This past weekend I had the pleasure of taking my RCF to MSR, just south of Houston, TX. MSR is a 17 turn 2.3 mile road course and this particular event was held by the Porsche Club of America (PCA). It was a 2 day event and each day consisted of 4 25 minute sessions with an instructor on board. My car is completely stock with the exception of the brake fluid, which was flushed and filled with Motul RBF600 for the event. Tires are stock Michelin Pilot Super Sports.

Driving Impressions:

I left the car in Sport S+ with the TVD in track mode. I didn't really know what to expect out of the car since this was the first time having it on the track. Overall, I was pretty impressed with how the car performed throughout the weekend. I could definitely feel the weight and heft of the car though. On the street, I have never felt the car was too heavy, but on the track you definitely start to notice how a weight diet could really make this thing shine on the track. Same goes for the suspension. On the street I find the suspension to be on the firm side and extremely tight, but on the track, it feels a bit soft. Although this is expected out of pretty much any street car unless it's a purpose built car (GT3, ACR, etc...)

I left the transmission in auto mode as I was curious to how it would perform in Sport S+. I loved the auto blip downshifts as I came hot into the corners. One annoyance was the kick down switch in the gas pedal. The key on corner exit is linear and smooth throttle application. This was a bit difficult when the kick down switch in the gas pedal almost acts as an on/off switch. There were times when I was on corner exit and would get into the throttle and the car would unexpectedly downshift, obviously not ideal for smooth and linear throttle application. Also, the transmission would sometimes hold gears longer than other times even if it was through the same corner or section of the track and carrying the same speed. Sometimes it would hold the gear at 6500 rpms, making throttle application very twitchy mid corner and other times it would upshift mid corner, unsettling the car just a tad. I don't really fault the car for this though, obviously it could have been alleviated by using the paddle shifters in manual mode. This would have allowed me to have control over the transmission and to be sure I was in the right gear when needed and to avoid unexpected downshifts/upshifts. Regardless, while still learning the track I felt more comfortable leaving the car in auto to focus more on the driving line rather than shifting.

I also left traction control/VSC on. Again, I wanted to familiarize myself with the car and track rather than turning the safety nets off since I have not driven the RCF in these extreme conditions before. The VSC/TC seemed to work great. I never felt it intervene prematurely or cut power when it wasn't warranted. The intervention was very minimal and in fact it probably helped my lap times rather than hurt them. A few times on corner exit the tail end did come out and the VSC/TC reeled things back into control but not in a violent or unexpected way, it just simply helped the car get straitened back out without the fear of over correcting. I suspect that maybe the TVD also helped keep things in check which prevented the VSC/TC from having to work a whole lot.

The brakes were fantastic, really no complaints there. The track had relatively short straights so the fastest part was probably about 125mph but I did not notice any brake fade. Again, I'm on OEM pads with Motul RBF600 fluid.

Overall I was very impressed with the car. For a car that is so enjoyable on the street, the list of shortcomings on the track were minimal. I was in the novice group so obviously there wasn't a lot of experience there, but I passed cars that should have much higher track capabilities than the RCF (GTR, Turbo S, 911's, Cayman's, Viper TA, etc.) It is extremely rewarding when you are going through the corners faster than cars of such caliber. The RCF gave me a lot of confidence that I could push and push the car and it never missed a beat. My next time around, I will probably put the car in manual mode and use the paddle shifters and might venture to put the car in "expert" mode, turning off the VSC/TC. Tires are still in decent shape after the weekend, I could get another full track weekend out of them with some street miles in between. I will however be upgrading to Michelin Pilot PS4's in due time. Just a fun fact: I averaged 6mpg for the weekend and burned a tick over a 1/4 tank of fuel for each 25 minute session.

 

Great writeup. Enjoyed reading it. You might want to use manual mode and aggressively downshift before every turn. I find auto mode to be too unpredictable and it locks up the torque converter only in manual/sport+ mode.

Quite a lot of the softness you mentioned, is the car rolling on the sidewalls under high lateral-G loads. It will reduce a lot once you get some aggressive tires with stiff sidewalls that will be more resistant to sidewall flex under lateral loads. Something like XL rated version of Pilot Sport 4S in 295/30 rear and 255/35 front is what I am looking at. I usually inflate the OEM MPSS up to 39 psi rear and 36 psi front and the rear is like hockey puck even at high speeds.

 

Yea, next go around I will definitely use manual mode. Having that predictability should help smooth things out a bit and make for some cleaner laps overall.

I did check my sidewalls between sessions and wasn't rolling on the sidewalls so at least the tires weren't flexing too much. Cold pressure was set about 33-35 and heated up to 39-40 on the track, it seemed to be an ideal pressure. Once these MPSS tires are shot, I'll go with the Pilot 4S.

 

That is interesting. I have only done spirited driving on streets so I take you know better about the behavior on the track. One of the things Lexus said for the 2020 RCF-spec Michelin Pilot Sport 4S was that the sidewalls had been broadened/strengthened quite a lot and I have read it definitely is an improvement over our stock Super Sports.

 

Yea no doubt the 4S will be an improvement over the PSS.

 

You were spot on; if, you were hitting 125 at MSR in an RCF. I have only approached that a couple of times and I came in too hot to settle for the rattlesnake; missing the line for the next four corners. Yes paddle shifting will make you think you are doing something; but, your laps time will most likely go down. I gave up trying; the car is smarter than l am. 275s on the front make a world of difference in the handling. Your pressure was appropriate from my experience and what various coaches have suggested to me. I was at Eagles Canyon for my second open track day there on the 14th. It's another great Texas track. I cannot say which I like better. I only go to MSR for 3.1 days now. I am jealous of you Texan living so close to several great tracks.

