Porsche Test & Tune

Table of Content

 

Porsche Test & Tune! INTRODUCTION

As a shop owner, I always feel the need to continue my own education on set-up, mods, etc. as they pertain to street cars that will see spirited drives and/or track conditions.  The latest test mule is a 2019 Carrera T in Miami Blue.  From the factory it came with carbon buckets, a manual transmission, and the simpler, lighter 2-wheel steering.  No sunroof or luxury add-ons other than the Carrera T full leather interior, which I do love!  The original owner added a 91 Octane APR tune (450hp) and H&R lowering springs.

Here she is, outfitted with the Vossen wheel set that came with the car along with the factory wheels.

Blue 2019 Carrera sports car with Vossen wheels parked on the road

From this base set-up, I initially set out to test its capabilities and see what (if anything) would be needed to turn it into a reliable and fast weekend track car without compromising it’s abilities as a daily driver.

My first answer came on the 2,850 mile drive to Ft Lauderdale, Florida (it’s new home) from Hermosa Beach, CA.  The front tires went from nearly new to garbage by the time I reached Gainesville, FL.  Check out the inner cords here:

garbage tires with inner cords showing

This is a tell-tale sign of a bad alignment, specifically toe.  We pulled off the Michelin 4S tires, installed a new set of Michelin Sport Cup 2s onto the factory Sport Classic rims (which I prefer cosmetically), and made the necessary changes on our Hunter Hawkeye Elite alignment rack. Here is a shot of the before and after:

Porsche alignment chart

Knowing the car would be asked to perform on the track, we wanted as much camber as possible from the stock suspension.  We maxed out the front, gaining a little more than most factory set-ups due to the lowering springs.  We then matched the rear camber to the front.  Potentially there is more negative camber available in the rear, but we wanted a more balanced set-up for initial testing.  Toe up front was set to be neutral, with a little toe in for the rear to promote stability under braking.  (This car will see a lot of time at Sebring).

The alignment changes were immediately apparent even on the daily commute, the front end was now behaving as a Porsche should.  But could the ride be even better?  And would the smaller brake package borrowed from the base Carrera really hold up to track duty?  A visit to Homestead Speedway would answer those questions.

For the brakes, we outfitted the car with Endless ME20 racing brake pads and did a complete brake fluid flush with Castrol SRF.  This was my first time trying Endless pads, but we chose them as they have a reputation to be relatively quiet on the street and we were hoping to find a pad that we could leave on the car all the time and not have to make changes before and after the track.  SRF is a long time favorite from my competition days and next to a good bottle of bourbon, it is my favorite fluid on the market.  Seemingly impossible to boil.

For the ride, we wanted to test the DSC V3 suspension controller, which has had rave reviews but we had yet to experience its effects first hand.  Our plan was to run two sessions with the stock controller, and then run 2 more with the DSC installed so that we could have back-to-back, same day driving comparisons.  I’d also have the one hour drive in the morning on the stock controller and the 90 minute drive home on the DSC to test its road manners.

Testing did not go as planned.  With my most recent track experience being in a Porsche GT4 outfitted with PCCB (hand of God stopping power), I cautiously explored the braking points of the Carrera T on the first couple of laps.  By lap 3 I felt I understood 95% of the feel and began to push harder.  Unfortunately, as I exited T12 I caught site of a black flag displayed in T13-T15 complex, which required me to immediately dive into pit entry located between T12 and T13.  Sitting parked at the end of pit lane waiting to go green again, the smell of burning brakes wafted through the cockpit.  I momentarily thought about the lack of a cool down for the brakes, but I’ve experienced many black and red flags over the years and it’s never presented an issue.

This time it did.  Back on track under green, my first push on the brake pedal sunk softly to the floor.  WTF!  Everything was perfect before the black flag.  I pumped up the pedal and proceeded cautiously, trying to troubleshoot, but it was evident by the time I made it to T6 that the brakes were cooked.

Sitting in the stagnant 93 degree heat without a chance to cool down caused immediate failure.  Did the pads glaze, fluid boil, or a combination of the two?  Would the stock brakes and Endless pads been just fine had it not been for the black flag?  I’ll never know.  But I do know that these events, while uncommon, do happen and I need a system that can survive the worst case scenario.  A change will be needed.

