I booked on this Trackday in 2015 but due to a failed output flange I only managed THREE laps !
This was the failure that ended the day early in 2015
They worked out at being the most expensive laps per £ I`ve ever done and not something I wanted to repeat. I gave the Golf a good going over and everything seemed to be in order before this event and it was loaded up in plenty of time with no jobs outstanding.
Matt and I finished work and drove down to the Premier Inn near Silverstone and adjacent to the Green Man inn. He had the sofa pull out bed.
Went into the Pub and had a good chat with Jordan and his mates whilst waiting for our food to arrive. They`d driven down earlier and we spent a good hour or so catching up.
Woke up and made the short journey to a very foggy Silverstone and it was obvious we wouldn`t be getting on track straight away.
Unloaded the Golf. You couldn`t see the length of the paddock and everyone soon realised the start would be delayed
Signed on in the chilly pit garage
Went for a wander around the paddock and returned to find a small gathering around the Golf. The skirt and wing are still damaged from the tyre blowout and that prompted quite a lot of discussion.
Darren gave the briefing and explained the rules for the day and why the start was delayed. The circuit did tell us they`d try and give us as much tracktime as possible once the fog lifted.
One chap asked how many people were on the day as it seemed busy in the briefing. Darren replied there were enough to make the day profitable but few enough to give us good tracktime.
He was correct. When the track was live there was hardly any waiting in the pitlane and there was plenty of room on track. The only issue was after a Red flag when everyone came into the pits and queued to get out.
It was mid morning by the time the track opened and we went out for the sighting lap. As soon as we pulled onto the circuit I knew something was amiss. The water temp skyrocketed and was almost in the red ! I shifted into 5th and cruised round, then the red flags came out.
Back into the pits to see what on earth was going on with the water temp. I`d replaced the water pump after DN16 as it had been squealing. Bonnet open and the water could be seen to be returning into the expansion tank as usual so I knew the pump was working. Initially I wondered if the thermostat had somehow stuck closed. That was something I hoped wasn`t the case as it`s a pain to access. The strange thing was I`d left the car idling at home after changing the thermostat and it got to temp and sat there quite happily so I knew the pump was working ok.
It turned out to be a massive airlock ! Revved the engine and it suddenly let out a large gurgle and the level dropped out of the bottom of the expansion tank. Put in a few litres of water and it was back to normal and never gave me an issue again.
I`ve refilled the system loads of times and never had this before. I`d brought the car up to temp in the driveway and it was fine at idle but as soon as I put some load on the engine the lack of water in the system showed itself.
We fitted the R1R`s as it was far too greasy for the Cups and went out for the first session.
Everything seemed OK apart from the clutch was sticking. It didn`t seem to be fully engaging and it was difficult to change gear. I ended up rev-matching as much as possible but I wasn`t able to Heal and Toe properly. The track was still slippery and I tried several lines in search of grip.
Stace was there in his Mini race car and we went our for a few laps with me following. The Mini turns in far better than the Golf in the damp and that`s pretty clear on this video.
What I`ve found is the plate diff has made turning in worse in the wet / damp . But it isn`t really an an issue in the dry. The previous ATB was `open` on deceleration but the Kaaz is a /65 which means when you lift off, the plates are pushed apart activating the clutches in the diff. The makes the car far more stable under braking but induces understeer on corner entry as the front axle is effectively locked.
If I just mash the throttle it still spins up both wheels and understeers as you`d expect.
What I need to do is apply just enough throttle to neither load or unload the diff so it becomes `open` but not too much to introduce too much understeer. Not ideal and quite tricky on bumps but something I didn`t experience at the Nurburgring as it was dry. The fact it`s much harder to do the required fine on/off throttle modulation in a Turbo car as it dumps boost through the BOV makes it much trickier. I suspect in an N/A car it will be easier to modulate in these sorts of conditions with a plate diff. The issue of part throttle control is something I noticed on my first session after fitting the Turbo and whilst I`m used to it now and can usually drive around it, I sometimes find it irritating. Not irritating enough to go back to N/A though….
If you go into a corner a little too fast, previously just lifting off would tuck the nose it but that isn`t the case now and it`s something I hadnt`t expected to be as noticeable as it was at Silverstone.
I`ll be modifying the ARB mountings over the winter so in the damp / wet I can quickly disconnect one end of the ARB to allow the front end to roll a bit more but reduce understeer. At the moment it isn`t something I can do and I think that would help this issue a little.
Simon let us share his garage which was most appreciated !
