TXE36

Oh, I knew right away when it happened that it was special. I was actively keeping my eyes way down the track, it happened, and I thought, "wow, that was cool and easy-peasy." The correction itself was done without thinking and I thought "damn, I don't even think I lifted".

In looking back, I think I've done it before and didn't put two and two together at the time. This time it was T3, a 90 degree left hander and I thought I did it because I anticipated the rear could step out. However, I do recall looking at the T4 flag station when it happened and I now suspect that had a lot more to with it. After all, at speed, the outside rear tire always has the possibility of stepping out.

I think I've had a habit of dropping my vision during an oops in order to make sure I don't hit anything, but that is an erroneous response. If the vision is kept up, you already know what things to avoid and where you want to go. It gets back to trusting one's mind.

I still have a tendency to want to look at apexes while I go by them - I think it is all related and I still think too much.

-Mike

DTMiller

Good work Mike. I had a student this weekend who really struggled with keeping traction control from coming on. We tried a couple things to be smoother and once we got his vision up and down the track suddenly he was faster AND the light wasn't coming on. Vision is an amazing tool.

TXE36

I got a really nice complement about it from a surprising source last night - I showed the clip to my wife and her unprompted response was "wow, you did a Dave Scott!".

Sometimes wives do say the darnest things. I think I'll keep her.

-Mike

Veloce Raptor

Wow that's a very kind thing for her to say. But we both know she has always been a keeper!!!

Vipertag313

Need advice for improvement at Sebring. This was during my 1st time ever Solo with the PCA. The session was pretty consistent overall, best lap to examine would be lap 6, I need to find areas that I can pick up some time - "What's the best way to get into the low 2:30's? -

Is there more speed to have in bishops?
Turn 1 too slow setting up 3,4,5?

Apologies for not loading Harry's Lap Timer into the video, I had it running and imposed the lap times into the video. I'll also attach a speed chart of Lap 6 to show apex speeds and such. The digital Speedo in the car is a good reference to use. Happy Viewing

Info:
'13 Boxster S (981) - PDK Transmission
Pagid Red Brake Pads
Prospeed RS680 Brake Fluid
Michelin Pilot Super Sport tires - 28psi cold
Stock Suspension
Stock Motor
Stock Weight
Best Lap: Lap 6 - 2:35.51

Lap 6 begins at 13:31

Speed Chart:

Veloce Raptor

Tough to tell without a throttle and brake trace since your car is so quiet. Speed seems very slow in 1 and 17 though...

zzyzx

Here's a good video on left vs right-foot braking...

NMM991

I'll ask some questions on heat cycling that have been asked and answered frequently but I have never seen definitive answers. I realize that there are several factor from ambient temperature to road surface to driving style that influences track life.

I run Sport Cup2s on a 2016 GT3 RS. What I think I know is that a heat cycle occurs every time the tire gets up to a certain temperature (170F?); that duration within reason 20 or 40 minutes is one heat cycle; that driving 30 minutes to work on a highway will constitute a heat cycle; that as a rule of thumb the newer generation Cup2s will get 25 maybe 30 heat cycles before losing significant grip.

If i run three 20 minutes sessions with 5 to 10 minutes in between each session, does that constituent three heat cycles?

Does buying heat cycled tires from the tire distributor or heat cycling them yourself for a few laps and then letting them sit for a few days extend the life of the tires?

Thanks. Please reference any links if answers are already available.

mdrums

17 turns at Sebring and if you can pick up a few mph/.25-.5 sec per corner or so you will drop lap times by a lot.

I can't see your eyes, don't know the braking and pressure, can't tell too much about throttle either. But it seems your are slow in T1, Bishops for sure...after turn in you can squeeze the gas to full throttle thru Bishops...should be back at full throttle in Bishops by mid turn and T17 you might be over slowing.

At this point of your driving you look pretty smooth not jerking around...nice!

I'd suggest you seek out a pro coach like Dave Scott on this forum or a Chris Hall, Seth Thomas, Ron Zitza...those guy are many many steps above the de instructors you've had. I had Chris Hall coach me a few times and I learned a ton...more than I can master.

