A watery end

And so, after a season of frenetic car building, engine swaps and sundry other excitements the RGB year ground to a halt at Cadwell at the weekend. It was, yet again, a wet weekend although a very enjoyable one. That the club managed to get 26 races on track over the 2 days, along with all the qualifying sessions, is a testament to how well organised it is. For something that only has two paid staff (and lots and lots of volunteers) this is pretty miraculous.

RGB, as you will know, has had rather too many wet races this season. Hopefully next year it’ll be a bit dryer.

Before rambling on about Cadwell, though, I’ve got a past race to acknowledge. I finally managed to process the video from the Pembrey races. To be honest the wet qualifying and race aren’t really worth spending the time on. The second race, though, was not too awful and here’s an edited video of the proceedings:

As you can see, it’s undeniable that the car is going better. Austen’s car (the white one with the Q20 stickers) was just zooming away from me earlier in the season so it now seems as all the work on the engine and exhaust is starting to pay off. What’s more, I still haven’t had the car near a rolling road. Looking at the lambda logs it’s clear that the AFR (air/fuel ratio) isn’t quite right and I’ll try manually tweaking the Power Commander for the upcoming Birkett. That is, it’s worth dynoing the car, but it isn’t far off.

Interesting, if you look at the graph here you can see two sections of the AFR graph, one (the black line) for the J15 at Cadwell and the other from the Fury from a couple of years ago on the same bit of track. If you look at the WOT bits (the flat bits at the left) you can see that the current car is running very slightly leaner which I’ll have to sort out. However, the 2008 engine, when off the throttle, towards the right where I’m braking and changing down—you can see the throttle blips—has a much leaner AFR trace. I suspect this indicates that the engine has overrun fuel cut-off.

In the gap between Pembrey and Cadwell I reverted to full-on transmission fretting mode having noticed, as I mentioned, that the new sprockets were already wearing. In musing about things it seemed to me that I’d actually made things line up properly. So, there was either some absolutely fundamental problem that I didn’t understand (not exactly unlikely) or perhaps the engine was actually moving. When I converted the engine mounts to the ’08 engine I ended up mounting the engine using some spacers. When I was hunting for some aluminium to make the spacers from I had some 20mm and some 40mm. I couldn’t face the tedium of turning the 40mm down to the required 25mm so made do with the 20mm stock. I was now wondering if that had made the engine  move slightly. Mind you, the spacers are roughly 10mm thick so there’s hardly much room for it to shift.

All the same, I decided to move the engine slightly and did indeed turn down that 40mm stock to 25mm and made a collection of new spacers. In the process moving the engine a teeny amount. I also made some spacers from the same stock for the diff mounting. I’ve used a stack of washers up to now but it seemed reasonable to do it properly. If you peer hard at the photo on the right you can see the new spacers on the engine and the diff mounts. Once all  that was done, and in the process I’d changed the gear ratio to something that, I thought, was more suited to Cadwell where we were next racing, I turned my mind to other things.

The first thing was the throttle cable. I’ve never been totally satisfied with the existing one for a couple of reasons. One is that it’s very long because it exits out the front of the pedal box and has to go around on its journey to the throttle bodies. The other is that because of the sharp bends I had to use a couple of noodle tubes in it and I don’t think they move that easily really, perhaps especially once they’ve had millions of gallons of water thrown on them.

So, I bought a new cable from Andy who sells lots of neat bits like this, but doesn’t really tell people about it. I’d decided that I was going to take the cable into the pedal from the other direction, in the same way I did for the clutch cable, and so needed some way of attaching it to the pedal itself. The photo here shows the end result. You can probably see that this pedal has been through some modifications. It was originally the pedal on an OBP “pro race” pedal box. Frankly, this product is junk. The construction is far too light meaning that it needs extensive beefing up to stop the whole thing flexing when you lean on the brake, the throttle pedal is so far from the brake that you’d need size 20 feet to be able to heel and toe, the throttle pedal flexes because it’s made from two plates that twist around each other and the throttle actuation is  too stiff because there’s a collection of couplings it goes through that introduce too much friction. Apart from that it’s fine. The pedal in the photo has been modified rather drastically. I’ve bolted the two halves together with some spacers to try and stop it twisting, I’ve re-welded the foot pad onto the body in a different position to move it closer to the brake, I’ve riveted a big piece of aluminium to the left so that I really can heel and toe and, now, I’ve bolted some more aluminium, with lots of holes in it, to the other side to actuate the cable.

