input shaft at a 1:23 ratio to the crankshaft pulley. At high engine rpm the boost produced is regulated to 5 psi and boost is used to force the input shaft pulley flanges together, causing the belt to rise, and the input shaft to be driven at a ratio of 1:13 to the crankshaft pulley. The actual input shaft ratio changes gradually between 1:23 and 1:13 as the closing flanges overcome the tension of the idler pulley. The planetary ball drive multiplies the input shaft speed by 4.4 to 1 to produce high impeller speeds, thus producing boost. A kick down set up is incorporated which forces the blower into high boost when there is a sudden power demand, and this is governed by a solenoid switched via inlet manifold vacuum, which drops on high acceleration. Lubrication was achieved by a cam driven oil pump mounted on the ball driver shaft immersed in an internal oil reservoir.
Initially the supercharger was only available for 1950 through 1953 Ford cars, although fast gearing up of mass production in October 1953 resulted in the kit range being extended to cover very nearly every commercially available V8 and straight 6 engine in early 1954. As well as manufacturing the supercharger McCulloch Motors also set up an installation shop so that initial owners would benefit from proper factory installations and consequently avoid bad early publicity whilst the dealer network was being established and trained up. McCulloch employees were given a 35% discount off the price of the supercharger kits, although the discount did not include the installation cost.
The lack of the dealer network in the early days meant that most publicity, apart from the initial press launch, was concentrated on the Los Angeles area. The new supercharger was lavishly displayed at the October 1953 PanPacific Motorama in Los Angeles using a 40 foot long stand. Three cars were displayed at the Motorama, a Ford, Mercury and a Cadillac powered Allard and the stand was staffed using an alternating pool of 35 McCulloch staff with actress Jane Easton (RKO and TV) recruited to front the stand. As a further publicity stunt by special arrangement the show’s Miss Motorama was also crowned Miss Supercharger and in personal appearances at the show and on television she wore a crown topped with a rotating replica of the VS57.
The general public were not the only ones targeted by McCulloch as they recognized the supercharger might have a market with the Hot Rod and drag race crowd. Under the pretense of showing ‘customers of the future’ the supercharger, McCulloch invited many clubs to witness performance tests of the supercharger, although given the relatively high pricing of the supercharger its unlikely that many of invited ‘customers of the future’ purchased the supercharger, although some were utilized on street/strip scene.
The VS57 supercharger was formally presented to the SAE on January 15, 1954 at Detroit’s Sheraton-Cadillac hotel to a convention audience of some 500 automotive engineers. The presentation was by John W. Oehrli and consisted of prepared text, colored movies and slides followed by a brief question and answer session. Earlier demonstrations to the Kaiser-Willys Corporation had sufficiently impressed them with the VS57 supercharger to cause them to shift it as standard on the Kaiser Manhattan installation of their 6-cylinder 226 CID engine in 1954, albeit labeled as a Kaiser supercharger. This was publicly announced in late January 1954 in the wake of the SAE meeting and it’s debatable whether the Kaiser-Willys adoption of the supercharger effectively killed off any interest by the majors.
The Kaiser installation used a maximum boost of 4 psi to increase the output of the engine to 140bhp, allowing the outdated engine to remain competitive, and was apparently well suited to the Kaiser engine due to the torque/hp characteristics. Anywhere up to 5,440 supercharged Manhattans were produced between 1954 and 1955, and Kaiser also used the VS57 on a few Darrin’s with the actual number of supercharged examples built believed to be just 3. A further 1,021 Manhattans were built for export to Argentina, and all but six are believed to not have been supercharged. The six Manhattan exceptions remained in the US and were retrofitted with superchargers. Unfortunately, as is well documented, the supercharged engines were not enough to save Kaiser from extinction in 1955. Packard, also in 1954, used a VS57 supercharger on their show car, the Packard Panther. This was a fiberglass-bodied sports car based on a 122 inch wheelbase with a 359 CID straight eight powerplant providing 275bhp with the McCulloch installed. Five of these unique cars were built, and they are particularly notable due to one example being timed at 131.1mph at Daytona in 1954, making it the fastest in it’s class at that time.