Knowing the brakes were compromised and testing would be limited, I quickly swapped in the DSC controller for the next session.  Heading out the brake pedal felt OK, so I went a little harder then before, but again with caution.  Sure enough, 3 laps in the brakes were gone as they never fully recovered from the morning session.  It was enough to form some initial impressions of the DSC though – in a word, fantastic!  Most evident was how the front end dive under braking dramatically improved.  With the chassis better balanced, it allowed for better trail braking towards the apex and a smoother brake release.  Through the higher g turns I could also feel the firmer settings on the outside corners, reducing body roll.  More confidence in the chassis resulted in more speed.  It was  quick test, but VERY happy with the change.  This was further reinforced on the drive home, where Normal mode felt more relaxed and comfy over the congested and torn up highway connecting Homestead to Ft Lauderdale.  Highly recommend mod!!

Go Big or Go Home

There are three general paths to improving the brakes on the base 991/992 Carrera:

1) Upgrade rotors to 350mm, preferably with a floating design

2) Source front calipers from the Carrera S, in addition to upsizing rotors

3) Get a Big Brake Kit, changing rotors and calipers on both axles

As the teaser pic indicated, we equipped the Carrera T with the AP Racing by Essex Road Kit. But in addition to the supplied Ferodo DS2500 pads that came with the kit, we also bought a set of DS1.11 pads. The former for the street, the latter for the track.

The right choice depends on a lot things, skill level and budget probably being the most important. While each rung up the ladder is more expensive, there is also an argument to be made that step 3 could be the cheapest. If you are committed to the sport and know you will keep improving, lowering lap times and stressing your equipment then it will ultimately be cheaper to equip yourself for the end game rather than upgrading 3 times.

I also have a bit of a brake fetish. IMO, it is the single most controllable variable when it comes to car set-up and performance. Sometimes you get the set-up wrong, tires can go off, your gearing might not work on a particular track, etc. but with the right equipment your brakes can and should perform exactly the same every time. Achieving repeatable events, every corner with zero fade is the goal. The only change in your braking should be due to changes in track conditions or tire wear. It’s a wonderful feeling as a driver when you don’t have to think about that variable and you can focus on other things.

The kit arrived quickly and it was impressive, even just sitting in the box. The level of quality and attention to detail is evident everywhere, and the only additional thing you’ll need to complete the install is fresh brake fluid.

Here are a couple of beauty shots, one showing a corner installed and the other a profile view of the new brakes wrapped by the factory wheels.

We also took this time to check the total weight and corner weights of the car with the new brakes installed.  Total weight came out to 3,165 with half a tank of gas.  In theory, this should equate to 3,114 on an empty tank (using 6lbs per gallon).  While we did not weigh the before and after of the brake package, research seems to indicate that the bigger brakes add 16lbs.  Interestingly, Porsche’s published weight for the car was 3,142 lbs.  Factor in my carbon bucket seats and IPE exhaust, and I’d say these figures are exactly as anticipated and probably on the lighter end of the 991.2 T spectrum without specifically going after weight saving mods.

The corner weight results were even more exciting.  After the total weight was gathered up, I got in the car (street clothes, no helmet) and measured the corner weights.    The rear weight was just under 62% and more importantly, the cross weight was a near perfect 49.7%!  No additional corner balancing necessary!!

The excitement of testing her at Sebring is really starting to build now ….

Final Test Day Prep

The final prep for Sebring included a full brake fluid flush, including the ABS module.  Normally this is not necessary, but doing so allowed us to eliminate any potential issues that could be lurking in a car that was still new to us.  The current factory procedure flushes the ABS module, the lines, and calipers in a single step by applying 29 psi of pressure to the fluid reservoir and using the PIWIS to activate the internal ABS pumps.  It’s an interesting procedure as the car makes some really loud grinding like sounds and spits fluid out of the bleeder valves like a broken sprinkler head.  While this is happening you have to manually pump the brake pedal and watch the PIWIS as it gives you a countdown timer on each corner.  If I remember right, the shortest time was about 30 seconds on a corner while on the RF it called for a full 2 minutes.  It was a good leg work out.  You go through a ton of fluid doing this, so I do NOT recommend using SRF.  Just too expensive as most of it will get wasted.  Thus we made the switch to LiquiMoly Race Fluid.  We are huge fans of everything LiquiMoly, so while not as good as SRF, we were confident this would get the job done for our upcoming test.

The Ferodo DS1.11 pads were installed and bedded in on the street.  My initial impression was that the torque upon initial tip in on the pedal was a bit weak, but then felt strong and linear throughout the remainder of the range.  There was absolutely no brake squeal on the street, a pleasant surprise for the 2 hour and 15 minute drive to Sebring.  And I am pleased to say that my criticism of the initial bite went away after a proper warm-up and bedding on track.  Once the rotors were properly coated and up to temp, they felt great!

Lastly, we suffered through horrible wind buffeting in the cockpit during the short test at Homestead.  We remedied this by installing Blackmill Performance wind diffusers, so this would also be tested at the track.  Installation just took a few minutes and the fit is decent, some small coverage gaps over the factory triangle that only I would notice since I did the install.

