The Wonderful Carburetors of Edoardo Weber

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Carburetors are like watches; the $10 Timex and the $1000 Patek-Philippe work on the same principle. It's the attention to detail that makes the difference.

Andrew Trahan

By Griff Borgeson

"What is the best carburetor?" You can ask this question throughout the civilized world today and the answer is pretty certain to be, "Well, Weber . . . naturally."

Awareness of Webers was limited almost entirely to the Italian racing fraternity when, after the 1952 GP of Italy at Monza, one of the carburetor company's racing consultants suggested to English mechanic Alf Francis that a pair of 36DCOs ought to give his Alta engine another six or seven horsepower. The Weber man had been doing this sort of thing for his firm since 1925 and was authorized to say that if he was wrong there would be no charge for the new carburetors. Francis accepted the offer and went to Bologna to put the 117-bhp Alta engine on one of Weber's dynamometers.

In his book, "Alf Francis—Racing Mechanic," he tells how they mounted the dual-throat carburetors the next day, only guessing at jet sizes. The seven additional bhp registered on the
scale immediately. Then the Weber technicians noted that the engine's inlet manifold could be improved upon, designed and quickly fabricated a new one and got another 5.8 bhp. By
experimenting with the ignition timing they found another four bhp. Then they removed the 36DCOs and installed a pair with 38-mm throats, which gave a steady reading of 136.8 bhp. Further tuning of these brought the engine's output to 143 bhp, at which point Francis, delirious with joy, drew the line and headed for the next race.

One of the things that impressed him most was the bill he was handed—$235, the price at that time for the two new carburetors. There was no charge for the five days of bench testing, the labor of several highly trained men or for the 22% increase in engine output. When Francis insisted that he must treat the crew to a modest feast they refused, saying that they had only done their job. Finally he resorted to the ruse of claiming that it was his birthday, making refusal un-genteel and therefore unthinkable.

This anecdote illustrates a few of the factors that underlie Weber's remarkable success: an exceptional knowledge and an enthusiasm for racing; placing a value on racing experience that is independent of cost; all-out service to the customer. These attitudes and policies had been fixed by the founder decades before.

Andrew Trahan

Edoardo Weber got into the carburetor business in the early 1920s. He was born in Turin in 1889, the son of a father who had come from German-speaking Switzerland and had become plant manager of a local textile mill. The son received a fair technical education, worked in the young Fiat plant for a few years and in 1914 became service manager of the Fiat agency in Bologna. He did some racing but the bulk of his spare time was devoted to mechanical experiments and early in 1920 he finally quit his job to go into business for himself. As today, the cost of gasoline in Italy was extremely high. But kerosene was still cheap and Weber went to work on the design and manufacture of a device that would enable truck engines to use this fuel. It was a massive and elaborate contraption which incorporated heat from the exhaust system and three separate carburetors, one for warming up on gasoline, one for normal running on kerosene and one for water, which served as an anti-detonant. Weber sold just enough of these to move on to better things.

He knew his Fiat engines perfectly and began modifying them for increased performance. He designed and built his own overhead valve conversion for the Fiat 501 and produced a series of cars which, in full racing form, would do about 90 mph, as opposed to the 50 mph of the production model. He did this by means of a Roots-type supercharger, which he also made, and his own carburetor, the first one he designed for use with gasoline alone.

Significantly enough, this was a form of dual-throat carburetor. The period was late 1924 and the idea was hardly new. In America the Zenith Duplex and the Ball and Ball double carburetor already had been developed for use on V-type engines. Much closer to home, American ace Jimmy Murphy had raced at Monza in 1923; his Miller 8-cylinder engine bristled with four Miller dual-throat updrafts in what was the classic American speedway practice of the day. If Weber didn't see these authentic forerunners of the modern DC, doppio corpo carburetor (and Count Zborowsky's Miller was running them too) he at least had to have heard about them. However, for the first several years he adapted the dual-throat principle to other ends.

