Over 6 months ago, we started the winter overhaul of the car before the turn of the year and the coldest weather.
Our first issue to solve was that our fuel gauge had stopped reading accurately. This was a problem when we felt we were low on fuel at the Birkett Relay race, so went to add more and the tank was full (reading just over half on the gauge).
After looking and ultimately not finding any better aftermarket solutions we remove the sender and pump from the tank and repaired the Porsche/Bosch unit ourselves and it now reads accurately.
Next we did the usual maintenance of brake discs, pads and changing the fluid. We also added slightly larger spacers at the rear.
We also replaced the earth and positive cables in the engine bay which run from a central junction point to the alternator and starter motor. These are known weak point causing hot start issues. A problem if you stall mid race.
Our other major work was to identify and resolve the poor handling I had in the Birkett Relay race at Silverstone. The rear of the car was breaking traction into high speed corners since we removed the rear wing and front splitter.
After a couple of months of looking, I picked up a genuine used bumper - these are becoming both rare and ever more expensive. Our emergency spare that has seen better days can be retired back to the loft.
In our first pre-season track day in February we picked up an oil leak on the top of the engine. It was easily rectified by reconnecting the oil filler tube properly which I had taken off when doing the re-wiring work.
We reduced the ride height all round - there is no real limit on this under the Calm Porsche regulations. We lowered it more at the back to reduce the amount of rake. All changes are designed to increase rear grip. Whilst doing this I found the main chassis x-member had come loose (1 bolt completely missing!) so the engine was moving left to right though corners which wouldn't have helped!
We also experimented with using the rear spoiler of the Boxster deciding to keep it slightly raised on balance. Our data traces show some big differences between running the aero kit vs not. Without - the car accelerates faster on the longer straights to slightly higher max speed. However with aero any corner over 50mph can be taken much faster resulting in higher mid corner and corner exit speeds which is where lap time was gained.
This year the Motorsport UK regulations are aligning with the FIA international standards for fire extinguishers. Ours was nearly end-of-life anyway, but the new design required replacement of the plastic piping with larger diameter aluminium piping and increased the no. and size of spray nozzles. All the wiring and trigger buttons were also replaced with the kit.
During the track day we also noticed a crunching into 3rd gear had developed which is probably a worn synchromesh. At some point this will break completely so we needed to address it. The Boxster S 6-speed gearbox is incredibly expensive to repair - mostly due to the cost of special tools needed and any gear rings and bearings. There are few parts shared with other makes so no cost saving measures.
I took a gamble and picked up a used 60K miles gearbox and we spent the Easter weekend replacing it, skipping the first race event of the season. The process is pretty straightforward unbolting the drive shafts, chassis supports and exhaust, before removing the gearbox itself. Putting the replacement in was easier than when we replaced the engine knowing we'd have to line the splines up and pull the gearbox the last inch by sample doing up the 8 differently sized bolts!
Before we race we did another track day at Snetterton with Michael driving most of the day and getting plenty of dry and wet laps in to boost confidence.