Carburettors in F1?

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
nokivasara
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Carburettors in F1?

Post by nokivasara » Sat Apr 20, 2019 5:41 pm

How long was carburettors used in F1?
Or did they perhaps use fuel injection from the start? FI certainly had been around for a while in aviation before the first ever F1 race.

Zynerji
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Re: Carburettors in F1?

Post by Zynerji » Sat Apr 20, 2019 7:37 pm

I expect that the true death of carbs in F1 centers around G-forces when cornering due to mechanical and aero grip increases.

Just_a_fan
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Re: Carburettors in F1?

Post by Just_a_fan » Sat Apr 20, 2019 9:08 pm

Injection has been used since the 1950s.
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bill shoe
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Re: Carburettors in F1?

Post by bill shoe » Sat Apr 20, 2019 10:12 pm

The Honda Museum in Motegi, Japan has many many epic motorcycles, road cars, and race cars on display. In the middle of this they have a set of carbs. You read the placard and find out these carbs were an upgrade to their mid-60's F1 engine. This engine went on to win a race with these carbs. Apparently these carbs carry such reverence within the company that they occupy a permanent spot in their official museum.

In the mid-to-late 60's the last carbureted F1 engines transitioned to very simple mechanical fuel injection which in many ways had similar drawbacks as carbs. Those late-60's fuel injection systems plus 256,342 incremental improvements give us the fuel injection systems F1 has now.

Dr. Acula
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Re: Carburettors in F1?

Post by Dr. Acula » Sat Apr 20, 2019 10:16 pm

Zynerji wrote:
Sat Apr 20, 2019 7:37 pm
I expect that the true death of carbs in F1 centers around G-forces when cornering due to mechanical and aero grip increases.
Not really. So called diaphragm carburetors work perfectly under high g forces, vibrations and even when they turned upside down. They're even used in aerobatics airplanes.

In race cars it was in the mid 50's when mechanical fuel injection was starting to get a common thing.

Tommy Cookers
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Re: Carburettors in F1?

Post by Tommy Cookers » Sun Apr 21, 2019 10:05 am

pressure carburettor was a useful generic term for non-float 'carburettors) because not all had diaphragms
the term injection carburettor was used by Bendix-Stromberg (USA) and speed/density carburettor by SU (UK)
the supercharger always 'sucked through' these
though DI was quite widely used from WW2 on big US engines and universal on WW2 German engines

manoeuvring mostly wasn't an issue
float carburettors are liable to cause icing due to venturi effect
injection carburettors use a positive spray pressure and so don't need a venturi
carb icing must be checked/cleared in flight using 'carb heat' - though this check is also required with injector carburettors

most aerobatic aircraft have one or other of 2 engines - a version of the O-360 or O-540
they all seem to use some kind of throttle body injection or injector carburettor
you can tell by the gasping and wheezing from post-flight bleeding-down of some internal pressure (engine not pilot)

I guess today injection or injector carburettor is on most non-aero versions today
there's argument over poor mixture distribution in these engines - because this limits leaning
yes - even with injection there's apparently no altitude compensation so the pilot will need to lean manually
these are uncalibrated systems - though manual leaning is aided by having an EGT gauge


F1 wasn't mostly fuel injected till 1965 - when it became available on Coventry Climax and BRM customer engines
fuel injected meant Lucas - the first injection that was adjustable enough for F1-type response
(yes M-B won on Bosch DI and Vanwall won on Bosch PI in the 50s F1)
Last edited by Tommy Cookers on Sun Apr 21, 2019 6:07 pm, edited 3 times in total.

saviour stivala
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Re: Carburettors in F1?

Post by saviour stivala » Sun Apr 21, 2019 12:32 pm

Pressure carburetors versus suction carburetors in the 1930-1940 boosted (supercharged) racing engines era which might be of interest to some.
From the 1937 Mercedes-Benz M125 5.7-litre eight report:- “Expectations for a dramatic power increase had been high since late September 1936, when Mercedes first tried a suction carburetor system on the 1935-type engine. Suction systems, in which the supercharger draws a fuel/air mixture from the carburetor and then pumps it to the engine, had been widely adopted by competitors like Auto Union and Alfa Romeo but were not fondly regarded by Mercedes-Benz at Unterturkheim. All its new racing engines since the mid-1920’s had superchargers that blew through the carburetors, so the company had a vast found of knowledge on the operation of pressure-carburetion system. But Scheerers findings brooked no argument. Tests on a 1936-type engine with a suction system gave power increase of 32% at 2000rpm and 11% at 5800. Peak output was 488bhp at 5500. Cautioning that these results did not reflect the changes that would be needed to get smooth throttle response in the car, the engineer estimated that the M125 would deliver 583bhp on the normal racing fuel blend and as high as 597bhp on WW fuel, a blend that was good for power but not for fuel economy. It was to happen, but not easily. A power curve taken on the first M125 in mid-February with suction carburetion, showed 580bhp@5800rpm on standard fuel blend and even better output at medium and low speeds than had been forecast. This was an excellent result. But when installed in the car the eight refused to respond to full throttle smoothly unless carburetor size was drastically reduced. Nor did it want to react quickly to a blip of the throttle for downshift. After these discouraging trials the 1937 season was started with pressure carburetion of the proven type.
The sacrifice in peak power incurred was relatively small, a matter of 5 to 10 hp, but the loss was substantially greater at lower engine speeds. Torque was strikingly reduced. A comparison made in June 1937 on a single engine with the normal test fuel and settings suitable for racing showed the difference:-
Pressure carburetor = 3000rpm, 6.2 psi boost, 316bhp, 750Nm torque.
= 5800rpm, 13.3 psi boost, 550bhp, 675Nm torque.
Suction carburetor = 3000rpm, 10.2 psi boost, 361bhp, 857Nm torque.
= 5800rpm, 11.3 psi boost, 556bhp, 683Nm torque.
To find a suction-type carburetor that would give the needed throttle response the Daimler-Benz design office reverted to the example of a 1924 2-litre racing Mercedes eight, the M218, which had an updraught instrument incorporating an Automat, a weighted sliding venturi. Much like that unit in principle, the new carburetor had 2-updraught 62mm throats, each with a 48mm Automat venturi."

gruntguru
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Re: Carburettors in F1?

Post by gruntguru » Mon Apr 22, 2019 7:23 am

I sense that Tommy was referring to something other than a "blow thru" carburettor when he used the term "pressure carburettor".

The advantages of the upstream (suction) carburettor would no doubt be intercooling and supercharger cooling. The downstream (pressure) carburettor would offer better throttle response via a throttle disc closer to the engine.

I wonder if anyone tried to get the best of both worlds by positioning a (constant venturi type) carburettor upstream of the supercharger with the throttle plate downstream of the supercharger?
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