![Sagaris engine](https://upload.wikimedia.org/wikipedia/commons/5/5c/Sagaris_engine.jpg)
The TVR Speed Six was the name of a
naturally aspirated straight-6 engine manufactured by
TVR, and used in several of their cars including the
Tuscan,
Cerbera
''Cerbera'' is a genus of evergreen small trees or shrubs, native to tropical Asia, Australia, Madagascar, and various islands in the Indian Ocean and the western Pacific Ocean.
Three trees of this genus are mangroves, '' Cerbera floribunda'', ...
,
Tamora,
T350,
Sagaris
The sagaris ( grc, Σάγαρις and Σάγαρι) is an ancient shafted weapon used by the horse-riding ancient Saka and Scythian peoples of the great Eurasian steppe. It was used also by Western and Central Asian peoples: the Medes, Persia ...
and
Typhon
Typhon (; grc, Τυφῶν, Typhôn, ), also Typhoeus (; grc, Τυφωεύς, Typhōeús, label=none), Typhaon ( grc, Τυφάων, Typháōn, label=none) or Typhos ( grc, Τυφώς, Typhṓs, label=none), was a monstrous serpentine giant an ...
.
![TVR Cerbera Speed Six - Flickr - The Car Spy (8)](https://upload.wikimedia.org/wikipedia/commons/a/ab/TVR_Cerbera_Speed_Six_-_Flickr_-_The_Car_Spy_%288%29.jpg)
The engine's prototypes (referred to as AJP-6) were designed and delivered by independent engineer
Al Melling
Alwyn "Al" Melling is a British automobile engineer.
Fashion design
At the beginning of the 1980s he was involved in the fashion industry, and owned a company in London throughout the 1980s which designed ladies' fashion garments. As owner he ...
(the "A" in AJP) as both 3.0 and 3.5 litre units.
Many of its key
cylinder head
In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinders and forms the roof of the combustion chamber.
In sidevalve engines, the head is a simple sheet of metal; whereas in more modern ...
design elements (particularly the
valvetrain
A valvetrain or valve train is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. The intake valves control the flow of air/fuel mixture (or air alone for direct-injected engines) ...
) were first seen in the 1991
Suzuki GSX-R750 (M) motorcycle engine (also a Melling design).
The key design features were an all
aluminium alloy
An aluminium alloy (or aluminum alloy; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principa ...
block and head,
with
cast iron
Cast iron is a class of iron– carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impur ...
cylinder liner
In a reciprocating engine, the cylinder is the space in which a piston travels.
The inner surface of the cylinder is formed from either a thin metallic liner (also called "sleeve") or a surface coating applied to the engine block. A piston is se ...
s,
double overhead camshaft
An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion cha ...
s, finger follower 24-valve actuation, one
throttle
A throttle is the mechanism by which fluid flow is managed by constriction or obstruction.
An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ...
and injector per cylinder (
throttle-body fuel injection
Manifold injection is a mixture formation system for internal combustion engines with external mixture formation. It is commonly used in engines with spark ignition that use petrol as fuel, such as the Otto engine, and the Wankel engine. In a mani ...
), equal length tubular
exhaust manifolds dual 3-way
catalytic converter
A catalytic converter is an vehicle emissions control, exhaust emission control device that converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalysis, catalyzing a redox chemic ...
s and a
dry sump
A dry-sump system is a method to manage the lubricating motor oil in four-stroke and large two-stroke piston driven internal combustion engines. The dry-sump system uses two or more oil pumps and a separate oil reservoir, as opposed to a con ...
lubrication system allowing the engine to be mounted lower in the vehicle
chassis. These features enabled the engine to provide lightweight, compact dimensions, extremely fast throttle response and high peak
horsepower
Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are t ...
.
