Forgive the blatant mis quote of the Jamaican Bobsleigh Team, but I’m very happy to report that all those hours since last November slaving away over a hot pot of polyester resin to make new air ducting body work, have not been in vain. At Brands Hot she kept cool very cool… cooler than a Bob Marley fan in Calgary!
My Data logs show that the coolant temperature never moved from the range 72-83 deg, this was over the course of 2 races and 1 practice at Brands Hatch which because of its bowl type nature is the hottest track we go to. Ambient temps were 25+ degrees c so this was a pretty stern test of the cooling circuit.
So, I’m pretty chuffed with that. Also remember that the coolant temps are measured as the coolant is exiting the head before it reaches any radiators, so it much be entering the head at around 60 deg c. This leads me to ponder if I have now got too much cooling in the car, and could possibly lose one of the radiators, and save the weight of both it and the fluids. I think I’ll knock up an alternate cooling circuit that circumvents rad 2. then when we’re next on a test day we can can quickly swap the configuration (leaving the rad in place) and decide if that extra weight is really necessary.Also I might re add the thermostat and bypass hose for those less hot days when she’ll be difficult to warm up.
Oil temp continues to be a bit of a puzzle. Its is much more under control… last year I couldn’t complete the races because the oil rapidly grew to 150-160 deg C. At Brands over the course of the race it grew to about 120-130 deg C, which is eminently better and completely tolerable, but still vastly different to the water, which after all is passing through the hottest part of the engine. There is something else going on here I think. The temp sensor for the oil is tapped into the steel sump plug, which is very close indeed to the exhausts. This part of the engine bay gets very very hot, and I have for example melted thermoplastic components in this area, so I wonder if the steel sump plug and castings are heat soaking the exhaust heat into the sensor, and giving a false reading.
SO I think I’ll pop some heat shielding on the sensor, and consider measuring the rest of the oil circuit at points such as the entry and exit of the cooler, the remote oil filter and so on. Either way it is no longer terminally hot so it will fall some way down my priority lists. Infact it meant that I could concentrate on racing rather than temperatures!
We had only one failure over the weekend, the front right brake calliper decided to blow a seal just as we were rolling the car off the trailer. It had been fine at home the day before when we bled the brakes, but just holding the car on the brakes on the trailer saw the pedal go soft and brake fluid leak (pee) out.
Arrgh! This is the second time the callipers have done that to me, fortunately I carry spares and it is only a half hour job to fix and re bleed the brakes…. but if it had happened on the startline or at scrutineering that would be bad. The fault is with a little O ring which is easy to replace, but I guess it “ages” and hardens and flattens out and then fails at unpredictable times. I guess I should “life” the O rings and rebuild the callipers more frequently to prevent this problem. More likely I’ll just replace the callipers with some Wilwood Powerlight callipers, which I’ve had floating around the garage for a while.
So onto the racing.
In practice I managed a 54.0 which is none to shabby , but in no way sparkling, considering its 8 months since I last drove the car, and I hadn’t had a chance to test, but as usual RGB is monstrously competitive and it was only good enough for 16th on the Grid( of 23) and 7th of the 10 man class B lineup. The front of RGB class B is now in the low 52s/High 51s. Still it was a reasonable start.
Race 1 was interesting. We were waiting on the grid, with the light showers that had been falling all day occasionally showing up, and it was a little drizzly when we got underway. The track was a patchwork of varying grip levels, Paddock had just been rained on and was proper slippy, and front row man Paul Rogers in the black contour, did a full spin to the inside, and somehow we all missed him. the rest of the corners were fine, but the entry to clearways was again slippy. I had made a place or two on the start, and spent 11 laps trying to get on terms with Austin in front but he was gapping me by about a 1/2 a second a lap. eventually I fell into the clutches of Phil Alcock behind and he passed me on Lap 11 I think. I had several attempts at passing Phil in his Class C car, but couldn’t quite get far enough alongside to ensure that he wouldn’t turn in on me at the apexes in his usual robust defensive style. And then my brake pedal went soft and long as the fluid boiled in the callipers, such that I was lifting off early and “pumping” it up at all the corners. As a result I lost another couple of places and ended up 17th. Best time was 54.32. But it was very nice to be back, and even nicer to see the temps under control. The weekend was being filmed by Motors TV so perhaps my Battle with Phil will get some coverage. Here’s a shot (taken by Derek’s Dad) of me and the recovering Paul R entering Paddock.
Race 2 on the Sunday, was a similar affair. and I was generally pretty tentative and my lack of seat time is shown everywhere, by poor lines, and hitting the limiter etc. I started OK, and this time the front runners all made it round Paddock pretty easily, but the same is not true of the exit Druids. Tim got pushed off the track by Matt Green in a fairly blantent move, and this left him spinning and recovering. I arrived closely following Bob Mortimer, Bob Junked right to reveal a rejoining Tim, and I had very little time to do much.. We nearly had Blue on Blue contact, but somehow I avoided him. Its at about 30 seconds in in this video.
After that I just seemed to be going backwards, I lost a couple of places, and got overtaken by James Walker and Neil, again I tried to keep with Neil and was way quicker through Paddock and the twisty side of the circuit but he opened several car lengths on me along the straight. There followed about 5 laps of me continually pressuring Neil on the twisty part of the circuit, nearly having enough to get him at the turn in to Clearways only to be out dragged down the straight.
Eventually I ran wide at Druids and that dropped me into the hands of Paul Rickers who eventually passed me a couple of laps later. Again I was just outdragged by him for the remainder of the race, and he eventually caught Neil too and beat him on the line by a 100th of a second. Great stuff from a racing perspective but frustrating
Ohh and the brakes went away again so I had to continually pump up the pedal before each corner.
So my crap driving aside I was most concerned by my lack of straight line speed. Both me and the car are Lardy and combined we’re at least 50 KG heavier than Neil in his nice new BDN. I wonder if I’ve finally reached the end of the development road with this heavy old chassis because weight simply hurts you everywhere.
Later examination of the data (Neil and I are happy to share) showed a couple of points.
Even when I have a higher apex speed, and am on the throttle harder and at WOT way earlier than Neil He arrives at the next corner going quicker. At Paddock he had a 5mph advantage over me (120 vs 115). That can only be a power/weight/drag issue. 
, and the friends I showed it too suggested my engine is down on power.
Also the data showed small rpm spike after each gear change which is clutch slip, and my speed plateaued for about half a second after each change. That’s not helping!
So all in all a mixed weekend.
Temps under control – check!
Drove like a numpty – check!
Before the next meeting I need to check the valve clearances, ( as this can cost you power) change callipers and brake fluid, fit brake cooling ducts, change the clutch and …. have a long hard think.