Our Northloop `season opener` trackday had been planned since December and we had over 20 cars booked on the event. Not only is it a trackday but it`s a good chance to meet up with friends at the same time. A group of 20 of us went out on Friday evening for a meal and a beer. What a great start to a trackday.
Woke before the alarm. As usual... Breakfast in the hotel then a short drive to the circuit. We were one of the first there.
At Oulton I`d had the misfire when I tested the Megasquirt 2 CPU so was keen to sort it. A MASSIVE thank you to Gurds who spent the time replicating the fault and then tried many filter combinations until he found the ones that removed the phantom triggers. He sent me the necessary settings and I added them to the ECU. After noise testing I drove through the tunnel, nailed it in 1st and it revved straight round to 7,300rpm. No hint of a misfire !
Knowing the ECU was fixed was a big weight of my mind and I queued up for the sighting laps knowing everything was working. I was on the new Pirelli rain tyres, not because it was raining but because I wanted to scrub them in so that if I ever needed them in the rain I would have already worn off the release agent.
Rockingham, is the slippiest surface I`ve ever driven in the wet and several people span on the sighting laps. Graham who is a regular trackday driver span on the first corner of the first sighting lap. Grippy it was not. Fuelling was still rich and it smoked on acceleration at 4,000rpm. We were both looking at the AFR which dropped to 10.2 at this point. No issue, we just changed the fuelling table after these laps.
Came in after the sighting laps, checked tyre pressures and then went straight out for 2 laps to get the tyres cleaned up and check the boost delivery and fuelling.
Absolutely no issues whatsoever apart from the front screen started misting in the corners. We were coming back in to swap the wheels anyway so Matt applied the Anti-fog at the same time. The beauty of a large group going together is you can book out 8 adjacent garages which made chatting to mates between sessions dead simple.
I fitted the Pilot Sport Cups, they were an old set I wanted to kill off before getting some better ones put on the rims before the Nurburgring in April.
First lap out and they were sliding everywhere and I had that tricky couple of laps where I was trying to get heat into old tyres but not sliding everywhere. As soon as them started warming up they were fine. Simon also swapped onto better
tyres at the same time.
Because we were all next to each other, there were several `coffee stations` in the garages, various people had brought tea, coffee, biscuits etc and it meant you could have a cuppa and a chat between sessions which added to the relaxed atmosphere of the day. Unfortunately, nobody brought any Milk ! Gurds very kindly popped out and bought 8 pints .
The circuit was open and there were no queues whatsoever.
By now the track was drying out and I was able to press on a bit. Gurds had turned up for some passenger laps so I took him out. It was his first time since I`d fitted the plate diff and it was interesting to hear his thoughts. Traction was good but the lack of ball joint extenders to correct the roll centre seemed particularly noticeable at Rockingham. Perhaps it`s the slower corners and change of direction ? I`m not sure but it was particularly noticeable here. The Golf was incredibly stable through the high speed corners and I was able to close up on cars that had pulled away in the slower bits.
There was a good dry line starting to appear now and I was able to start pressing on even more. I always find the rain helps show up what the airflow is doing. The inner `scoop` is ducting air into the brake ducts but is causing some turbulence on the outside of it which is flowing all the way out to the end plates. Not a big issue, just interesting to me.
Back in, checked the tyre pressures and the front right was at 44psi. Yeah, that`ll be why it was understeering more and more as the session went on.
Between sessions I parked in the garage and gave everything a once over. A couple of fuelling tweaks to the ECU map but only fine tuning as we`d done most of it at Oulton.
I don`t often make the time to look round other cars but as we were all in the same garage I did it much more than usual.
Lou went out for a lap with Steve in the Caterham and really enjoyed it too !
I`ve never seen anyone so relieved to see the chequered flag waved for lunch. A selection of sandwiches and snacks for lunch and then some cake. Unfortunately we hadn`t brought a knife so had to use the teaspoon handle instead.
The sun was out and the circuit was dry
Once the tyres had warmed up I was able to press on and try a few different techniques, in particular left foot braking. I still don`t have the necessary finesse to do this properly but the only way to improve is to keep doing it and I was much better by the end of the day. I`d taken Ian out and a few others and then Chris asked if he could jump in for a session as he hadn`t been out with me for years. Ian jumped in with Alastair in the Elise and Ste & Karan also planned to go out. Was it finally going to happen ? Al, Ste and me all on track in working cars at the SAME TIME !!?? It did and oh what fun it was too ! I was in the lead for the first few laps then let Alastair past so I could follow him.
Ste tagged onto the back of me and then I let him past to follow. It was a fantastic session and the differences between the cars was really apparent. The Elises had a noticeable advantage out of the slower corners. I simply couldn`t live with them. The last chicane onto the banking was where I really struggled to keep up too, apart from one lap when I went through it just right and kept up with Alastair. Then we got tot he banking and I reeled them both in every lap. The Aero was working and the Golf was absolutely planted through there. Then I braked for Deene hairpin and the pedal went to the floor ! It had felt a little bit soft the lap before but not that bad. Basically I`d boiled the brake fluid. What`s particularly frustrating is that I have new fluid at home and had already planned to flush it after this trackday before I went to the Nurburgring in a month ! Lesson learned, Rockingham is hard on brakes and in future I`ll ensure the fluid is in good condition. After a cruise round the banking I came back into the pits where we all parked up to discuss the session. You know it was a good one when everyone is talking at once.
It has taken us a few years to all be on track together but it was worth it. The day could have finished right then and I`d have been happy.
Matt jumped in for another session where we were watching the boost control and fuelling. The Fuel was almost spot on but it was overboosting slightly.
Then Cat hopped into the passenger seat for the last session.
No particular drama until the next to last lap when I came across Rich exiting the pits. Quite simply, he hadn`t seen me at all and started moving towards the outside of the track. I thought he was going to stop but he just kept coming.
Well, until I flew past at just under 130MPH.... He came across straight after and couldn`t stop apologising. I can understand why it happened, whilst he knew he wasn`t supposed to move across after exiting the pits, the Golf isn`t a particularly bright colour and as you can`t run with the headlights lit on UK trackdays it can blend in a bit. Especially somewhere as grey as Rockingham. Daytime running lights would certainly have helped in this scenario. Fortunately no harm done but it was a timely reminder of what could happen.. I ran open loop boost control before lunch then switched to closed loop after. Running closed loop gave a noticeable urgency straight after a gearchange and I wasn`t quite sure why. Looking at the data afterwards it was obvious. Open loop simply sets the boody solenoid duty at a fixed percentage for the revs, in this case 34%
What the closed loop control does is set that to 100% until the boost is within 0.2Bar of target when it switches to PID control. This gives maximum spool and reduces the time to reach target. The green trace is steeper on closed loop control. After the target is reached it oscillates a little but I can tune that out at the Ring in April.
Over the entire afternoon session peak revs were 7385rpm with zero misfires and peak boost was 1.3Bar instead of the usual 0.9 to 1.0 This was overshoot from the boost control and whilst I know I could turn up the boost, I`ll stick to the
1.0Bar that I know works reliably for a while
Day over and it was time to load up. Tools and tyres onto the trailer first and by then the garages were empty as just about everyone else had left.
By the time we`d packed up and were about to leave, everyone else had already gone.
Tyres were well worn and I`m quite happy to bin them now
when is the next one !?" whilst packing up, you know it went well.
A final thanks to Neil, Gary, Nick and Martin for their photos. Without them there wouldn`t be any of the Golf on track and not as many in the paddock which would make this report a much shorter and less interesting one.