DamonB

I can probably get my info up at lunch. The start and finish I labled purely from memory. According to our track maps the start was also quite closer to the center of the track than I labled it.

DamonB

Here is the plot from my best run this past Sunday. umrswimr and I competed on this course albeit in different cars. I can already see we do some things differently just by looking at the laterl vs accel g but keep in mind umrswimr turned a 59.3 to my 60.6. Even PAX'd he put 4 tenths of a second on me. I left my map uncorrected so it matches umrswimr's and I plotted my run on the same color scale as his:

Usage 100%+ = white
Usage 90%-100%= light blue
Usage 80%-89%= dark blue
Usage 70%-79%= pink
Usage less than 70%= red

Ideally you want to see lots of light blue and some white. It's impossible to drive at 100% the entire time because the car can only transition and settle so quickly; there are times you intentionally under drive it in order to set up for what's coming. Even so comparing all my runs without a doubt agrees with what I felt in the car and how I judged my relative performance.

The scores for both umrswimr and myself are slightly lower than we are used to seeing. The reason this is so is because the two 180 degree right handers at each end of the course were slightly banked so this allowed higher cornering loads there compared to the rest of the course which was flat. Geez doesn't know part of the course is cambered so it sees both of us cornering higher in those areas and less in others. Therefore it feels we didn't corner the car to its full potential on other parts of the course. This is no big deal and the rule that applies is to only compare scores from the same course as it would be an unfair comparison otherwise. Geez is meant to show you what you could have done differently to improve yourself that day, not to build be some sort of performance database of your car. Although it can help with that you must understand what the unit is really capable of and how it arrives at the numbers it does.

We got 3 runs that day. My first run was poor as I got behind in several spots around the course and picked up 3 cones. My second run was much better and faster but again I picked up a cone or two and still didn't drive as well as I am capable. The third run I drove much better and turned in my fastest time but I still drove conservatively as far as placing the car close to the cones because I didn't have a clean run yet. I needed to drive faster, smoother and not hit anything! Because of this my third run was less aggressive through the first quarter of the course as there were some tricky offsets here and above all I needed to get through cleanly.

Comparing the maps from our cars looks like umrswimr was pushing pretty hard in the first sweeper after the start. My car had the same problem here as well but it appears his was worse. I think that's why his map overlaps itself (without any correction added. I could also be wrong; his car is different than mine and his software adjustments are different. That could account for it as well). At the same time at the opposite sweeper my car was drifting slightly on the throttle as I came around and my map here looks like a larger radius corner compared to umrswimr's. This is because my car was sliding slightly tail out and I think his map more closely resembled what the course actually looked like here. Normally we would edit the maps to make them correct but here we didn't so we could see the difference in eachother's raw data from different cars.

Both of us were on Victoracers though umrswimr's appeared to be in great shape and mine are on the way out. His car certainly outcornered mine on that surface.

Umrswimr

Dang!!! GawdD@mn, I got my azzz kicked!

It definately looks like you were traction limited throughout the course.

Notice how we both made the same "double correction" coming out of the slalom and into the first offset chicane. (It's the third and fourth right-hand spikes) in the lateral column. The difference was that Damon knew what his car would do and hit the same lateral G force both times. I'm not nearly as good and I tried a corning force then dialed in more once I realized it would stick.
Same goes for the first of the two sweepers: Damon got on the throttle right off the bat and drove through the corner. I slowly rolled onto the gas because I wasn't sure it would stick. The second corner I had more confidence in and was more agressive with the throttle. Remember these corners had a good deal of camber and we didn't exactly sure how much it would stick. At least I wasn't. If I read his description correctly, he opted for the "more throttle" approach and had a bit of oversteer. I opted for the "less throttle" approach and left a lot of time out there.... Somewhere in the middle is probably the best approach.
My VR's have about 8 events on them and are in quite good shape, relative to Damon's.

DamonB

I cropped and rescaled our lateral and accel graphs and posted them together. umrswimr is on the left and I am on the right. The absolute readings of the graphs between us are different but you can see how we differ in what were doing in the same spots on the course.

