Dynamometer

Dynamometer (pronounced dahy-nuh-mom-i-ter)

(1) A device for measuring mechanical force or muscular power (ergometer).

(2) A device for measuring mechanical power, especially one that measures the output or driving torque of a rotating machine.

1800–1810: A compound word, the construct being dynamo + meter.  Dynamo was ultimately from the Ancient Greek δύναμις (dúnamis; dynamis) (power) and meter has always been an expression of measure in some form and in English was borrowed from the French mètre, from the Ancient Greek μέτρον (métron) (measure).  What meter (also metre) originally measured was the structure of poetry (poetic measure) which in the Old English was meter (measure of versification) from the Latin metrum, from the Ancient Greek metron (meter, a verse; that by which anything is measured; measure, length, size, limit, proportion) ultimately from the primitive Indo-European root me- (measure).  Although the evidence is sketchy, it appears to have been re-borrowed in the early fourteenth century (after a three hundred-year lapse in recorded use) from the Old French mètre, with the specific sense of "metrical scheme in verse”, again from the Latin metrum.  Metre (and metre) was later adopted as the baseline unit of the metric system.  Dynamometer is a noun; the noun plural is dynamometers.

The modern meaning of dynamometer (measuring the power of engines) dates from 1882 and is short for dynamo-machine, from the German dynamoelektrischemaschine (dynamo-electric machine), coined in 1867 by its inventor, the German electrical engineer Werner Siemans (1816-1892). Dynamometers, almost universally referred to as dynos, are machines which simultaneously measure the torque and rotational speed (RPM) of an engine or other rotating prime-mover so specific power outs may be calculated.  On modern dynamometers, measures are displayed either as kilowatts (kW) or brake-horsepower (bhp).

Evolution of the Turbo-Panzer

Porsche 917 Flat 12 being run on factory dynamometer, Stuttgart, 1969.

During the last hundred years odd, the rules of motor sport have been written by an alphabet soup of regulatory bodies including the AIACR, the CSI, the FISA and the FIA and these bureaucrats have made many bad decisions, tending often to make things worse but every now and then, as an unintended consequence of their dopiness, something really good emerges.  The large displacement cars of the mid-1960s contested sports car racing in one of the classic eras in motorsport.  Everyone enjoyed the competition except the rule-making body (the CSI, the Commission Sportive Internationale) which, on flimsy pretexts which at the time fooled nobody, changed the rules for the International Championship of Makes for the racing seasons 1968-1971, restricting the production cars (of which 50 identical units had to have been made) to 5.0 litre (305 cubic inch) engines with a 3.0 litre limit (183 cubic inch) for prototypes (which could be one-offs).  Bizarrely, the CSI even claimed this good idea would be attractive for manufacturers already building three litre engine for Formula One because they would be able to sell them (with a few adaptations), for use in endurance racing.  There’s no evidence the CSI ever asked the engine producers whether their highly-strung, bespoke Formula One power-plants, designed for 200 mile sprints, could be modified for endurance racing lasting sometimes 24 hours.  Soon aware there were unlikely to be many entries to support their latest bright idea, the CSI relented somewhat and allowed the participation of 5.0 litre sports cars as long as the homologation threshold of 50 units had been reached.  A production run of 50 made sense in the parallel universe of the CSI but made no economic sense to the manufacturers and, by 1968, entries were sparse and interest waning so the CSI grudgingly again relented, announcing the homologation number for the 5.0 litre cars would be reduced to 25.

The famous photograph of the 25 917s assembled for the CSI’s inspection outside the Porsche factory, Stuttgart, 1969.

This attracted Porsche, a long-time contestant in small-displacement racing which, funded by profits from their increasingly successful road-cars, sought to contest for outright victories in major events rather than just class trophies.  Porsche believed they had the basis for a five litre car in their three litre 908 which, although still in the early stages of development, had shown promise.  In a remarkable ten months, the parts for twenty-five cars were produced, three of which were assembled and presented to the CSI’s homologation inspectors.  Pettifogging though they were, the inspectors had a point when refusing certification, having before been tricked into believing Ferrari’s assurance of intent actually to build cars which never appeared.  They demanded to see twenty-five assembled, functional vehicles and Porsche did exactly that, in April 1969 parking the twenty-five in the factory forecourt, even offering the inspectors the chance to drive however many they wish.  The offer was declined and, honour apparently satisfied on both sides, the CSI granted homologation.  Thus, almost accidently, began the career of the Porsche 917, a machine which would come to dominate whatever series it contested and set records which would stand for decades, it’s retirement induced not by un-competitiveness but, predictably, by rule changes which rendered it illegal.  

917LH (Langheck (long tail)), Le Mans, 1969.

