Analysis of an introduction of a V6 engine in Saab 9000
Compiled 2019 by Olle Granlund, Kent ”Drutten” Gustafsson, Stig-Gösta
Johansson, Jan-Olof Gundberg, Erik Svendsen and Per-Gunnar Björck.
Saab 9000 was at the introduction in 1985 equipped with a turbocharged 2,0 l
4-cylinder inline engine developed and manufactured at the Saab facility in
Already after one year, Saab begun the development of a new 4-cylinder 2,3 l
engine with twin balancer shafts. The improvement of performance, fuel
consumption, noise and vibration (NVH) was significant and the market
reaction was very positive.
By the introduction of the new turbo engine, Saab could offer power and fuel
consumption that well met the requirements at the time. This was verified by
the sales figures which increased considerably in the beginning of the
90-ties. Saab had also by this turbo engine demonstrated its technological
competence and was regarded as the leading manufacturer of turbo engines.
Primarily in the US market, the customer priority was, due to low fuel costs,
not low fuel consumption but silent and vibration free cars and engines with
6 or 8 cylinders were preferred. The lack of a 6-cylinder engine in the Saab
range could not be fully compensated by the 4-cylinder variants.
The introduction of a 6-cylinder engine was vividly discussed by the Saab
board where the marketing department was worried of a loss in sales in the
To assess the modifications required to install a 6-cylinder engine in Saab
9000, it was decided to install a number of V6 engines in Saab cars under
strict secrecy,. Beyond the engineering challenges, the objective was to
find out if the properties expected by the US market could be fulfilled.
The conversions were successfully performed by the Trollhättan engine
laboratory technicians Kent Gustafsson and Stig-Gösta Johansson with some
support from staff in the laboratory and powertrain installation groups.
2. Overview of the installed motor
3. Engine types
Ford had two V6 engine types in production at the time frame of this project,
Ford Essex which was manufactured in England until 1988 and primarily
used in cars built in England like Ford Consul and Capri, and Ford
Cologne which was manufactured in Cologne (Köln), Germany and fitted to
for example Ford Scorpio.
Ford Cologne engine
The engine type which was tested in Saab 9000 was Cologne which eventually
replaced the Essex engine in English Ford cars. The manufacturing facilities
for the V6 engine were at the time in rather poor condition (like factory
with earth floors and insufficient power supply) and Saab was offered to
move the equipment to its manufacturing partner Valmet in Finland for
continued production of engines and spare parts. However, Saab declined and
Ford continued the engine production themselves until 2011.
The engine was of traditional design with cast iron engine block, central
camshaft and push rods and in principle of the same engine family as the V4
engine installed in Saab 96 from 1966.
A Saab car was converted in the spring of 1986 by a gas car builder in
Hengelo in the Netherlands.
It was assessed in the Hamburg, Germany, region and thereafter the project
was dormant for 1-2 years. After a refurbishment of the installation by the
Saab technicians, further assessments were made.
The engine power was limited which made launch performance insufficient but
drivability was acceptable.
The VW VR6 engine was a concept intended to facilitate the transverse
installation of a 6-cylinder engine in cars of the Golf class normally using
4-cylinder engines. The configuration has both cylinder banks in a narrow
angle under a common cylinder head face. In the first prototype engines, the
angle was 10,5 degrees but was later changed to 15 degrees.
A single aluminium cylinder head with double camshafts was used for both
cylinder banks. The piston crowns with combustion chambers were inclined 7,5
degrees. The early engines had 2 valves/cylinder and later engines 4 valves/cylinder.
Cylinder head with 2 valves/cylinder
Two engines in an early prototype stage were installed in Saab 9000. One as
a drivable car and the other for crash test. It was, however, never tested.
The engines were easy to install thanks to their compact dimensions but
would have required adaptations to fit the height of the engine torque rod
in the Saab 9000.
On the VR6 engine, the starter motor is located on the transmission side and
both the Saab F35 manual and ZF HP18 automatic transmissions would have
needed new clutch and converter housings. On the test cars, the transmission
intermediate plate had to be modified with a starter pinion support bearing
(with a grease nipple!). The VW clutch disc was converted to fit the F35
The engine was perceived to have a smooth-running characteristic and
Mazda typ JE-ZE was originally used for longitudinal installation in
the rear wheel drive Mazda 929. It is a 60 degree V6 engine with double
overhead camshafts which made it large both length and width. The cylinder
block is cast iron and the cylinder heads are aluminium.
Mazda JE-ZE engine
The engine was sourced as a complete crate engine with many accessories.
The rear engine face had to be moved further left than in the original Saab
9000 which made the driveshafts very short. The engine was less suitable for
the installation and on the test car both the upper and lower engine mounts
had to be compromised like using the thermostat housing as an attachment
The driving assessment showed good drivability but probably less power than
the nominal 205 hp.
Mazda engine installed in Saab
The SHO-engine, which is based on the Ford Vulcan 60 degree push rod
engine with cast iron engine block, was developed and manufactured in
cooperation with Yamaha to be installed transversely in Ford SHO. It was
high-tech and revolutionary when introduced in 1988. The aluminium cylinder
heads had double overhead camshafts and the inlet manifolds were of variable
length and with a very attractive appearance.
Ford/Yamaha SHO engine
Ford did not accept to sell separate engines to Saab but an engine was
supplied by ASC (American Sunroof Company). Also a complete car was
purchased for reference.
The installation in the test car required an extensive wiring adaptation
since the engine wiring harness was part of the vehicle harness. With a
dedicated wiring system, the engine would otherwise had been well suited to
installing in Saab 9000.
This engine gave the best impression regarding performance and drivability.
Very good noise and vibration (NVH) levels, both inside and outside. And it
was beautiful even without ”beauty” covers.
4.2 Alfa Romeo
The Alfa Romeo V6 engine tested had a cast iron block and aluminium
cylinder heads with one camshaft per head and 2 valves/cylinder. It had been
used in the Alfa Romeo 75, 90 and GTV as a longitudinal engine. At the time
of the installation in Saab 9000 it was already fitted to the Alfa Romeo 164
which was a car using the same platform and engine bay as Saab 9000.
Alfa Romeo engine
It was therefore a simple operation to install the complete powertrain
including the Alfa/Romeo C530 manual transmission in the Saab 9000.
installation in Alfa Romeo 164 with the same engine bay as Saab 9000
The Alfa Romeo cars were later to be offered also with a double overhead
camshaft variant with 4 valves/cylinder.
The impression from the Saab 9000 evaluation was the engine was good looking
and had a sporty engine note.
The six Saab 9000 cars converted to 6-cylinder engines demonstrated that it
was technically feasible but to a variable degree.
The anticipated properties regarding noise and vibration were reached or
could have been reached given further development work.
The possibilities for assessments and optimisations were limited due to the
strict secrecy and deviating priorities with in some development groups.
Overall, the Yamaha engine was judged to have the best prerequisites from
properties and installation point of view and would have had the possibility
to meet the expectations from the US market.
However, none of the tested engines came to be used in Saab 9000.
6. Introduction of a V6 engine in
When General Motors took control of Saab in 1989, the conditions changed and
Saab got access to the V6 engine used by Opel/Vauxhall both in longitudinal
and transverse applications. The engine was manufactured in Ellesmere Port
Since the Saab 2,3 l engine and transmissions had been modularised to have a
common engine transmission interface with Opel and this interface was also
used by the V6 engine, it was fairly easy to install the engine in Saab 9000
with both the F35 and the AF40 transmissions.
The engine was offered in Saab 9000 1994-1996 as naturally aspirated B308i
with 3,0 l and 210 hp.
GM B308i engine