Umrswimr

Now this is interesting: (I'm on the left, he's on the right)

First, I highlighted the second chicane of the course in pink. It's a weird apex lefty before you enter the right hand sweeper. Notice how mine is a constant G force relative to Damon's. If I had to guess, I'd say he overcooked this spot and he started to slide... I beleive this is what caused him to question the car's ability to handle the sweeper as he mentioned above.
Sooo, he corrects it with a very brief but firm stab of the brakes (circled in green) once the car gets straight (notice the lack of lateral G's as this point) to get the car under control. This allows him to roll BACK onto the gas in the entrance to the sweeper whereas I'm basically just throttle-less "cruising" around the corner. I can't touch the gas or brakes beucase it's pretty much at the limit of traction (or so I though). That slight decelleration circled in green on my trace is not braking but decelleration due to the turn. I coasted through this corner. Kids, don't do this. It's bad. Don't coast- it means you fooked up.

Now, the other thing I noticed that we did widely different is shown by the red and orange lines. Basically we're unwinding and accelerating through a left hand sweeper before a three cone "slalom" that's really just an excuse to slow down. It's a sweeper left into a hard left (red line) into a right then another hard left (orange line). We both lay into the brakes at the same point, but I lift and take the three cones without touhing the throttle or brakes. I'm humming along at 65 MPH at the red line on the map. 60 MPH by the orange one. Now, I did this coasting. See previous statement about how stupid this technique is. Damon, like a rotary-powered kamikazee, stabs the brakes hard, trail brakes the left AND right cones before getting BACK onto the gas for the last left (orange line)!

Holy CRAP!

Nice work!

DamonB

Here are the same graphs from above with some things highlighted. I'm actually quite suprised how similar our graphs are considering the different cars with different drivers.

umrswimr lateral and accel graphs on the left, mine on the right. Neither of these is showing right or wrong, these are just differences I see in our driving of two different cars.

The area at the top of the graph before the first green bar is the start and into a fairly evil offset slalom. You can see both of us got loose in the third right hander as there is a bobble in our lateral acceleration as we are catching the car during the slide while also trying to slow down for the next gate which was quite close. Our graphs look much the same here except for my braking real hard before the last turn just before the green bar. My car wasn't sticking well at the rear so I slowed it down to be certain I cleared that last gate without catching a cone. umrswimr went through there without the braking so either I was flat going too slow there or his car worked better.

The area between the green bars is the first long right hand sweeper. If you compare the lateral accel graphs you can see that umrswimr turns in harder and more abruptly than I. My cornering force builds more gradually before peaking and rolling off more gradually. The rear of my car felt unsettled here and I was trying to upset it as little as possible. I don't know how umrswimr entered this corner but I drove the first half of it as a classic roadcourse corner. I set myself up very wide at the entry so I could more slowly turn the car down into the corner while trail braking. You can see my very brief and hard stab of the brakes midway through turn in as I set the car up heading towards the apex. On the way out of the sweeper you see both of us stab the brakes again to slow the car for a wicked kink which you had to get right in order to carry the next slalom successfully. Again my braking was done harder and over a shorter amount of time given the difference in our spikes. During this hard spike you can see my cornering was not much. You have to trade cornering grip for braking grip and so I was braking the car hard as I was unwinding the steering out of the corner. umrswimr appears to be doing the same thing but his car is doing more cornering and less braking compared to mine in that spot.

Between the red bars was a fun corner. umrswimr happened to get a pic of my car in this spot:





The approach to this corner is the exit of a slalom that dumps you into a downhill right hander that then cuts to the left just at the bottom of the hill before climbing up again (the pic shows my car at the instant it's heading back to the left out of the kink). My car would come out of this slalom with me steadying the rear of the car with the gas pedal (notice we were both accelerating hard just before the first red bar) before heading back to the left. Basically it felt like I came down the hill standing on nothing but the left rear tire and with just the right amount of throttle the car would point around and slip right in there before cutting it back to the left. Again my turn in is less abrupt than umrswimr's but the whole time you can see me playing with the throttle as I tried to manage the drift through the corner. That third run was the only time I got it right and I wish I could have done that corner over and over all day long. It was fun to slide the car down the hill, catch it at the bottom and then immediately swing it the other way as you climbed another hill.

