Designed to win – Porsche 908/3 – Part 1

By David Boote

Royale S2000 Image by KJG Photograpy.  https://www.kjgphotography.co.uk

PART 1 / 2 – The build up

The inspiration for this article originates from an epic road trip around the Targa Florio circuit that I made with my wife in 2017. It was a bucket list item !

My interest in motor sport began in the early 1960s and from early on my imagination was captured by the epic road races. Inspired by a tour of the 1955 Mille Miglia route we decided to attempt a lap of the Targa Florio circuit in Sicily.

After a wonderful drive down through Europe in our Honda S2000 on holiday in 2017 the day had come for us drive a lap of the Piccolo Madonie circuit which was the shortest of the three routes and used between 1937 and 1977. It didn’t take us long to realise that our best was going to be quite pedestrian compared to those of my heroes from the early 1970s in their race prepared Porsches & Ferraris. The reason was not, as you might think, to do with my talent behind the wheel but rather that so many sections of the road had subsided due to the volcanic nature of the island and we would arrive around a corner to find a large piece of road missing and the edges marked by nothing more than a few traffic cones!

After a few scares and realising that we eventually had to drive our car back to the UK we continued at a more moderate pace which, by enlarge was governed by how much we could see of the road ahead which, considering the very twisty nature of the roads, was not a lot…… most of the time !

The experience left me trying hard to imagine what it must have been like to race a 1970’s Porsche or Ferrari for 6 hours solo round what was really just a tarmac rally stage.

Fast forward to 2020 and my friend Nick Bailey, ex Clubmans racer, had decided to return to racing with a Historic Sports 2000 Royale S2000M. Having worked together previously on Nick’s cars he had asked me to help with the preparation of the Royale. The car came with a new set of body panels and Nick produced a picture of a Porsche 908/3 in the iconic Gulf colours from 1970 and asked if I had any more pictures in my motorsport book collection that could be used for reference.

I didn’t need a second invitation to re-visit all my books on the Targa Florio and Porsche sportscars! And this ultimately rekindled my interest in the history of the Porsche 908/3 and the reasoning behind its design.

Although Porsche had an amazing team of drivers for its 917s which were the weapons of choice for their attack on the World Sports Car Championship in 1970 the engineers, possibly with input from the drivers, looked at two specific races – the Targa Florio and the Nurburgring 1,000km, ( run on the full Nordscheife circuit), and decided that maybe they should build a car better suited to the nature of those two long & tough circuits, which were going to be demanding on both drivers and cars. Hence the birth of the 908/3, which was designed specifically to race on only those two circuits of which the Targa Florio was by far the more extreme.
So how did Porsche approach the task? Group 5 sports cars such as the Porsche 917 and Ferrari 512 were allowed an engine capacity of up to 5 litres provided twenty-five cars were built but prototypes were limited to 3 litres. However, allowing for the nature of the Piccolo Madonie circuit in particular, Porsche decided that 3 litres would provide ample power and therefore they would build a pure prototype to take on its demands.

Porsche already had the 908/2 prototype which in coupe and spyder form had convincingly won the 1969 World Sports Car Championship and the Targa Florio. However fundamentally that car was a compromise as it had to compete at all the circuits on the calendar including Le Mans. Hence Porsche turned its design attentions to its 909 Bergspyder hillclimb car from 1968. The roads used in the European Hillclimb Championship were narrow and twisting, closely resembling those of the Targa Florio.

 

The Porsche 909 in hill climb spec weighed in at a mere 384 kg and was by far the lightest car that Porsche had produced. The engine was the flat eight carried over from the 908/2 and used a magnesium alloy block and aluminium heads to produce 360 bhp with a weight of 180kg.The extensive use of exotic materials including magnesium, titanium and beryllium with minimal aluminium chassis tubing and wafer thin bodywork were unlikely to survive the demands of the Targa Florio without some further strengthening. The challenge for the engineers therefore was to maintain the lightweight philosophy inherent in the original design yet put strength (i.e. weight) back into the car BUT in the right places. Another key consideration for the Targa Florio was that the car needed to be as agile and responsive as possible which meant putting as much of the weight as they could between the front and rear axle with as close to a 50/50 split as possible. To achieve this the differential was placed behind the gearbox as in the 909 moving the engine closer to the centre. As a result of this, and because they wanted a very short wheelbase to achieve the desired agility, the 908/3 drivers sat directly ahead of the engine and found their feet, surrounded only by the few fragile tubes placed ahead of the front axle line which were part of the original the 908/2 design. This fact that was not lost on one of the 1971 drivers, Brian Redman. In his book “Daring Drivers, Deadly Tracks” he says that he was also told when on the grid for the 1971 race “If you’re going to crash, don’t crash on the right side. That’s where the fuel tanks are located.”

With the finished design of the 908/3 the fuel tank, driver and battery were all placed on the right supposedly to give optimum weight distribution for the predominantly clockwise circuits in use at the time, yet the 908/3 was only designed to race at the Targa Florio and the Nordschleife which ran anticlockwise and clockwise respectfully which would suggest that a more neutral set up would have been preferable?

The 908/3 ended up weighing 540kg/1190lb which gave it a power to weight ratio of 666 bhp per ton. This coupled with its weight distribution and short wheelbase with very little front and rear overhang gave it all the power and agility that Porsche required for its limited programme. In addition the dimensions and very simple bodywork, devoid of any wings and spoilers, gave the 908/3 a very purposeful and dramatic appearance enhanced by the colour schemes of the sponsors. The fibreglass bodywork looked stunning in either Martini or Gulf livery and weighed a mere 12kg. As an illustration of the continued obsession with weight saving they glued the rear light lenses into place to save the weight of the screws!

 

In testing the drivers were impressed by the cars performance, however they were less enamoured with the forward seating position and lack of protection. Nonetheless typical of the drivers in those days, they would chose a fast but dangerous car over a slow but safe option, and trust their abilities and belief that “a big accident wouldn’t happen to them”.