The ten month gestation was impressive but there were teething problems.  The fundamentals, the 908-based space-frame and the 4.5 (275 cubic inch) litre air-cooled flat-12 engine, essentially, two of Porsche’s 2.25 (137 cubic inch) litre flat-sixes joined together, were robust and reliable from the start but, the sudden jump in horsepower (HP) meant much higher speeds and it took some time to tame the problems of the car’s behaviour at high-speed.  Aerodynamics was then still an inexact science and the maximum speed the 917 was able to attain on Porsche’s test track was around 180 mph (290 km/h) but when unleashed on the circuits with long straights where over 210 mph (338 km/h) was possible the early cars could be lethally unstable.  The first breakthrough in aerodynamic dynamic was serendipitous.  After one high speed run during which the driver had noted (with alarm) the tendency of the rear end of the car to “wander from side to side”, it was noticed that while the front and central sections of the bodywork were plastered with squashed bugs, the fibreglass of the rear sections was a pristine white, the obvious conclusion drawn that while the airflow was inducing the desired degree of down-force on the front wheels, it was passing over the rear of body, thus the lift which induced the wandering.  Some improvisation with pieces of aluminium and much duct tape to create an ad-hoc, shorter, upswept tail transformed the behaviour and was the basis for what emerged from more extensive wind-tunnel testing by the factory as the 917K for Kurzheck (short-tail).

Porsche 917Ks, the original (rear) and the updated version with twin tail-fins, Le Mans, 1971.

The 917K proved a great success but the work in the wind tunnel continued, in 1971 producing a variant with a less upswept tail and vertical fins which bore some resemblance to those used by General Motors and Chrysler a decade earlier.  Then, the critics had derided the fins as “typical American excess” and “pointlessly decorative” but perhaps Detroit was onto something because Porsche found the 917’s fins optimized things by “cleaning” the air-flow over the tail section, the reduction in “buffeting” meaning the severity of the angles on the deck could be lessened, reducing the drag while maintaining down-force, allowing most of the top-speed earlier sacrificed in the quest for stability to be regained.

The Can-Am: A red Porsche 917/10 ahead of an orange McLaren M8F Chevrolet, Laguna Seca, 17 October 1971.  Two years to the day after this shot was taken, the first oil shock hit, dooming the series.

The engine however had been more-or-less right from day one and enlarged first to 4.9 litres (300 cubic inch) before eventually reaching the 5.0 limit at which point power was rated at 632 HP, a useful increase from the original 520.  Thus configured, the 917 dominated sports car racing until banned by regulators.  However, the factory had an alternative development path to pursue, one mercifully almost untouched by the pettifoggers and that was the Canadian-American Challenge Cup (the Can-Am), run on North American circuits under Group 7 rules for unlimited displacement sports cars.  Actually, Group 7 rules consisted of little more than demanding four wheels, enveloping bodywork and two seats, the last of these rules interpreted liberally.  Not for nothing did the Can-Am come to be known as the “horsepower challenge cup” and had for years been dominated by the McLarens, running big-block Chevrolet V8s of increasing displacement and decreasing mass as aluminium replaced cast iron for the heaviest components.

The abortive Porsche flat-16.

In 1969, the Porsche factory dynamometer could handle an output of around 750 bhp, then thought ample but even 635 bhp wouldn’t be enough to take on the big V8s.  For technical reasons it wasn't feasible further to enlarge the flat-12 so Porsche built a flat-16 which worked well enough to exceed the capacity of the factory's dynamometer beyond its limit; the new engine was allocated a notional rating rated of 750 because that was the point at which the machine's graduations ended.  Such a thing had happened before, resulting in an anomaly which wasn’t for some years explained.  In 1959 Daimler released their outstanding 4.5 litre (278 cubic inch) V8 but their dynamometer was more antiquated still, a pre-war device unable to produce a reading beyond 220 bhp so that was the rating used, causing much surprise to those testing the only production model in which it was installed, the rather dowdy Majestic Major (DQ450 saloon & DR450 limousine, 1959-1968).  In either form the Majestic Major was quite hefty and reckoned to enjoy the aerodynamic properties of a small cottage yet it delivered performance which 220 bhp should not have been able to provide, something confirmed when one was fitted to a Jaguar Mark X (1961-1970 and badged 420G from 1967) for evaluation after Jaguar absorbed Daimler.  The V8 Mark X effortlessly out-performed the six cylinder version (rated at a perhaps optimistic 265 bhp.  Unfortunately, Jaguar choose not to use the Daimler V8 in the Mark X, instead enlarging the XK-six, dooming the car in the US market where a V8 version would likely have proved a great success.

The Can-Am: Porsche 917/10, Riverside, 1972.

Estimates at the time suggested the Porsche flat-16 delivered something like 785 bhp which in the Can-Am would have been competitive but the bulk rendered it unsuitable, the longer wheelbase necessitated for installation in a modified 917 chassis having such an adverse effect on the balance Porsche instead resorted to forced aspiration, the turbocharged 917s becoming known as the turbopanzers.  Porsche bought a new dynamometer which revealed they generated around 1100 bhp in racing trim and 1580 when tuned for a qualifying sprint.  Thus, even when detuned for racing, the Can-Am 917s typically took to the tracks generating about the same HP as the early Spitfires, Hurricanes and Messerschmitt which in 1940 fought the Battle of Britain.  Unsurprisingly, the 917 won the Cam-Am title in 1972 and 1973, the reward for which was the same as that earlier delivered in Europe: a rule change effectively banning the thing.  Still, when interviewed, one Porsche engineer admitted the new dynamometer "cost a boatload of money" but he was reported as seeming "pleased with the purchase." so there was that.