Regards,

Bret Travis

 

I am surprised you feel that way. From my observation, maybe because I have driven only manual for 18 years and do my own heel-toe/rev matching, I find the auto mode leaves you in the wrong gear coming out of a turn more often than not and it takes a second or so for it to discover you are full throttle and need a lower gear. I always downshift to 2nd or 3rd in the braking zone/corner entry depending on how fast the turn is and then with a wide rev range and long gearing, carry the whole turn in that gear in high rpms then have instant power available as soon as I go full throttle out of the turn. If you lift off the throttle mid-corner, the auto mode might upshift and then going full throttle out of the turn, it will take a second to realize it needs to go back down.

Also, the auto mode does not have the torque converter locked, which causes some slippage (slushbox feel). Manual mode in sport+ locks the torque converter with the head snapping shifts.

 

Yea, we were running counter clockwise and my fastest section seemed to be on the back straight before going into the sweeper. A couple of the corners I feel that I was pretty much at the max of the cars capabilities (was holding 73mph through the carousel) and a few of the corners I need to work on being more consistent with the line and smoother transition between the tight corners. I was definitely turning quicker lap times than any else in the green (novice) run group.

 

While holding high RPM's might be best for some corners, there are other corners that you definitely don't want to be at 6500+ RPM's while going through them. For instance, the carousel. It's a very long corner where you have to hold a smooth line and minor throttle inputs are needed to correct your line. At 6500 RPM's, the car would be way too twitchy which you don't want when you're at the limits of adhesion and close to 1G. It's best to use the broad powerband and lay into the throttle progressively. As you straighten the wheel, you continue to give more throttle input. So for example, that corner is ideal at about 4,500 RPM's and then you still have plenty of revs to use as you progressively come out of the bend and into the straight. And also that way, you don't require another upshift before you're all the way straightened up.

But yes, once I get more experience with all the other aspects of driving on the track, using the paddles could be beneficial to give that extra control and confidence that the car wont unexpectedly upshift or downshift . But until I get more practice, auto mode would probably still be faster, allowing me to concentrate on other areas I need work on rather than shifting.

 

Yeah, agreed you don't want to be over 6500 rpm feeding in the throttle through the turn because it might be a bit too twitchy and also powering out, you would hit the rev limiter very quickly as it covers the last 900 rpm to rev limit quickly.

Though, I like to have the car a bit twitchy through the turn at higher rpms as it inspires more confidence to go through the turn because it allows stronger lift-off engine braking, which is more instantaneous. Luckily, this engine at 5500+ rpm gives more than enough throttle response/engine braking.

My general rule is if I pretty come to almost a stop before the turn like a switchback etc., I go down to 1st gear and then power out (can get the tail out easily). If it is a slow speed turn then I would go down to 2nd gear and anything above 55+ mph (around 5600 rpm), I would use 3rd gear. What mode are you using for the TVD?

 

Lifting mid corner on the track can also cause a spin. I know what you mean tho on the street, it's nice to feel the sharpness and responsiveness of the car when you're that high up in the RPM's. On the track tho, smoothness is key. Keeping the chasis settled and balanced plays a big role.

TVD was in track mode the whole time. I plan to do an AutoCross soon and will put the TVD in slalomn mode for that event.

 

Maybe, I will make a video next spring to demonstrate it through a fast, long sweeper.

You are right, if you lift it enough to upset the balance of the chassis. Just light modulation of course and not lifting off entirely (TVD also only works when you are on the brakes or on the throttle) I find makes the nose pointing a lot easier especially when going through a turn fast. It is a psychological thing in my head where having that high rpm steering and throttle response gives me more confidence in pointing the nose and that if the nose does not follow where I need it to, I can always do a slight adjustment through throttle.

The flip side of which makes me feel nervous, but it could be because my perspective is from the streets where there are more narrow and have curbs etc. You have experience on the track so I don't pretend to put myself in your shoes as on the track as the mindset is different it since there is so much width available to work with.

 

That GT3 is beautiful!

 

I'm not a fan of VSC on the track. I road raced motorcycles long before I went to the track in a car, and found out the VSC will let you do impossible things at the expense of your brakes, even as a novice. It will also make car placement precision very difficult in some circumstances. I left it on my first track day, lost my brakes (Carbotech XP12s) in the last session of the day, and turned off VSC the next day only to find out the sweeper I was flat pedaling through could only take half throttle without VSC. But again, I came from two wheels, and being hard on the gas is pretty standard with bikes.

Don't believe you beat those other cars. You beat those other drivers. My second track weekend I was easily chasing a GTR. The next year after getting out of the green group, a GTR passed me like I accidentally found reverse. It's not the car, it's the nut behind the wheel.

Tire pressures on the track are usually right in the range you mentioned. You're typically looking for 40 - 44 psi hot.

Your tires look surprisingly good for OEM alignment. Still lots of outside shoulder blocks left.

AFA lifting in a turn - if you are in manual mode you use it to transfer weight to the front. Not a full lift, but just enough to plant the nose and minimize understeer. These cars have strong understeer designed into them at every possible juncture from the factory, so knowing when and how to lift to weight the front is invaluable.

Last but not least, just when you think you've found the limits of your car, someone blows past you mid-corner and shows you there is still a lot to learn. AMHIK.