19th February 2012
MX-5 Club of NSW track day - Wakefield ParkFirst club trackday for 2012 and my first opportunity to try out a new set of Dunlop Star Specs. The BOM forecast was showers and afternoon thunderstorms, but Mike worked his magic, announced that "it will not rain today" and lo ... a perfectly dry track was presented to us. It was pretty hot though, reaching a maximum of 28C. The conditions were much the same as for the club's
20th Feb 2011 trackday, when I had a best time of 1:18.89 on a new set of RE001s, so it was going to be interesting to see how these Star Specs compared (OK OK, different day and everything, but it's the best comparison I can make right now).
_MG_1035 by
Tiit Saul, on Flickr
There were 81 drivers booked in, but four drop-outs reduced the final number to 77. I was relieved to be roped in at last minute again to serve as a trainer, and Eric Hardas was my first-timer student. I always love doing the training - it's great fun introducing newbies to the track. Eric has only had his standard SE for a few months, so he was a quite nervous and ended up with a 1:27.72. Plenty of room for improvement there Eric.
"The apex is over there Eric"
_MG_1684 by
Tiit Saul, on Flickr
The guys at Gary's Motorsport where I bought the Star Specs, recommended a fairly low hot pressure of mid 30s. I wasn't quite sure to trust that advice, so I started with 34psi cold just to be safe. A couple of the valves seem to be a bit dodgy as I had trouble getting my pressure gauge to seat properly and give a reading. So I'm not quite sure exactly what pressure was in two of the tyres!
Run 1 with my hardtop fitted as an experiment, produced a 1:18.11 on Lap 3. Back in the garage, a rushed pressure adjustment reduced them back down to around 37psi hot where I left them for the rest of the day. I'll play with different pressures next time when the valves are replaced.
_MG_1558 by
Tiit Saul, on Flickr
I had to rush off to jump into Eric's car for the first-timer training, got through that and then jumped in my car for Run 2, only to discover that I had
lost my key!
I missed my run and spent the next hour frantically searching every conceivable place, inside my car, inside Eric's car, retracing my steps to search the ground, stripping off my race-suit to search inside it and my boots ... nothing
! Eventually I admitted defeat, phoned Fiona and begged her to drive down with the spare key. She had no plans, and the Volvo needed some kms for the novated lease, so she came to my rescue! What a great wife!
Meanwhile, my Class 1 compatriot Phil Lea generously offered a drive in his car. So I slapped my numbers on his doors and did the next two runs in his stock NA6. I've dríven it before at Marulan, so knew what to expect. I initially thought it was faster than mine because a) I misread Phil's GPS timer, and b) I was changing to 4th quite a bit sooner. But his car was ultimately about a second and a half slower than mine - my best lap was 1:18.96. It's amazing how much difference is made by only power steering, aircon, different wheel alignment (heaps more front camber), and more hardcore brake pads (Hawk Blue front, Hawk HP+ rear), in an otherwise identical car. It was locking the rear brakes into the fish-hook, and getting too much understeer in the high speed corners. No reason why it can't match my car's times though, with a bit of tweaking to the set-up. And much of the difference may have simply been due to his fitment of RE001s versus my Star Specs.
Needless to say, I treated Phil's car with the utmost care and respect!
_MG_2788 by
Tiit Saul, on Flickr
No idea why I've got the wheels pointed in that direction.
_MG_2884 by
Tiit Saul, on Flickr
Fiona and Alex arrived with the spare key while I was out on my second run in Phil's car - she wondered why I wouldn't answer my mobile
. We had a really ordinary lunch together in the cafe - the food quality was strangely very poor compared to usual
- new management? Alex had come down with a cold overnight and was pretty miserable, but cheered up when he got to "drive" Little Reddy for a few laps around the carports (sitting on my lap). They headed for home when I was called up for the next run. I did Run 4 with the hardtop still on, and couldn't improve on my first effort. Best lap was 1:18.25, which was 0.14s slower than the first run.
_MG_3228 by
Tiit Saul, on Flickr
By now people were already starting to pack up as it was quite hot, so I flipped off the hardtop and went straight back out again with the soft-top raised for part 2 of the experiment. Run 5 was immediately quicker with a best lap of 1:17.85 - 0.4s faster than with the hardtop. My optimal times were 1:17.92 with the hardtop and 1:17.39 with the soft-top - 0.6s faster than with the hardtop. So my conclusion is that
running with the hardtop is about half a second slower than with the soft-top raised. Subsequent analysis unsurprisingly revealed that the difference was due to
slightly higher top speed at the end of the straights (especially the shorter ones): 2.4km/hr into turn 10, 0.6km/hr into turn 2, 1.0km/hr into turn 3, 1.9km/hr into turn 8 (little difference for main straight because acceleration is slow in the higher gears). If my class permitted me to remove the soft-top frame and run with the hard-top only, there would be less of a difference. However, for now the hardtop can go back in the garage where it belongs!
Back in my car at turn 10, and if I'm not mistaken, I think I can see air under both inside tyres!
_MG_3537 by
Tiit Saul, on Flickr
_MG_3539 by
Tiit Saul, on Flickr
I had two more runs with the soft-top to finish the day. On Run 6, I improved my time to 1:17.67 (lap 2) and 1:17.68 (lap 5). Between those, I had entertaining excursions onto the grass at turn 5 and turn 2
. Run 7 included 1:17.89 (lap 1), 1:17.62 (lap 2), 1:17.70 (lap 5) and a couple of big time-sapping slides on the other two laps (1:18.41 and 1:18.30).
OK, so what's my first impression on the Star Specs? They felt
really good – nice grip and progressive to slide – I felt a lot more confident across the top of the hill and could have pushed a little more than I did into turns 3 and 4.
Last February in similar conditions I struggled to get 1:18.89 on RE001s. This time I did a 1:17.62, so there's a 1.27 second difference due to the tyres. Comparing my best "optimal" lap on each day it was 1:18.52 versus 1:17.12, which gives a 1.40 second difference. Comparing my GPS data indicates that most of the difference was made in turns 4/5 which gave me a faster exit for 6/7 (0.3s), and then much quicker entry speed for 8 (0.8s). So hopefully as the year cools down and gets quicker, my street tyre PB will drop from 1:16.80 into the mid-15s.
In summary, I learnt three important lessons today ...1) Using the hardtop with the soft-top lowered is about 0.5 seconds per lap slower than running with the soft-top raised. Carrying that extra 20kg saps the straight line acceleration.
2) Star Specs are about 1.3 seconds per lap faster than RE001s. This confirmed expectations based on experience from Victorian supersprinters. For comparison, proper R-spec RE55s are 2 seconds per lap faster than RE001s.
3) ALWAYS CARRY A SPARE KEY!!!
Only a year ago, he was doing 1:22s. Wow! Ian sure gave Phil Munnings a scare, and he had to pull out a big PB (1:13.61) to win Class 6 on the day. 
