Nissan Silvia rally car build part 4

29/12/2015

We were down to the last few weeks before the debut rally and some long hours were being spent on the Silvia.
With the major mechanicals and the exterior sorted it was onto the list of smaller items to get the car ready for competition.
The owner had found a set of used Velo race seats and so we went about fabricating the brackets for the seat mounts. The job was made easier with custom seat mounting tubes already welded in when we got the car, however it was still a time consuming process. You might think that mounting race seats should be easy. Drill, bolt and you’re done. The reality is that it can take a full day or more on each seat to get it in the correct position. Generally the driver’s seat position will be set to the driver’s preference with the co-driver as far back and as low as possible to keep the weight as low as possible. It wasn’t too much drama on the left side of the car, the right side was another problem altogether. With the owner’s height of nearly 2m, getting the driver’s seat position ideal proved quite a challenge. We worked through numerous scenarios before we got the best compromise and even then the grinder and welder came into play to modify the seat mounting tubes. We also made up a pair of harness bars that were bolted directly under the crutch strap holes in the seats. Without getting too technical, the rules are very specific about the position of harness mounts to ensure occupant safety in an accident and this is why we had to fit an extra bar under each seat.
The rest of the six point race harnesses were fitted as well as a new spare wheel tie down strap. Other items such as jack, tools and safety triangle also found their way into the boot in readiness for competition.
In the front of the car, an aluminium bracket was fabricated and a Monit G100 rally computer fitted to aid the co-driver with navigation. After trialling our first Monit a couple of years ago, we now use these as our standard fitment on all rally cars.
The Silvia was then loaded onto the trailer for trip to Precision Exhausts. We never got an exhaust with the car so a full system was needed. Starting from the dump pipe flange, a new 2.5” system with a flex joint and single hot dog was fitted. Why not a 3” or larger system? First bigger pipes mean more clearance issues and have more chance of being damaged on a rally. Second, you can only feed so much power into the rear wheels before it is lost as wheel spin. With a factory intercooler and modest boost pressures, the 2.5” system is more than up to the task of efficiently expelling waste gasses.
Incidentally the drives on and off the trailer were the first trips that car had made under its own power since who knows when. As expected, nothing fell off, leaked, rattled or squeaked so we could move onto the next phase, testing.
Two weeks prior to the first rally, we got the car and owner up to our venue for some seat time. A few steady laps to check over everything and then we took to putting the car through some of its paces. The owner spent several hours finding his feet with the car and getting used to the power and behaviour of the turbo on the dirt. The focus was on getting lines right and keeping it neat as we knew the upcoming rally would have tight and narrow roads.
When the car was loaded onto the trailer at the end of the day, we only had three minor issues to resolve. 1.) The driver’s seat needed to be angled back slightly further. 2.) Permanently wire in the second radiator fan to provide better cooling at low speed and 3.) Replace a leaking output seal on the diff.
Once back in the workshop, all of the items were quickly completed and then the last few tasks could be done. A thorough clean inside and out was followed by a coat of wax to seal the now fully cured paint. A set of HDPE mud flaps were then cut out and aluminium brackets fixed to the body work. The flaps were then drilled and cable tied into position.
We had our sign writer Richard make up some name stickers to go on the front guards and got the car through event scrutineering, passing with flying colours.
With a wheel alignment our last item, we focussed on the peripherals for the rally. The Silvia’s spares package was arranged and boxed up including wheels and tyres. Most of the other parts were duplicates from the build. The idea to enter this event was to give the car a shakedown and the driver some rally experience in preparation for the 2016 season.