Worthy of note is that the high performance
BMW S54
The BMW M54 is a naturally aspirated straight-6 petrol engine produced from 2000 to 2006. It was released in the E53 X5 and is the replacement for the M52 engine. The S54 is the equivalent high performance engine, used in the E46 M3, the Z3 M ...
engine is also of a very similar configuration. Straight-6, throttle body EFI,
DOHC
An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion cha ...
24-valve finger follower
valve actuation.
In order to reduce unit production costs, the engines that actually went into production, called Speed Six, were TVR modified versions of the initial AJP-6 prototypes with and capacities. Prominent modifications were alterations to valve train geometry, a switch from a billet steel
crank to cast iron (with a crank damper), different
connecting rods,
oil filter
An oil filter is a filter designed to remove contaminants from engine oil, transmission oil, lubricating oil, or hydraulic oil. Their chief use is in internal-combustion engines for motor vehicles (both on- and off-road ), powered aircraft, r ...
relocation to the inlet side of the engine, and removal of the exhaust cam oil feed. The two different capacities were achieved through stroke alterations from a con-rod design able to accommodate two different stroke lengths, and different
piston crown designs altering the
compression ratios. The bore diameters were shared. Pistons were made in Italy by Asso Werke from pre-existing casts, initially designed for the
Rotax
Rotax is the brand name for a range of internal combustion engines developed and manufactured by the Austrian company BRP-Rotax GmbH & Co KG (until 2016 BRP-Powertrain GmbH & Co. KG), in turn owned by the Canadian Bombardier Recreational Produc ...
-
Aprilia RSV 1000 engine. Those casts, refused by Rotax, were modified and used to produce the smaller Speed Six pistons.
Unfortunately, during TVR’s development of the original MCD design, it was decided to remove the drilled lubrication oil-ways from the camshaft centres to the peak of each of the camshaft lobes, resulting in starvation of lubrication and early versions of the Speed Six engine suffering from poor valve-train durability leading to many warranty claims against TVR.
German and French tuners and owners have, since, re-introduced these oil-ways, returning the motor to its original, efficient and reliable design.
Other third party development work has also mitigated this issue by using revised material harnesses for the cam lobes, finger followers and valve guides. Softer valve springs and valves with thicker stems were also utilised. Engines that have had these modifications performed have also improved durability.
The initial 4.0 litre version of the engine as used in the Cerbera produced with the final incarnations of the engine having TVR claimed outputs of in the
Tuscan S
Tuscan may refer to:
Places
* A person from, or something of, from, or related to Tuscany, a region of Italy
* Tuscan Archipelago, islands off Tuscany, Italy.
* Tuscan, South Australia was a railway siding and locality in the Murray Mallee regi ...
,
Sagaris
The sagaris ( grc, Σάγαρις and Σάγαρι) is an ancient shafted weapon used by the horse-riding ancient Saka and Scythian peoples of the great Eurasian steppe. It was used also by Western and Central Asian peoples: the Medes, Persia ...
and
Typhon
Typhon (; grc, Τυφῶν, Typhôn, ), also Typhoeus (; grc, Τυφωεύς, Typhōeús, label=none), Typhaon ( grc, Τυφάων, Typháōn, label=none) or Typhos ( grc, Τυφώς, Typhṓs, label=none), was a monstrous serpentine giant an ...
.
TVR further developed the Speed Six into the limited-production
V12 V12 or V-12 may refer to:
Aircraft
* Mil V-12, a Soviet heavy lift helicopter
* Pilatus OV-12, a planned American military utility aircraft
* Rockwell XFV-12, an American experimental aircraft project
* Škoda-Kauba V12, a Czechoslovak experim ...
Speed Twelve racing engine. TVR also experimented with
supercharging
In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement.
The current categorisation is that a supercharger is a form of forced induc ...
the Speed Six engine for use in the Typhon/T440 model. However this proved unsuccessful due to cooling challenges so the few Typhon/T440 models that made production were instead fitted with standard naturally aspirated 4.0L Speed Six engines.
References
{{DEFAULTSORT:Tvr Speed Six Engine
TVR engines
Straight-six engines