13th May 2011

Brands data analysis

While my times at Brands were tolerably respectable, there's still plenty more time to be found by improving the driver before I think seriously about improving the car. A point Tim made quite forcefully having seen some of the in-car video footage from Brands... This is, of course, where the data from the DL1 comes in handy - as the old saying goes, the stopwatch doesn't lie, and a DL1 not only doesn't lie but tells it exactly like it is. As ever, it's useful to have a benchmark to compare myself against, and once again I'm using the data Adrian and Tim kindly gave me from their qualifying sessions in 2010. It's interesting to compare Tim's data, together with my data from last year and this year.

For example, the graphs on the left show Tim's best qualifying lap from 2010 (black), my best race lap from last month (orange) and my best race lap from 2010 (red). It immediately apparent from the time slip trace at the top that last year (the red trace) I was losing lots of time through Paddock, Surtees and Maclaren/Clearways. The orange trace is much flatter, which means I'm losing less time compared to Tim. I'm losing a little time under braking into Druids, doing OK through Graham Hill, but then losing a lot of time through Surtees, and a little more at Maclaren. Obviously the corner I have to concentrate on next time is Surtees. Which is sort of knew already, really. Still, it's nice to know I'm not doing too badly round Graham Hill, as it felt 'orrible. Looking at Surtees in more detail, it seems as though I need the same level of improvement round that corner again - last year I was roughly 10mph down on Tim's speed through Surtees, and this year the gap was down to about 5mph. However, this is simply because Tim's using the grip envelope better - he's pulling about 1.3g in total, which is about the limit AO48Rs can generate without downforce and on a flat circuit, while I'm only getting to about 1g through there. Time to put in another large order of brave pills...

Justified and ancient

I've added a little white to break up the large expanse of matt black on the car. Rather aptly, I finished off adding these three letters at 3 a.m. Why? If I had to explain, you wouldn't understand... :)

And rather more productively, I've decided to provide the FuryRacer with a new set of boots. Some of the tyres are now three and a half years old, and are getting not only rather old but rather worn. So I've ordered a set of new tyres from Polley Motorsport, and hopefully (if they arrive at Snetterton early enough on the Friday) then I'll be able to get them fitted in between the third and fourth test sessions so I can get them scrubbed in before practice on Saturday. After all, I need to get all the speed I can for Snett - it looks as though Adrian will be racing, and it'd be nice to give him a decent run for his money. And a new set of tyres certainly won't hurt in that respect. Now all that's really left to do is to fervently hope that it doesn't rain...

21st May 2011

Snetterton testing - Friday 20th May

Amazingly, I made it to Snetterton in time to take part in the first test session. This was the first time I'd driven the new revised Snetterton circuit. In effect, there are two areas of the track, and some changes to the names of some of the corners. This is the old circuit -

And this is the new Snetterton 200 circuit. It's the one we were racing on, and is the one closest to the original circuit configuration.

There are essentially two changes to the old circuit. The first new bit replaces Sears corner, leading onto the back straight, which has been renamed the Bentley Straight from the Revett Straight. Sears was a straighforward medium-speed right-hander. It's been replaced by Montreal, a very tight hairpin, followed by a 90 degree left-hand corner (Chapman). The key is getting a good exit from the left-hander at Chapman in order to ensure good exit speed onto the straight. This means taking the first part of the hairpin quite tightly, which further tightens an already tight corner. Basically, Montreal is sloooooooow. And dull. I haven't heard a good word about it yet. The new Coram is another kettle of fish. The old Coram finised in a short straight and then the Russell right-left chicane. The new Coram is a slightly tightening right-hander, followed by a tight 90 degree left-hand corner called 'Murray's'. The tricky thing about it is that you end up having to brake for Murray's while still going through Coram, and braking hard while cornering is of course rather tricky. The first few sessions I spent learning the new circuit, and remembering how to do some of the corners which haven't changed. The new circuit is considerably slower than the old circuit, so it was useless to try and compare times. This is mostly due to Montreal, which takes ages to trundle round. However, comparing my pace with other RGB cars I've raced against previously suggested I was going at a reasonable speed. I was certainly going faster than the red Porsche 911 which was out on track - as usual, fast in a straight line, but amazingly slow round the corners, particularly accelerating out of the corners which is rather odd for a rear-engined car. However, there wasn't really that much traffic - the sportscar session had been divided into two groups, so the Locosts which usually get in the way weren't on track at the same time as us.