He has a high power Supra and Silverstone gave a graphic example of just what difference power makes when you have opportunity to use it
However it doesn`t always go so quickly in the corners
The long straights meant I could carry out some tests on the boost delivery. I was running a `damp` boost map which just means there is less midrange boost which reduces the chances of wheelspin when conditions are tricky. It`s a dead simple change, I just click a `Load Wet Map` button on the phone in the car and it changes the Solenoid duty cycle map to be more progressive. If it dries out I click `Load Dry Map` and it reverts to the slightly more aggressive mid range delivery.
I also tested some new setting on the Boost Button which give me an instant 1.1Bar at the press of a button, regardless of which delivery map I`m using.. They didn`t work ! The oscillation is just as bad as before. This is purely down to the limitations of the Megasquirt 1 Closed loop control. I can only check it when on track and always forget to test several setting out on a day. I must get this fixed and will aim to do so next year.
The circuit were true to their word and didn`t stop for lunch which gave us an extra hour of trackime to replace the missing hour due to the fog. Can`t fault them for that at all ! It was drying out so I decided to fit the worn Cups. The idea was to wear them out at Silverstone but they are so low I obviously couldn`t run them when it was damp. Whilst they are down to the wear markers and no good at displacing water, they are still good enough in the dry. I`d taken spare wheels with Cups mounted incase these wore out but that never happened.
Whilst I was fitting them Polay made sure the passenger seat was his for his long awaited session in the Pinderwagen ! He`s been waiting for a couple of years and circumstances have meant he just never had the opportunity. This time he made sure nobody else was getting in that seat before him.
We went out for a few laps and then had to pit again.
Did a short session with Karan and the clutch was getting worse making engaging gears tricky. Had a bit of an issue with a driver who thought the overtaking rules meant moving to the right then nailing it with almost 400HP under his right foot, but otherwise an enjoyable session.
As everything was fine, Polay jumped in again. He had a great few laps and came away with a huge grin on his face. This sort of reaction is what I enjoy the most about trackdays. Taking people out for a session and them coming in beaming at the end of it is hugely satisfying.
I was experiencing a slight misfire on high boost. I`ve had this before when I was running Copper spark plugs. Switching to Iridium had solved it but the symptoms were the same. A slight hesitation / miss at high boost. I removed all 4 plugs, they were in good condition
More pleasing was the colouring was spot on
Checking the Gap and the issue was obvious. All 4 had opened up slightly to 0.031″
Regapped to 0.025″, went back out and the misfire had gone. I hadn`t checked them for a while so I`ll make sure I don`t leave it as long next time.
Everything was going well apart from the clutch. That was getting harder and harder to engage. When I started the car in the pits, even with the clutch fully depressed the gears crunched when selecting 1st and the car started creeping forwards. I was changing gear with minimal clutch use on track. So long as I rev matched and applied light pressure on the gearlever it was pretty easy. I ould slot into gear once the revs were correct. Obviously this meant I could not Heal & Toe but I was only using 3rd and 4th anyway. I tried a full lap in 4th but it just bogged down on the slower 3rd gear corners.
George had been around for a lot of the day socialising and I took him out for a session at the end of the day. All was going well until we were going down hanger straight and I tried using the clutch to go from 3rd to 4th. The pedal operated as usual but the clutch wouldn`t disengage. I freewheeled off into the `Wing` pit entry and stopped by the marshall point. Explained I hadn`t dropped any fluid, but I had no drive. The marshall was absolutely fine and asked if I wouldn`t mind waiting until the end of the day. It was 15:55 and the day was due to end at 16:00 so it was no big issue to wait and spectate for 5 minutes. The gravel was already there, nothing to do with me !
The track closed and we were towed back the wrong way around the circuit. It was a little strange seeing the circuit car going the opposite way. The beauty of having the steering pump and Servo powered electrically meant I could brake and steer just as easily as when driving which makes being towed a lot easier. Don`t get me wrong, I don`t want to get towed..
There were plenty people around to help me push the Golf onto the trailer which was appreciated. All strapped down and a steady drive back up the M1.
Gearbox removed the next day and the reason for not being able to disengage the clutch was pretty obvious. The friction plate was in pieces !
Overall a very enjoyable day and much more successful that 2015 although I still ended up with a broken car at the end of it. This time I only lost 5 minutes of tracktime, last year I only had 5 minutes… The circuit couldn`t have done more to open the track as soon as possible, work thorough lunch and as late as daylight allowed to give us as much tracktime as they could.
The diff made it trickier in the damp as I explained earlier but I can address that with modifying the ARB so that can be disconnected in the wet/damp and finally addressing the roll centre correction by adding some balljoint extenders. Neither are particularly major issues and I will sort them over the winter.