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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.

   1. Background

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 Södertälje, Sweden.

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 USA.

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 types




    3. Engine types

   3.1 Ford

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.


   3.2 Volkswagen

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.


    
  Engine block                                   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 input shaft.

The engine was perceived to have a smooth-running characteristic and driveability.


4. Mazda

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 point.

The driving assessment showed good drivability but probably less power than the nominal 205 hp.


      
        Mazda engine installed in Saab 9000


   4.1 Ford/Yamaha

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.

        
          Engine 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.


   5. Summary

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 Saab 9000

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 in England.

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



 

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