Diffuser modsOver the Christmas Break I'll be extending the width of the rear diffuser from 600mm to 1040mm, which is a 70% increase and should help produce even more down force at the rear of the car. I'll be joining the carbon sheets to the diffuser using 2" carbon tape (CF-TP-50), and (AT30-S-0115) AT30 Epoxy Hardener with (EP-L2-05-A) EL2 Epoxy Laminating Epoxy slow cure epoxy resin, from Easycomposites.
And I've finally managed to draw the shock absorber spacer in Sketchup. Looks simple enough to do, but it needed drawing in a specific order for it to work.
Upgrades timeI've fitted both the remaining Bosch potentiometers to the front suspension dampers. Now I can get the wiring started.
I'm getting a pair of 15mm aluminium spacers machined for the rear dampers, to locate the springs further down the damper bodies, which will hopefully prevent them from touching each other. As the suspension is compressed, the rocker arms on the rear suspension rotates the tops of the dampers inwards which is what's causing the interference issue between both the springs. The Eibach 750lb springs are a bit fatter than the 650's I took off, and sit much closer together. [Basically, the Intrax dampers are too large for the gearbox mounts, if Ohlins or some other dampers were fitted, with smaller diameter springs, then we wouldnt have this problem]
Pete Goulding has bought an X-47 hybrid turbo to replace the X-27. He is hoping to see 340BHP, and is now planning on also replacing some of the intercooler pipework. It will be interesting to see if the turbo produces the manufacturers claimed power, as it is supposedly running 1.9bar pressure at peak power, which is 0.7bar more than I'm running, to produce 313BHP. But as a comparison, the SBD EcoBoost is also running 1.9bar to make 350BHP, so maybe there is no getting away from having to run that level of boost, to climb above 320BHP.
Christmas is fast approaching. I really needed to replace my AWS race suit, as I've used it every year since 2002, and it was looking rather tatty. A quick trip over to Grand Prix Racewear at Silverstone last weekend, and I came away with a very snazzy OMP 3-layer race suit, in navy blue, and when I tried it on, it fitted so well, so I'll have to lay off the mince pies over the holidays or I wont be able to fit in to it at Combe in March. I took advantage of their Black Friday 10% discount, and I hope it lasts as long as the AWS one did. At least I now have a spare dry race suit to take wit me, for those weekends where we get rain both days. :D
Linear potentiometers fittedI've fitted two of the linear pots to the rear dampers today. It took a while to work out the easiest way to do this. The pots are only 750mm long, so unfortunately they're shorter than the dampers, hence the little brackets on the rocker arms to attach the pots. I've placed a mounting bracket at the base of the dampers, which is a very solid place to bolt it to, so there'll be no movement or flexing there. I'm looking at using either mini Sure-seal or Deutsch DTM connectors on the loom, I'll make a decision this week and get some ordered.
Linear potentiometers wiring conundrumAll the springs are fitted and the car is back on four wheels again. Now I can concentrate on the wiring in the linear sensors for the dampers to record the suspension travel. The Bosch sensors came with short leads fitted with ITT Canon connectors, however I've drawn a blank finding any compatible/cheap sensor loom plugs that can be used to connect them up, so I'll just cut them off and fit 3-pin mini sure-seals.
But how to wire them up? There are a pair of pressure sensors used to monitor the front and rear brake pressures, that can be read using Life View. These are located in the front crash box, next to the master cylinders, and both sensors connect to the chassis loom down by the drivers feet. If I unplug the pressure sensors, and instead plug in two of the linear potentiometers, the ECU will show the spring movement, for the bpf and bpr channels.
Another sensor I can sacrifice is the steering wheel angle sensor. So I can run one rear damper sensor cable, to the steering wheel angle sensor input, and again that can be read in Life View. That leaves just one more input to connect the fourth Bosch sensor, and I dont have anything suitable that I can re-use.
This way, the ECU can be used to show several of the sensor movements, without having to get the ECU reprogrammed. Also I only have two spare analogue inputs left on the Syvecs X10 expander, and with the ECU still locked, I'd not be able to read the data off the X10 anyway, so it'd be pointless connecting the sensors up to the X10.
But, the downside of re-purposing these sensors, is that I lose visbility of steering wheel angle and brake pressures, which I need for analysing my performance when on track. So in order to log suspension movement, I'm going to have to look at a 3rd party data logger, and at the moment the AIM Evo4 with Glonas/GPS @10Hz appears to be the best bet. However, I'm then stuck with two sets of logger data, that cant be compared back to back, as they're both totally different systems to one another, and then there's the issue of synchronising the data.... If only the ECU were unlocked and we had full access.
Linear PotentiometersI've acquired a set of Bosch linear sensors to fit on the dampers. They've come with ITT Canon kpse6e8-33p-dn-a34 connectors, so I'll either need to find the female to plug these in to, or remove the connectors and fit Sureseal connectors, whichever is easiest. The Eibach 750lb springs are now fitted to the rear dampers, and the springs that were on the rear, are now going on the front, to raise the front from 550 to 650lb. So the car will be running springs which are 100lb/in heavier than before. Was 550/650 and will now be 650/750 Front:Rear
BSC AwardsI received the Kent Trophy, for winning the 1600 Forced Induction class from the British Sprint Championship last weekend. It was a good evening, and nice to catch up with everyone.