The widow-maker: 1975 Porsche 930 with the surprisingly desirable (for some) “sunroof delete” option.

The experience gained in developing turbocharging was however put to good use, the 911 Turbo (930 the internal designation) introduced in 1975 originally as a homologation exercise (al la the earlier 911 RS Carrera) but so popular did it prove it was added to the list as a regular production model and one has been a permanent part of the catalogue almost continuously since.  The additional power and its sometimes sudden arrival meant the times early versions were famously twitchy at the limit (and such was the power those limits were easily found), gaining the machine the nickname “widow-maker”.  There was plenty of advice available for drivers, the most useful probably the instruction not to use the same technique when cornering as one might in a front-engined car and a caution that even if one had had a Volkswagen Beetle while a student, that experience might not be enough to prepare one for a Porsche Turbo.  When stresses are extreme, the physics mean the location of small amounts of weight become subject to a multiplier-effect and the advice was those wishing to explore a 930's limits of adhesion should get one with the rare “sunroof delete” option, the lack of the additional weight up there slightly lowering the centre of gravity.  However, even that precaution may only have delayed the delaying the inevitable and possibly made the consequences worse, one travelling a little faster before the tail-heavy beast misbehaved.

In what may have been a consequence of the instability induced by a higher centre of gravity, in 2012 Lindsay Lohan crashed a sunroof-equipped Porsche 911 Carrera S on the Pacific Coast Highway in Santa Monica, Los Angeles.

The interaction of the weight of a 911’s roof (and thus the centre of gravity) and the rearward bias of the weight distribution was not a thing of urban myth or computer simulations.  In the February 1972 edition of the US magazine Car and Driver, a comparison test was run of the three flavours of the revised 911 with a 2.3 litre (143 cubic inch) (911T, 911E & 911S) engine and the three were supplied with each of the available bodies: coupé, targa & sunroof coupé, the latter two with addition weight in the roof.  What the testers noted in the targa & sunroof-equipped 911s was a greater tendency to twitchiness in corners, something no doubt exacerbated in the latter because the sliding panel’s electric motor was installed in the engine bay.  Car and Driver’s conclusion was: “If handling is your goal, it's best to stick with the plain coupe.”  She anyway had some bad luck when driving black German cars but clearly Ms Lohan should avoid Porsches with sunroofs.

Kestrel

Kestrel (pronounced kes-truhl)

(1) In ornithological taxonomy, a common small falcon (especially the Falco tinnunculus), of northern parts of the Eastern Hemisphere, notable for hovering in the air with its head to the wind, its primary diet the small mammals it plucks from the ground.

(2) Any of a number of related small falcons.

(3) A brand-name, used severally (initial upper case).

1400–1450: From the late Middle English castrell, from the Middle English castrel & staniel (bird of prey), from the Middle French cresserelle & quercerelle (bird of prey), a variant of the Old French crecerelle, from cressele (rattle; wooden reel), from the unattested Vulgar Latin crepicella & crepitacillum, a diminutive of crepitāculum (noisy bell; rattle), from the Classical Latin crepitāre (to crackle, to rattle), from crepāre (to rustle). The connection with the Latin is undocumented and based on the folk belief their noise frightened away other hawks.  However, some etymologists contest the connection with the Latin forms and suggest a more likely source is a krek- or krak- (to crack, rattle, creak, emit a bird cry), from the Middle Dutch crāken (to creak, crack), from the Old Dutch krakōn (to crack, creak, emit a cry), from the Proto-West Germanic krakōn, from the Proto-Germanic krakōną (to emit a cry, shout), from the primitive Indo-European gerg- (to shout).  It was cognate with the Old High German krahhōn (to make a sound, crash), the Old English cracian (to resound) and the French craquer (to emit a repeated cry, used of birds).  All however concur the un-etymological -t- probably developed in French.  Kestrel is a noun; the noun plural is kestrels.

In taxonomy, the variations include the American kestrel (Falco sparverius), the banded kestrel (Falco zoniventris), the common kestrel (Falco tinnunculus), the greater kestrel (Falco rupicoloides), the grey kestrel (Falco ardosiaceus), the lesser kestrel (Falco naumanni), the nankeen kestrel (Falco cenchroides), the Seychelles kestrel (Falco araeus) and the spotted kestrel (Falco moluccensis).  Although the bird had earlier been described as the castrell, in the early seventeenth century the small falcons were more commonly known as windhovers, the construct being wind + hover, reflecting the observations of the ability of the birds literally to hover when facing into the wind.  A now more memorable term however was the one dating from the 1590s: The windfucker (or the fuckwind).  In English, for almost two centuries, any use of the F-word could be controversial and its very existence seemed to make uncomfortable one faction of lexicographers who at one point managed to strike it from almost all dictionaries of English.  They were also revisionists of historical interpretation and claimed windfucker & fuckwind were errors in transcription, the original folk-names being windsucker & suckwind.  To give theis theory a bit of academic gloss, they assembled charts of regionally specific pronunciation in the Late Middle and early Modern English to illustrate the extent to which the archaic long S character ( ſ ) often took the place of an < s > at both the beginnings and middle of words, the argument being the long S was misread as a lowercase ( f ).

