The JTS engine (Jet Thrust Stoichiometric) is a
gasoline direct injection
Gasoline direct injection (GDI), also known as petrol direct injection (PDI), is a mixture formation system for internal combustion engines that run on gasoline (petrol), where fuel is injected into the combustion chamber. This is distinct ...
engine produced by
Alfa Romeo
Alfa Romeo Automobiles S.p.A. () is an Italian luxury car manufacturer and a subsidiary of Stellantis. The company was founded on 24 June 1910, in Milan, Italy. "Alfa" is an acronym of its founding name, "Anonima Lombarda Fabbrica Automobili." ...
. It exists in two forms,
straight-4
A straight-four engine (also called an inline-four) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft.
The vast majority of automotive four-cylinder engines use a straight-four layout (with the ...
and
V6, and was introduced into the Alfa lineup in 2002.
Four-cylinder
2.0

The JTS engine debuted in 2002 in the
Alfa Romeo 156
The Alfa Romeo 156 (Type 932) is a compact executive car produced by the Italian automobile manufacturer Alfa Romeo. It was introduced at the 1997 Frankfurt Motor Show as the replacement for the Alfa Romeo 155. The 156 received a positive rec ...
.
The engine was based on the 2.0
Twin Spark (itself a variant of the
Pratola Serra engine family), replacing Twin Spark with direct injection, dubbed "Jet Thrust Stoichiometric". This improved power from to , but more importantly, torque climbed from to . In 2003, this engine was introduced to the
GTV/Spider coupé and roadster and it was fitted to the
GT from launch.
In spite of its benefits to power, torque and economy, the JTS was not used in the smaller 147 or the larger 166, and much less in other models from the
Fiat Group
Stellantis Italy, formerly known as Fiat Group Automobiles S.p.A. from 2007 to 2014 and FCA Italy S.p.A. from 2014 to 2021, is the Italian subsidiary of the multinational automaker Stellantis, dedicated to the production and selling of passe ...
. This was allegedly because the JTS engine cost a lot more to produce than the Twin Spark.
*Displacement:
*Power: @ 6400 rpm
*Torque: @ 3250 rpm
Applications:
*2002-2005
Alfa Romeo 156
The Alfa Romeo 156 (Type 932) is a compact executive car produced by the Italian automobile manufacturer Alfa Romeo. It was introduced at the 1997 Frankfurt Motor Show as the replacement for the Alfa Romeo 155. The 156 received a positive rec ...
*2003-2004
Alfa Romeo GTV & Spider
*2004–2010
Alfa Romeo GT
The Alfa Romeo GT (Type 937) is a coupe automobile that was produced by the Italian automaker Alfa Romeo between 2003 and 2010. The GT was introduced in March 2003 at the Geneva Motor Show.Fiat Chrysler Automobiles EMEA PressNEW ALFA GT COUPÉ, ...
1.9
It was only in 2005, with the arrival of the 159, that more variants of the JTS were produced. The 2.0 JTS gave way to a 1.9 L variant with and a 2.2 L version with . The 1.9 JTS and 2.2 JTS form part of a new engine family and are completely different from the 2.0 JTS. Both 1.9 L and 2.2 L have chain driven camshafts and
variable valve timing
In internal combustion engines, variable valve timing (VVT) is the process of altering the timing of a valve lift event, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combination with varia ...
on both inlet and exhaust camshafts. Both 1.9 and 2.2 JTS engine blocks were supplied by GM to the Fiat group and belong to the
GM Ecotec engine family. Both models are mapped to either a six-speed manual gearbox plus a reverse gear, or a Formula One inspired sequential gearbox also having six gears and reverse.
*Displacement:
*Power: @ 6500 rpm
*Torque: @ 4500 rpm
Applications:
*2005–2011
Alfa Romeo 159
The Alfa Romeo 159 (Type 939) is a compact executive car manufactured and marketed by Alfa Romeo between 2004 and 2011. Introduced at the 2005 Geneva Motor Show, as a replacement for the 156, the 159 used the GM/Fiat Premium platform, shar ...
2.2

With the arrival of 159, a 2.2 JTS was also introduced. The engine block is sourced from GM (
Ecotec L61).