The front and rear downforce in Newtons is now calculated for the differing DJ wing angles, and the replacement springs are on order, due to arrive next week, then I'll get on with fitting them and arranging to go and do some testing.
Front SM153 wing, 1300mm span, 170mm chord short 540mm flaps, and vortex entrain endplates, in Newtons
Rear SM183 Dual Element wing, 1380mm wide, 1380mm 160mm chord endplates, in Newtons
BSC CalendarThe BSC Calendar is now finalised. This list shows the events that are confirmed.
Work is progressing well on the wheel frequency calculations. I've created a spreadsheet that Pete and I are both using to determine how much stiffer the springs will need to be for the given downforce my DJ wings are going to produce. I'll still need to go testing, but it will hopefully guide us in the right direction.
I'm just reviewing the springs fitted to the front and rear shock absorbers, to decide what sort of rate I should change them to, to compensate for the downforce from the DJ Wings. I came across the following table in the User's Manual, which should allow me to identify whats fitted, and what my options are for upgrading. The run sheets from when Radical raced the car shows that they swapped between the 88 N/mm (500lb) and 106 N/mm (600lb)springs, but the car came with a very large selection of spare springs, so we'll see whats available. I dont want to make the car too stiff, or it'll be harder to drive, so we'll have to try a few different ones out and see how the handling changes.
The second attempt at making a rear wing bracket is now complete, using the 50% thicker 6mm aluminium sheet. I've retained the 10mm aluminium tubular structure that I'd had made for the first bracket. The key was to mount the tubular structure as low as possible to the gearbox mount, as that was where the bracket was flexing. I can still displace the wing by pressing down on the end plate, but, its far more rigid than before, and with the wire ropes fitted to the diffuser, these will help stabilise the wing further when travelling at speed.
With the wing bracket now sorted, I just need to check the spring rates fitted to the front and rear dampers, and see what came in the box of spares from Radical, as I'll probably fit the next hardest springs I have, to help combat the additional downforce and prevent the car from grounding out.
I popped over to Curborough last weekend to watch the orange sister car being put through its paces by Pete Goulding. Pete recently bought a front and rear wing kit from Elite Carbon, and on the very first outing at Blyton the weekend before, the new rear wing broke. Pete had gone for a dual element design, 1400mm in width, similar to the standard rear wing design on both cars. However, after climbing over 100mph, the lower wing couldnt handle the deflection from the total downforce that both 1400mm wings were producing, and it sheared at the point where the wing mount was bonded to the lower wing. Pete had to remove the new wing and refit the original, as it wasnt something that could be repaired at the trackside.
Pete has since taken the wing assembly back to Elite Carbon and they're working on the replacement. It should really have incorporated a vertical strut, to distribute the force from the top wing, on to the lower wing mounts. Or the lower wing needed to be made far stronger to take the combined loads. So for Curborough, Pete was running the standard Mygale rear wings, keeping the Elite front wing on the car, and he was suffering understandably from oversteer.
Still, he finished well at Curby (or Cowborough as some people like to call it) and scored enough points to place him 5th overall in the 2017 HSA Championship. I only finished 26th this year, fourth in class, as I was concentrating on the British Sprint Championship, and it's hard enough to commit to one championship, without having to worry about the expense of competing in two. All credit to Pete, he's had a great year, with several FTD's, even with the lower engine power output compared to mine, but I'm still improving, I beat him once, and we had a 1-2 at MIRA, and in 2018, with both cars running uprated aero, it should be interesting to see how much higher we can place in both championships.
Over the winter, Pete is planning on replacing his Pumaspeed Turbo (X37), possibly with a Turbo Technics Revo like mine, and he's aiming for more power than me, naturally. I reckon my Mountune engine could take more power, but to be honest, its proven 100% reliable, and I'm interested in seeing how the performance changes with the aero, before I plan any more power upgrades. My engine only runs 1.2bar to make 313BHP, and the low pressure helps keep the intake charge temperatures down, which prevents the engine suffering from detonation. I'm told that the SBD EcoBoost engine runs over 2.5bar to make 350BHP, which seems to me to be a bit on the high side. But I'm sure with a bit more boost, the Revo turbo/Pro-Alloy intercooler combination on my engine could easily see it reach over 340BHP. I'll let Pete be the pioneer this time ;) and I might just go back to NMS for a small tweak in the Spring to raise the power levels.
For now, its time to go testing, then I'll take the gearbox off for its bi-annual service with MBR, and then wait until March next year for the first round of the 2018 BSC. And in the interim, work on my fitness, and keep my eye in with some simulator work. I want a permanent Top 12 number in 2019, so 2018 is going to be a challenging year.