Over the winter, I’m seriously thinking about throwing the pedals away and doing something properly. It’d be nice to buy a Tilton pedal box but I don’t think my bank account could stand it! All the same, I bolted everything back together and with the new cable it worked much more smoothly than it did before.

So, with all that done it was time to go to Cadwell. After the outing at Pembrey reminding me that I really needed to test at a circuit I had booked the test day at Cadwell before the race weekend. However, when I got there I discovered that someone at Cadwell had had a fit and organised the test session in a completely hopeless manner. There were three groups, which got essentially equal time over the day. One group was the single seaters, fair enough, but one of them was for the Saxmax drivers. This is a formula for 14-17 year old drivers and it’s not  being very successful this year. However, MSA rules require that they’re not on circuit as the same time as us as we’d scare them. (Frankly, it’s the other way round.) However, this meant that a third of the track time was reserved for Saxmax, of whom there were about 8*. The final group was us, MR2s, Locosts, Stock Hatches and a few oddballs. That is, I didn’t get a single clear lap all day. However, I did manage to get slightly dialled in. But, depressingly, I never got near my best Fury lap time. Some of this is because I didn’t get any decent laps. Some is because I just need more seat time in the new car. However, a good deal is because I still don’t have the balance right. I’ve been thinking about this a lot since the Cadwell weekend and I’m pretty convinced that I need to work out some way of moving the aero centre of pressure backwards. I think the splitter is doing a sterling job of sticking the front end down but the rear is still too wayward although it’s much better than it was at the beginning of the season where my first track outing was marking by shooting backwards under the bridge at the end of the Snetterton Revett straight. (Or whatever they call it now.) Perhaps I should also try softening the rear springs a bit. Hmm, too much to do.

All the same, the test day wasn’t a complete waste of time although as usual it was marred by drivers of larger machinery not looking in their mirrors and seeing a little RGB car going much faster than them. Pride of place must go to the white Elise whose driver must be partially sighted after blocking me three times on the same run down the Park straight. And a special mention goes to the MR2 drivers who’ve clearly decided that a demon wheeze is to fold their wing mirrors in. I was half way past one of these in the braking zone when I realised that his mirror was folded in and there was every chance that he had no idea I was there. Pillock.

The weather on the test day was great. However, the Saturday started cold and gloomy and the forecast was for it to rain later. Qualifying, though, was dry. The problem with qualifying at Cadwell is that the circuit’s very narrow meaning that everyone trips everyone else up and because it’s a long lap you only get about 9 laps in. As it was I ended up 9th (5th in class) and 10th (6th) in the two races. Pretty poor really. One of the problem is that there’s been a bit of  a step change in RGB and the front runners are now in out and out race cars and I’m nowhere near them. (But then, a couple of front engined people are quite close to them so that might well be an excuse.) Colin is building a BDN so will probably be zooming past me after this weekend. Hence, this was probably the last outing for his trusty Fury, seen here with me in race 1.

You might wonder why Colin is ahead of me in his old class C car. Well, when it finally came around to the first race it was raining. I got a not too wonderful start, the start straight at Cadwell is very narrow, and after a lap or so screwed up my braking at Mansfield and had a half-spin. In the process Colin and Tim Pell got past me. Half a lap later and Tim spun in the Hall Bends and the race was red-flagged, not before I’d got past Colin again though, albeit just under power on the straight.

I got a similar start at the restart although after a lap or two I got past Gary when he spun at Mansfield in just the same way that I had. By now I’d realised that changing down going down the hill, and trail braking as I usually do here, were both a bad thing. I was just trying to get the car home without too many heroics. And, I did so, although in a rather lowly 8th place (4th in class). Still, it’s all points.

