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Ok, Speed District Laguna track day is in the books. The weather was beautiful ~70F and sunny, but the track was extremely dusty and slippery. It was an interesting experience with the slicks, and I will post a tire comparison/notes later. Best time of the day was a 1:35.03, which beat out the R1S by a few tenths, but on a different day, no question the tires are capable of low 1:34.
Everyone's times were sliding according. Here is a short list. To note, Aleks did that 1:35 in his 991 GT3 with new Cup2s, so pretty darn fast.
Since Speed District includes free photos, here are a few action shots, just for fun.
Nice and consistent times there! What was the db for today?
Yeah, the tires were nice and consistent throughout the session. I was trying to push pretty hard, but the traction and performance was what it was. It was a 90DB day. Despite having 200CEL headers and side delete the car passes sound with the GPS box and turn down pipes.
With my season effectively over, I thought I would do a quick write up and comparison of the tires used over the last two years. This is always a fascinating topic to me, as people seem to have wildly different experiences and expectations about tires.
As background, I have done about 50 track days over the last 2.5 years, starting out as a complete newbie (i.e. Laguna times of 1:59) to being reasonably fast and consistent now (Laguna times of 1:35). My experience with various tires has significantly changed as the speed increased, and I think that is a very important factor to keep in mind (i.e. the guy that gets 50 heat cycles out of Cup2s, cannot be going very fast). Couple of other items to consider:
- The car has a very stiff mono-ball suspension and stiffer spring rates than stock (600/800 or so)
- The car has front and rear aero, which has also significantly altered the wear of tires, especially in the front
- The alignment on the car is very aggressive and not really meant for street driving
- The car has a wide front end, which allows for a much wider tire/wheel in the front; while it helps with tire heat management to an extent, it also puts more stress on the front tires as they can carry a lot more grip
- The car is pushed pretty hard on the tracks available to me; of course better drivers can extract more speed and more longevity, but I am just an amateur hobbyist learning
- The track speed and surface will also have a huge impact, so my evaluation is limited to Sonoma, Laguna and Thunderhill. All three fairly different, but none are super fast (i.e. over 150mph) or banked
With that said I will try and capture my thoughts on the BridgestoneRE71R, Cup2, NT01, BFG R1S and Michelin Slicks. I will try and logically evaluate the following attributes:
- [Longevity] - counted in heat cycles. I know this is tricky as HCs can be counted differently, but for my purpose a heat cycle would be one 20-30 minute DE session. So if I say 5 HCs, it likely means 100 minutes of driving.
- [Responsiveness] (scale of 10) - going to use this term primarily for the turn in and change of direction characteristic of the tire. Obviously primarily impacts the behavior of the front tires.
- [Grip] (scale of 10) - use this term for lateral g-loads and cornering speed. Also will try and describe cornering behavior of the tire.
- [Braking] (scale of 10) - primarily evaluating straight line braking performance. Obviously I don't have equipment measuring the exact stopping distance, so it's more of a "feel" and stability assessment.
- [User Experience/Fear Index] (scale of 10) - totally subjective, but I found each tire to have very different driving characteristics, which mentally can help you relax or can cause you to be stressed, therefore impacting your lap times.
- [Cost] - kind of self-explanatory.
Lastly I will try and describe some of the predominant characteristic of the tire (good or bad). With all that said, let's give it a go.
Michelin Cup 2
Basically bread and butter of GT3 tracking. I used these tires in the 19 inch configuration and sizing of 235/35/19, 265/30/19 and 305/30/19 and run them at 32/34 hot.
Cost = [~$1800] - One of the most expensive tires. Longevity = [10-15 HCs] - After 10 HCs the times and maximum g-load steadily drops session after session. Responsiveness = [8] - This is a real highlight of the tires. To me they really stand out in the way they respond to steering inputs. They have a very crisp and sharp turn in characteristic that does not significantly change as HCs come up. Grip = [7] - This score may seem a bit harsh, but I need to leave room for the non R-compound tires. The interesting thing for me was the fact that the lateral grip significantly falls off as HCs pile up. Very noticeable difference between the first 10HCs and the next 10. Braking = [7] - Overall I was a little disappointed with the braking characteristics, especially compared to some of the other tires. The Cup2 stop the car, but seem to squirm and struggle as part of the process. You really have to concentrate on the activity and positioning of the car (not a bad thing, but can be distracting lap after lap). User Experience = [10] - Another highlight of these tires is how vocal they are, how compliant they are, and how safe they feel. Essentially, if you push the car beyond its limits, the tires will squeal, followed by safe understeer, or safe and controllable oversteer. In either case, I always felt very comfortable pushing the tire to my perceived maximum.
User Notes = In summary these are very well performing tires that are very user friendly and have reasonable longevity. The turn-in and overall responsiveness rate is spectacular compared to the competition. They also do not cause any kind of rubbing and are a good fit for the vehicle. However, given their high cost and average longevity, they are simply not an effective trackday tire for me.