It was an intellectually clever way to attempt to remove vulgarity from English but etymologists today give little credence to the theory, noting that the undisputed French sources provide no support.  It may be assumed kestrels came to be called windfuckers & fuckwinds because when displaying their expertise at hovering in the air when facing into the wind, the movements of their bodies does make it look as if airborne copulation is in progress.  Of note too is that in the sixteenth and seventeenth centuries, the same disapprobation didn’t always attach to “fuck” which, although there was a long history of meaning “fornication”, it had also been in figurative use to describe anything from “plough furrows in a field” to “chop down a tree”.  Fuck was from the Middle English fukken and probably of Germanic origin, from either the Old English fuccian or the Old Norse fukka, both from the Proto-Germanic fukkōną, from the primitive Indo-European pewǵ- (to strike, punch, stab).  It was probably the popularity of use as well as the related career as a general-purpose vulgar intensifier which attracted such disapproval.  By 1795 it had been banished from all but the most disreputable dictionaries, not to re-appear until the more permissive 1960s.

Fieseler Fi 156 Storch, Gran Sasso d'Italia massif, Italy, during the mission to rescue Mussolini from captivity, 12 September 1943.  The Duce is sitting in the passenger compartment.

Windfucker thus became archaic but not wholly extinct because it appears in at least one British World War II (1939-1945) diary entry which invoked the folk-name for the bird to describe the German liaison & communications aircraft, the Fieseler Fi 156 Storch (stork), famous for its outstanding short take-off & landing (STOL) performance and low stalling speed of 30 mph (50 km/h) which enabled it almost to hover when faced into a headwind.  The Storch’s ability to land in the length of a cricket pitch (22 yards (20.12 m)) made it a useful platform for all sorts of operations, the most famous of which was the daring landing on a mountain-top in northern Italy to rescue the deposed Duce (Benito Mussolini, 1883-1945; Duce (leader) & prime-minister of Italy 1922-1943).  So short was the length of the strip of grass available for take-off that even for a Storch it was touch & go (especially with the Duce’s not inconsiderable weight added) but with inches to spare, the little plane safely delivered its cargo.

Riley was one of the storied names of the British motor industry, beginning as a manufacturer of bicycles in 1896, an after some early experiments as early as 1899, sold its first range of cars in 1905.  Success followed but so did troubles and by 1938, the company had been absorbed into the Nuffield organization.  Production continued but in the post-war years, Riley joined Austin, Morris, Wolseley and MG as part of the British Motor Corporation (BMC) conglomerate and the unique features of the brand began to disappear, the descent to the era of “badge engineering” soon complete.  The last Rileys were the Elf (a tarted-up Mini with a longer boot which was ascetically somehow wrong) and the Kestrel (a tarted-up Austin 1300), neither of which survived the great cull when BMC was absorbed by the doomed British Leyland, marque shuttered in 1969, never to return.  The rights to the Riley brand name are now held by BMW which has never even hinted there may be a revival, their unhappy (and costly) experience with Rover presumably a cautionary tale still told in Bavaria. 

Pre-war Riley Kestrels: 1938 1½ litre four-light Kestrel Sports Saloon (left), 1939 2½ litre Kestrel fixed head coupé (with post-war coachwork) (centre) and 1937 1½ litre 12/4 Kestrel Sprite Special Sports (right).

It was a shame because the pre-war cars in particular had been stylish and innovative, noted for an unusual form of valve activation which used twin camshafts mounted high in the block (thus not “overhead camshafts (OHC)”) which provided the advantages of short pushrods & optimized valve placement offered by the OHC arrangements without the weight and complexity.  Also of interest were their pre-selector transmissions, a kind of semi-automatic gearbox.  Among the most admired had been the 1½ & 2½ litre Kestrels (1934-1940), most of which wore built with saloon coachwork in four or six-light configurations although there were also fixed head (FHC) and drop head coupés (DHC) as well as a few special, lightweight roadsters.

The Kestrel Beer Company's "Flying Kestrel", built by Webster Race Engineering.