See you at Sebring this fall. I run a Carrera GTS in Chin mostly.

k.jeffries

Good question.. you get so many different answers on this topic probably because different types of tires behave differently... One thing most manufacturers agree on is that after initial heat cycle a full 24 hours is needed for that first break in run to be effective.

As far as having the tires pre cycled or doing it yourself if you have enough rims to do two or three sets I think doing it yourself is the best just because of the added benefit of making sure the tire isn't funky out of the box. Problem is some events you just don't get enough track time to be swapping tires for the first couple sessions so that pre cycled tire option is nice (anybody remember SCCA SF Region one day Nationals at Laguna? No heat cycling time there just run em)

As for what constitutes a heat cycle I don't think anything on the highway is going to have a huge impact on that? that might become more of an age thing than a heat thing. I wouldn't know to be honest.

I've never really run the same tires on the highway that I run on the track for an extended time but I've always assumed any track time that brings the tire up to full race temp and then allows it to cool down out of it's nominal range is a heat cycle. Tires do cool down out of operating temps fast.

When I was running Formula Mazda I can tell you the difference between Hoosiers and Yokohomas was night and day in how they acted as they cycled through....

These were both full race tires. Biased ply construction, same sizes and in their prime not too much different in performance but the Yokos just kind of reached a point where performance was steady not what they were new but not horrible whereas the Hoosiers just kept getting worse and worse as they wore. There was a definite time to toss them out usually with decent rubber still on them. The Yokos you could run until the cords started showing and never notice the same drop off

That's probably why it's hard to nail down a solid answer, each type of tire behaves differently, even different compounds of the same tire can behave differently as they cycle through. Tire guys are our friends when it comes to this stuff. A good tire guy can speed up the learning curve.

NMM991

Thanks for the feedback. I reached out to a Michelin guy that I met at a manufacturer's event at Lime Rock, and this is what he had to say about the Pilot Sport Cup2:

"There's no way to say exactly how many heat cycles you can expect. That really depends on a lot of factors. Length of run on each cycle, track temp, track surface texture, driving style, tire age, etc. Generally, we don't see a big change in performance throughout the life of the tire, but we often wear them out before we get as many cycles as you have on them.

Regarding break-in, the PSCup2 tires are generally "track ready"; however, we recommend that you start with OE pressures and gradually bring the tires up up track temp, making pressure adjustments as the tires warm until you reach the desired hot pressure. Just try not to overheat the tires during the first cycle.

We don't consider "street driving" as a heat cycle. Unless you're really having some fun "

Not a complete answer, but there are so many variables that there are no simple answers.

JJE997.2RS

Getting more used to the race car and after some more development was able to push a little more. Obviously was braking much better the second time and carrying some more speed as I got more comfortable with the car. Car is a 99 M3 on R7's weighing about 3050lbs no Aero.

Don't have video because I am an idiot.

The 2:29 was in about 100 degree weather at Sebring. The 2;30 was probably 80ish.

The car is not accelerating as much as on the straights. You can see that I gain time braking and in the turns and lose time under acceleration.

The question to the gurus is. Does ambient temp make that much of a difference to acceleration? If so,how much time did I lose?

I hope that STU legal aero, a built STU legal engine and driving the car like a man can get me to sub 2:24. Thoughts? I dont know how else to show the data other than this:






TIA

Veloce Raptor

Ambient makes a huge difference with a modern engine. ECU's adapt to ambient and will retard timing as ambient rises. In addition, cooler air is more dense and thus has more O2 per cc. Thus hot air is less dense. This is why turbo cars have intercoolers--to cool the intake air. Modern Porsches are especially dramatic with adaptation which harms overall acceleration. This can start at ambients around 75F. However, I used to have an E36 M3 race car like yours, and straightaway speeds etc were definitely off on hot days, just like yours.

JJE997.2RS

So besides 15 and 16 which I blew in the 29 lap, would it be safe to subtract the time I lost on the straights and come up with a "theoretical" lap time?

Veloce Raptor

I don't know. In my own experience, I'd lose about 2 seconds a lap on a 2.9 mile track, and 3-4 seconds at COTA, when it was above about 85f