1958 Buick Limited: One-Year-Only Chrome Behemoth’s Flight Pitch Dynaflow Was An Early CVT – Its Air Suspension Was Just A Nightmare

Photo showing the right side of a Blue Mist 1958 Buick Limited four-door hardtop with an overlaid banner for the Flight Pitch Dynaflow transmission

The 1958 Buick Limited was one of the biggest, gaudiest, grandest cars of a notoriously grand and gaudy era for Detroit. It was an expensive flop that lasted only a single year, but beneath its glittering chrome, the Limited offered some ambitious technology, including excellent finned aluminum brakes, a disastrous self-leveling air suspension, and the most complex of Buick’s torque converter automatic transmissions: the triple-turbine Flight Pitch Dynaflow, an early type of CVT similar in some respects to the planetary e-CVT transmission in a modern Toyota Prius.

Closeup photo of the Limited badge on the rear fender of a silver 1958 Buick Limited
1958 Buick Limited Model 756 convertible in Silver Mist / Mecum Auction

A 1958 Buick Limited — Limited Series 700 in the factory specifications — was the tip-top of the Buick line for ’58, reviving a nameplate Buick had used in the late ’30s and early ’40s. The 1958 Limited shared the 127.5-inch wheelbase of the already massive Buick Roadmaster, but had an extra 8 inches of rear overhang, bringing its overall length to a colossal 227.1 inches — “nearly 19 feet of luxury-built car,” said the brochure.

Left front 3q view of a blue 1958 Buick Limited four-door hardtop
1958 Buick Limited Model 750 4-door Riviera hardtop in Blue Mist / Bring a Trailer

The Limited was available as a two- or four-door hardtop or a convertible, with prices starting at $5,002, around $218 MORE than a 1958 Cadillac Series 62. (Stephen Pellegrino has previously compared the 1958 Limited with the Series 62.) That price got you lots of standard equipment (power steering, power brakes, power windows, a power seat, but curiously not a heater) and as much chrome as GM Styling VP Harley Earl could browbeat his staff into adding.

Color photo of Harley Earl in a styling studio, wearing a blue suit
Harley J. Earl (1893–1969), vice president of GM Styling Staff through late 1958

There’s a well-known story about the design of the 1958 Buick and how it got its abundant bling, which stylist Henry Haga (who was in the Buick studio when the ’58 models were designed) related to Dave Crippen of The Henry Ford Museum in 1986. To envision this scene properly, it’s important to understand that Harley Earl was an enormous man — well over 6 feet fall and built like a linebacker, albeit always perfectly groomed and a very natty dresser — and he had an extremely intimidating physical presence. (Very, very few of his staff would have dared to call him “Harley” within his earshot; if you were not a senior officer of the corporation or a longtime personal friend, he was “Misterl.”) Haga explained:

Haga: The issue here was a new Buick, and it was a ’58. The ’59 was being formed, but you still had to live through the ’58, and you had the old body style, which was rather bulbous and heavy and not sleek like the Chrysler’s. And I remember Harley coming in and saying, “Now, now, guys, I want you to do a sweepspear, and I want you to do some hood scoops, bubble bombs, Dagmars, portholes, and rockers, and chrome wheels. And I want you to do all those, and then I’ll be back, and then we’ll decide what we’re going to do.” And then he left — clip, clop, clip, clop, clip, with his huge wingtips, you know, immaculately dressed. You would always hear his pace — clip, clop, clip, clop — and everybody’d freeze.

Crippen: A slow-measured tread?

Haga: Right. Came back the next day, and he says, “Jesus Christ, fellas, you didn’t hear me — you just got a sweeps[spear]. Where’s all the other paraphernalia?” And, of course, it was hanging on the boards all over. He said, “Now, why don’t you do what I say? Put it all on.” So, we put every kind of chrome piece we could on that side view rendering, and he said, “There, guys, now you’ve got it.” Clip, clop, clip, clop, he walked out, and we all looked at each other. “He’s serious! This is it! This is a go-to-press!” And if you’ll remember, the ’58 Buick, it had everything on it.

Front view of a silver 1958 Buick Limited convertible
1958 Buick Limited Model 756 convertible in Silver Mist / Mecum Auction

The 1958 Buick did indeed have almost everything, including its flashy “Fashion-Aire Dynastar Grille.” The only thing missing, surprisingly, were the signature Buick front fender “ventiports,” somehow lost in the shuffle; they would be back for 1960.

