HANDLING UPGRADES
Paul pushes on with the race car conversion, this month finishing off the suspension and brakes, and connecting up the fuel tank too…
You may remember from a couple of issues ago that I’d started to put the suspension together, using the new race-spec upgrades that would be needed? But
I got side-tracked after fitting the hubs and uprights and turned my attention to fitting the engine instead... Well, now the race-ready YB is all bolted-up, this month I’ve gone back underneath to finish off the suspensions and braking – but this involved a lot more than just bolting a few bits in place. Starting at the front, before I could fit any of the lower control arms or roll bars, firstly I needed to add a couple of small strengthening plates to the chassis legs where there new anti-roll bar mounting blocks would fit. The factory chassis has an indentation, but for optimum performance (and reliability) the new Group A roll bar mounting blocks really should be mounted on a flush surface. So, a strengthening plate was soon welded in place, primed and painted, and ready for assembly.
The new lower control arms mount from the crossmember to the bottom of the new alloy hubs, while a secondary compression-strut piece connects that bar to the anti-roll bar bracket. The bladed anti roll bars themselves then connect to the lower control arms via a drop-link – everything is adjustable, rose-jointed, and it all interlinks with one another to give precise and accurate control of the suspension geometry – it’s one of the biggest differences, if not the biggest difference, between the RS500 road cars and the BTCC racers. To finish it all off, a new set of AP Racing four-pots were added with new 330mm x 32mm floating discs too.
Then, it was time to turn to the rear. Again, the mounting points for the antiroll bar brackets were the starting point… mainly because they don’t exist at the rear! Unlike the fronts – which just needed strengthening – at the rear complete new ‘towers’ were needed to offer mounting points for the Group A bladed-style rear anti-roll bars. Once welded to the chassis legs, primed, and painted, these provide a stable base on which to mount the rear antiroll bar brackets; the bladed arms attach to each side of the rear beam while a tube
runs across the width of the car connecting everything together. Again, the rear brakes needed upgrading, and again AP Racing four-pot calipers are added although this time a tad smaller at 315mm and narrower at 28mm wide.
With that lot all back together, I just managed to find time to tackle another job this month… one that has caused me a fair bit of apprehension. Why? Because it meant cutting two whacking great holes in the side of the car! I am, of course, referring to the two fuel fillers that needed fitting to the rear quarters. Unlike the previous system – which was filled from inside the boot – the race cars require a proper motorsport-spec filler in each side. So, after measuring, marking, more measuring, and yet another quick measure-up, I fired up the saw and cut the required holes in the rear quarters. To say I was relieved when everything slotted into place was an understatement!
Now the fillers are all connected up to the tank, I can mark the fuel system off my to-do list. The list is definitely getting shorter, but so is the number of days before race day, so I can’t rest on my laurels and need to keep the pace up.