So, it was time for Lydden.
(Well, it was time a couple of weeks ago but there doesn't seem to have been the time to get this written.)
We got down to Lydden on the Friday evening and spent a merry time in the paddock meeting up with all the RGB crowd. It had been 7 weeks since the last race and it was nice to get back to it. There were a couple of new drivers this time: Simon Mayne had a Locostalike of some form and Simon Trepass had Martin Bell's old road-going Fury. More of the latter later.
Qualifying was wet and greasy and just horrible. Problem is, it started raining in the assembly area and I, and most others, were on dry settings... Hence most of us spent most of the time backing off to find a lap and then trying carefully. One of the few people I saw overtaking was Henry Carr who tried to get past Graham Hills at Devils Elbow and put them both into the tyre barrier as a consequence. The word idiot comes to mind. According to the datalogs I didn't go above 75% throttle opening at any point. Any more than that and it was instantaneous wheel spin. Still did 75mph though. I mean, 75mph along a little country lane in wet and greasy conditions is a bit mad, isn't it?
As a consequence of the traffic (24 cars on a small circuit) there were a lot of similar times, I was a gnat's crochet above 1min and in 14th place. As my main intention had been to get into the Class C race (only the first 21 were going to be allowed in) I was pleased. In retrospect, I should have gone slower.
Come the race it was now dry, except I was now on a compromise wet/dry setting as it all looked a bit gloomy. We went off to the start and after the usual countdown they waved a green flag at us. ZOOM, just about every behind me set off at full racing speed and I, and a few others, bemusedly followed them. I really thought there was going to be a big coming together at Chessons as there were a lot of cars locking up and a lot of gravel flying about. (Presumably the latter had ended up on the track after a previous race.)
Most of the way round the various dimwits (all of whom are really this year's new batch) realised what was wrong. That is, as they were waving green flags at us then that must mean it was a green flag lap. We sort of unwound ourselves as we came down Hairy Hill. Come the start I just tried to stay out of trouble and got a really pathetic start where most of the field just came past me. First lap round and there were spinning cars at the elbow. I braked just in case and Colin Duce ran into the back of me as a consequence, not too hard though and the first thing he did after the race was come up and apologise. A lap or so later and I arrived at Chessons to find cars all over the place. They stopped us down Hairy Hill where we waited for 20 mins while they cleared it up. What happened was that Matt Rowe's engine blew. Chris was next through and spun on the oil and stopped sideways across the track. Graham was next through and also spun and went sideways into Chris's car. Hence the front of Chris's car was really badly smashed up and the rear of Graham's car was pretty biffed. Worst of all was Graham who had suffered that apparently normal RGB injury of broken ribs as a result of a GRP seat breaking and him being slammed into the transmission tunnel. I sat over on Hairy Hill wondering why the ambulance was taking so long...
After the restart the carnage continued. By now I was just keeping out of the way. One lap I came around the hairpin just after Henry and Simon Trepass (who's apparently an instructor at Bedford) to find cars flying around. Apparently, Simon was well past Henry on the inside at the exit and Henry turned into him. Henry doesn't see it that way but all of the observers did; I asked. What's more, there's this black and yellow scuff on Simon's car just in front of the rear wheel which was apparently Henry's front wheel.
Two laps later and John Goodwin finally loses it big time, apparently he'd been suffering the whole race and leaves bits all over the track just after the hairpin. The race is finally stopped and John actually gets fourth place...
Very unpleasant. Not impressed by driving standards from all the new boys and seriously thinking about finding somewhere else to play.
Oh, I was 11th, but irrelevant really.
A bunch of us spent most of Sunday morning repairing Simon's car and we eventually finished with about 5 mins to spare. Actually a fairly uneventful race and I was 11th again. Felt must better at the end about things though.
One thing, I'm getting more and more concerned that my new(er) engine is actually down on power compared to the old one. The DL1 actually estimates power output and this engine is consistently down compared to the old one on that basis, even on the same track in similar conditions. It could easily be wrong of course, or perhaps all that weight I put on over Christmas is having and effect. Whatever, I've discovered that PowerTec in Peterborough is the place to go to RR my car. I've booked it in for this coming Monday so we'll see what happens.
While I was at Lydden I decided between the races to re-bleed the brakes a they
felt a bit bungy. However, when doing that there was a problem in that one of the bleed nipples sheared off! That
was a bit of a bummer. However, even worse was that this weekend I tried to get the nipple-bit out of the caliper
and failed totally. As is often the case in such situations I ended up with a broken off piece of a stud extractor
jammed in the caliper as well as the bleed nipple.
I can't really think of a guaranteed way of getting this out so I've just phoned Martin Bell at Fishers and ordered a new half-caliper off him. The only problem is that HiSpec are not renowned for getting parts out early so I'm hoping there won't be a problem sorting this before the Silverstone race. I suppose I could race with the caliper in this state, but I don't really want to.
For some time now I've been meaning to stiffen up the mounting of the steering rack. Most
of the racers use chunky aluminium clamps whereas I've got the cooking steel ones with bits of rubber in there.
So, I bought some aluminium clamps from Rally Design and fitted
them this weekend.
You can see them in this photo here and they do seem to firm things up nicely, at least as far as I can tell when twiddling in the garage.
The only problem is, doing this has highlighted a potential problem. I noticed when I got
the new chassis front end that the rack mountings were not supported in the way that the original ones had been.
This photo shows the new ones and you can see that they're just welded on a single strut that goes down to the
chassis. This strut isn't supported at all which seems odd given the large sideways loads that this part of the
car takes.
