Basically when a car is first built the original basic design is produced as a working / tested product. The basic design evolves and changes to meet customer demand and to account for changes in the market. These changes are usually made quickly and cheaply so that greater profit can be made for the manufacturer. If changes were not implemented in this way there would be no point in making the changes because there would be nothing in it for the manufacturer, the changes would be too little to late and not benefit the market or the cost of making the changes would override the sales increase or production savings. The other possibility is that there was some sort of compromise during the original design and build so a part of the system (component) does not perform as well as it could. Nine times out of ten there was a solid reason for the apparent misatake during the design of a component; cost, environment, time, resources, ect, ect..

In the case of the location of the battery in the Saab 900 it seems that it ended up there during the evolution process. The Saab 900 evolved from the Saab 99 and is a very similar car. The main difference in the 900 is that the nose is longer than it was on the 99. One result of this is a more spacious engine compartment and hence a nice empty space in front of the wheel arch to locate the battery. The battery on the 99 is located high up on top of one of the wheel arches. The opposite area on the 900 is filled up with a very restrictive intake system.

So if the battery is located in front of the wheel arch then that should be ok really? Well yes, but as a result, the battery ended up being very close to the exit from the turbo’s turbine housing. Saab overcame this issue by putting a tight 90 degree turn just at the point where the exhaust gasses escape from the turbo. The gasses travel very fast at this point and the Saab solution actually restricts the flow of the exhaust gasses. So a good case to modify.