Between the third and fourth sessions I got some new tyres fitted by Polley Motorsport. Expensive, but given that some of my tyres were both nearly three years old and virtually tread-free, it was time to get them done. In the process, I also got the wheels, with the new tyres, balanced with the sensors from the TPMS (Tyre Pressure Monitoring System) I'd recently treated myself to. Because I don't have a wife/girlfriend/pit monkey present at the races to help out (SWMBO doesn't like watching me race after what happened at Mallory in 2003) it's quite tricky checking my tyre pressures at the end of a test session. OK, in theory I could plan ahead and hide away a tyre pressure gauge somewhere in the pits, and then as soon as the session is over park in the right place for it, leap out, grab the tyre pressure gauge, check the tyre pressures, and then remember them until I get back to the paddock, in practice that's never too likely to happen. With the TPMS (or at least this version of it) you just replace the valve caps with some slightly larger units which have a pressure transducer, wireless sender, and battery built into them. They're pretty light at only 10 grams, but the instructions still recommend having the wheels rebalanced after they're fitted. They then talk to an LCD readout in a little box mounted, in this case, on the dashboard. The LCD readout gives you real time information on tyre pressures and temperatures, and has programmable alarms for both high and low pressure, although TBH I very much doubt I'd either hear the alarm or see the little faint LED alarm lamps when I'm driving the car.

In the fourth test session I started off by circulating at a faily gentle pace, scrubbing in the new tyres, and checking the pressures on the TPMS. After having done a few laps to scrub the tyres in I thought I'd trundle round slowly for a lap or two to see if I could get on the same bit of track as Adrian. After a couple of laps there was no sign of Adrian and I was getting a bit bored, so when James Walker came past in his newly-acquired ex-Duncan Marshall Phoenix (also with a 2004-2006 R1 engine) I thought it might be interesting to see how our respective paces compared. After one lap of following James round, he locked up going into Montreal, and I suspect as a result didn't get a very good drive out of Chapman. This meant I could get up nice and close down the Bentley straight, get a good tow, and motor past him about halfway down the straight. The session then promptly ended, and it was time to return home before coming back to Snetterton for the weekend's proper racing on Saturday. Best lap of the day came in the last session, with a 1:22.17, as usual about a second down on Tim's best lap time. Not bad, but plenty of time to come, especially round Brundle and Nelson (formerly the Esses) when I know I could carry a lot more speed if I could persuade myself it was a good idea to try...

Snetterton pratice/qualifying - Saturday 21st May

Since I'd raced at Snetterton before I didn't have to go to the first-time driver's briefing, despite the fairly substantial changes to the circuit. However, as a result of the alterations to the circuit, we each got a written notice when we signed on which provided details of the track changes, gave the usual warnings about putting four wheels off the track, and ended (in bold font capitals) by noting that the first lap of each practice session would be held under waved yellows, so NO OVERTAKING. The rationale for this was that this would enable us to spot where all the marshals' posts and lights are, since some of them have been moved as a result of the track changes.

Also as part of the changes to the circuit, MSV have added yellow and green lights to supplement the flags. These are particularly useful when the sun is low in the sky - if the sun's behind the marshals' post then all the flags look black, whereas the lights show up clearly. However, the written notice regarding NO OVERTAKING on the first practice lap, the fact there were yellow flags being vigorously waved at every marshals' post, together with the really rather noticeable yellow flags evidently wasn't quite enough for some of my fellow racers. Richard Wise came cruising past on the Bentley straight, although evidently then spotted the yellow flags for the first time, and dropped back into his original position. Tim Pell, however, came tanking past round Coram, evidently having either failed to spot, or deciding to ignore, all of the yellow flags and lights which had been so visible during the whole of the lap. Ah well, he very kindly oiled the entire circuit for us all later that day...