Right rear 3q view of a silver 1958 Buick Limited convertible with a white top and wire wheels
1958 Buick Limited Model 756 convertible in Silver Mist / Mecum Auction

The assumption in those days was that senior models needed extra brightwork in proportion to their higher prices, so the Limited was the flashiest and shiniest of the bunch, punctuated by the fifteen chrome hash marks that adorned each rear fender.

Dashboard and front seat of a 1958 Buick Limited convertible with red upholstery
1958 Buick Limited Model 756 convertible with red leather upholstery / Mecum Auction

How did this biggest and fanciest Buick drive? “Ponderously” seems to have been the best word for it. Buick in the ’50s was determined to achieve the softest possible ride, handling and back-roads composure be damned. On smooth, straight highways, it was almost magical — Buick called it the Miracle Ride — but if you drove a little too fast on a winding, bumpy road, the big Buick would lurch, bottom, and bounce like a hippo on a trampoline.

Buick 364 engine under the hood of a 1958 Buick Limited
1958 Buick “B-12000” V-8 engine was 364 cid, with 300 hp and 400 lb-ft in four-barrel form / Bring a Trailer

Increased size and weight had also taken its toll on Buick straight-line performance. For a while in the mid-’50s, a V-8 Buick could be a pretty hot number, but by 1958, even the smaller, lighter Buick Century gave only average acceleration. Motor Trend‘s 1958 Century needed 11.2 seconds to hit 60 mph and ambled through the quarter mile in 19.0 seconds at 79.7 mph, and even that required starting in L range. I didn’t find any instrumented tests of the 1958 Limited, but since the Limited weighed over 400 lb more than a Century and had no more power, it was undoubtedly even slower. Fuel consumption in stop-and-go traffic was also under 10 mpg, not a great selling point in a recession.

Left front suspension and wheel of a 1958 Buick Limited up on a hoist, showing the finned drum brake
Senior 1958 Buick models had finned aluminum front brakes / Bring a Trailer

Nonetheless, the 1958 Limited offered three advanced technological features worthy of note: its new brakes and transmission, which were standard equipment, and the new Air-Poise air suspension, which was optional at extra cost.

Press photo of a Buick finned brake drum with perforated iron inner liner
Front drum brakes for 1958 were now cast aluminum (except on Special), with perforated cast iron wear surfaces

First, the brakes, which were all good news. The brake drums on senior 1958 Buicks were the same 12-inch diameter as before, but they were now finned (“air-cooled,” the brochure said), and the front drums were cast aluminum. Effective lining area was up only a little from 1957, so the aluminum brakes wouldn’t stop any shorter, but their superior heat dissipation gave them much greater endurance. Motor Trend found that the number of hard stops Buick brakes could survive before fading completely had almost doubled from ’57. By 1958 standards, these brakes were first rank among American cars. Buick would continue to use the finned aluminum brakes on its full-size cars until front discs belatedly became standard more than a decade later.

Diagram showing the major components of the 1958 Buick Air-Poise system

Air-Poise suspension, a new option this year, was much more ambitious and far less successful. The air suspension was a GM Engineering Staff development, adopted in different variations by each of the GM automobile divisions for 1958. Air-Poise replaced the standard steel coil springs with air springs, which were charged by a two-cylinder engine-driven compressor at up to 290 psi, with an 820-cid high pressure storage tank.

Brochure excerpt with a series of small illustrations explaining the manual height control of the Buick Air-Poise air suspension system

The system was supposed to automatically pump up or exhaust the springs to maintain a consistent, level ride height regardless of load or road surface, which also gave a variable spring rate. Buick claimed that Air-Poise provided “superior road-holding ability,” a soft boulevard ride, and better composure over rough surfaces than steel springs. There was even a manual override to raise the suspension for extra ground clearance.