*Displacement:
*Power: @ 6500 rpm
*Torque: @ 4500 rpm
*Compression Ratio: 11:3:1
Applications:
*2005–2010
Alfa Romeo 159
The Alfa Romeo 159 (Type 939) is a compact executive car manufactured and marketed by Alfa Romeo between 2004 and 2011. Introduced at the 2005 Geneva Motor Show, as a replacement for the 156, the 159 used the GM/Fiat Premium platform, shar ...
*2005–2010
Alfa Romeo Brera
The Alfa Romeo Brera and the Alfa Romeo Spider (Type 939) are mid-size sports cars using the GM/Fiat Premium platform, manufactured by Pininfarina and marketed by Alfa Romeo as a 2+2 coupé and roadster respectively.
12,488 units of the Spide ...
*2006–2010
Alfa Romeo Spider
The Alfa Romeo Spider (105/115 series) is a two-seater, front engine, rear drive roadster manufactured and marketed by Alfa Romeo from 1966 to 1994 in four distinct generations, or ''Series'', each with modifications ranging from modest to exte ...
Six-cylinder
3.2
The ''JTS'' direct injection system was first used in a V6 engine in 2005 with the introduction of the Alfa 159 and Brera. This is not related to the
Alfa Romeo V6 engine
The Alfa Romeo V6 engine (also called the Busso V6) is a 60° V6 engine made by Alfa Romeo from 1979 to 2005. It was developed in the early 1970s by Giuseppe Busso, and used on the Alfa 6 with a displacement of and a SOHC 12-valve cylinder ...
, but is instead a derivation of the
GM High Feature engine
The GM High Feature engine (also known as the HFV6, and including the 3600 LY7 and derivative LP1) is a family of modern General Motors DOHC V6 engines. The series was introduced in 2004 with the Cadillac CTS and the Holden Commodore (VZ).
It is ...
; built in Australia by GM Holden. While it retains the High Feature engine's bore x stroke and chain driven camshafts, it is modified by Alfa for their performance,
fuel economy and sound characteristics. These modifications include: "TwinPhaser" variable valve timing (cam-phasing on both inlet and exhaust cams, thus the name),
gasoline direct injection
Gasoline direct injection (GDI), also known as petrol direct injection (PDI), is a mixture formation system for internal combustion engines that run on gasoline (petrol), where fuel is injected into the combustion chamber. This is distinct ...
and a higher
compression ratio
The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values.
A fundamental specification for such engines, it is measured two ways: the stat ...
of 11.25:1. It also operates with a lean burn system up to about 1500 rpm,
as on many other engines from the company and is capable of generating ,
a number matching the larger ''LY7'' 3.6 L variant used by GM. Alfa Romeo stopped using the V6 JTS engine in 2010.
*Displacement:
*Power: at 6200 rpm
*Torque: at 3800 rpm
Applications:
*2004
Alfa Romeo Visconti
The Alfa Romeo Visconti is a concept car made by the Italian car manufacturer Alfa Romeo, designed by Giorgetto Giugiaro.
The car was seen for the first time at the Geneva Motor Show in 2004. The car is a four-door fastback coupé
A coupe or c ...
(concept car)
*2005–2010
Alfa Romeo 159
The Alfa Romeo 159 (Type 939) is a compact executive car manufactured and marketed by Alfa Romeo between 2004 and 2011. Introduced at the 2005 Geneva Motor Show, as a replacement for the 156, the 159 used the GM/Fiat Premium platform, shar ...
*2005–2010
Alfa Romeo Brera
The Alfa Romeo Brera and the Alfa Romeo Spider (Type 939) are mid-size sports cars using the GM/Fiat Premium platform, manufactured by Pininfarina and marketed by Alfa Romeo as a 2+2 coupé and roadster respectively.
12,488 units of the Spide ...
*2006–2010
Alfa Romeo Spider
The Alfa Romeo Spider (105/115 series) is a two-seater, front engine, rear drive roadster manufactured and marketed by Alfa Romeo from 1966 to 1994 in four distinct generations, or ''Series'', each with modifications ranging from modest to exte ...
References
{{Alfa Romeo
Fiat engines
Gasoline engines by model