Porsche 962-108C (1988-1989)
The famous ‘Miller 962’ was rightly seen as the fastest 962 in the world, with wins at the Daytona 24hrs, the Porsche Cup and the Palm Beach GP in 1989.
As per IMSA rules, 962 -108 was an air-cooled 3 litre single turbo. Chassis 108 was delivered to Jim Busby Racing for use in the IMSA Camel GT Championship, along with 105, 106 and, later on, 119.
After delivery, 108 was prepared for the 1986 Daytona 24 Hours, the peak of American endurance racing, to be raced by Pete Halsmer, John Morton and Dieter Quester. Halsmer was cut off trying to pass a back marker, and crashed, luckily without serious injury to the driver. Although 108 seemed to be a total wreck, upon further inspection it was found that much of it could be reused. For the balance of the 1986 season 105 was used, whilst Jim Chapman was enlisted (with the permission of the factory) to build a stronger tub for 108 using honeycomb aluminium and a solid billet milled bulkhead instead of the factory’s sheet aluminium. Work went slowly, whilst the season was finished out by 105 and 106.
When Al Holbert of Holbert Racing (also in charge of Porsche Motorsports North America), heard of the new honeycomb chassis being built by Chapman, he made a series of attempts to acquire it for his own use. In the end a deal was done to swap the tub for access to 3.2 litre pistons and cylinders that were secretly giving Holbert a significant horsepower advantage over Busby’s team.
This tub, named CO1, was then installed into Holbert’s multi race winning 962-HR1. Chapman was then commissioned to build the next honeycomb tub, CO2, to go into what would become the ‘second coming’ of 108. Busby wanted the same power for 108 that he could see was there for Holberts 962s, who frequently outclassed him on the straights. Andial would not oblige, due to Holberts status as the official Porsche Representative.
So, typically, Busby tried another path. He asked Ed Pink, his engine builder, to see what could be achieved. By cracking the Bosch Motronic injection system computer and with some slight engine changes, he found he could offer another 80 bhp!
This new 962 was christened 962.108B and was transported to Daytona in January 1987. From then on, 108B was a very strong contender, achieving 2nd, 3rd, 4th and a couple of 6th placings but at Sears Point the 962 was again crashed, this time by Bob Wollek. Despite a spectacular crash, Wollek only suffered a dislocated shoulder, proving the Chapman tub is clearly the strongest and safest of all.
A by product of Jim Busby’s height also meant it is the roomiest of all 962s. So, Busby was once again looking at another Chapman chassis if 108 was to compete again in just a few months time, keeping the old tub to repair at a later date, a job that we are finally completing at the present.
16 weeks later, 962.108C was ready, sporting the familiar BF Goodrich livery. 1988 was the year of Nissan, with them winning 8 races in succession, but 108C ran fabulously at the legendary 1988 Daytona 24 hours – achieving both pole position and leading the race, ultimately coming in second to the brand new Jaguar XJR-9, after a fantastic race long battle. Had it not required repairs after minor contact, the story could have been different. Further improvements to 108C continued with the fitting of a rear brace for stability and suspension tweaks.
The body was altered to provide a ‘short nose, long tail’ layout, and downforce was improved by grafting the nose of a Porsche 956 onto the rear of the 962 nose. Further work on air entry points, wing positions and rear filling combined with Pinks’ engine improvements meant that Busby’s work, and faith, in 108 was about to pay off. Bob Wollek took two 3rd places, a 4th and a 5th in the remainder of 1988, co-driven by Mauro Baldi on several ocassions. This 108 also sometimes carried another designation – 962.108C2.
During testing, Busby realised he was onto something special. Busby could pull 800 more revs than before in some points, and the improved performance meant that spectacular passes were possible on the straights against other 962s. This was more than aerodynamics though – work on the waste gate meant that power could be boosted at low speeds to provide maximum acceleration.
Text from Historic Porsche. For more information check out their full article and history here.