Between the blue bars is the final 180 degree right hander into the finish. There was an offset at the entry and just after the exit on the way to the finish. We look nearly alike here. I know in my car I had to make a correction on the way in and then you can see me sawing back and forth at the wheel slightly all through the corner. I was sliding the rear out just a little in the second half so I could get up a bigger head of steam on the way out. Not a power slide by any means but I was letting the rear come out just a bit to help point the car. Looks like umrswimr was doing the exact same thing.

DamonB

Actually I'm not trail braking through that slalom; I'm accelerating through the first half of it; look at the graph again. Anytime the graph heads from the left to the right that is positive acceleration (even though it's on the "negative" side of the graph). There's the hard stop just before the slalom and then the car accelerates through the first couple cones. I gave up more before the slalom to ensure I could accelerate all the way through it and into the final sweeper. Keep in mind I'm driving a turbo car and I know I'm handicapped in slow areas. My thinking is to do whatever I can to carry as much throttle as possible because I can always slow back down if I need to, but I can't make the turbos spool any faster than they're able. I wanted to be sure I was on the gas and still accelerating so I could build as much entry speed as possible into the final sweeper. That was a long corner and I didn't want to take it slowly. I'd rather come in there fast and have to slow a little than come in not fast enough.

graph

Umrswimr

Actually, I believe you are trail braking through the first half. At the orange line, you're braking hard and you slowly release the brakes. There's a slight "pause" circled in green where you slide your foot from the brake to the gas mid-corner. Notice how that green "plateau" I circled is about the same G force as mine. I was just coasting here- slowed by the turning force....

If you had just quickly stabbed the brakes and released them, it would have looked like the spike circled in blue.

DamonB

Gotcha, gotcha, gotcha. I agree. I had to be trailing slowly off the brakes or the rate of accel would have been higher. Given that the slope changes more gradually I did in fact get on them hard and then trail off them as the car traveled through the slalom. I'll plot that section on the friction circle graph and that will show without a doubt what I did...

The spike circled in blue shows me going from very hard braking to very hard acceleration. The slopes of the lines on each side of the curve are close to flat so I did both very aggressively.

I'm still suprised how closely our graphs compare. I expected more difference in throttle use given the difference in our cars.

DamonB

Here is the same run again from my car. This shows the lateral and acceleration graphs as before but also adds total g, transition rate and usage graphs.

Total g shows the sum of all acceleration vectors on the car at that instant, so that includes both acceleration/braking and cornering g at the same time.

Transition rate shows the rate of change of lateral g values, so it describes how quickly the car is changing direction. A slalom would show as sharp spikes here while a large sweeping turn would be much more gradual. The sharper the spike the quicker the manuever was performed.

Usage shows usage of the car's tires at each point in time. Ideally this graph would be a straight line down the right side. This is of course impossible because as a car changes direction forces don't build instantly. Even so you would like to see as few spikes to the left as possible and when they are present you would like them to be over a very short fraction of a second. Any "clump" of peaks that point towards the left of the graph signify an area where I was not using all of the grip available. This may have been on purpose in slowing the car for a more important section coming or it may be pure under performance of the driver. Only the driver knows for sure and he must be honest with himself

These graphs are marked with a single red line; this is the slalom umrswimr discussed earlier. You can see that at the instant in time where the red line is drawn the car is at maximum lateral g to the left, acceleration (change in speed) is zero, total g is near maximum, transition rate is zero, and usage is 100%. What's this tell us? The car at this instant is making a hard left turn around a cone in a slalom. The red line is the exact instant where cornering levels peaked to the left (shown by the line intersecting the peak in the accel graph) just before turning to the right. The usage graph at the far right shows the red line intersect the graph at a 100% peak, so the car was "perfect" here. The usage graph is saying that all the grip available was used up, so the car at this instant is right at the limit of its ability. Since usage is 100% and cornering is also spiked at 100% there is no grip left for acceleration. Thus the red line intersects the acceleration curve at zero. The transition rate is zero because at the instant the line is drawn the car is steady state for a fraction of a second as it rounds the cone.