Those were days when octane ratings were pitifully low. The existing gasoline would tolerate only a very low heat of compression and therefore it was necessary on supercharged engines to mount the carburetor between the blower and the block. Weber's permanently engaged blower delivered pressurized air to a pipe which, according to the position of a valve, either fed the large carburetor throat or bypassed it to the atmosphere. This was a means of causing the blower to be "engaged" effectively only at full throttle. At all other times the small throat alone was used, drawing air from the atmosphere and not from the blower. The two throats funneled into a single one on the engine side of the carburetor. The entire system was admirably simple and worked well in many racing installations, some of which Edoardo himself continued to drive in competition.

His first real commercial success began when he adapted this same carburetor to the requirements of fuel economy. Deleting the entire blower circuit, he used the small throat for normal running and reserved the large throat for full-throttle demands, thus anticipating American 4-barrel practice that was still three decades in the future. Fiat 501 taxis were coming into mass use all over Italy and their thrift-minded owners bought the new Weber carburetor by the thousands. Fuel consumption was measured by the 17-liter can in those days (service stations and gas pumps were still in the future) and the Weber carburetor gave as much as 180-km per can versus the 100 km that was normal for that trusty workhorse of the Fiat line.

Andrew Trahan

Designing a successful carburetor for racing—where full-throttle operation is the rule and where fuel consumption usually is a minor consideration—is relatively simple because of the minimal attention required by the low-speed circuits of the carburetor. But Weber continued to be fascinated by the entire performance range and optimum fuel economy also remained a major challenge for him. Having abandoned kerosene as a cheap fuel he then turned his attention to stove oil, which then sold for one-eighth the price of gasoline. In this field he was successful again. And then came his real entry into big-time racing.

The Maserati brothers had begun manufacturing their own race cars in Bologna and it was only natural that, in 1929, they took their carburetion problems to local specialist Edoardo Weber. He designed the successful Type 55-ASS for the Maserati 8C2500, which launched him as the almost exclusive carburetor supplier to the House of the Trident from that time onward. The following year he built the 50DOS for the supercharged 1100-cc inline eight, still using a single throat. Then in 1931 Weber created his first dual-throat carburetor in the modern sense of the term. It was called the 50DCO and had two identical throats and two throttle plates which acted simultaneously. The sole purpose behind resorting to this construction was to cause the carburetor throat area to cover the length of the rotors of the 1100-cc engine's Roots supercharger.

Maserati enjoyed the most brilliant success in the early 1930s and Weber's fame and experience grew. Modena is close to Bologna, and Scuderia Ferrari began replacing Memini carburetors with Webers on its Alfas. By 1936 they were standard equipment on all Alfa Romeo race cars. When the Type 158 Alfetta appeared the following year it used a highly special Weber carburetor which had three 50-mm throats in line, still for the purpose of distributing the air/fuel mixture over the entire blower inlet area.
It was the year after the Alfetta's final conquest of the international road racing championship that Alf Francis carried the facts and figures of Weber performance back to England's racing fraternity. During the same period Ferrari and Maserati successes in North and South America began to turn the attention of the race-wise to the carburetors of the winning engines. Edoardo Weber, knighted by his government for his contributions to the nation's technology, died in 1945. But the seed that he had sown was to yield ever-richer harvests.

After Weber's death Fiat began to invest in the little company and by 1952 had acquired half of its assets. It was still essentially just a good-sized artisan workshop producing a few thousand carburetors per month when, at that point, Fiat bought most of the remaining Weber stock. New engineering and managerial talent and new capital were poured into the company and a massive development program was launched that was precisely in step with the beginnings of Italy's "economic miracle." Growth has been steady and today the onetime cottage industry is geared to produce over 100,000 carburetors per month, a volume that makes them competitive on a cost basis with the products of all the big, old-line European manufacturers in the field. The vast majority of these are ordinary, mass-produced "cooking" carburetors that come as standard equipment on practically all Fiats. Others, slightly more specialized, are fitted to many models of English Ford, Citroen DS-19, Simca 1500, BMW 1500 TI/SA and numerous others.  

However, it is the highly specialized carburetors for pure racing machines that say Weber to the enthusiast and in this field their conquests continue to increase. In the U.S. in the past year, for example, Webers have begun to replace the Hilborn injection systems that have been dominant in racing ever since the decline of the Stromberg 97. In the F1A world championships the carburetors most consistently used naturally are Webers. The name is synonymous with performance.