Track day impressions are next, I promise ...

 

Track Day Success

I LOVE this brake package. So much so that we are now a dealer for the product. First and foremost, absolutely no issues with heat management on a 93 degree day. Repeatable stops every single time, no exceptions. Torque was a little lower than what I am use to and what I prefer, but they communicate extremely well and make trailing off the brakes easier. This last part is exciting, because as you get into top end of the performance spectrum, more time is actually found via brake release as opposed to late, threshold braking. Of course we want to do both, but most people master the late brake before the early brake release. I think the excellent feedback here will help a lot of drivers trail in, release early, and carry more speed through a corner. Can’t wait to get more seat time with this package and work on this myself!

Track conditions were poor. Lots of rain the previous days washed away the rubber and gave us a very green surface. Additionally, it started hot and got hotter very quickly. The morning session was already over 80 degrees and by the third session it was into the 90’s, so a progressively worse track as the day progressed. I went to the track with a customer so that we could have some comparison points as well. He is a very good driver (instructor level), driving a base 992 with upgraded turbos and a mild tune (more power than me), and a mild brake upgrade consisting only of 350mm floating rotors and race pads. Here is the blow by blow:

Session 1: Lots of acceleration/hard stops to warm up and continue to bed in rotors. By the end of the first lap I could feel the brakes coming to me and as mentioned earlier, now had a hard pedal immediately upon application of the pedal now. From there I began my normal, cautious progression with a new car/new brakes to find the right braking points, getting shorter each time. Got faster by about 2 seconds a lap for a few laps, knocked off a couple of consistent laps, then pushed harder again for the last 2. Ended up with lap times maybe a little slower than the 981 GT4 given similar conditions. Very encouraging given that I wasn’t really pushing! Also recorded the top speed for the day (144.2 mph) since rising temps would continue to zap power as the day progressed. Wind buffeting was nearly completely gone, thank you Blackmill Performance!

Session 2: Best lap was about a second faster than previous best in the GT4! Let me say that again, this entry level-ish 911 beat the Cayman built by the GT department. With bad track conditions. Something about this chassis just agrees with me. I got in synch with the car, we both started grooving, and I knocked off 5 consecutive laps with a variance of just 0.12%.

Lots of credit goes to the brakes which ALWAYS felt the same every time I touched the pedal and to the DSC controller which seemed to brush off the bumps at Sebring as one would blush lint off their shirt. Completely neutral handling with the mechanical grip on-hand, which clearly was camber limited. When a car feels this good you stop thinking about the equipment and just drive. Then the speed just materializes on its own.

Session 3: Sweltering heat so the track was probably about a full second slower than the morning session. Still lowered the best time of the day by another 0.8 seconds. The improvement this time came from me managing the power better. Most of my experience is in high rev’ing NA cars, so having power at 1900 rpms is a new experience. In session 2 I was still a little timid with throttle application, not knowing if street tires with limited camber would handle the rapid acceleration. In this session I got more trusting and playful. The data shows I still left some on the table, so can’t wait to go again!

Speaking of data, max deceleration at Homestead was -1.13 g. That was stock brakes with Endless ME20 pads. Max deceleration with the AP Racing/Ferodo set-up was -1.31 g. That’s a 16% improvement that you absolutely feel in the car and see on the time sheets.

Next up … data analysis versus the customer driven 992

In God I trust, everyone else bring data

White Line: 991.2 T, APR Stage 1 tune (est. 450hp), AP Racing brake kit, manual tranny (my car)

Blue Line: 992.1 Carrera, upgraded turbos and tune (>450hp), GiroDisc 350mm rotor and pad upgrade, PDK tranny (customer car; experienced instructor level driver)

This is a NON-SCIENTIFIC look (different cars, different drivers, etc.) that should not be taken in absolute terms, but instead simply a directional look at how our car/driver combos perform relative to one another. Both are our best laps on the day, with mine being 1.3 seconds quicker.

Speed Trace: I am braking later and shedding speed faster. In some corners we reach the same terminal speed, in others I seem to roll a little more speed. His rate acceleration is better than mine, and in some corners he also gets back on the throttle sooner than I do. My manual upshifts are evident versus his PDK upshifts.

Accel GForce: The bottom shows peak negative G’s under braking. I’m consistently better, with a best of -1.3g on this lap. His best was -1.25, but with a lot less consistency. Most corners peaked below -1.13g, which interestingly is what I saw on my car at Homestead with the base set-up. When we spoke, he confirmed that he had trouble putting together full laps at max braking and even more trouble trying to string together consecutive laps, much less a full session.

