VIR with TSCC: Feb 2023
Couldn’t resist - finally added some power with a tune
Over the winter, changes to the car included:
H&R 26mm front sway bar was added (already had the 26mm rear installed)
BFI “solid” LCA bushings (rearward position)
Superpro poly LCA forward bushing (figured I’d replace while in there)
Heat cycled out RT660s were replaced with 245/40R17 Kumho V730s
8 Bit Performance ECU tune (very conservative “stage 1” custom tune: 23psi tapered to 16 at redline)
Motul 600 fluid was flushed out to be replaced with Endless RF650
I decided I'd try something a bit different this time and got some Endless 650 fluid. The Motul 600 has never been a *problem* except on my very first HPDE (had to bleed after first session as the pedal sank - I chalked it up to an air bubble in the ABS module that got released when engaged on track)... BUT something I have noticed the past several events is after multiple HARD laps on day 1, the pedal would get just a BIT lower. Like maybe 1/8 to 1/4in lower before it initially engages. It never degraded beyond this point, but it's something I just didn't really like. This brake fluid is basically a test to see if the fluid is the cause of it or if there may be something else going on.
I have read about some others [on Porsche forums] having a similar problem with Motul 600 and it being fixed after switching to something else. I still wouldn't hesitate to run Motul again if I needed to. It was between Endless 650 and Castrol SRF... I chose the Endless because it comes in metal bottles (which preserves freshness considerably longer), and also in 500mL bottles vs 1000mL for the SRF. It’s generally advised to toss open brake fluid bottles after a month or so.
As far as changes to the car: here were my subjective thoughts on how they performed:
8 Bit Performance tune: Fantastic. No issues with overheating (I believe 255 maybe 260F was the most I saw all day on oil temps). +10mph or so vs stock on the straights... perfect.
LCA bushings (solid rubber TTRS rear and Superpro poly front): Probably helped but it's subtle.
Kumho V730s: I was not a fan of them. They got greasy relatively quickly every session. I'd get maybe one hard lap in and they started pushing because they're just done. They were *fun* to drive on, they squeal a lot to tell you when they're angry, etc. In the rain they suck if it's standing water. I drove 55-60mph the whole way home in the rain Sunday. This may have been due to not being able to heat cycle the tires prior to the event. See below.
26mm H&R FSB (paired with 26mm RSB): Fantastic. Did not make the car a pushy mess, at least not on the first couple laps each session (see tires above). I do wonder if perhaps the additional front rate was putting too much heat into the outer front tire... Or it added enough grip due to now less camber loss that it's generating more heat in the outside front? Check out the post Thoughts on Front and Rear Sway Bars for more on that.
Endless 650 brake fluid: Fixed my problem of the pedal sinking halfway through a session. Perhaps now that I could be harder on the brakes I'm also putting more heat in the front tires? I know after a cooldown lap, by the time I got back into paddock my front rotors were seeing a bit over 800F... meaning much higher in use. Rears were at 350F by then. [Note: These rotor temps were indeed WAY off - check out the article Performance Pack Brakes on Track where I later used temp indicating paint to see how hot they’re really getting].
About 2 weeks prior to the event in early February, I broke my left foot. DSG for the win right? Despite the pain hobbling around paddock, as always I had a great time at VIR with TSCC.
I set a new personal best (video at the top of the page - 2:14.97). Some of the speed came from the tune of course, but with the tire change from RT660s to V730s, lateral grip was definitely down overall.
The V730s really need a good scrubbing in (get FULLY up to temp, approx 180F tread temp followed by a cool-down with no use for 24 hours) prior to delivering optimal grip, which unfortunately I just did not have time to do. My average corner speeds through most of the track were down compared to December on the RT660s. In this case most of the time drop came from the tune - approximately 0.3 sec on the bridge straight, 0.5 sec on the back straight, and 0.5 sec on the front straight.
Most of my non-straight line improvement came from an 0.4 sec drop through the esses + 0.1 sec through South Bend despite the tires, and an 0.2 sec improvement through Hog Pen. The remaining 0.3 sec of improvement came from a bit here and a bit there on track.
The only other thing worth mentioning at this point is that the car was now burning a bit of oil on track - approx 0.5 quart total over the entire weekend. Negligible and was somewhat expected.
Here are a few other highlights of the weekend:
So what does the car need next? More camber. It could use some more front end bite, plus will help further with tire wear since it is still wearing the outside edges. Experimentation also needs to be done with the front sway bar settings - it was kept on “soft” for the entire weekend.