Andrew Trahan

Nearly everyone who is aware of this assumes it to be so because of special design features that are exclusive with Weber, but this is not the case at all. The facts are that Weber uses the same basic jets as everyone else and there are no structural characteristics that are typically Weber. From the design standpoint it is normalissimo. The most distinctive feature of most high-performance models, perhaps, is the ease with which jet, emulsion tube and venturi sizes can be changed.

There was a time when certain makes of carburetor had their own typical architecture and were different from all others. However, all the major patents in this field expired long ago and for many years the world's leading carburetor manufacturers have had the free use of each other's ideas. Some ideas originated by Weber now are used by many other manufacturers and Weber is indebted to many of them for ideas which it has borrowed. The result is that all modern carburetors are basically the same, have the same essential circuitry and design features. Weber happens to be very strong in the 2-throat field but is far from being alone there and has no exclusive claim on that principle. The reasons for Weber's excellence are deeper and more subtle than mere design.

The most fundamental reason is the firm's traditional and absolutely uncompromising pursuit of quality in every sense. From the earliest days it has been Weber's practice to tailor its carburetors to specific engines, as opposed to producing one carburetor that can be adapted to a diversity of engines. The tailoring process requires that searching studies be made of each specific powerplant, that its peculiarities and perhaps faults be analyzed and compensated for by detail refinements within the carburetor. This of course consumes a great deal of time and money but Weber's reputation indicates that it pays off.

Another of the "secrets" underlying this reputation is the really exquisite perfection of manufacture and inspection of each part of each carburetor. The tolerances of machining and finish of all calibrated parts are practically nil and policing them is the sole job of a remarkably high proportion of the firm's more than 700 skilled workers. Then, after assembly, each carburetor's performance is checked out on a precision test rig. In all cases where it is possible, all racing carburetors are dynamometer-tested on the type of engine for which they were designed. The firm is ardently dedicated to the policy that a defective or inadequate product must not leave the plant. To achieve this result a level of quality control is enforced that leaves nothing to chance.

Weber's present standards of quality and performance all derive directly from the old days of hand production, small volume and high unit cost. They have been carried over into low-cost mass production by means of massive investment in automated precision machinery and by very advanced techniques of industrial management. Weber has two well-staffed engineering departments, one for the design of products and the other for the design of the machines to make the products. The majority of its intricate machines for the mass production of high-precision parts are designed and built on its own premises, meaning that many of them are unique. A tour of the plant gives the visitor the feeling that this must be how fine watches are mass produced, yet Weber measures its output not in units but in tons.

Another key to Weber superiority is, of course, its four decades of racing experience and the boundless lessons learned in this very exclusive school. Then, during the last ten years, Weber has had ever-increasing experience with automobile manufacturers not just in Italy, but in all the major European countries, plus the United States and Japan. The problems presented by each new client and solved by Weber's technical staff have given it worldly sophistication of the greatest value.

Still another source of Weber's success is Italy's system of motor-vehicle taxation and her high cost of fuel. These factors result in high specific outputs being demanded from engines of very small displacement, running at very high rpm. This demands large-diameter venturis which, in turn, raise a whole series of problems in the design of the carburetor's fuel and air circuitry. Weber has welcomed the challenge of the small-displacement, high-revving engine and over the years has mastered the subtleties of extracting optimum performance at low rpm and low manifold pressures from these engines. The lessons learned from this special discipline are of course applicable to carburetors for larger engines. But here, again, superiority is not achieved through important structural differences but through subtle refinement of universal principles.

The service situation for Weber carburetors is less rosy, and a complaint that we frequently hear from American users is that they just can't find anyone in their vicinity who can do a proper job of working on Webers, even though they go to carburetor specialists.

A good man is always hard to find and there just aren't many who understand any sort of carburetor well. Those who may be quite at home with certain makes often are incapable of figuring out even simple variations on familiar theme. The same is all too true of engine mechanics, plumbers, physicians, and so on.

In spite of its size, automation and over-million-units-a-year output, Weber continues to maintain a small, quiet inner sanctum where the elite of its craftsmen and technicians continue to make the world's finest racing carburetors, by hand. Certainly this department never can show a direct profit. But indirectly it is the very soul of the whole organization.