With the IVA booked for the week after Snetterton the first thing I had to do was bolt back on the bits I’d take off – fire extinguisher, brake bias adjuster, ARB adjuster, video camera etc. I also uploaded the ‘normal’ map to the Power Commander and fitted it onto a new bracket in the engine bay – it kept falling off the velcro fixing I had previously. It’s new position also keeps it in cooler air.
Since Donington I’ve given much thought to the car’s handling and after discussion with Ian and Brian decided to shift the car’s aero balance rearward by means of adjusting the rake. When I originally set the car up I set the ride height at just over 80mm all round so my plan now was to introduce a bit of rake with the rear slightly lower than the front. On Saturday afternoon I stuck the bags of sand in the cockpit, stuck some fuel in the tank and set about measuring it again. To make this easier I made myself a simple ride height gauge. Demon Tweeks sell one for £227 plus VAT but mine comprises a block of aluminium with a hole tapped through it for an 8mm bolt. Slide the thing under the corner, unscrew the bolt till the head butts against the underside of the car, pull it out and read the height using a vernier caliper. Simple but effective. It also shed some light on why the rear of the car’s a bit lively – both front corners were 73mm with the rears at 85mm and 82mm, giving about a 10mm rake. Clearly the front springs have settled quite a bit. So my plan now was to reset the suspension with zero rake and see how it feels at Snetterton.
The suspension is adjusted using the turnbuckle pullrods so it didn’t take long to get it to 80mm all round then I got the car onto the weighing platforms to look at the corner weights. It was a little out with the diagonal at 52.9%. So I adjusted the suspension again till I had the diagonals at 50% then got her off the scales to check the heights again. Miles out with the left front at 97mm and left rear 78.5mm. I ran out of time and resumed Sunday morning with a few more cycles of adjusting ride heights followed by adjusting corner weights. Eventually I got it back to 50% across the diagonal with all 4 corners within less than 2mm of each other.
With the car now pretty much ready for Snetterton next weekend I headed back to the IVA to do list. One of the time consuming things to do was to make a new passenger seat. I’d made a start on this on Saturday afternoon by blanking off the handbrake mechanism and the rails at the sides with cardboard and sitting in the first bag of foam. After a couple more mixes of foam the seat was ready to carve to shape – trimming the edges, smoothing off some of the ripples and doing the cutouts for the harnesses. I ended up sticking it back in a bag and adding a bit more foam to fill out the area around the handbrake to make sure it enclosed all the non rounded edges of the bracketry.
Attention then turned to headrests. So far I’ve been using some of the foam roll cage padding wrapped around the vertical strut Brian has welded into the chassis for a headrest. This has been OK for racing but I need proper headrests for IVA including one for the passenger side. I decided to make some from MDF to start with with some foam padding and covered in vinyl. Following a quick telephone conflab with Brian to discuss options I made a start on the driver’s headrest. There are various IVA regs specifying maximum gap from the seat, minimum height and minimum width etc. and once I thought I’d got my head round those I cut out a blank and machined a pair of 6mm bolts so I could countersink them and glue them in as captive bolts. Once this was done I glued some foam on there and covered it with vinyl backed cloth. The result isn’t perfect but will do the job, although it looks far worse in this dimly lit shot than in real life!
The passenger side is a bit more tricky so I opted for a much taller headrest so I could bracket it off the top of the roll cage as well as the diagonal. With captive bolts glued in and some aluminium brackets made I then got that padded up and covered. I’m pretty happy with the headrests and once I’m confident they are in the right place (and don’t need to be adjusted forward at all) I may well take them somewhere to get them upholstered a bit more neatly. In this shot the passenger one isn’t actually bolted on, the roll cage will get some foam tape trim before it gets fixed on there.
Then it was time to get all the tools etc. packed up ready for the trek to Snetterton on Thursday evening. With testing booked for Friday and a double header weekend I should get plenty of seat time. and of course it’s the RGB Marshals’ BBQ on Saturday night