After I'd got past Al Boulton, who was industriously bedding in his brake pads by braking at unusual places on the circuit, and a few of the RGB newbies, I had a traffic-free track ahead of me. However, Sam Cooke had spun at Montreal on the exit, and was stationary by the side of the track. Unfortunately, because I then tried to get round Montreal slowly without using too much right foot, the car understeered like a pig and I went rather wider, and rather closer to Sam, than I'd intended to. Still, no harm done and Sam survived to fight another day. Despite having the benefit of an unusually clear circuit for the next few laps, my best two lap times were both considerably slower than the day before, at 1:23.25 and 1:23:54. That put me 16th on the grid out of 32 cars for race 1, and 15th for race 2. Solidly mid-table, but rather annoying given that I knew I could have gone faster. However, looking at the times, even a second faster would only have moved me up the grid a place or two, so I reassured myself that it probably didn't make that much difference.

Snetterton Race 1 - Saturday 21st May

The first of our two races, on Saturday afternoon, was great fun. Quite a bit of good close racing, and the video footage from it would have been considerably more interesting than most of my in-car footage. Unfortunately, my video recorder didn't record it for some reason best known to itself (although it's possible that I simply forgot to turn the camera on) and so it's still photos only.

I got my usual poor start, but just managed to stay in front of Adrian (the blue car in the photo on the left) and Rob Grant (in the purple Phoenix) who'd been on the row behind me. Adrian had managed to get alongside me going into Montreal, but by the Bentley straight I'd pulled back ahead and started looking at having a go at James Fowley (the yellow and orange Fury in the photo) and David Wale (the white BDN), two class A cars which were ahead of me. This ended up with me, James, and David going three-abreast into Brundle, the net result being that I got ahead of James but remained behind David. James and I then had a fantastic race over the next five laps, swapping positions quite a few times, with David and Tony Gaunt just ahead of us. At one point James rather surprised me by braking early for Murray's, which caused me to instinctively stamp on the brakes. Since I was, of course, still cornering round Coram at the time, this put the car sideways, and I passed James on the inside of the braking for zone for Murray's with the car fish-tailing one way and then the other. In fact, I managed to compromise my braking so much that I came alarmingly close to running into the back of Tony Gaunt, who'd been ahead of James at the time, but by the very narrowest of margins managed to avoid doing so by taking a massive chunk of kerb on the inside. Of course, my bizarre choice (sic) of line meant that I was dog slow accelerating out of Murray's, and so James got me back again down the pit straight. Sadly, our little battle was ended when James span at Montreal, and so after that I had a few laps with no other cars in close proximity - by this time David Wale was a fair way up the road. Still, at least my record of not having driven into another car remains intact, for now.

Although there were no other cars in close proximity, I could see a small white speck in my rear view mirror, which I knew must be Austen, who'd gone grass-cutting earlier on the exit of Chapman. Austen's in the same class as me, and has a very similar car - same model of car, same engine, same live axle suspension. So I really hoped that I'd be able to stay ahead of him, especially given the large gap between us. However, I immediately (and rather absurdly) started feeling under immense pressure to do so, then started over-driving, and going a good second a lap, on average, slower than I had been previously. Of course this allowed Austen to catch up, and although I held him at bay for a while, he got round the outside of me at Riches. A few laps later, with Austen still only a couple of seconds up the road, and on my last lap of the race, the leaders came through. I made sure I didn't get in their way, and then saw the chequered flag. All in all, a really fun race. The dicing with James Fowley was great, and although it was disappointing that Austen managed to get past me, and that I got another rubbish start, I did end up finishing 13th, so once again solidly mid-table. That worked out as being 5th in class, which I was also pretty pleased with.