Nitto NT01
The 997 platform allows the use of 18 inch track wheels and the essential track tire for many years has been and remains the NT01. This was my first exposure to R-Compounds and have used these tires extensively. For these tires I use 18 inch wheels and the 245/40/18, 275/35/18 and 305/35/18 sizes at 33/35 hot pressures.
Cost = [~$1200] Longevity = [15-20 HCs] - This is a big highlight of the NT01 tire. They last a very long time, comparatively speaking, and do not significantly drop in performance. For my setup they simply start to overheat once the HC count goes up. In other words each session I will have 3-4 fast laps before the front tires start to suffer and slow down. Responsiveness = [6] - The NT01 definitely does not have the delicacy of the Cup2s and has way less feel. The performance is still there, but your driving technique and inputs change quite a bit. The tire feels a bit muted. Grip = [7] - The NT01 is definitely on par grip wise with the modern tires. It maintains strong lateral-gs throughout it's life. While it may be a tad slower than a Cup2 for the first 2-3 HCs, it certainly makes it up on the average speed over its lifetime. Braking = [6] - By far my least favorite part of the tire. Granted it is likely very much setup specific, but the front triggers ABS much more often than any of the other tires. This especially becomes a problem as the HC count goes up. User Experience = [9] - Another highlight of these tires is how low maintenance they are. They work with most tire pressures and in most conditions. They are not as vocal as Cup2, but just as predictable and safe feeling.
User Notes = In summary these tires are the workhorse of a trackday car. Very cost effective and very easy to use. The tires are rather tall and do cause some fender liner rubbing (front and back) based on setup. A downside of course is the limited selection of sizes in 19 inch, so don't see them as often anymore on modern GT cars. While cost effective there are other tires that are more modern or faster at a similar price point.
Bridgestone RE71R
The newest R-compound on the market, and virtually found on every single GT4 on the track. Only comes in 19 inch sizing. I used these on 19 inch wheels in 255/35/19, 265/35/19 and 305/30/19 sizes with hot pressures of 33/35 hot.
Cost = [~$1200] Longevity = [10-15 HCs] - To me the RE71R are like a modern day version of the NT01. They do not seem to last as long as NT01 but are slightly more consistent. They also don't drop off in performance as much as Cup2s over their life. Responsiveness = [7] - This is a tough one as the RE71R is a tall and heavy tire. They are not as muted as NT01, but don't have the fidelity of Cup2s, so somewhere in-between. They require more of a "muscle" approach to turns, rather than finesse. Grip = [7] - The grip of this tire is very good and definitely on par with new Cup2 or NT01. They do exhibit a very interesting characteristic where both front and rear tires have a small amount of slip angle before the grip kicks in. This creates a very interesting driving experience as you have to build up trust before you can really push hard. Braking = [9] - This was by far the biggest surprise to me. In straight line braking performance they nearly equal the R1S. No drama, no squirm, just strong stopping power the entire session. It could be the fact that the tires are tall and chunky, but very confidence inspiring braking performance. User Experience = [8] - The tires communicate enough, but are more pressure sensitive than NT01. Also the tires are very tall and don't properly fit the 997 platform, so expect rubbing and other fitment issues. Overall, my go to R-Compound track tire going forward.
User Notes = Highly cost effective and fast tire. Essentially my go to R-compound going forward. Excellent braking performance with reasonable feedback. The initial cornering slip angle takes a while to get used to, as the car definitely moves more than on Cup2 or NT01. Not a huge deal for me on the track, but the tires do rub the fender liners and are likely not ideal for street use on my car.
BFG R1S
Entry into the world of DOT approved slicks and actual track tires built for purpose. These tires are far more cost effective than Hoosiers, but only come in specific 18 inch sizes, which luckily works for me. I use the "S" version which is the sprint tire designed to heat up quickly. It does not last as long as the non-S version, but is very convenient for DE where you only have 20 minutes per session. It is somewhere between Hoosier R7 and A7 performance wise. I use the 265/35/18 and 315/30/18 sizing with 35/35 pressure hot.
Cost = [~$1200] - By far the most cost effective tire here when considering price/performance. Longevity = [10 HCs] - The "S" is really dependent on track condition and temperature. If you drive the tire in 85F+ weather they will last a single day. Otherwise the average has been 2 fast days. Responsiveness = [7] - This is an interesting attribute for me. When the tires are new the turn in is precise and fast, however the tire does not have the "feel/fidelity" that the Cup2 has. As the tires age, the front end starts to exhibit significant understeer, which becomes very frustrating. It is essentially the polar opposite behavior of the Cup2, which retains its nice turn in as it ages. Grip = [9] - The cornering grip of this tire is epic. It retains this grip through most of its life. As mentioned above, as the tire ages the front slows down, but the lateral loads remain very strong. The tire does have a fairly thin sidewall and is not as comfortable at the limit, sometimes exhibiting "skipping" rather than sliding due to the stiff suspension. Braking = [10] - Absolutely phenomenal braking performance. Can brake later, harder and more consistently than any of the tires mentioned above. I think as much time is gained from the braking performance as from the increased cornering speeds. User Experience = [8] - The tires are very flexible around pressures, however they are very ambient temperature sensitive and do not give a lot of feedback when it comes to the limit. As the tire ages, lap times remain fast (e.g. 2 day old R1S is as fast as a brand new Cup2), but the number of "***-clenching" moments increase as well, as the grip becomes much more of an "on/off" experience over time.
