ADR Sport 2 Sports Racer

ADR Sport 2 Sports Racer

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andylaurence

Original Poster:

438 posts

213 months

Monday 1st September 2014
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After breaking the class record several times at Clay Pigeon and still not having my name on it, I was determined to fix it. A slow start in practice put me on a 74.44 coming into the timed runs, which was under the class record, but not under my best time. In the first timed run, I put in a 73.35, followed by a 73.39 and a 72.90. All three were under the class record and the final one half a second off my personal best when the chicane wasn't set out correctly. I was happy with that and even happier that the club gave an extra run afterwards.



It was coming into the second lap of this final run that the moment happened. I turned into the corner and heard a noise as the car spun to a halt. I was bemused, thinking the chain had gone and locked the rear end. It hadn't - the stud in the bottom of the upright keeping the wishbone attached had sheared. The rear wheel was flapping in the wind and there was no lifting equipment for the recovery team. I had to retrieve my trailer and winch it on with the help of all the marshals. Lucky it happened there though, as the consequences of a similar failure at Castle Combe the following weekend would have been severe.



Talking of Combe the following week, it was Sunday evening and scrutineering was at 07:30 on Saturday morning. The stud, naturally, was not available off-the-shelf. Luckily, Grant Motorsport stepped in and manufactured 3 new ones out of EN24 steel and removed the snapped off one from the upright as well as making a new brake line, which was nipped down to the braid. McGill Motorsport supplied some new rod ends for the wishbones (one had broken in sympathy) and it was all finished with 10 hours to spare before scrutineering. All I needed was some sleep!

andylaurence

Original Poster:

438 posts

213 months

Monday 1st September 2014
quotequote all
Having finished the car just a few hours before the event, I wasn't feeling wholly prepared for the Dick Mayo Sprint held by Bristol Motor Club at Castle Combe Circuit. I was wholly prepared though and I rocked up at 07:00 as usual to get scrutineered as early as possible, grab breakfast and make time to chat to all the people I was bound to bump into at my home event. Importantly, I was competing against Andrew, who I'd cajoled into buying a Van Diemen RF01X from Dermot's emporium and this was his first ever sprint. Baptism of fire!

Other notables in the class was Matt Carter, fresh from his 3rd place finish in the run offs of the British Sprint Championship, Clive Wooster (who beat me at Llandow), Luke Trotman (who had forgiven me for taking his pot at Prescott) and Tom Arnold, who hoped his electrical gremlins were finally behind him after replacing ... everything! It was boiling hot and my objectives for the day were to beat my class record and take 2nd place (or nobble Matt's car and take the win). I wasn't feeling nasty, so I chose to aim for 2nd place!

On the first practice run, I needed to test the brakes, so I gave them a good firm press between Folly and Avon Rise to make sure I'd stop going into Quarry. I was back onto the pace by Hammerdown and the second half of the lap went together quite well. Given the brake testing, 4th place wasn't a surprise, but I was incredibly surprised to be within a second of my class record and only a few tenths off Luke in 2nd place. Matt had taken 3 seconds off the class record - foregone conclusion!

The second practice run was my opportunity to put a stamp on the timesheet and I put in a reasonable run that was 1.3 seconds inside my class record. Result! Matt was now 4 seconds under the record, Clive was also a few hundredths inside it and Luke was just 3 hundredths off it. I the day finished like that, I'd be happy, but Clive has a tendency to go faster each run, often by a second.

My afternoon started with the first timed run being a solitary hundredth quicker than my practice run. Unexpectedly, everyone else went slower, probably as a result of the heat cooking the tyres. Even Clive! That was one objective complete - I'd shattered my class record, even if Matt had obliterated it. Git! The second timed run was all or nothing and I went 2 hundredths slower, probably as a result of a little oversteer on the exit of Quarry. I'd like to say I was perfectly consistent, but I think the track conditions worsened at the same rate I improved. It was a good result though as the video shows the start line was a few feet further back and Castle Combe had decided to put tyres on the apexes for some reason, so the lines were a little more wiggly than normal!

There's been a lot of "I think" and "probably" here without a lot of evidence. There's a good reason for that. I've pulled out the Race Capture Pro as it's being replaced by a Xoombox from Xoomspeed. That neatly coincided with the little read-only tab on the SD card in the RacePak falling off, so it couldn't write to the memory card. The Xoombox will provide some solid data (whilst interfacing perfectly with Xoomcentre, which I've been using for a while as an analysis tool) as well as giving the possibility of adding launch control, traction control, flat-shifting, down-shift blipping, and even full pneumatic shifting. I've been collecting components from Chinese sellers with mixed success to build a dash (sequential shift lights and gear indicator) and pneumatic control system.

The closest I have to data at Combe is to compare video with my 2013 times, but not the class record as the video failed last year. I've split the track into several sections to compare the times. The first thing to note is that my 64 foot times were a few thousandths quicker, most likely reflecting the track temperature. By the end of the pit lane, I was 0.18 ahead this year, most likely for the same reason. I lost 0.12 through Folly, which suggests the car is accelerating less quickly. This isn't surprising as I was running the wing in its high position with the flap backed right off. It's more drag than the low drag configuration, but it doesn't correlate with the rest of the lap, perhaps because of alternate gear ratios and the other aero changes made over the winter. I was quicker from there to Avon Rise, probably through more commitment over the Rise. Maybe I wasn't flat last year or my line was different to account for the lower grip.

A few more hundredths through Quarry brought me back to a 0.15 advantage over 2013. I gained time to The Esses, suggesting a quicker exit speed from Quarry, which is what I felt at the time. Significant time was gained in The Esses, which is strange as I felt there was more to come and I thought I had always been fast there. Despite that, I seemed to have found nearly half a second and a few more hundredths through Old Paddock. I also gained significantly through Hammerdown, which suggests that either the ratios/aero changes have improved performance at these speeds or the extra speed carried through Old Paddock multiplied the gain on the run to Tower.

Significant time was made through Tower, which I know is my nemesis. I also managed a few tenths through Bobbies to finish 3 seconds ahead of my first timed run in 2013. The comparison is shown in the graph below.



Before finishing this write-up, I should point out Chris Buckley's performance. He'd never driven a sports racer, a car with slicks or an aero car and he turned up in his newly purchased Radical SR8. He knocked 15 seconds off his first practice time to finish barely a tenth behind me and set a new >1800cc class record. We've agreed to double drive our cars for the last two events, so he'll be aiming for my class record in the ADR at Clay Pigeon, whilst I aim for FTD in his SR8 at Combe in October...