Side view of a silver 1958 Buick Limited convertible with a white top and wire wheels
Air-Poise was an extra-cost option this Limited convertible lacks; wire wheels are from an earlier Buick Skylark / Mecum Auction

Unfortunately, these early GM air suspensions had many reliability problems. They inevitably leaked, for one, and because they were only “semi-closed” (under some conditions, they drew outside air through the engine air cleaner), moisture buildup in humid conditions could cause internal corrosion. Worse, even when it was healthy, the Air-Poise system just didn’t work very well. Motor Trend offered this caustic evaluation of a 1958 Super with Air-Poise suspension:

On glass-smooth roads the ride of the car was as good as it is in a car with coil springs, but on roads with irregular surfaces, such as concrete roads with ridges at a right angle to the direction of travel, the wheels would hop up and down in an uncontrolled manner. The wheels didn’t move far but their movement was enough to set the car’s frame and body to vibrating. The hood and fenders could be seen doing a jig in time with the wheels. On one of the concrete freeways in the Los Angeles area wheel movement became so bad at the limit of 55 miles per hour that the entire car and the legs of its passengers were vibrating. On really rough surfaces, or when holes or filled spots in the road were hit, the wheels would go completely out of control and the hood and front fender assembly of the car would clatter like a tin barrel half full of tin cans rolling down a hill. Some of these bumps would cause the horn ring on the steering wheel to chatter. On turns and corners the car would lean badly, making it uncomfortable for the driver and passengers. The lean was bad even when car speed was reduced to the bare minimum.

Some types of dips at street intersections would cause the rear to bottom with a thud that shook the whole car. This happened only on dips that had the right angle and depth but it didn’t matter whether there was a load in the car or not. Some dips that wouldn’t make the rear end bottom would cause it to bounce unusually high. As it wasn’t possible to tell from looking at a dip whether the car would bottom or bounce, I got to the point where I would just grit my teeth for all of them and take what came.

M/T thought the system might be made to work okay with further development, higher spring rates, and firmer shock damping, but as it was, they called Air-Poise “a most undesirable feature” and “much inferior” to conventional springs.

Rear view of a silver 1958 Buick Limited convertible with its white top up
1958 Buick Limited Model 756 convertible in Silver Mist / Mecum Auction

1958 Limited and Roadmaster buyers wary of Air-Poise could simply not order it, saving themselves about $188 and a lot of future headaches, but the new Flight Pitch Dynaflow transmission was standard equipment on the senior Buicks. (It was optional on lesser models, costing about $75 extra on a Century or Super and a hefty $296 on a Special.)

Labeled B&W cross-section of a 1958 Buick Flight Pitch Dynaflow transmission

If you’re a ’50s Chevrolet fan, the workings of Flight Pitch Dynaflow might sound somewhat familiar. As an engineer from Borg-Warner pointed out at the time, Flight Pitch was “essentially an enlarged version of the Chevrolet Turboglide with a different method of controlling the variable pitched stator blades.” Buick had not been copying Chevrolet engineers’ homework — the basic concepts for both these transmissions came from a GM Engineering Staff product study group project, which Buick and Chevrolet both decided to adopt. Chevrolet had just been first out of the gate, introducing Turboglide in 1957.

Underside of a 1958 Buick Limited, raised on a hoist to show its transmission and sump
Despite extensive use of aluminum, Flight Pitch Dynaflow had a dry weight of 200 lb / Bring a Trailer

I said in the opening paragraph that Flight Pitch Dynaflow was a continuously variable transmission (CVT). Technically speaking, ANY torque converter could be considered a CVT, but most torque converter automatics use the converter primarily as a clutch for some other type of stepped-gear transmission. Even in transmissions that were intended to rely mostly on the converter, like the early Packard Ultramatic or Buick’s twin-turbine Variable Pitch Dynaflow (which I described in detail in an earlier post), there was a separate manually shifted planetary gearbox for low range and reverse.

Color-coded diagram of a 1958 Buick Flight Pitch Dynaflow showing how the turbines connect to the planetary gears

Flight Pitch Dynaflow went a few steps beyond that. It had two planetary gearsets in a case behind the converter housing, which at a glance looked sort of like a three-speed automatic. It wasn’t — the planetary gear elements were connected directly to the different converter turbines, as shown in the above schematic, which I’ve color-coded to better illustrate the power flow. The reaction elements (highlighted in fuchsia) were controlled by overrunning clutches.

Graph showing output torque vs mph at full throttle for each of the three turbines of a Flight Pitch Dynaflow transmission

The planetary gears multiplied the torque from each turbine, but the amount of torque was constantly changing depending on engine and output speeds, so the gearing also served to COMBINE the outputs of the three turbines. As the above graph shows, the first turbine transmitted the most torque at low speeds, with the second and third turbines taking over as speeds increased. At high speeds or when cruising, the third turbine transmitted all the torque, leaving the first and second turbines to freewheel in the stream of moving oil. Because the operating ranges of the turbines overlapped, there was never any noticeable shift, just a smooth flow of power.