Given the performance nature of the supercharger and its possible appeal to motorsport enthusiasts McCulloch also actively promoted the VS57 at Carrel Speedway at the Memorial Day meeting on May 30 1954. A supercharged Kaiser was entered in the 250 mile endurance run and it qualified 12th in the 33 car field. A crash with another car resulted in engine damage and an early retirement for the Kaiser after 55 laps. More positive publicity was achieved via a static display of a MG TD equipped with a McCulloch supercharger, the pace car for the race being garnished with McCulloch supercharger banners and the winner of the 500-lap stock car classic, John Torres driving a Dodge, being presented with a VS57 supercharger.
Further local publicity was achieved in May 1954 when the KTLA TV station transmitted an hour-long show about the VS57 supercharger. The show, which was titled ‘City at Night’ and which covered nighttime activities in Los Angeles, started at 10 pm and tracked supercharger production from die casting through to final assembly, and featured on-the-job interviews with McCulloch employees and management. The telecast opened with Fred Breer explaining the advantages of the supercharger for overtaking and altitude driving, and then for the main part consisted of vice president Sherwood Egbert talking through the production process. The close of the show featured presentations by John Oehrli and John Thompson.
National publicity for the supercharger was mainly achieved by single page adverts in some of the motoring presses in early 1955, and by an ongoing column written by John Thompson in Motor Trend which was first published in November 1955. These detailed achievements of the VS57 supercharger and also listed dealers who conducting McCulloch installations. This column actually ran through to March 1958 when Paxton changed ownership.
The VS57 enjoyed steady sales as an aftermarket performance accessory during the mid 50s, although these sales never met the production capability of 5,000 units a month that the McCulloch factory had. Studebaker was the next major manufacturer to adopt the VS57 in 1957. An enterprising Los Angeles dealer, as a $390 option, had previously offered the Studebaker Speedster with the VS57 in 1955 but this cannot be counted as factory production. Studebaker offered the VS57 installed on the Golden Hawk with the 289 CID engine producing 275bhp, equaling the output of the previous year’s heavy 352 CID engine, and giving the Studebaker a reputation as a performance vehicle. Supercharged Golden Hawk production continued into 1958, with the total 1957-1958 manufacture being 5,234 units. A total of 4,809 supercharged 289 CID Packard Clippers were produced in 1957, these being re-badged as Studebakers. A further 588 supercharged 289 CID Packard Hawks were produced in 1958 before the doors finally closed at Packard. Once again the VS57 was associated with the demise of an automobile manufacturer (but thankfully not the cause). Ford also retailed the VS57 in 1957 as a dealer installed power pack option, which reputedly resulted in a few dual-quad and triple-deuce configurations as well as standard single four-barrel configurations.
Total production of the VS57 during the 50s is believed to be in excess of 46,000 units, which gives an indication of the popularity of the unit, despite being quite an expensive accessory for a car of the period. The VS57 did however gain a reputation for being unreliable. Owners of high annual mileage vehicles often neglected servicing of the superchargers, which with the 3,000-mile servicing requirement of the VS57 often caused failures. This was compounded by hot rodders of the 50s also causing high failures of these superchargers, either by running at full boost all the time, resulting in overheating, or with the use of oversize crankshaft pulleys and high revving engines to produce higher impeller speeds and higher boost levels (also resulting in overheating). Despite these issues however, many thousands of vehicles during the 1950s ran well-serviced VS57’s for thousands of miles without any problems whatsoever.
Early Novi And Roots Superchargers
Supercharger manufacture and development was not restricted to the VS57 and Paxton Products were actively involved in researching new designs of superchargers. One significant early product that Paxton Products developed was the supercharger used on the Novi cars raced at Indianapolis. These were engine oil cooled conventionally mounted superchargers which were gear driven at a ratio of 5.25:1 and had impeller speeds of up to 40,000 rpm. The supercharged Novi V8 engines were capable of producing up to 650 hp from 180 CID, however power is not everything and they were generally unsuccessful in racing, although this was not attributable to the supercharger. The Novi name, and its connection with Paxton, still lives on today as Paxton Automotive currently produce a range of high-output gear-driven Novi superchargers.
Paxton Products even developed roots type blowers. Although these never went into production on a volume basis they could occasionally be seen at the drag strip. A one off McCulloch roots blower was run by John Bandimere from Denver, Colorado, on his 1955 Chevy at the 1955 national drags and apparently ran sizzling times.
Click here for Paxton-McCulloch Supercharger History - Part III
Last edited by Michael; 09-01-2009 at 07:49 PM.