Corner GForce: Used in conjunction with the other graphs, this helps illustrate our different driving styles. I tend to brake and turn in later, utilize trail braking to rotate, and carry more corner speed. The 992 is squaring off the corner more and jumping back on the throttle before I am. What I like about this is, looking at his graph, is that I think I can do what I am doing AND jump on the throttle sooner like he is. That will make for a nice lap, so I have something to shoot for next time out.

In sum, a great day that really validated how good this brake package is. As mentioned, I was impressed enough to set the shop up as dealer and we will be equipping the customer’s 992 with the same package soon. Props out to AP Racing and the team at Essex, they were great to work with as we worked through the various options for our test mule!

As a final note, once back at the shop we installed the DS2500 pads for the street. Did not have an opportunity to bed them in, so just drove. They worked great right out of the box. The pad material mated well to the racier compound, they grab at all temps and so far, are completely silent.

IMPROVING SAFETY

After so many years piloting fully caged, purpose built race cars I am now trying to learn to adjust to the compromises and challenges that a dual purpose car presents.  Not having a cage, or even a roll bar is new.  As is a 3-point belt and lack of a head and neck device.  With the Carrera T being built to be primarily a road car I did not want to install a half cage/roll bar.  However basal skull fractures really suck, so I did want to come up with a solution that would allow me to add that protection back into the mix.

After considering multiple options, I settled on the FVD harness bar (https://www.fvd.net/us-en/FVD58099100/fvd-brombacher-harness-bar-991-coupe-standalone.html) and the Schroth 4 pt belt designed for the Porsche LWB seats (https://www.schrothracing.com/item/porsche-belt-for-carbon-seats/tuning-Harnesses).  The bar is very sleek in a you hardly know it’s there kind of way, and likewise, the 4-point belt installation will also nearly disappear when not in use since there won’t be a sub strap coming up through the seat.

The harness will also allow me to use existing head and neck restraints I have on hand.  While I preferred the Hans in the race cars, I found that the back it too large to be used with a Porsche LWB seat.  It hits the headrest and forces your helmet forward.  The solution is the Necksgen Rev 2 Lite, which I previously used in my GT4 dual purpose car.  The picture shows the size differences.

Install process is next …..

INSTALLING THE HARNESS BAR

If you are no more than medium sized, fit and limber, this job can be done with the both LWB seats in place.  And if you install the harnesses as I did (more on the later), there is no need to remove them for that either.  So I made the decision to leave the seats in place and did the job crawling in and out of the back seat as needed.  And thankfully I can confirm that no humans were injured during this process.

Step 1:  Remove the rear most carpeted section immediately under the glass.  It pulls straight out.  Then pop the trim pieces off the rear luggage shelf and fold the big carpeted piece in the middle and remove that as well.  A tip from another Rennlister advised that the side interior panels could be left in place, so that’s it for interior removal!

Step 2:  Install the vertical brackets over the threaded bosses in the floor.  You do this by slipping the brace behind the interior panel on the side and the bottom falls naturally into place.  Hand tighten the provide bolts to hold it in place.

Step 3:  The top of that brace with the threaded hole should now be directly behind the interior panel where there is an indented circle marking the location.  You can feel where the bolt hole is behind the panel and how it lines up with the circle.  It is nearly dead center and provides a great template.  This is the only permanent modification – you have to drill a hole through the circle for the bolt to go through.  I used about 5 different bits, very high quality bits, slowly increasing in size until the bolt would pass through.  Happy to say that my full leather interior panels did not fray in the process!

Step 4:  This turned out to be more difficult than anticipated!  You now slip the harness bar over the rear strut tower bolts and position so that the top lines up with the holes you just drilled.  The surprise was that the tolerance is so tight on the base plate that it didn’t want to just slip over the studs.  It was a wrestling match.  I eventually ever so slightly drilled one hole a little larger and then tapped it down with a small hammer.  Then once over the studs you can tighten the bolts over the studs to push the base plate all the way down.  BUT … doing so changes the location of the top bolt hole.  This then becomes an iterative process of moving each side up and down until everything lines up at the top of the harness bar.  You’ll want an electric or air powered tool for this with a 13mm socket, not a rachet.  There is a lot of back and forth to get it right.  Here are the strut tower studs.  You use the 2 studs closest to the front of the car.  You can also see the circle that I referenced earlier in this photo.