Of late, one 1935 Riley Kestrel has enjoyed an unusual afterlife.  In 2020, Scotland’s Kestrel Beer Company commissioned the UK’s Webster Race Engineering to create from one something to use as a land speed record (LSR) contender.  Dubbed “Flying Kestrel”, it’s powered by a turbocharged 2.5 litre (151 cubic inch) Audi TSI inline-five attached to an Audi A6 manual transmission, the power delivered to a Ford 9-inch differential, for decades a mainstay of drag-racing and anywhere else big power and torque needs to be handled.  After setting seven records during a 2021 campaign, the Flying Kestrel returned to Webster for fine-tuning including a new exhaust manifold, turbocharger blanket, and nitrous system for boost and cooling, a key gaol to reduce engine-bay heat.  On the dynamometer, the inline-five registered 991 horsepower (739 Kw) & 753 foot-pounds of torque (1022 Nm) and thus configured an attempt will be made on 17 June 2024 to achieve 200 (322 km/h).  LSR vehicles with much less power have often exceeded 200 mph but typically they have used bodywork with aerodynamic properties more obviously suited for the purpose.  It’s not clear if Webster’s Riley has been subject to much wind-tunnel testing but it may be assumed the shape is far from ideal as an LSR competitor and for some runs it has been fitted with rear fender skirts (spats), a trick in use since the 1920s.

Flying Kestrel with rear spats fitted during 2021 campaign.  Note the holes in the fenders which were added, not as a weight-saving measure (a la the frame of the Mercedes-Benz SSKL (1929-1932)) but to reduce lift at speed, the fenders tending otherwise to act as "parachutes".  The same technique was used by Zora Arkus-Duntov when trying to counter the alarming tendency of the front end of the Chevrolet Corvette Grand Sport (GS, 1962-1964) to "take off" as it approached 150 mph (240 km/h).  For reasons unrelated to aerodynamics, the GS programme proved abortive and of the planned run of 100-125 for homologation purposes, only five were built, all of which survived to become multi-million dollar collectables.      

The spats are one of the rare instances where adding weight increases speed, attested by the tests conducted during the 1930s by Mercedes-Benz and Auto-Union, both factories using spats front and rear on their LSR vehicles, extending the use to road cars although later Mercedes-Benz would admit the 10% improvement claimed for the 1937 540K Autobahn-kurier (highway cruiser) was just “a calculation” and it’s suspected even this was more guesswork than math.  Later, Jaguar’s evaluation of the ideal configuration to use when testing the 1949 XK120 (1948-1954) on Belgium roads revealed the rear spats added about 3-4 mph to top speed though they precluded the use of the lighter wire wheels and did increase the tendency of the brakes to overheat in severe use so, like many things in engineering, it was a trade-off.  More significantly perhaps, when travelling at speeds around 200 mph, “lift” is an issue and one which has afflicted many cars which have adhered well to the road at lower speeds.  Succinctly, the problem was in a 1971 interview explained by the General Motors’ (GM) engineer Zora Arkus-Duntov (1909-1996) who described the 1962-1967 (C2) Chevrolet Corvette as having “just enough lift to be a bad airplane.”  At speed, it’s another trade-off: the desire to lower aerodynamic drag versus the need for sufficient downforce for the tyres to remain sufficiently in contact with the earth’s surface for a driver to retain control, those few square inches of rubber the difference between life & death, especially at around 200 mph.  It’s hoped the “Flying Kestrel” proves a "windfucker" and lives up to the name figuratively, but not literally.

1935 Riley 1½ litre Kestrel (Chassis 22T 1238, Engine SL 4168) with custom coachwork (2004)

The intriguing mechanical specifications and the robust chassis has made the pre-war cars attractive candidates for re-bodying as an alternative to restoration.  Not all approve of such things (the originality police are humorless puritans as uncompromising as any Ayatollah) but some outstanding coachwork has been fashioned, almost always the result of converting a saloon or limousine to a coupé, convertible or roadster.  The 1935 1½ litre Kestrel above began life as a four-door saloon which was converted to a DHC during 2004 and the lines have been much-admired, recalling (obviously at a smaller scale) some of the special-bodied Mercedes-Benz SS (1928-1933), the more ostentatious of the larger Buccialis (1928-1933) and the Bugatti Royale (1927-1933).

A kestrel windfucking.

Sonoramic

Sonoramic (pronounced sonn-o-ram-ick)

A form of enhanced induction for internal combustion engines; sometimes called cross-ram or long-ram induction.

1959:  A compound word constructed by engineers (apparently with no contribution from the marketing department), the construct being the Latin sonō (make a noise, sound) + the English ram + -ic.  Sonō was from the primitive Indo-European swenhe (to sound, resound) which was cognate with the Sanskrit स्वनति (svanati) (to sound, resound).  The more productive Latin derivative was Latin sonus (sound, a noise) from the primitive Indo-European swon-o, again from the root swenhe.  Ram was from the Old English ramm (in the sense of "battering ram", from the Old High German ram, thought probably related to the Old Norse rammr (strong) and the Old Church Slavonic ramenu (impetuous, violent).  The suffix -ic was from the Middle English -ik, from the Old French -ique, from the Latin -icus, from the primitive Indo-European -kos & -ḱos, formed with the i-stem suffix -i- and the adjectival suffix -kos & -ḱos.  The form existed also in the Ancient Greek as -ικός (-ikós), in Sanskrit as -इक (-ika) and the Old Church Slavonic as -ъкъ (-ŭkŭ); A doublet of -y.  In European languages, adding -kos to noun stems carried the meaning "characteristic of, like, typical, pertaining to" while on adjectival stems it acted emphatically; in English it's always been used to form adjectives from nouns with the meaning “of or pertaining to”.  A precise technical use exists in physical chemistry where it's used to denote certain chemical compounds in which a specified chemical element has a higher oxidation number than in the equivalent compound whose name ends in the suffix -ous; (eg sulphuric acid (H₂SO₄) has more oxygen atoms per molecule than sulphurous acid (H₂SO₃).  The engineers were influenced in their coining of sonoramic by the debut three years earlier of the sonogram (thereby creating sonogramic), a form of diagnostic imaging used in medicine.  Sonoramic is a noun; the noun plural is Sonoramics.  There are no standard derived forms but there are owners who might have coined the informal adverb sonoramically to describe the way their machine does its stuff.