User Notes = Given the low cost and blazing fast lap times this is the most cost effective and most logical track tire for my car. The downside of course is the fact that it is not street-legal and the car needs to be towed, as well as the limited tire size. There is also the problem of speed as many DE days end up being boring lapping on your own. I have started to switch between RE71R and R1S based on which cars/friends show up.
Michelin Slicks
I am actually not going to spend much time on this. The bottom line is that the slicks are superior to any tire mentioned above in every perceivable performance measure. However they are designed to last a 60 minute sprint race, which translates to 2-3 DE sessions before they start degrading. You add the cost of ~$2200 for a set, and it makes zero logical sense to use them for DE. I thoroughly enjoyed my set and they yielded some very fast and consistent times, but were not really much faster than the R1S, which means that my skillset is just not good enough to take full advantage of them. I will close the chapter on these until some time in the future.
Overall Summary
Sorry for the long post, but I hope that sharing my impressions is somewhat informative/fun for the community. Please understand that setup and driver skillset is a huge factor in all this and I am sure many of you will have different experiences. I had a pro driver drive my car with these tires on their last legs and still set super fast times, so it is all relative. With that said my current tire setup going forward will be the R1S on 18 and RE71R on 19 wheels based on track, event and temperature, as well as goals for the day.
It has been a while since an update and I have not been able to track for the last month or so, despite the fact that we are entering the prime track months here in NorCal (nice and cold weather). I thought I would share the most recent circumstances while I prepare for a few more days later this year.
During the last event at Laguna I felt a loss of top end power at the track, resulting in some rough idle in the pits. Engine temperature was fine, oil pressure was fine and no CEL lights. Shut the car off and took it home for further inspection. Oil showed this...
Doh! One vulnerable part of this engine? The dang camshaft bolts, and sure enough.
I have to give huge props to Alekshop, Sharkwerks and Porsche of Fremont for helping diagnose the problem and make some very good recommendations on next steps. Ultimately the car ended up with my local dealer, Porsche of Burlingame, as they were extremely accommodating and have been able to work with me and Porsche of North America to help get the repair addressed. Without going into unnecessary detail, let's just say that I am thrilled with the resolution of the problem. The bolts backed out and sheered off a very small amount of the material, as I caught it early, so the damage was minimal if any at all.
In addition we discovered that my titanium center muffler had a small crack. The Fabspeed reinforcement bar surely helped prevent the crack from spreading. The issue has been addressed with some quality ti welding.
While the engine was out we also noticed that the alternator mount cracked, so that was replaced as well!
Of course while engine was out a number of accessories and preventative items were addressed as well. Engine leak-down tests showed an average of <~3% across the cylinders with the engine cold, which is great news given that the engine has 46k miles. I checked my records and noted 31 engine maintenance items (e.g. oil changes, diff fluid changes, sparkplugs, coils, belts, hoses, etc.) over the last 30 months, so that must have been helping, but all mechanical things eventually break.
The car should be ready in another week or so with a two year warranty on the engine, at which point the car will go to Thunderhill and Laguna before year end. Can't wait as I have had withdrawal symptoms!
In the meantime the dealer gave me a new Boxster S as a loaner...that car itself deserves it's own post later!
WOW! Amazing, good for you and nice to see/hear RECTOR stepped up to the plate for you considering the current presentation of your vehicle. Most dealers would not be so kind.
WOW! Amazing, good for you and nice to see/hear RECTOR stepped up to the plate for you considering the current presentation of your vehicle. Most dealers would not be so kind.
Cheers,
VID
I think it definitely helped that I serviced 6 Porsches with them and the fact that I have been very transparent about the car since the beginning. They did some of the work on it over the years. But yes, they definitely went above and beyond to accommodate.
Well, after 6 weeks or so, finally got the car back from the dealer. Just firing it up and driving the first few miles you can tell that it feels great! Luckily John had a local private day at Thunderhill, so decided to test everything by trial of fire.
The first session the car felt amazing and after not driving for 2+ months and 42F weather the car did 1:55.4 first session of the day. It was going to be a good day! Unfortunately second session I got a CEL and a relative limp mode.
Turns out one of the camshaft sensors failed and stopped sending the signal to the ECU. That was the end of my day. Car went back for that "easy" fix and is back together ready for the next event! The sensor definitely fixed the issue as it feels faster than a Civic now!
If it does not rain, next up is a Friday/Saturday event at Laguna with HOD and Speed District. After that it will go through a 20-30 hour detail as a year end present. Can't wait to try out the various new coatings
09-16-2018, 05:57 PM