Step 5:  Wedge the included spacer between the bar and the interior panel and then slide the included bolt through the bar, spacer, and interior panel so that it can be bolted to the brace hidden behind the panel.  I used a skinny punch to line everything up and you can slide your hand behind the panel to feel the punch going through the bolt hole.  For me, one this was done the bolt still struggled to make it through.  Everything was lined up so I surmised that the hole in the panel was off just a hair or slightly too small, so I drilled again with everything all lined up and this cleared the path.  Bolt then went in like butter.

Step 6:  Until this step the bolts should have been left fairly loose.  Now torque everything down and install the carpet.  You are done!

Up next … the harnesses

ATTACHING THE HARNESSES

The Schroth belts I purchased were designed specifically for the Porsche Carbon LWB seats.  The lap belts come with hardware attached that allows you to secure them to the same bolts the stock seat belts use, thus securing them to the steel seat base.  The harness buckle is of the push button variety (required for NHTSA approval) and attached to the right-hand side lap belt.  What I don’t like about this set-up is that when you are on the street using the 3-point belt, you must drape the harness buckle over the side of the seat to get it out of the way.  At a minimum that will make noise as it swings around hitting the seat and center tunnel, and at worst could potentially leave a mark on those parts of the car.

I solved the issue by modifying the right-hand side lap belt.  I cut off the attached hardware and installed a seat belt receptacle in its place, securing it properly as you would to a roll bar.  This allows me to plug that lap belt into the seat belt receptacle when at the track and completely remove it when I am on the street.  As an added bonus, because I am using the seat belt receptacle on track, no annoying messages from the car saying the driver is not belted in.

And oh by the way, no need to pull the seat out of the car to do this.  😊

The shoulder belt installation is pretty straightforward.  Make sure they are crossed at a 20-25 degree angle and use the collar locks to keep them in place.  I think I got the angle right but I will fine tune once I have a proper protector in hand.  And keeping with the ethos of this being a street car first, its nice that I can simply push the harnesses out of the way when not being used and leave them resting on the back “seat”.  I’ll probably tie them up as well to make sure they don’t move around and make noise.

With everything complete, I’m planning a trip to Homestead in a couple of weeks to push the car a little harder and decide what’s next for the project!

DASH PROGRAMMING

Out of the box, there are a couple of limitations that Porsche placed within the digital dash.  The first is the Coolant Temperature, which does not display the actual water temp.  Instead, it smooths out the display so that 194 degree F appears on the dash over a very wide range of temps.  Presumably it does this so that the average Porsche owner does not freak out and call the service department when temps hit 210 or more.  Interestingly, the GT cars are programmed to show the actual temps, so I guess Porsche thinks the GT driver is more evolved.  My car, while a lowly street car, identifies as a GT car so gauge reassignment is in order.  😊

The second issue is the Turbo pressure gauge is artificially limited to 1 bar, or about 15 psi.  On a stock Carrera T that’s fine, but mine has a Stage 1 APR tune so I am pushing more than that.  But we won’t know how much more unless we over-rule the instructions Porsche preprogrammed.

To change the temp gauge I used an Autel Maxisys Ultra to change the XY mapping that controls the gauge.  X is the actual temp and Y is the temp output to the gauge.  The pictures below show how X and Y do not match from the factory, to get an actual reading all we do is rewrite the Y values so that they are the same as the X value at each stage of the measurement.

For the Turbo gauge, I used the PIWIS III.  The first step is to put the device into the Engineer Programming mode.  A word of warning, once you do this the device only speaks German.  No joke.  You then go into the instrument cluster, find the turbo section, and change the values for both Normal mode and Sport mode.  Note, the latter Sport mode makes the change for both Sport and Sport +. 

I forgot to take a pic of when I made the change, but the pic below is an example of how the PIWIS page looks and shows a Macan set at 1.20 bar.  I changed my car to 2.0 bar, which should give plenty of headroom for any future changes, should they come.  And in case you are wondering, a quick test drive down the street already revealed boost pressure of 22 psi.  This should be my current max, but will keep on eye on things during longer drives to confirm the measure.

Zunsport Outer Grille Set

Given the track visits this car will see, I decided to add some additional front end protection to the wide outer grill openings.  I chose Zunsport because of their design that does not require the front bumper to be removed.  Literally a 10 minute install and the fit it very good to excellent.  Most won’t notice it is not a factory piece.  I had previously used their product on my old 997.1 GT3 and feel like they have gotten even better in their design.  No drilling required and completely reversible.  Worth the premium over some competing products.  BTW, the T is on listed not the Zunsport website but it’s the same as the 991.2S kit.

I will say that I do prefer the factory look to the grills, but worth the trade-off for the protection.

