You are correct about braking. Thing is, as you can see from the videos, there were many fast cars out there, and there were a few who were slower but didn't let me past on the straights. This really gets me going when they do this, but I just keep some distance instead of getting worked up. My idea was that since I never had a single lap where I was "alone", I'd thought I'd go less aggressive on the brakes, and instead squeeze more laps out of my session. Now that I have a feel for these tyres at their limits, I can try and post a hotlap next time. I just feel too inexperienced as of yet to be attacking the braking zones so close to others.
All very smart and sensible. đź‘Ť
I'm not sure if it exists at Zolder or with the particular group you're running with, but a lot of clubs in the US, aside from normal track events, also have car control clinics. They do various exercises, all under the eye of an instructor:
- skidpad car control - learning to control and balance the car at the limit of adhesion
- threshold braking - correct braking technique and calculating braking points, brake and turn, etc.
- wide vision exercises - exactly what it sounds like. But also teaching you to 'look ahead'.
If you have the chance, try and sign up for something like this. To be honest, the track, or rather say on the track 'during' a track event, is not really the place to learn car control. That's better zeroed in on a 2nd gear autocross run through some cones in an empty parking lot. But a lot of tracks have a skid pad area you can push hard at lower speeds where there's plenty of run-off and no worries about another car up along side you when you're doing it. Ask around and look into it. If you do that even a few times it will probably help tremendously with your confidence and car control skills.
I wanted to ask you for some general tips on how to spot correct tire wear and pressures. I ran at 2.6 bars, and beyong the initial flex of the tyre which is natural for this Hankook tyre, I didn't seem to notice any exessive slip, or loss of grip with sudden direction changes.
One important thing to remember is that pressures build while you're pushing hard on track. The ambient temperature, the temperature of the road surface, the lateral loads, rotational forces, lateral force, friction, and probably hard, repeat braking more than anything (pads build up heat on the rotors which transfers to the hubs which transfer to the wheels which heats the air in the tires). So even on a cold day with near freezing temperatures, you'll eventually build up to the same pressures if you're pushing hard enough. But the moment you come off track or even start a cool down lap, those pressures drop pretty quickly. So by the time you come back to the paddock and measure pressures, they've probably dropped about 0.15~0.25 bar compared to what they were running 'hot'.
Every tire is different and reacts differently. Street tires will have more baseline grip and can operate over a more effective range of pressures. But their limits are still much lower. Under pressured tires will make the car will feel like it has 'slow' reactions. It's slow to correct and you'll feel a bit of 'flex' under hard braking or transient maneuvers. Over-inflated and the car will probably understeer on initial turn in and then oversteer when powering out. And the grip just won't be there. But these are very general answers.
Also, you mentioned a 235/40R17 tyre size. What were your findings with different tyre sizes to pick this size as a favourite?
I started with 215/45/17 Dunlop Starspecs. Then moved up to 225/45/17. Then changed rims and went to a 235/40/17. Keep in mind that I've had a big pool of resources to draw from.
(1) The FT86 boards has a great section for track driving, although it's not quite as active now-a-days as it was 2-3 years ago:
http://www.ft86club.com/forums/forumdisplay.php?f=39 There are some incredibly knowledgeable people in that thread that you can draw from.
(2) My own shop:
http://azpinstalls.com/web/ These guys are all former racers and they ran a car for two season in the FT86 cup at NASA events. They were able to do a LOT of experimentation with different suspension settings, wheel and tires sizes and make direct comparisons, similar to the video that
@Ridox2JZGTE posted.
(3) The co-owner of the dealer where I bought my car is an amateur racer.
https://www.johnstonstoyota.com That would be Steve Jardin. And he's also been very generous with his time and expertise.
The general consensus is that 235/40/17 is just the 'sweet spot' between grip & fit with the FT86 platform. If you're autocrossing, you probably want the widest tires you can fit becasue you're going out on 'warm' tires and running for 60 seconds--so there, go for a 255. The tires are barely coming up to temperature when you're done. As opposed to 20-30 minutes out on track. So you want a tire that's wide, but not so wide that it creates an aero block and adds (instead of reduces) unsprung weight. Remember, every 1 kg of unsprung weight is equal to about 5 kgs on the rest of the car. And with a 255 the contact patch is so wide that it creates frictional losses in straight line speed that the car just doesn't have enough power to overcome. When I first mounted my Enkei wheels (they were about 5 kgs lighter than my stock rims, it was a revelation--the car just felt so much lighter and quicker from that alone). Most people who tried running 255s on track felt that on long straights it was slowing them down more than they were gaining in the corners.
I've asked for a price quote on a Milltek secondary cat-back system. The only thing I now miss from this car is sound experience. I might go the header + cat-back route, to get that boxer sound out, but without becoming overly loud. The limit at Zolder is 95dB, so I need to be careful. My friend fitted a GT4 exhaust to his Cayman S and is now running at 117dB...
I doubt you'll be anywhere near 117dB. That' way over the limit for most tracks in the US. Many have 'unmuffled' days but they're normally saved for actual races. Cat back + header will also force you to change the tune in the ECU or you'd never pass an emissions inspection and your car will not be able to take advantage of the free flowing header without it. You'll make more power and it's nice but I can tell you it will be really annoying on the road. I can't say much because I did it myself but my advise would be to leave the header and exhaust and install aftermarket control arms and top hats so you can adjust the camber and put whatever is left over to a coach.
It's such a wonderful track.
:tup: 
(I know) It will cost a lot less than full coil overs. And a hyrbrid alignment will help preserve the tires on track and improve turn-in response without causing too much tire wear on the road. Maybe something like -2.0 of camber in front and -1.5 in the rear. And zero out the toe, if you're comfortable with it. But other than that, if you're going to spend any more money, I would suggest at this stage you hire a driving coach. For every EUR 1 you spend on a good instructor it's worth an EUR 10 you spend on go fast bits for the car.
You need to be fully awake before trying it. 
