Rare Car Archive

Makes › Fiat Italy › "Mephistopheles" (Eldridge special) · Historically significant · 1923 One-off

Fiat
"Mephistopheles" (Eldridge special)

Fiat-based aero-engined land speed record car (Eldridge, Arpajon 1924), held by Fiat

IDENTIFICATION CARD · FIAT "MEPHISTOPHELES" (ELDRIDGE SPECIAL) 1923
No licensed photograph yet. Photographs are published only when their licence permits it.
1BuiltRegistry reported
0Chassis documentedin this archive
1SurvivingIndependently researched
Contents
  1. 01Overview
  2. 02Production & history
  3. 03Specifications
  4. 04Colours & options
  5. 05Individual cars
  6. 06Reference

01Overview

At a glance

Built
1 Built
Years
1923
Engine
Inline six-cylinder, Fiat A12 aero engine with separate cylinders · 21,714 cc / 21.7 LFactory: 21,714 cc
Power
194 kW / 264 PSFactory: 260 hp · converted
Top speed
234.98 km/hFactory: 146.01 mph · converted
Body
Not yet verified
Designer
Ernest Eldridge (rebuilt from a 1908 Fiat SB4 with a Fiat A.12 bis aero engine)
In this archive
Not yet verified
Surviving
1 (independently researched)

Sources and any conflicting figures are in the sections below.

Why it matters

A 1908 Fiat Grand Prix-type racer fitted by Ernest Eldridge with a 21.7-litre Fiat aero engine, in which he set a world land speed record at Arpajon in 1924. The car survived and has been run in Britain since the 1950s.

How rare is it?

Six separate kinds of rarity – never combined into one number.

Model rarityOne-off 1 · Built1
Specification rarityNot yet assessed
Colour rarityNot yet assessed
Individual rarityNot yet assessed
Historical rarityNot yet assessed Production figure not yet verified.
Survival rarityNot yet assessed 1 · Surviving1

Each kind of rarity is rated separately and never combined.

02Production & history

Production

Every figure says what it counts.

What is countedFigureBasisStatus
Total model productionThe single car built is preserved 11 Surviving examples Independently researched
Total model productionMephistopheles as rebuilt by Eldridge (built: 1) 11 Factory production Registry reported

Independent counts (e.g. engine and colour) are never combined into a calculated figure. Surviving examples are never presented as original production.

History

The car began as a Fiat SB4 built for George Abercromby in 1908 and was driven by Felice Nazzaro at Brooklands. After the First World War it was raced again, wrecked its engine in 1922 and was bought by Eldridge, who lengthened the chassis by 18 inches and installed a six-cylinder Fiat A12 aero engine.

Eldridge lapped Brooklands at 125.45 mph and set the 146.01 mph record at Arpajon in 1924, after a protest that the car lacked reverse gear was answered by modifying it. He later sold it on; in the 1950s the Naylor family recommissioned it.

Variants

How each version differs from the standard "Mephistopheles" (Eldridge special).

No variants documented yet. Have a source? Contribute it.

03Specifications

Technical specifications

Engine

Engine familyNot yet verified
Engine codeFiat A.12 bis2,3 Independently researched
LayoutInline six-cylinder, Fiat A12 aero engine with separate cylinders4 Independently researched
Cylinders64 Independently researched
Displacement 21,714 cc / 21.7 LFactory: 21,714 cc4 Independently researched
Bore 160 mmFactory: 160 mm4 Independently researched
Stroke 180 mmFactory: 180 mm4 Independently researched
Compression ratio4.3:14 Independently researchedEarly A12 figure; later versions used 4.75:1.
ValvetrainFour overhead valves per cylinder via rockers from a rear-driven overhead camshaft4 Independently researched
Fuel system4 Solex carburettors3 Independently researchedBig Scale Models says only two carburettors; Ultimatecarpage gives four Solex.
Power 194 kW / 264 PSFactory: 260 hp · converted4 Independently researchedRating of the A12 engines in general; Old Machine Press (S2) gives 300 hp for the A.12bis fitted.
Power at 1,700 rpm4 Independently researched
TorqueNot yet verified
Redline 1,800 rpm3 Independently researched

Transmission & drivetrain

GearboxOriginal 1907 Fiat gearbox, final drive by side chains4 Independently researched
Gears43 Independently researched
Driven wheelsRear wheels3 Independently researched