Looking at the photos from the race, like the one above, it is alarming how much the Fury rolls round the corners. OK, Austen's car is rolling quite a lot as well, but mine is rolling to the point where if I did have a splitter 3 inches above the ground (the regs require a 75mm minimum ride height) then it'd be scraping along the track. This is, to a degree, merely the result of an intentional decision on my part to start off with the car relatively softly sprung (and therefore relatively forgiving in its handling) and then progressively stiffen up the chassis as my driving improves. I've already done this once, going from 150lb to 180lb springs, but I've decided its time for another step in that direction, so I've ordered some 200lb and 225lb springs. The plan at present is to put 200lb spring on the rear and 225lb springs on the front - if that leaves the car too understeery then I'll fit 200lb springs on the front as well. The trouble is that there's a limit to how stiff you can go at the back of the car - the rear axle weighs a significant proportion of the car's overall weight, so anything significantly over 200lbs and you just lose all rear-end grip due to the axle bouncing around everywhere. Still, there's plenty more time to come both from driver and car, so that's something I'm happy to live with for now.

Snetterton Race 2 - Sunday 22nd May

Pride, they say, comes before a fall. So my smug satisfaction in the fact that I'd done nothing on the car since Brands other than some rather pointless painting and draining the catch tank was bound to be entirely misplaced. So it transpired. On Friday during testing I thought I could feel a bit of play in the nearside rear wheel bearing. The bearing includes the oil seal which stops the diff oil sloshing around the live axle from spilling out, and that was certainly not doing its job entirely well since there was a slight weep of hypoid under the end of the axle. However, there was nothing that I could do about it there and then - replacing a rear wheel bearing on standard Escort shafts is a pretty involved job involving specialist mandrels and a hydraulic press. The car was also making a progressively louder shrieking noise under power, which I assumed (I suspect wrongly) was the wheel bearing complaining. Turns out it was rather more serious, but I'm getting ahead of myself...

My start in the second race wasn't actually too bad. Colin came tanking past me on the left, and Adrian pulled alongside me on the right, but I was baulked slightly by David Wale in his BDN who seemed to get a launch which was no better than mine. Reminding myself that it was an 18 minute race, I backed off, and slotted in behind Adrian round Riches. However, my equally cautious exit from Montreal and Chapman meant that Tony Gaunt could get alongside me down the straight, while I watched Adrian and Colin do a nice little dosidoh down the Bentley straight. That meant I was now three places down from my grid position, which is about par for the course due to my woeful starts. If everything ran to plan, I would now spend the race getting back to roughly the position I started from on the grid...

Tony managed to get past Adrian going into Riches, which left me behind Adrian again. I got a good exit from Montreal through Chapman so hit the Bentley straight right behind Adrian, and the Genesis punches a nice big hole in the air so I was able to pull up and alongside him, and then get past under braking for Brundle. Then everything went a bit pear-shaped. Getting on the power nice and early on the exit from Nelson, the car suddenly started making a horrific banging sound, almost like a propshaft in its terminal death-throes beating against the chassis. I immediately put my arm up and slowed right up as the whole of the field went past me. I limped back to the pits with the car making some truly spectacularly nasty noises. I still had drive, of a sort, and the engine revved cleanly enough with the clutch down. Pushing the car through the paddock later, however, the transmission would suddenly lock solid from time to time. I still thought it might be that the wheel bearing had collapsed, and the transmission locking up was when the bearing seized. However, whatever the reason, my day's racing was over and with James Walker's help I pushed the car onto the trailer and strapped it down. Time to take it back home and investigate the reason for all those unpleasant noises.

So all-in-all, a sort of mixed to middling weekend. Qualifying was OK but not great, Race 1 was really fun, Race 2 was a bit of a disaster. And I have a nasty feeling that both my free time and my wallet are about to take a bit of a beating... Thanks as ever to Dan and J-Ro for the photos. Cheers chaps.

29th May 2011

Break it down...