What these graphs say about this one instant are that it was nearly perfect. I used 100% grip at the very short instant where I actually changed direction around the cone. If I had been faster here I would have slid as the tires had no grip left to offer. This would have shown as a lower lateral acceleration (the car is sliding) and a lower usage score. At that point I could look at the acceleration graph and figure out if I was doing too much braking or accelerating. If I had been too slow the lateral acceleration may still peak but the usage scale would have shown a low reading. At that point I would know I was not aggressive enough there as I could have used the extra grip to also be braking or accelerating the car.

I'll post another example up with the same graphs but this time I'll show a "bad" spot and explain what I did vs. what Geez tells me I could have done.

Umrswimr

Another little bit of analysis... First, the red line on the map corresponds to the same spot Damon discussed above (and the dialog box). Ironically, we both took this corner exceptionally well as shown in the graph and the dialog box. We both maxed out the cornering perfomance of the car at this point. Zero transition, max cornering, no throttle, and 109% utilization. This was actually the highest G left turn on the course for my car- 1.22g's.

And now a spot where I could've gone a lot faster. The green lines show the exit to the slalom into the entrance to the first 180 right hand sweeper. On both runs, I set up too far inside which forced me to take the entry slower. Stupid mistake.
So as I come up to the sweeper, I'm short shifting the car to third gear (I'm going 61 MPH at this point) and instead of tapping the brakes and then rolling back into the gas for the sweeper, I hesitate and just let it coast around the corner. I'm not really sure why I did this exept perhaps that was concerned about overshooting a cambered corner and sliding sideways at 60 MPH into the dirt. At any rater, there was plenty of grip left at the beginning of the corner. So part of the hauge drop in utilization is the gear change, the rest of it is just plain bad driving.

I've known for a while that I am very cautious during high-speed corning. I blame an incident with a "No Parking" sign for that. Now I have proof that I'm too conservative and it's time I fixed it. My other problem is that as recently as the last autox event, I was OVERdriving the car. Since we only got three runs here, I didn't want to blow an entire run because I overcooked a corner. Better to be slow and clean than faster with a spin or a cone- at least in my mind. In this case, I think I was entirely too cautious. Had we gotten the fourth run, I think I would've done a lot better. There's easily 2 seconds left out there.

DamonB

I tried to rescale the graphs from both of us again. If the graphs aren't scaled the same they can be very misleading because one graph will look "sharper" than the other. umrswimr on the left, myself on the right. I'm still impressed with how alike all of these look considering he's in an ASP C5 with a torquey v8 and I'm in an FD with stock twins; both on race tires.

The only things I really see differently between us are that I tend to use the brakes harder and over a shorter distance (this could be tires, pads, driver, car, who knows?) and my transition rate appears to be slightly higher (this could be tires, shocks, distance from the cones, driver, car, who knows?).

Data is a tool and it's always nice to see what other people do. There's always more than one way to skin a cat! One trend I find interesting is the entry and exit of the first sweeper. Both of us have a low usage value during turn in and another low one as we "un-turn" or track out. This was a big sweeping turn and tires can't load instantly; you have to manage the buildup of the cornering forces. As you turn in you are letting the car take a set while the cornering forces build up and while the car is transitioning during this turn in you will have a low usage score. If you attempted to aggressively yank the car down into the apex your usage value would surely score higher in the area of turn in but you would also load the tires too agressively and the very next moment after the car turned in you'd find yourself loose, pushing or sliding wide as the momentum of the chassis changing direction slams into the tires all at once and breaks them loose. Shocks are the real key in transitions such as this. The better the shock is setup for the car the harder you can turn it in without the weight transfer overloading the tires and breaking them loose.

In a slalom you can manage much higher transition rates and usage scores because you can make the momentum of the chassis work for you. As you are yanking the car around the cones the tire will change direction before the vehicle does; the vehicle is always lagging behind the tire. If you can time the momentum of the chassis to "hit" the tires right at the instant you want the car to change direction the other way you can in fact corner harder, but only for an instant. If you were not immediately turning back the other way the momentum of the chassis would pull the car into a slide. As it is in a slalom if you can shock the tires with the weight transfer right at the instant you turn the wheel back the other way you are in essence catching the car with opposite lock at the exact instant it's about to break loose.

