Fastivus at Summit Point: September 2023
On the Shenandoah Circuit at Summit Point this year!
Group photo just in front of the bridge straight - courtesy of Jon Felton of TrackDaze
I was glad the event was moved back to Shenandoah this year. It puts a big emphasis on handling and driver ability more so than most other tracks (in my opinion). Last year running the Jefferson circuit was only due to a hurricane-induced reschedule.
Changes to the car since the VIR trip back in July include:
MK8 PCV retrofitted (more info HERE) - to fix the smoking issue on track
034 extended lower ball joints (info on them HERE) - mainly to add more camber quick and easily
255/40R17 front and 245/40R17 rear Kumho V730s - I’ve been running the reverse stagger for autocross, but this was the first time on track. Normally I’ve run 245/40R17 square. - wanted to experiment since it’s late in the year and see if they felt better than the square setup or not.
Slightly more boost on the tune - was wanting to test the MK8 PCV as much as possible, and also I’ve always kind of been more conservative than most so just wanted to push a bit further.
My dad and I rolled in to the Summit Point Shenandoah paddock around 6:00pm on Friday night for the “meet and greet” and also to run the car through tech. One less thing to worry about in the morning.
The weather was absolutely perfect - Sunny and 65F in the morning and about 75F in the afternoon. Session number one was spent getting familiar with the track again, but noticed some very strange behavior from the suspension when going over the “ski jump” most notably. The amount of added bump steer was definitely noticeable which would make the car get squirrely as it came back down to Earth after getting light over the jump. It was borderline undriveable in my opinion. In the video below you can see the car toes out SO MUCH on compression - this is what was causing the sides of the car to grab one way and then the other.
Grip seemed good in slower corners, but the car was very “edgy” to drive near the limit. It MAY have been due to raising the roll center (while at stock ride height) or also from the additional bump steer induced by the ball joints. Either way it was not the best - and I knew this was a risk since they are intended for a lowered car - I was just wanting more (and cheap+easy) camber.
Fortunately I brought my toe plates with me so I went ahead and added about 3mm of toe-in before the 2nd session to try and tame the uneasiness of the front end - and it worked at least well enough to feel confident enough pushing the car as-is for the remainder of the day.
Session #2 was a lot of fun - Lots of cars to play with and was never really held up too badly. I wasn’t looking to push the car super hard due to the weird suspension behavior, but was able to drive at a consistent 8/10ths pace putting down 1:44s/1:45s (with a couple slower due to traffic) and then a 1:43.93 on Lap 6 despite the traffic. There was absolutely a 1:41 in the car as is, and realistically with the suspension issue sorted a 1:39 is attainable.
I’ve been trying to get to the bottom of a weird brake pedal issue: the pads feel GREAT for about 5-10 min on track, then they start getting super touchy and hard to modulate. You’ll notice some expletives braking into T1 right at the start of Lap #7. I’ve been logging ABS intervention, ESP intervention (because even with everything “full off” it still comes on), and a “brake overheat” flag that gets sent out by the ABS module. You’ll notice that brake pressure spiked a bit higher - I’m fairly sure I’m not just forgetting how to slow down partway through the session - I believe it to be some kind of intervention going on.
If you go through VCDS under “advanced measure values”, you’ll see that you can view individual wheel brake temperatures. It is important to note they are modeled temperatures. Which means as soon as you throw track pads on (that work better and stand up to heat)… the model is instantly full of bad data. I THINK there is some funny business going on, but I need to figure out the PID addresses of the temperatures to see what they actually are while driving. I have so far only found the PID for the brake overheat flag itself, though I suspect it is primarily used for disabling XDS (if it were on in the first place, mine is disabled). There is also some VW documentation I stumbled upon for something called “brake overboost” - which is one of the adaptations that can be performed on our cars:
This is something I had wanted to test at VIR back in July, but other issues did not permit me to do so. I ran all 3 sessions with “overboost in brake system” disabled via VCDS, hoping it would fix the issue - but unfortunately the problem persisted.
Based on nobody else really having this exact issue of mine, I think it may be the Ferodo DS3.12 front pads just being way too grippy for the V730s. Ferodo’s mu graph does not show it getting any grippier with heat, but I think a combo of the tire grip going away and the brake pads continuing to grab hard just makes them harder to module. I might be trying a session at VIR Oktoberfast with the ABS fuse pulled just to rule that out entirely, though would prefer to keep the ABS functional in general.
Eventually I’ll be using my CAN bus sniffering software to go a LOT deeper into all these brake adaptations, but it’s been hard to do with other priorities.
Moving on: The 3rd and final session of the day was probably my most fun - playing with buddies in traffic and I also had a friend riding passenger so he could make the most of his final session when the time came.
Due to the weirdness in the suspension, I did actually throw my GoPro on the door to watch the RF wheel while driving - it’s in the picture-in-picture video above, but if you watch it at full size it is immediately obvious of just how much everything is moving with suspension travel. It might not be as bad when lowered, but I have a friend with these ball joints on a lowered Alltrack that I intend on running the bump steer gauge on at some point in the future to verify.
You’ll see it most visible going over the “ski jump” steering wheel is straight but wheels visibly toe-in on droop and toe-out on bump. If you open in Youtube you can look at the description for the exact time stamps.
And lastly: The MK8 PCV valve worked great! Had zero issues with smoking, EPC lights, etc all day. Did not get any excessive knock except for ONE instance - which I’m 98% sure is “false knock” due to hitting a curb at the same time. Data and video going over my findings and comparing to past problems are here:
Next step is to experiment with a “full retrofit” of the MK8 valve by installing the 034 TMD with pressure going to the Tiguan venturi as outlined in the PCV video #6 before I leave for vacation next week. As soon as I come back I’ll be going over the car to inspect everything, reinstall the OEM ball joints, and get it ready for VIR Oktoberfast with NASA.