Fluid dynamics and resonant conditions

1960 Chrysler 300F with long-ram Sonoramic 413 cid (6.8 litre) wedge V8.

All else being equal, increasing the volume of the fuel-air mixture (energy input) flowing through an internal combustion engine (ICE) increases power and torque (energy output).  One way to increase the throughput is to use an external device such as a supercharger or turbocharger but it can be achieved also by creating resonance in the induction system, this done by designing a passage which uses the physics of fluid dynamics to increase pressure in specific spaces.  Obviously uninvolved in the engineering, Chrysler’s marketing people claimed in 1960 the Sonoramic was new technology but for many years the principle had been used in racing engines, the mathematical equations determining acoustics & resonance having been published by German physicist and physician Hermann Ludwig Ferdinand von Helmholtz (1821–1894) in a scientific paper published in 1863.  Indeed, the concept had before been used on road cars but always in a discrete manner; what Chrysler did in 1959 with their elongated tubular "ram-runners" was make a dramatic fashion statement in designer colors.

Representation of fluid dynamics under specific resonant conditions.

Essentially, the Sonoramic is an implementation of Sir Isaac Newton's (1642–1727) first law of motion, more commonly known as the law of inertia: “An object at rest tends to stay at rest and an object in motion tends to stay in motion” and it’s the second part which Sonoramic exploited.  During the intake cycle of an engine, the fuel-air mix flows through the intake manifold, past the intake valve, and into the cylinder, then the intake valve shuts.  At that point, the law of inertia comes into play: Because the air was in motion, it wants to stay in motion but can’t because the valve is shut so it piles up against the valve with something of a concertina effect.  With one piece of air piling up on the next, the air becomes compressed and, being under pressure, this stuff has to go somewhere so it turns around and flows back through the intake manifold in the form of a pressure wave.  This pressure wave bounces back and forth in the runner and if it arrives back at the intake valve when the valve opens, it’s drawn into the engine.  This bouncing pressure wave of air and the proper arrival time at the intake valve creates a low-pressure form of supercharging but for this to be achieved all variables have to be aligned so the pressure wave arrives at the intake valve at the right time.  This combination of synchronized events is known as the "resonant conditions".

Long (lower) and short-tube (upper) Sonoramic intake manifolds.

Most of the Sonoramics produced were "long-tubes" with a tuned internal-length of 30 inches (760mm), generating prodigious quantities of mid-range torque, optimized for overtaking under highway conditions.  These characteristics were ideal for road cars but also built were a small number of the so-called "short-tube" Sonoramics, a somewhat misleading term because both shared the same external dimensions.  The critical difference was the short-tube units had only a 15 inch (380mm) length of the internal passages resonance-tuned and this, at the expense of mid-range torque, produced much more power high in the rev-range making them more suitable for competition.  Used by Chrysler to set a number of speed records, these were the most charismatic of the breed and a handful were built with manual gearboxes.  At auction, in November 2010, the sole 1960 Chrysler 300F short-tube Sonoramic convertible with the Pont-a-Mousson 4-speed gearbox, sold for US$437,250.

Sonoramic in silver, one of the "long tube" versions tuned for mid-range torque.

The first four generations of Chrysler's 300 letter series had used increasingly larger versions of the Hemi V8 and the 1958 300D with a 392 cubic inch (6.4 litre) version even was (briefly and abortively) offered the novelty of a very expensive fuel-injection system.  The Hemi, heavy and expensive to produce, was in 1959’s 300E replaced by the larger capacity, wedge-head 413 (6.7) which matched it for power but lacked the mystique, something substantially restored in 1960 when the 300F debuted with the sexy Sonoramic.  Ram Induction today is common, although contemporary designs, integrated with fuel-injection systems, are not as photogenic as the original Sonoramics.  As well as raw aluminium, the tubes were available in the designer colors of the time, red, gold and blue and opinion is divided about which look is the coolest but, impressionistically, red ones seem to be the most photographed.  That is likely a function of the red having been produced in the greatest volume (followed by the silver) while the gold (used on the expensive Chrysler 300s) was comparatively rare.  The blue units seem never to have been fitted to standard production cars and because the look can be re-created with high-temperature paint, collectors suspect there are now more blue tubes than were ever produced by the factory.