Because of this if you look at the highest absolute peaks in cornering loads they will nearly always tend to be in slaloms or areas of very high transition rate as opposed to long corners that have a slower rate of transition. In the particular case of these graphs below the two long right hand corners still rate nearly max g loads, but that is because they were cambered and the rest were fairly flat. Normally you would see a greater difference in maximum cornering load of a long corner vs an abrupt transition.

Umrswimr

Wow... Those are creepy right next to each other like that... I didn't expect them to look that similar.

Umrswimr

Yesterday's autocross was an interesting one: it was pouring rain in the morning, dry in the afternoon.

The forcast called for a 90% chance of rain all day, so I opted to run on my street tires (Kumho MX's in stock 245/275 size) versus my usual race setup of Kumho Victoracers. My VR's would be good in the rain if they were new, but being the end of the season means that they are basically bald. They're still great tires in the dry, but in standing water...

It stopped raining before the first car went out, so the track had standing water but it began to dry. My first three runs were on a VERY wet track. In the wet, I got beat by one car- an SM prepped WRX on V700's. Damn AWD cars in the rain.

The plot below shows the GEEZ! graphs. You'll notice the large red areas between the corners- that's because you had to be very careful with your inputs. Roll onto the gas nicely, roll onto the brakes cleanly... No sudden moves, no funny business. My smoothness rating was 96% here. Overall, the Kumho's provided good grip (0.87 g's) and I was sitting pretty at the top of the pile...




However, wouldn't you know it- the sun came out. Now all those cars which were slippin' and slidin' all over the place in the rain on R-compounds were out with a vengeance. I immediatelly lopped 3 seconds off my time in the rain, but it wasn't enough to compete- race tires just had significantly better grip. Especially in the braking department. I had a hard time adjusting my braking points- the car just wouldn't STOP!

I knew that I had to be nearly perfect to even stay in the hunt for top points and I suppose I did ok, timewise: 43.4 versus some of the CS Miatas and a BS M3 running mid 42's. Looking at the GEEZ! plots, it appears there wasn't much else I could do: this is my best performance since I bought the unit a few months ago.

Overall, I scored a 92.46% overall utilization percent which is higher than I've ever posted before. It appears that the dry conditions were good for at least a full tenth of a G worth of traction. What it doesn't show is how much easier it was to transition between inputs. Compare these results to those posted a few replies up when I was on race tires: R-compound tires are worth the better part of TWO tenths of a G when compared to street tires. (Disregard the braking G's since the event at TMS never had a full ABS braking section like this event) Keep that in mind the next time you race a car on R-compounds; there appears to be some truth the the belief that they're worth ~2 seconds on a course....

Umrswimr

One more little observation: I forgot how much easier it was to race on street tires. They communicate to you, they break away with a nice linear feel, and the generally don't do anything to get you into trouble. By contrast, race tires seem to give you ZERO feedback until it's waaay too late.
This re-enforces my belief that novice drivers should spend as much time racing on street tires as possible. You learn how the car performs a LOT more quickly and with less fanfare than race tires.

DamonB

So what happens in the rain? This past Sunday there was a nice steady sprinkle the entire day. The course stayed wet the entire time but with little water actually puddling. During the course of my four runs it got wetter and wetter. I stayed on the very worn Victoracers because at first the drizzle was just in spurts and as long as cars were running the line stayed dry. Once it came to my runs (of course) the drizzle changed to full time sprinkles and the course stayed wet. My four runs were:

51.126
50.480
51.835
47.908

For the first run I softened all the shocks up but not wanting to get wet I didn't bother to soften the front bar (I should have). Car was an absolute mess on the first run. Wouldn't turn in, wouldn't corner, wouldn't accelerate. Hard race rubber with absolutely no tread is not the way to go in the rain Second run I dropped the pressures 10 psi (!!!) on all four corners. Car was considerably better, it was just still wet out there. Third run I tried dropping another 3 pounds on the rear only hoping to get some rear traction. Didn't help and the run was even slower as the rain was picking up a little.