This second photo is the original chassis. (And, just to confuse you, the photo
was taken with the chassis upside-down.) You can see that here there is an additional strengthening strut between
the rack mounts. I did in fact strengthen this further, after the original
Mallory incident, with some gussets welded in here.
The problem I noticed with the new mountings is that with the car sitting on ground not going then by moving the steering wheel there is noticeable side-to-side movement of the rack that's coming from the supports flexing. This seems, to be honest, spectacularly poor and fits with something that someone else said about this new chassis design.
So, I guess I shall be taking front end of the car apart over the next few days and welding in some more supports here. I did query this design with Mark Fisher and he said that it was a deliberate move so as to avoid damaging the chassis when a front wheel was biffed. I think perhaps they've got a bit far on this and the additional support needs to be put back in the chassis.
I spent some of today at Powertec in Peterborough getting the car rolling-roaded.
To be honest, it wasn't really that useful and perhaps I should just have put the money into the limited slip diff
fund. What we did was pretty much guided by the lambda readings (as in the bottom bit of the graph). In particular
we lowered the needles so as to lean the earlier part of the lambda graph (I think the needle in the Keihin carbs
does the sort of job that the progressions drillings do in a sidedraught Weber and used a larger main jet so as
to richen up the top end. However, the results were nonetheless interesting. If you click on the little graph here
you'll see the full Monty. To be honest, what would be
really nice is a wideband lambda sensor that I could leave in the car. I could then connect that to the datalogger
and get some lambda readings under race conditions which could be very useful. When I got the new exhaust I nearly
asked Tony Law to weld a lamdba boss into the exhaust, I wish I had now as it would have been very useful. Oh well,
something else for the winter rebuild list...
Back to the graph, if you compare it with the original readings then you can see that the new exhaust has indeed liberated more power at the top end, which is pretty much what it should have done.
In fact, it looks very much as if I should increase the point at which I change up as I think changing where I do at the moment (about 10,500) means that I drop further down the power curve than I should.
I stripped the front end of the car so as to get at the steering rack supports
properly. You can see in this photo the way they just stick up from the chassis in an unsupported fashion.
The plan is to weld a cross brace between the supports and the central vertical post. Not sure yet whether it'll need some additional triangulation but I suspect not. Luckily, I've got lots of 25mm square ERW tubing left over from making the tyre rack.
On with the steering rack. After some faffing about I welded in a chunk of square
tubing between the rack support and welded that it the central upright on the chassis.
Unfortunately, the only Hammerite I had was some silver stuff so it looks rather odd. Matches the rack clamps though.
I re-assembled all the front end, refilled the cooling system and checked that it all worked still, which is did!
Best of all, the rack didn't seem to squirm from side to side as I twiddled the steering wheel. It'll be interesting to see what the steering feels like when next on the track. Having taken some chunks of rubber out of the system and stopped the supports moving about it seems likely that it will feel different, at least.
Finally, I checked the steering alignment, which miraculously was still OK, even though the rack had been sitting on the garage floor for a couple of days.
Next thing was to re-check the corner weights. I've had so many other people in the car
recently that I've lost track of where the spring platforms should be. So, I tracked down the cam7 corner weight scales (not easy, they had migrated to Reading!) and set them up with the
car and me on top of them. Depressingly, but perhaps not surprisingly, I was now another 15kg overweight compared
to when I weighed the car on March 1st this year. This is really horrible...
This is probably the result of all the GRP that's been put into the bodywork since the beginning of the year.
So, I really need to start putting into practice some of the ideas I've had for losing some weight (apart from spending even more time in the gym that is, which I need to do anyway). First one was to drill a whole stack of holes in the top of the right hand sidepod. I also enlarged the hole in the other sidepod. Given how thick this sidepod has got this all saved me about 500g. So, all I've got to do is to drill similar holes in about 20 times this amount of bodywork! Hmmm, that's going to be hard. One of the things that's creeping further and further up the winter fettling list is buying a complete new set of bodywork. Problem is, I've just looked up the price...
This coming weekend we're racing at Silverstone. I'm wondering about going testing on Friday which I'm increasingly thinking I will, even though it's going to cost a load of dosh. I don't feel as if I've had any time to just drive the car for a while now and it would be nice to do so. What's more, although the Silverstone club circuit is really very simple it will provide an opportunity to drive one corner at a time and think about the effects of things. Having done some calculations of the wheel frequencies, I think I'm going to try some higher race springs at the rear. Luckily just about the one component for a kit car that isn't ridiculously is the springs, meaning it's almost possible to buy a selection of them to try out.
As I think I mentioned, the timing beacon detector I made a while ago turned out to be non-functional. (That's what an engineer says when it doesn't
work.) I've got two hypotheses for this:
- The beacons at the circuit are not modulated and just work at base-band, meaning that the detector I'm using doesn't realise that there's anything there.
- The car goes past the detector so quickly that the DL1, which samples every 10ms, doesn't see anything.
I think I actually think the first one of these is the most likely. However, in order to eliminate the second hypothesis I thought I'd make up a modified detector that stretched out the pulses seen by the detector. It's also got a socking great LED on it so that I can easily tell when it's been triggered. As you can tell from the photo this one's a bit more complicated than the last one and it also seems to be absurdly sensitive. However, I'll package it up and try it out at Silverstone at the weekend, just to see if it sees anything of the timing beacon. I put money on it not seeing anything, to be honest. I think I really need to redesign the front end to use a photo-diode so that any old IR transmission is detected.
I've been poring over the datalogs from the Oulton park trip with Tim Harmer. Something he said at the time about the front and rear of the car not matching seems to chime with something in the detailed analysis and it makes me think that I need to try some very slightly stiffer springs at the rear. Hence, I've ordered some 250 lb/in springs for the rear. Luckily, springs are cheap!