1958 Chevrolet Corvette “Fuelie” with fuel-injected 283 cubic inch (4.6 litre) V8.  The Rochester mechanical fuel injection worked better than the Sonoramic but didn’t look as good.  In 1958 the fuel-injected Corvette was Corvette was available with 250 (Code 579) or 290 (Code 579D) horsepower (HP), the more powerful almost twice as popular, selling 1007 compared with 504.

Engineers and other real nerds tend to use terms like “short ram” & “long ram” for the induction system but because of the attraction of the word, most today seem to prefer “Sonoramic”.  Within the corporation, Dodge used “D-500 Ram Induction” and Plymouth called it “SonoRamic Commando” but when installed on the letter-series Chrysler 300s, both “Ram Induction” & “Ram Injection” appeared, the latter apparently exclusive to print advertising (which at the time tended to be more in magazines (not necessarily specialist automotive publications), the agency’s tactic to engage in a bit of what would later be called “ambush marketing” by piggy-backing on the image created by General Motors’ successful promotion of the mechanical “fuel-injection” system their Rochester division was producing for Chevrolet and Pontiac.  These days, such an approach might be labelled “deceptive and misleading conduct” but if folk in the early 1960s weren’t more forgiving, they were less litigious.

1958 Plymouth advertising.

The Sonoramic's plumbing couldn’t match what fuel-injection achieved but as the acceleration tests and high-speed runs confirmed, it did what it said on the tin and was considerably cheaper than the intricate mechanical mechanism.  However, there were drawbacks to the simplicity because unlike most of Detroit’s other implementations of dual four-barrel carburettor (“dual-quad” to the nerds) the Sonoramics ran permanently with all eight throats feeding the engine, each unit attached to the opposite bank of cylinders.  On systems where the carburettors were more closely placed (in-line or side-by-side), the usual practice was to use just one except when needed, the same principle as the “demand superchargers” used during the inter-war years by Mercedes-Benz in which the blower was engaged only when the upper gears were in use and the throttle was pushed wide open, high in the rev-range.  What that meant was the dual quad cars delivered fuel economy which was “poor” rather than “atrocious” but they appealed to a demographic which accepted that for everything one does there’s a price to be paid and gas (petrol) then was cheap although not quite as cheap and its expression in pre-inflation dollars & cents make it appear to twenty-first century eyes.

Sonoramic in red, one of the rare "short tube" versions tuned for top-end power.

Anyway, when filling up, owners of Sonoramics had the consolation of being able to open the hood and gaze lovingly at their sensuous tubes, a construction visually more accomplished than Rochester’s business-like hardware.   Unfortunately the affection didn’t always extend to the behaviour when starting a Sonoramic on a winter morning, the combined 120 inches (3 metres) of cold aluminum far from ideal at maintaining the fuel-air mix in the required aerosol.  Until the metal was warm, fuel was prone to condensing, creating what was soon known as the dreaded “puddling effect” and in colder places some owners improvised “heated inlet manifolds”, the most simple approach being a pair of incandescent light bulbs rigged above the tubes for 30 minutes prior to starting, one instance where the inherent inefficiency of the old technology (where much energy was lost as heat rather than light) proved useful.  Others gave up and had the system exchanged for a prosaic single four-barrel carburetor, an echo of Chrysler’s miserable experience in 1958 when 35 cars were built with Bendix “Electrojector” fuel injection.  Unfortunately, the on-board analogue computer (which which had performed reliably in testing) proved fragile in real-world conditions and all but one of the cars was returned to dealerships in response to a corporate recall to be converted to the standard dual-quad apparatus.  It would be decades before advances in solid-state technology made electronic fuel-injection a viable mass-market product.

One of the Sonoramic’s relations: 1993 Mercedes-Benz 600 SEC (C140).

Despite the impression probably gained by the few souls who now trouble themselves to see what lies under a hood (bonnet), long-tube induction is common but now usually concealed beneath enveloping plastic moldings (sometimes fashioned from real or fake carbon fibre as the price tag rises).  The manufacturers have sound reasons for doing that but the expanse of flat, black plastic is an uninspiring sight compared with things like the 6.0 litre (365 cubic inch) Mercedes-Benz V12 (M120).  The C140 was unusual in that it was the last of the “SECs” and the first of the “CLs”, its mid-life spent as an “S”. the alpha-numeric trajectory of the 600:

1992 600 SEC (Not sold in North America)

1993 600 SEC (Global)

1994-1995 S 600 (Global)

1996-1997 S 600 (North America) & CL 600 (Rest of the world

1998 CL 600 (Global)

1999 CL 600 (North America only)

Republic P-47 Thunderbolt test-bed with XI-2200 V16 (1945).