Once I'd got home and dropped the car off on the Sunday (and then gone to the Shed, dropped off the trailer, gone back home, and had a nice cup of tea and a sit down), I set to finding out what had caused the cacophony of nasty noises that afternoon. Having taken the panels on the top of the transmission tunnel off, so I could get to the propshaft, it soon became apparent that my theory that all my woes were due to a duff wheel bearing was not surviving empirical testing - with the handbrake on, and both rear wheels immobile, it was still possible to turn the propshaft freely. Also, you could, by turning the propshaft and the wheels, get the transmission to lock in the same way it had previously. However, when this happened, the wheels could still turn so even if the halfshaft bearing was a bit leaky, it was still turning. The propshaft, on the other hand, seemed fine. Once it was disconnected from the diff, it turned nice and smoothly and all the UJs seemed fine. All this pointed towards it being either a snapped halfshaft or, more likely, a blown diff. The only way to find out was to remove the halfshafts and drop the rear axle so I could get the diff out. So that's what I started doing.

The process of removing the halfshafts and rear axle on the Furyracer is a fairly involved process. This is, in no small part, due to the fact that the axle wasn't of course designed for use with brake calipers and discs. Once the wheels are off, its necessary to unbolt the rear calipers and suspend them from somewhere convenient (already done in the photo on the left), unbolt the brake caliper bracket, find all the spacer washers which have spread all over the garage, then undo the bolts holding the retaining plates, find all the spacer washers which have spread all all over the garage, remove the halfshafts with a slide hammer, unclip the brake hoses and pipes, the handbrake cables, and the cables going to the wheel speed sensors, and then, and only then, can you think about unbolting the rear axle from the suspension arms and dropping it from the chassis. Fortunately, things are fairly quiet at work at the moment, so I've been able to bunk off and do all this at home. Unfortunately, things are fairly quiet at work at the moment, so I'm not earning the cash which I suspect will be needed to fix everything. Ah well, swings and roundabouts, snakes and ladders...

One of the things which makes dropping the rear axle such a PITA is the fact that by the time the car's on axle stands the rear axle is 2 feet off the ground. It weighs the best part of 50kg, is very nose-heavy, and the nose is up inside the transmission tunnel so you can't even just drop it vertically down - it has to go backwards first, and then down. All of this, combined with the fact that it's about four feet wide, means that it's a tricky, and generally pretty painful, job to do single handed. In order to ease the process, I've made the cradle on the right. It bolts to the saddle of my trolley jack - I tapped some M8 threads into the chunkier bits of the saddle, and the caphead bolts go into them. With the cradle holding the axle in place it's remarkably easy to undo the suspension bolts, especially as you can use the trolley jack to raise and lower the axle to help get the bolt alignment spot on so the bolts can slide out.

Once all the bolts are removed, you just pull the trolley jack backwards (there's just enough room between the back of the axle and the fuel tank to allow the diff nose to clear the lower chassis rail in the transmission tunnel), and drop it down. Then you can quite happily trundle the axle around the garage on the trolley jack. OK, it took a wee bit of time to make, but I now keep on asking myself why I didn't make this earlier... With the rear axle off the car and lying in the back garden, it was the work of a moment (and an air ratchet) to undo the nuts holding the diff in the axle casing, take the diff out, and see what had gone wrong. By this stage it was fairly obvious that there was something badly wrong - when I picked the rear axle up to take it off the cradle, it rattled. And I don't think rear axles are supposed to do that...

I think it's probably true that the amazing deductive powers of London's pre-eminent consulting detective, Mr. Sherlock Holmes, were not necessary to spot the problem with the diff. Just in case there is anyone out there who hasn't worked it out yet...

...the clue is that these bits of metal are teeth from the crownwheel and should, in an ideal world, still be part of it. So, the diff's blown. Rather sad, as this was the diff which Zena bought me from an autojumble in Harrogate and heroically carried for over a mile to get it back to her parents' car. Still, I've consoled her with the thought that it's how it would've wanted to go, dying in the heat of battle. It is, after all, better to burn out than to fade away. After a brief mourning period, I've bought a new 3.54 CWP from Rally Design which is actually made by Tran-X but which Rally Design manage to sell for considerably less than Tran-X do. I know that aftermarket non-OEM CWPs have a rather mixed reputation, but Tran-X have a pretty solid background and paying £190+ for a used 3.54 diff of unknown provenance (which is what they're going for on eBay) seems an unattractive proposition. I've also ordered a pair of Tran-X halfshafts, on the rather spurious basis that given that the driveshafts are out, now's as good a time as any to fit some. Actually, there is a very good reason for using aftermarket halfshafts, but I'll cover that once they arrive...