Diagram of the power splitting device of a Toyota Prius
Toyota Prius Hybrid Synergy Drive e-CVT power splitting device with planetary gears

As I mentioned in the first paragraph, the power split device in the e-CVT of a modern Toyota Prius uses planetary gears to combine the power inputs from its internal combustion engine and motor/generators in a broadly similar way. (Director/animator E.A. Hart has created a cool online simulator to show how the different input speeds combine through the planetary gears to produce different output speeds.) The relationships between the speeds of the different elements are fixed, since they’re a function of the number of teeth on the planetary gears, but they can be combined in an infinite number of ways, and the output is completely stepless.

Graph showing output torque versus output speed in rpm for a triple-turbine transmission and an ideal 100% efficient converter

A 1958 Buick wasn’t a hybrid and didn’t have multiple power sources to combine, so what was the point of combining multiple turbines like this? Any torque converter is a compromise: If you could design an ideal converter with 100 percent efficiency, its output curve (output torque versus output speed) would be a nice, smooth parabolic arc, but that’s impossible in the real world. By using the planetary gearing to combine multiple turbines with different blade characteristics, the total output of the Flight Pitch transmission was much closer to the ideal, as shown in the above graph. It was like combining three different torque converters into a single unit.

Right front 3q view of a pink 1958 Buick Limited two-door hardtop with a white roof
1958 Buick Limited Model 755 2-door Riviera hardtop in Reef Coral with a Glacier White roof / eBay via autoevolution

This had two important real-world benefits. First, the triple-turbine converter produced a much higher “torque ratio” than a conventional three-element converter (or even the Buick twin-turbine converter). A typical automotive torque converter has a torque ratio of around 2 to 1 with the output shaft stalled (not moving); Flight Pitch had a stall ratio of 4.75 to 1 in Drive, which was pretty close to the starting ratio of a conventional three-speed torque converter automatic starting in first. Second, Flight Pitch could continue to multiply torque up to much higher speeds — Buick claimed that with the throttle wide open, there was some torque multiplication up to about 90 mph — which meant better overall acceleration.

Right rear 3q view of a pink 1958 Buick Limited two-door hardtop with a white roof
1958 Buick Limited 2-door Riviera was very rare — only 1,026 were built / eBay via autoevolution

As the man from Borg-Warner pointed out, Chevrolet Turboglide had many of these same characteristics, but Buick had a new trick up its sleeve with its variable-pitch stator. A stator is a set of reaction blades that multiply torque by redirecting the fluid flow within the converter; the angle of the blades determines how much leverage they can exert and thus how much torque multiplication the stator can deliver. A few years earlier, Buick had figured out that they could set up the stator to CHANGE the angle of its blades when the driver mashed the accelerator all the way to the floor, giving a little extra kick for acceleration. Chevrolet adopted that system for Turboglide in 1957, and a similar “switch-pitch” concept popped up again in the ’60s (on the early Turbo Hydra-Matic and some versions of the Super Turbine 300 two-speed).

B&W diagram showing the controls of the infinitely variable stator of a 1958 Buick Flight Pitch Dynaflow transmission

Unlike those switch-pitch converters, which changed between one high and one low angle, Flight Pitch Dynaflow had an infinitely variable stator, which could change the angle of its blades to any position through a range of about 55 degrees based on the position of the throttle. The idea was that this would enable the converter to respond almost directly to the accelerator pedal “to select the exact level of performance the driver desires.”

Diagram showing the way Grade Range drove the T1 blades to oppose engine rotation

This was important because unlike the twin-turbine Variable Pitch Dynaflow (still fitted to many 1958 Buicks), Flight Pitch Dynaflow didn’t have a separate low range. With other Dynaflow transmissions, you could move the shifter into “L” for better acceleration or downhill engine braking up to about 45 mph. You couldn’t do that with Flight Pitch Dynaflow or Turboglide. Instead, they had a “Grade Range” position for use on step downhill grades. It caused the planetary gears to overdrive the first turbine at 2.86 times the speed of the output shaft, producing massive engine braking.