After a very convivial evening in the paddock, a feature of RGB races, Sunday dawned if anything even gloomier than Saturday. I fiddled around with the car a bit but couldn’t really see how I could do much without fitting some socking great wings which are not exactly legal. This time I got a pretty good start although I wasn’t really forceful enough with David at Coppice and let through and a near spin left me with both him and Austen in front. Down the Park Straight though and into Park I managed to out-brake Austen. (Austen’s driving this year is very good compared to where he was last year. He’s got the car going very well now. At Snetterton earlier in the year he’d just driven away from me under power so perhaps all my modifications are starting to bear fruit. I was now behind David in the BDN and pulled off, coming out of Coppice up to Charlies 1, what was my overtake of the year. After that I didn’t see anyone and had, really, a rather tedious race. I finished in 8th place (6th in class) which is nothing like good enough. As a consequence I’ve got a list as long as my arm of things to do to the car over the winter. I just hope that I survive the Birkett!

Here’s a video of the second race, at least the interesting bits. It’s not very long…

*And, of course, you might wonder how these kids were there on a school day when surely some of them are 16 or younger?

7 thoughts on “A watery end”

  1. Hi Tim
    I’m paul with the black j15 that was at cadwell. I would be interested what you got you lap time down to in the friday test session

    thanks Paul

    1. HI Paul,

      Problem is, I didn’t get a clear lap in all day. However, the fastest lap I actually did was 1:36.4. However, the theoretical lap (the times from the best sectors added together) was 35.2. Far too slow…


  2. Hi Tim

    Nice to see the J15 starting to work for you.

    I have to say how disappointed I am at the path RGB has taken with these weird and wonderful appendages sprouting from various cars plus the influx of mid-engined race cars that have never been near a ‘Road’. What is the difference now between RGB & Bikesports?

    1. Fair comment, but it’s hard to see how you regulate things. I’ve thought long and hard about how to encapsulate the notion of “a road-going car” in the regs when, frankly, almost none of the cars on the grid has ever been near a road. I don’t think there is a way to do this. The kitcar formula tries to specify these things in a long and complex collection of classes with the result that the formula is having a real hard time, in huge contrast to us. We’ve had a lot of success by simplifying the formula (which is the current 1 litre formula).

      There is, though, a significant difference between us and Bikesports, not least the fact that we’re a growing formula. We have standard engines and road tyres, wings aren’t allowed and we have to have at least 75mm ground clearance and side-by-side seating. (Just that last point effectively changes the fundamental shape of an RGB car.) All of those things change the formula hugely. For example, some of the bikesports guys buy a new set of slicks for each meeting. We typically use one of two sets for the entire season.

      But, those weird and wonderful appendages make a real difference; I kind of like that but know others don’t. Again, though, you’d have to come up with some way of describing them so that they’re not allowed. I’ve tried and failed (and to be honest the horse has bolted by now). Any suggestions, though, gratefully received.


  3. All valid points as I’m sure you know. I used to like turning up to races in my Phoenix and watch cars that looked the same screaming around. Now they look like creatures from the black lagoon.

    I would suggest the answer is to allow a set, single plane, rear wing which would do away with the ridiculous ski slop on the Spire (and make it look like the road car) as well various things people like Austin are fitting.

    Just a thought from an outsider.


  4. The trouble is that while drafting a rule to allow people to run a single plane wing is very easy, drafting a rule which bans things which are ‘ridiculous’ is very hard since it ends up being an entirely subjective assessment of what is ridiculous and what isn’t. And if you let people run a rear wing, there’s every reason to think they’ll still add all other kinds of aero appendages unless there’s a rule to stop them.

    The Kit Car chaps tried rules requiring ‘standard’ bodywork. In a series like this, with one-offs, specials, and manufacturers who’ll basically build you whatever you want, that just doesn’t work. Certainly didn’t work for them.

    The problem is that aero is deeply significant. I wish it wasn’t for all sorts of reasons, some of them involving cars and some of them involving bicycles. But the fact is that aerodynamic efficiency is both important and, nowadays, understood. Short of having a time machine and transporting everyone back to the Good Old Days when no one understood about downforce, I don’t think there’s any realistic alternative to the current rules.

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