So, one dead CWP. Building diffs is one part science and, in my experience, nine parts experience and feel. So I'm going to leave it to someone who knows what they're doing. For one thing, there's a possibility that bits of shrapnel have found their way into the Quaife ATB unit. I'm hoping very much that they haven't, but it is possible, and I don't trust myself to either assess whether they have or, if necessary, to strip it down and find out. So the bust diff, and the new CWP, are going off tomorrow to Competition Transmission Services in Luton. I've previously used Road and Race Transmissions near Sevenoaks for all my transmission-related work, but they're a bloody long way way and while they've always done what I've wanted in the past there were a couple of things I thought they should have spotted on the Striker's rear axle which they didn't. And anyway, I'm going to Luton anyway tomorrow to fly off to see SWMBO anyway, so it's pretty convenient to go to Mr. Gearboxman.com. Oh, and I think I'll have the diff built up into a new alloy diff nose (saving 5kg in weight) provided the ATB unit's OK, and I don't have to buy a new one of them. Well, it'd be rude not to really, provided the Quaife ATB unit isn't goosed and I don't have to buy a new one of those. And while Mr. Gearboxman.com is sorting out the back end of the car, I'm going to go back to playing with the varied assortment of front hubs I've got to see if we can lose a bit of weight at the front end of the car...

Front hubs

My garage is blessed with three pairs of front hubs. From left to right, we have the original Ford iron units (skimmed slightly by me), the silver Hi-Spec aluminium hubs which don't really fit and the gold Hi-Spec ali hubs (actually Tim's) which don't fit at all. Now the original Ford units work OK, but they are made of densest pig-iron and are a bit heavy. The silver ones are aluminium, and so lighter, but there's still quite a lot of material there. The trouble is that they aren't the same size as the Ford units - the shoulder for the inner bearing race has been machined about 5mm too deep, so the entire hub sits that amount too far inboard. Due to this it's basically impossible to tighten the hubs properly in order to preload the wheel bearings. Also, although they are aluminium, there's quite a lot of billet there - they look as though they've been designed for ease of machining rather than ultimate weight-saving. The gold ones are beautifully machined, and lighter than the silver hubs, but even worse than the silver ones when it comes to actually fitting.

The main problem is evident from this photo - there are two shoulders inside the bore of the hub. The top one is for the grease seal, the lower one is for the inner bearing race. As you can see, on the HiSpec hub, the recess for the grease seal is considerably deeper than that on the Ford hub, which in turn means that the recess for the bearing race is too deep. By about 7mm, roughly. This means the hub actually clashes with the upright, and is completely unusable. About par for HiSpec gear then... That's not the only problem. The recess for the inner bearing is also too deep, albeit only by less than 1mm. In fact, other than the bores of the bearing recesses, there isn't a single dimension on the HiSpec hubs which is the same as the Ford hub. In fact, there isn't a single dimension which is the same on the two HiSpec hubs. I'll do some more accurate measurements and post the results up here in due course. The other problem (yep, there's more...) the gold hubs have is that the central spigot on the hub flange (which fits inside the central hole in the wheel) is too large. So, even if you managed to fit them to the car, the wheels won't fit on them. I could rail about HiSpec's ineptitude, but it'd merely be variations on a well-established theme...

So the plan is to weight the silver and gold hubs and see what the difference in weight is. If it's significant, I'll see if I can remachine the gold hubs so they're actually usable. If it's not *that* significant in the great grand scheme of things, I'll use the silver hubs, on the basis that they need considerably less machining done to them, and Tim can have the gold ones back...