Chrysler’s interest in ram tuning was an outgrowth of the desire to exploit the findings of research undertaken during the war developing very high-performance piston engines for fighter aircraft.  This had culminated in the XI-2220, a 2,220 cubic inch (36.4 litre) V16 aero-engine which, rated at 2450 HP, was tested in a Republic P-47 Thunderbolt (1947-1945), an appropriate platform given the P-47 was then the biggest, heaviest single-engined fighter ever to enter service (among piston-engined aircraft, it still is).  Although the indications were that close to 4000 HP was achievable (at least for short durations under the EWR (emergency war rating protocol), with the advent of the jet engine the days of the big piston-engined fighters were nearly done so the V16 project was cancelled, a fate suffered also by the other outstanding big aero-engine of that last generation: the Napier-Sabre H24.

XI-2220, V16 aircraft engine (1944-1945).

The lessons learned however would be applied on the ground instead of in the skies because although big capacity piston engines had mostly been rendered obsolete for fighter aircraft, a few generations of some a bit smaller were about to start roaming American roads.  The cars and their engines would be like nothing before seen in mass-produced, affordable cars, Chrysler adopting for their new 331 cubic inch (5.4 litre) V8 in 1951 the V16’s hemispherical combustion chambers, a feature it would use for most of that decade and the next and such was the aura of the name it’s used still, even if things inside are now a bit less hemispherical.

Chrysler A-311 V8 experimental engine.

The new Hemi V8 had obvious performance potential and the engineers experimented with the tuned-length induction system used on the V16 before the aero-engine's final supercharger/turbocharger combination was adopted.  So successful was the ram-tuned V8 (named A-311) attempts were made to contest the 1952 Indianapolis 500 but the race’s sanctioning body understood the implications the remarkable new powerplant would have on their carefully-curated ecosystem of owners and sponsors so declared it didn’t comply with the rules (even tweaking them a bit to ensure it never would).

Ramcharger Club’s 1949 Plymouth with extreme ram-charging.

The research however continued and, although it’s not clear to what extent their efforts received factory-support, in the late 1950s some of Chysler's young engineers formed the drag racing-focused Ramchargers Club using, somewhat improbably, a 1949 Plymouth business coupe fitted with a particularly extravagant implementation of the technology, a surrealistically tall intake manifold, a device built for dynamometer testing and never intended for a moving vehicle.  They dubbed the Plymouth "High & Mighty".  Bizarre it may have looked but the cartoon-like Plymouth achieved results which vindicated the approach and a less obtrusive version of the system was made available on certain Plymouths, Dodges and Chryslers, the highest evolution of Sonoramic offered on the 300 letter series cars until 1964.

Lindsay Lohan enjoying the effects of fluid dynamics.

Not content with applying the science of fluid dynamics only to the induction system, the Ramchargers used it also for the exhaust headers.  Rather than additional power, the commendably juvenile quest was for noise, the exaggerated, trumpet-like tubes using the megaphone principle which increases volume by raising acoustic impedance.  The desired result was achieved and although there's no record of anyone with a decibel-meter taking a reading, the old Plymouth was said to be spectacularly loud; megaphone exhausts subsequently were banned.    

Chrysler Slant Six with Hyper Pak.

Chrysler didn’t restrict the ram induction idea to the big-block V8s, using it also on the short-lived (1960-1962) Hyper Pak performance option for the both 170 cubic inch (2.8 litre, 1959-1969) and 225 cubic inch (3.7 litre, 1987-2000) versions of their Slant Six, the engineers taking advantage of the space afforded by the angled block to permit the curvaceous intake runners nearly to fill the engine bay.  The Hyper Pak wasn't seen in showrooms but was available as an over-the-counter kit (literally a cardboard box containing all necessary parts) from Dodge & Plymouth spare parts departments and its life was limited because it became a victim of its own success.  Although less suitable for street use because it turned the mild-mannered straight-six into something at its best at full throttle, in the race events for which it was eligible it proved unbeatable, dominating the competition for two years, compelling the sanctioning body cancel the series.  Success isn't always rewarded.

Although it was the longer lived 225 version which gained the Slant Six its stellar reputation for durability and the ease with which additional power could be extracted, there's always been a following for the short-stroke 170 because of its European-like willingness to rev, the characteristics of the over-square engine (unique among the slant-six's three displacements (170-198-225)) unusually lively for a US straight-six.  Despite some aspects of the specification being modest (there were only four main bearings although they were the beefy units used in the 426 cubic inch (7.0 litre) Street Hemi V8), for much of its life it used a tough, forged steel crankshaft and high-speed tolerant solid valve lifters, features which made a robust engine.  Despite that, after the Hyper Pak affair, Chrysler showed little interest in any performance potential, knowing the US preference for V8s, something which doomed also Pontiac's short-lived single overhead camshaft (SOHC) straight-six (1966-1969).  A version of the 225 with a two-barrel carburetor (rated at 160 horsepower, an increase of 15 over the standard unit) was offered in some non-North American markets where V8 sales were not dominant and it proved very popular in South Africa, Australia, New Zealand and Central & South America but only when tighter US emission regulations forced its adoption did a 225 with a two barrel carburetor appear in the home market, installed to restore power losses rather than seek gains.