Chassis, body & dimensions

ChassisSteel ladder frame (Fiat SB4 chassis, modified)3,2 Independently researched
Front suspensionRigid axle, semi-elliptic leaf springs, friction dampers3 Independently researched
Rear suspensionLive axle, semi-elliptic leaf springs, twin friction dampers3 Independently researched
BrakesRear drum brakes only (token transmission brake)3,5 Independently researched
SteeringNot yet verified
Body constructionNot yet verified
Wheelbase 3,683 mmFactory: 3,683 mm3 Independently researched
LengthNot yet verified
WidthNot yet verified
HeightNot yet verified
Front trackNot yet verified
Rear trackNot yet verified
Kerb weightNot yet verified
Dry weightNot yet verified

Performance

Maximum speed 234.98 km/hFactory: 146.01 mph · converted4 Independently researchedRecord run at Arpajon, 1924.
0–100 km/hNot yet verified
Fuel tankNot yet verified

“Not yet verified” means no source has been checked for that value yet. Nothing is estimated to fill a gap.

04Colours & options

Factory colours & interiors

Original paint and trim, with the number of cars in each where a source gives it.

Not yet documented. Have a source? Contribute it.

Factory options & codes

Codes are shown exactly as written by the manufacturer.

Not yet documented. Have a source? Contribute it.

05Individual cars

Chassis register

Every documented car, with its colours, history and where it is now. Open a row for the full record. Known chassis are not automatically authenticated originals.

Not yet documented. Have a source? Contribute it.

Competition history

Every race result of the individual cars, in date order. Click a chassis number to open its full record in the register.

Not yet documented. Have a source? Contribute it.

Auction & sale history

Documented public sales of the individual cars. Click a chassis number to open its full record in the register.

Not yet documented. Have a source? Contribute it.

See one in person

Museums where an example of this car can be seen.

No example is documented on public display yet. Have a source? Contribute it.

06Reference

Identification guide

How to tell an original from a replica or later conversion.

In Eldridge form the car has a 160 x 180 mm six-cylinder Fiat A12 engine with separate cylinders, four overhead valves per cylinder and 24 spark plugs, plus the original 1907 gearbox and side-chain final drive. The chassis was lengthened by 18 inches.

Sources

Each number links to the exact facts it supports.

  1. 1
    1923 Fiat Mephistopheles Level B ultimatecarpage.com
    • Numbers built: 1
    • Numbers built: 1; actually survived
    Accessed 2026-11-12
  2. 2
    Fiat Mefistofele Level A Fiat (fiatpedia heritage, web archive copy)
    • The Mefistofele's engine is a Fiat A12 bis
    • sits on a Fiat SB4 chassis, modified to fit the Fiat A12 bis
    Accessed 2026-11-13
  3. 3
    Fiat Mephistopheles Level C Wouter Melissen · Ultimatecarpage.com
    • A.12 Straight 6
    • Fuel feed 4 Solex Carburettors
    • Red Line 1,800 rpm
    • Gearbox 4 speed Manual
    • Drive Rear wheel drive
    • Chassis steel ladder frame
    • rigid axle, semi-elliptic leaf springs, friction dampers
    • live axle, semi-elliptic leaf springs, twin friction dampers
    • rear drum brakes
    • Wheelbase 3,683 mm (145 in)
    Accessed 2026-11-13
  4. 4
    The Eldridge Fiat Level B Motor Sport Magazine (June 1961)
    • 6-cylinder, 21,714-cc A12 Fiat aero-engine
    • 6-cylinder
    • 21,714-cc A12 Fiat aero-engine
    • 160 x 180 mm, 6-cylinder
    • 160 x 180 mm
    • compression ratio of 4.3 to 1
    • four oh valves ... operated via rockers from a rear-driven oh camshaft
    • These engines gave 260 bhp at about 1,700 rpm
    • 260 bhp at about 1,700 rpm
    • original 1907 Fiat gearbox is retained, likewise final drive by side chains
    • broke the World's Land Speed record at 146.01 mph
    Accessed 2026-11-12
  5. 5
    Sir Ernest Eldridge, Fiat Mefistofele and Arpajon Level D Big Scale Models (web archive copy)
    • brakeless front wheels
    Accessed 2026-11-13

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