The other concern I have, and will test, is about air flow.  I’m far from an expert, but I think it’s reasonable to assume that the grill will reduce airflow and potentially reduce the car’s cooling capacity.  What I don’t know is if this is enough to have a material impact to cause concern.  Can I still do a full day of 30 minute track sessions in S. Florida heat and humidity?  As mentioned, my stock gauges have been reprogrammed to read actual temps and I have baseline data from this summer, so keep an eye on this thread next summer for the head to head comparisons …..

Nankang CR-S v2 Tire Testing

Since retiring from competition I’ve had to reacclimate myself to the world of dual purpose tires, meaning, tires that can be driven on track but also get you there and back without a tire change. And they can also handle rain both on and off track. These tires generally fall into the general category of “200 Treadwear Tires” and have options available Michelin, Yokohama, Bridgestone, Nankang, Goodyear, Dunlop and others.

On my former 981 GT4 I had used both Bridgestone’s RE71 and Michelin’s SportCup 2 with success. With the Carrera T I have been exclusively on the Sport Cup2. Both are great tires, but both also carry a price point that can sometimes be hard to swallow. So with that in mind, I decided to test Nankang’s newest offering to see if they could compete with the name brands but at a lower price point.

First part of the test was the 2 ½ hour drive to Sebring the day before being on track. This would allow for some minor heat cycling before being on track and also give me a feel for the tire’s road manners. My overall impression was that the sidewall felt like it had a lower spring rate than the Michelin, causing a bit of bouncing with the DSC controlled PASM in Normal mode, which in and of itself is softer than the stock tune. I was not a fan of the ride, but not intolerable. But if you only had one set of wheels and intended to drive daily on this set-up, this could be a deal breaker for some.

Monday morning track conditions were dry with temps reaching the low 80’s by 10am. For comparison, my last run on Sport Cup 2s at Sebring had temps in the low 90’s, so favorable conditions relative to that run. Not knowing the correct pressures my car would like, I set cold pressures in the 25-26 range (each corner is a little different based on years of testing here) and set out on track.

The first three sessions all produced solid results, each recording a best lap about ½ second quicker than the Cup2s. Different days and conditions, but still promising. They react VERY differently to heat and pressure than the Cup2s, so I worked throughout the day to dial that in. In session 1, the front rose dramatically higher than the rear, something I’ve never seen before on any tire here. And it did so without the car pushing to cause it. Apparently, the narrower front reacted more to the heat than the wider rear. This was an overall theme – they are more sensitive to heat and pressure than a Cup2. More on that thought later. By session 4 I had a feel for the tires and knew that the tires liked a little lower pressure than the Cup2s. I made the adjustment and knocked another ½ second off the lap time from the earlier sessions despite the highest ambient temps of the day.

Day 2 had fantastic track conditions. The temperature at the start of the morning session was about 63 and the car IMMEDIATELY felt fast. The Turbos were in a happy place and the increased grip in the tires brought back memories of that magic level of grip you feel during a quali session on sticker tires. In my first hot lap of the session, I immediately bested my top time from the previous day by another 6/10 of a second. And did so in traffic, having to execute passes in T7 and T13. There was a lot more time left in this tire! Traffic did not allow me to bank anything better during the session, but sectors times showed there was a lot more on the table available. This brings me to the next observation – these tires are faster on Day 2 than Day1.

Session 2 had temps rise to 73 degrees, but still a very fast track. After warming things on my out lap I had clear track for Lap 1 and banged out the best time thus far – a 2:25.2. It was effortless and I felt I was just beginning to scratch the surface of the capabilities of the car and tires. Following that lap, I put my head down and consciously attempted to put down a flier. By T13 I was well ahead of the previous lap, a positive delta of about 7/10ths. But then, up in the distance, I saw a slower car that I was certain I was going to catch. And sure enough, I had to abandon the lap in T17 as he was sight seeing in T17 when I needed to turn in towards the apex. Thankfully, using the Garmin Catalyst, I was still able to see my Optimal Lap made up of Laps 1 & 2 – and it was a 2:23.7!! This is pretty damn quick for a street car on 200 treadwear tires and a camber-limited (nearly) stock suspension. Kudos to Nankang!

 The following laps did not reach the previous peaks, leading to my final observation – this tire is peaky, it does not sustain its grip over longer sessions as well as Cup2s. I was still consistently banging out times faster than the Cup2, just not at “quali pace”.

Tire wear across the 6 sessions over two days was excellent. Mostly even across the tire, and no significant chunking. The inside of the front showed a little feathering on the innermost tread, a result of the open inner shoulder design, but nothing significant. Pics attached.

An additional note about the tire wear. This is what your tires should look like after beating on them. I constantly see people cording tires over the same run time and it’s the result of a poor alignment, bad pressures, overdriving the car, or all 3!! If you are experiencing that problem, seek out some help and get this dialed in. It will save you a ton of money.