Photo of the shift quadrant of a 1958 Buick Limited with Flight Pitch Dynaflow
Shift pattern of the Flight Pitch Dynaflow was P R N D G — there was no L range / Mecum Auction

Shifting to “G” would slow the car so dramatically that it could actually chirp the rear tires, like dropping a manual gearbox into first while on the move. Buick warned not to attempt this if you were going more than 45 mph, and it obviously didn’t help acceleration.

Left front 3q view of a silver 1958 Buick Limited convertible with its white top up
1958 Buick Limited had a curb weight of close to 4,900 lb (over 5,000 lb with air conditioning and air suspension) / Mecum Auction

On paper, the continuously variable Flight Pitch Dynaflow seemed like an almost ideal automatic transmission. In the real world, it was not so hot. Flight Pitch did okay in full-throttle acceleration, once you got used to the fact that engine speed increased a lot faster than forward progress. It was in moderate part-throttle acceleration where it started to seem like Buick might have outsmarted itself. Testing a 1958 Buick Super with Flight Pitch Dynaflow, Motor Trend complained:

Acceleration to pass another car was out of the question without shoving the throttle to the floor. Any throttle position that didn’t bring the [stator] low pitch into action was inadequate to change the car’s rate of speed quickly enough to pass with any degree of safety. This is ridiculous in a car that has an engine rated at 300 horsepower. With the throttle on the floor, car speed would pick up well enough for passing but until the foot was pulled out of the carburetor the engine would over-rev badly in relation to the speed of the car. The over-revving didn’t seem to hurt the engine, but it didn’t contribute to comfortable driving. … With the throttle on the floor the car accelerated well for a heavy car but the commotion in the engine compartment was embarrassing if there were other cars nearby. Once up to speed, the throttle could be backed off and the car would maintain speed without any fuss.

In side-by-side comparisons, M/T found that response with the less-complicated, theoretically less-efficient twin-turbine Variable Pitch Dynaflow was “so much better than with the Flight Pitch that the cars could have been made by different companies.”

B&W photo of the case, tail extension, and first and second turbines of a 1958 Buick Flight Pitch Dynaflow
Flight Pitch Dynaflow had some iron parts, but the major components were aluminum, either permanent mold (shown) or die cast

As with the Air-Poise suspension, Flight Pitch Dynaflow suffered more than its share of reliability woes. It had taken Buick a lot of work and a horrifying amount of money to get the transmission even close to ready — this was the division’s first real experience with complex aluminum castings — and it had many bugs. Since the cheaper Variable Pitch Dynaflow was just as smooth and easier to drive, all that effort seemed like a waste.

Grille, headlights, and hood ornament of a blue 1958 Buick Limited
1958 Buick Limited 4-door Riviera was the most common body style, with 5,571 built / Bring a Trailer

Overall, the 1958 Buick was just the wrong car at the wrong time. A sour economy in 1957–1958 led many Americans to decide they were tired of grandiose size and extravagant glitz, and even the cheapest Buick Special offered far too much of both. Buick sales had been down for 1957, but they tumbled a FURTHER 40 percent for 1958. The Limited suffered the worse, selling just 7,508 units. Unsurprisingly, it would not return for 1959, although Buick reused the name again later. Flight Pitch did return for 1959, renamed Triple Turbine and somewhat improved, but it was no longer standard even on senior models, and it lasted only one more year. Buick air suspension was limited to the rear springs for 1959, now acting mostly as a self-leveling system. It too disappeared for 1960.

Side view of the tail fins of a silver 1958 Buick Limited, seen from the right
1958 Buick Limited convertible was extremely rare — only 839 were built / Mecum Auction

Air suspensions and continuously variable transmissions both returned later, and CVTs are now quite common, although it’s taken an awfully long time for the real-world benefits of both technologies to come close to the advantages they seem to have on paper. Some people would argue that they’re still not quite there yet, more than 65 years after these glittering and ambitious land yachts came and went.

Related Reading

Curbside Comparison: 1958 Buick Limited vs 1958 Cadillac Series 62 – Chrome Plated GM Luxury (by Stephen Pellegrino)

CC Tech: Inside Buick’s Turbine Drive (Twin Turbine) Automatic Transmission (by me)

Full-Size Buicks Of The 1960s: How Buick Reinvented Its Lineup Between 1959 And 1970 (by me)

1959 Buick Electra 225 Convertible: As Bat-Winged As The Batmobile (by me)