[ Pobierz całość w formacie PDF ]

gasket. Despite the teams attempts the engine wouldn't restart and the car was put away.
The major teams made the trip over to New Zealand for the Nissan Mobil 500 series at
Wellington and Pukekohe.
Wellington [Missing details] won by a European BMW M3
Pukekohe got off to a slow start after Wellington  the track was still undergoing work being
bought up to international standards, pushing the Friday practice session to Saturday morning.
Overnight rain saw the conditions as wet (we bogged the Fairmont doing donuts in the car
park). Skaife did the morning session, with the team mucking around with the suspension. My
main memory of his session was the GT-R doing a huge backfire - leaving a smoking patch on
the track.
Mark Skaife and Jim Richards qualified third on the grid behind Dick Johnson (who lost two
engines on Saturday) and Brock, both in Sierra RS500's. In the race it took Skaife two laps to
get past the Sierras. The Nissan game-plan called for the car to pull a 30 second lead, and then
settle into a more relaxed pace. By lap 23, the GT-R's lead was out to 20 seconds over Brock.
We were entertained with the DJR RS500 blowing intercooler hoses off multiple times, and
another Sierra smacking into a kerb.
The GT-R kept leading until lap 32 when Skaife reported a loss of power  one of the turbos
had blown. The car was retired. The European BMW M3's also expired within a couple of
laps, one with a blown engine, and the other with accident damage. The Brock Sierra cruised
to the finish and took the flag.
There was a good interview with Fred Gibson published in Auto Action which gives some
interesting insights: In Japan, the top GT-R teams are reported to have reached the 600hp
mark in competition, up from 570hp that most of them have been running with. The main
problem with the Australian developed GT-R's were brakes, the cylinder bore or block
cracking and the turbos. For 1991 the rules were relaxed on brakes, so that problem could be
Page 55
The Sky Is The Limit Articles
more easily worked through. The blocks had been cracking due to a harmonic in the engine 
up until Pukekohe the team had been using a block every race. New engine mounts were used
to cure this. The turbo failures were blamed on quality control at Garret  the Gibson team
invested in their own balancing machine so they could assemble their own turbos instead of
buying complete units from Garret in Japan.
January 1991
A bit of background is needed here as the 1993 rule change was essentially influenced by
these events and conditions.
The CAMS motorsport body was in trouble. It was running out of money, and needed
restructuring. To compound the issue, there was a general downturn in the economy. CAMS
responded by charging large registration fees of AU$6,000 per car for the ATC, and tracks
were charged AU$10,000 to host a round. In addition, because the Group A format was
administered by FISA in Europe, the regulations were hard to work with. This had caused
delays in getting the new VN Group A Commodore homologated for competition.
The rules were revised for the 1991 season aiming to keep the fields even. The Sierra's had
85kg removed from their minimum weight, bringing them down to 1,100kg. They also got a
six speed gearbox. The Commodores also lost some weight  75kg down to 1250kg, and a
host of freedoms including the entire inlet system, the valves and ports were free, and the
inner wheel guards could be modified to fit wider tyres. The BMW M3 was allowed to run
similar freedoms as the Commodores, at a featherweight 960kg. The GT-R had it's minimum
weight increased to 1360kg. [the reporting of weights is not consistent  the homologation
weight of the GT-R was 1260kg, yet the press report an increase of 35kg from 1325kg. Go
figure]
In April, the minimum weights are further revised with an across the board increase of 2.5%
in all cars. This was done so the private teams didn't have to resort to expensive exotic
materials to reach the same weights as the factory teams.
The season looked like being a difficult one  the entries were well down, with a core group
of 12 cars contesting all rounds, and very small fields. Even at this stage there was talk of
making a full grid at Bathurst by allowing the standard Group E production cars to join the
Group A race.
Page 56
The Sky Is The Limit Articles
February 1991
The first round of the ATC at Sandown. Jim Richards qualified on pole, with Mark Skaife
0.04 seconds behind. Skaife was complaining of some problems. Behind them it was wall to
wall Sierra's, now a little faster with their new 6 speed gearboxes and lighter minimum
weight. The field was small, only 19 cars on the grid.
The race itself was over with a minute of it starting. Jim and Mark blasted off the start line
and had a 20 meter lead over the next car on the track. On lap 2, Jim laid down a new lap
record  1m 15.70 seconds  quicker than the fastest of the Sierra's by 1.31 seconds. Ouch.
One interesting moment occurred at the three quarter mark in the race  the new BMW M3 of [ Pobierz całość w formacie PDF ]