So in conclusion, I am certainly a fan of this tire but with some reservations. It is absolutely faster than a Cup2 for a lap or 2, but can not run laps as consistently due to its sensitivity to heat and pressure. If I were time trialing, the Nankang would be my tire choice. But over 30 minutes, the Cup2 might be more satisfying even if you won’t equal the best lap times of the Nankang. I do think I’ll gain better consistency as I lock in on tire pressures a little more, but I think my conclusion will remain sound overall. That said, a tire that peaks a second or more faster and then falls back but still remains fairly comparable, at a price point a couple hundred dollars lower might be the right tire for you!

So my plan going forward? Utilize the Nankang during the cooler months when I have a shot at fast laps and a personal best. Over the hot Florida summers when lap times will be off anyway, I’ll use the Cup2. Threat of rain, probably Cup2 but I still need to test the Nankang in the rain.

Would love to hear the thoughts of others who have run these two tires against one another …..

Nankang Tire Update and new Handling Issues

We had some cool weather this week in Florida and I took advantage of the favorable track conditions to visit Sebring again. This would be for heat cycles 7 through 10, and a test of targeted hot pressures of 32psi.

In sum, 32psi does to be the happy place for this tire. My last visit there said my theoretical best was 2:23.7, and I logged several laps there, lowering the theoretical best to 2:22.7. (My best logged laps included having to pass traffic). The cool air really helped on the power side as I hit 150mph on the back straight, something I haven’t done since I competed in the 430 Challenge. On the downside, mechanical grip was less than anticipated and the track surface itself was good, but not ideal. Some new/updated observations:

  • The Nankang is fast and peaky, nothing changed here. The rhythm is out lap, fast lap1, faster lap 2, then they fall off. Still quick, but the magic lap was consistently on lap 2.
  • At these lap times, the car is hitting it’s limit with the current set-up. The rears are rolling over a bit and I was fighting high speed and mid-speed oversteer. Turns 1, 13, 14, 16, and 17 required a fair amount of pitch and catch. The car requires a high level of confidence in your car control abilities to push towards these lap times.
  • My physical driving condition is not what it used to be! I’m only doing 6-7 track days a year these days. During season, when I competed, I did that every month. Putting in some laps near the limit and fighting/managing oversteer took a lot out of me! The data even showed my heart rate maintaining a consistent aerobic level for about 4-5 laps, and then rising and spiking as the session went on. I still work out and in very good shape, but the work outs today are different then the driving specific training I use to do and it shows, big time. For those who committed to lowering lap times, my advice is to not forget about your own physical training. I promise you’ll gain lap time and consistency – and it’s free!

Next steps for the car are to address the oversteer I experienced. I remain committed to trying to keep the car stock (for now), so I will get the car back on the alignment rack and see if there is more negative camber available back there. I originally maxed out the front (-1.9) and matched the rear to it, so I never really tested how much more was available. Based on these last results I think the car will benefit from a change, if it’s available, and can handle it without introducing understeer.

Will report back after she is racked again ….

New Alignment Specs

For this alignment, the focus was finding more negative camber for the rear. Turns out the factory adjustment gave plenty, I could have cranked it up to -3.2/-3.3 or so. Instead I took about ½ of the available adjustment and settled in at -2.6 and -2.7. I’m still siding with caution, not wanting to go too far an create a situation with understeer.

The other change was to dial in a little toe out in the front. The incoming specs seem to show that crashing over curbs had knocked the alignment out into a fairly large toe out condition. The car was quick, so why not keep a little. LOL

I’ll be at Homestead a week from today to test the new settings. A very different environment than Sebring and understeer is more prevalent here than at Sebring, but I think I should be able to get a good feel for the changes.

Hoping for the best and will report back ….

Homestead Track Day Update

This past Wednesday I was able to get back out to the track and play a little on the new alignment settings. Homestead is very different than Sebring, with fewer opportunities to test the changes that were made for high speed oversteer. So let’s call this a play date instead of an actual test. But a few observations and an update on the wear rates on the disposable items (brakes and tires):

T6 and T7 at Homestead make up a double apex right hander that tops out third gear as you hit track out. This is probably the best test Homestead can offer of the new rear settings, and I did feel a difference. In particular the left rear seemed to squat and sit down as opposed to the gentle slide I had felt in the past. This did allow for me to get back on the throttle sooner, which I later confirmed with the data I logged on my last visit here back in September. Top speed at the end of the long straight that follows was 3mph faster. Also, visually, it appears that the rears were not rolling over to the same degree. The graining I saw at the beginning of the sidewall was not evident this time. This looks like a win, but really need to withhold final judgement until I am able to get back to Sebring.

The front brake pads have finally hit their limit. I went into the day knowing the front pads were a bit thin, and for the first time I felt heat soak effecting performance. I had to brake earlier than on my last visit to compensate, confirmed by data, as I did not have full confidence this time out. Still, they made it 7 days and were absolutely serviceable and safe, but just a bit below peak performance.

Rear brake pads still have lots of life. It’s worth noting that I run with traction control and PSM OFF. Being a street car, Porsche still has it lurking in the background, but unless a decent sized error is made it does not intervene. Thus I am seeing dramatically better rear brake pad life than others have reported. The decision to turn this stuff off is a personal one based upon your own perception of its need and your own level of risk tolerance, so this is my personal choice and not a recommendation to others. 

The tires completed heat cycles 11-13 and still show lots of life left. Certainly not as fast as the first few cycles, but still plenty quick enough. Wear continues to be very even across the tread on all four corners. I will take tread depth measurements when I get her back into the shop and report back.

The nature of this event did not allow for an ultimate test of lap times, but the car was still quick. This was a Porsche only event and the Advanced group was dominated by GT cars. That said, this little T held it’s own against everything except a GT2 RS. This “base Carrera” was one of the two quickest cars on track, the other being a 991.2 GT3 with PDK driven by a guy who Club Races with NASA, a group I use to run with. We had not met before, but after driving in close quarters after the first session we had a chat, learned about each other’s experience, and built instant trust in one another. From there we basically ran nose to tail with similar lap times all day long and had a blast!! Our lap times were nearly identical, but our different driving styles made for a playful exchange, especially in the braking zones and slower sections. (I couldn’t quite keep up on the straights).

Fastest lap was a 1:38.3, and I felt there was easily another second available if conditions allowed an attempt at a hot lap. And in fact the Garmin showed the optimal lap was 137.3. For perspective, last visit there on a very hot September day on Sport Cup 2s was about a second slower. Not a true comparison given very different conditions, but these Nankangs are holding up well!

Brake and Tire Wear Rates – with Pics and Data

Yesterday I performed a brake fluid flush with SRF and switched the wheels, tires, and brake pads back over to their street configuration. In doing so, I took the time to take some measurements and pictures of the pads and tires:

Tires – Both front and rear tires measured roughly 5/32” across the tread. Maybe a hair lower in some spots but negligible. So not only are the tires wearing evening across the surface, both the front and rear are showing similar wear rates. For perspective, new from the factory the tread depth is 7.3/32”.

I’m very impressed by these results. This is a testament both to Nankang and to the set-up we have on the car. The combination of the alignment specs, near perfect corner balancing, and DSC PASM controller have worked beautifully together to create a car that is both fast and easy on the equipment.

Front Brake Pads – The front pads measured 4mm and are done. When they get this thin they simply can’t dissipate heat well enough to handle a track session. Besides heat soak, you start running the risk of the pad coming apart on you. But to Ferodo’s credit, the face of the part stayed together all the way to the end.

Rear Brake Pads – The rears measured 6mm, so 50% more pad material left, but only about 2mm of useful life. I would expect 2 more days left here and I’m pleased to see the fronts wearing faster than the rears, as a car should.

Brake Rotors – Both the front and rear rotors look fantastic! Very little veining, no grooving of any kind, and a nice linear wear rate. The rears are interesting, as you can see how the pad only makes contact with a small portion of the rotor. Truth is, the rear rotor is too big for this car and is adding unnecessary weight. Remember, this is the road kit on this car and not the competition kit, so the large rear rotor was designed for cosmetic reasons as opposed to the ultimate level of performance.

Miscellaneous Notes

The front calipers have tinted themselves gold in the middle section, a sign of the heat they are being exposed to. The parts of the caliper you can see when a wheel is mounted still look great.

I also thought it would be fun to snap a pic of the factory g-force meter. Suffice it to say this car has been driven as Porsche intended. 😊

Used Oil Analysis

I’ve used Blackstone Labs for years to monitor the health of my cars, particularly those that visit the track. So back in January I sent off a sample that had 2,772 miles of hard driving on it. The oil I used then, and refilled with, was LiquiMoly MolyGen 5w40. I also used a Ceratec additive from LiquiMoly.

I won’t repeat the report itself, but I think the big take away is we need consistent monitoring to detect trends, and we should get another read at 2,500 miles as opposed to trying to push intervals. The comparison to Universal Averages should be taken with a little grain of salt as well, as the nearly 2,800 miles on my oil were done at significantly higher rpms than the averages.

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