So now I'm pissed off The Z06's are having a tough time of it too but they are on softer Hoosiers and are turning 48's and 49's. After completing my third run I head straight to pit and change to street tires. It's raining, I'm by myself and I only have a few minutes to get back in grid ready to go. I pull back in on street rubber just as the car before me heads out; just made it. One run left and the time to beat in SS is a 48.7. With some tread under me now I turn a 47 without even trying too hard. It was still slippery but what a difference it makes when you're not sliding everywhere. I guess that's why they call race tires slicks

These plots show my second and fourth runs. The only difference in the car between the two runs is worn race rubber on the left and Kumho MX street tires on the right. Rain was actually heavier during the run on the right. The scores are roughly similar but notice the difference in cornering and braking g between the tires. Acceleration was the same because of the course layout and it was still so wet you couldn't put much power down. The run on the right was a full 2.5 seconds faster but it wasn't due to driving better, it was due to being able to get some stick in the car. Notice the red lines on the strip charts and see how much more aggressive the street tire acceleration curve is just below the red line compared to the race tires.

So here's a case where there is a large difference in lap time of the car but only a small difference in scores. I wasn't necessarily driving poorly on the left but my car's performance was severely limited due lack of grip. My driving slightly improved for the last run but lap time saw a huge drop as I added much more performance potential to the car by changing tires. I drove it with the same "talent" but automatically went faster. In this case the driver was pretty consistent as the scores show, but the car went a whole lot faster because of its increase in potential.

DamonB

Do you guys read this stuff? The thread has a lot of hits so I assume somebody is. If people aren't really interested I won't bother; no big deal. Don't want people thinking I do it just because I'm full of myself

Now that autox season is over I hope to get some track time in over the winter and share that.

'85 GSL 302

I'm extreamly interested in it. I just have nothing constructive to say...

dbgeek

^ I'm with him...
I find it fascinating, and actually take notes about some of your comments. I'm just starting as a novice in an 86 Sport FC, and have attended several classes (Evo, and Novice). ALthough I still can't seem to find "the line", I'm getting more comfortable in the car, and am able to think about and apply a lot of the stuff you racing types talk about. My notebook of comments/reminders is about 2 pages long right now, but it grows every time i drive.

Thanks for the updates/insight!
pete

gfelber

Of course! This is great info, keep it coming.

I think we're pretty clear on how the product works as well as its limitations, however, I'd really be interested in reading how Geez! has improved your driving. For example, has and emphasis on smoothness improved your runs? Are you better able to determine when or where on the track smoothness is required versus, say, tossing the car in a corner, etc?

Gene

DamonB

For me, Geez is a coach. No matter how good/bad the tires are are how fast/slow I am compared to everyone else Geez will show me how well I as the driver performed. The Evo schools helped me tremendously but I felt I had plateued in my driving; I didn't know what to change and what to do to keep climbing the learning curve.

Once I started using Geez within the first couple events I identified some areas where I consistently under drove the car. For me high speed slaloms was the biggest. I had always driven them conservatively to avoid cone penalties but I didn't realize how much time I was really giving up. I probably drove most fast slaloms about a foot off the cones, now I shoot for inches. Stay right on top of the cones so you can use as little steering as possible and stay on the gas! Geez showed me how much faster I could really go by driving the slaloms aggressively. Long story short steer as little as possible, but that means you must be right on top of the cones.

I also do not try to move the car around so much in sweeping turns. If I'm not exactly where I want to be at entry or mid corner I will hold what I've got (assuming I can still exit roughly where I wish to be) rather than upset the car. Geez has shown me that it's better to let the chassis stay consistent then give up some cornering force for an instant while I move the car around. Cornering forces take time to build and go away and everytime you steer the car you're upsetting it and you have to wait for it to settle again. Leave it in a steady state as long as possible when in long sweeping corners rather than constantly hunting around. When Geez said I drove an area absolutely perfectly I can reflect with what I felt in the car and know THAT'S how the car feels when it's right.

Another biggie was course evaluation. A good autox course forces you to compromise in places and I wasn't sure I always made the right choice. With Geez I could drive once my way and then another way and compare them. Should I brake earlier here so I can get on the power earlier or do I banzai in and gather up the car so I don't give up as much speed on the way in? For this particular spot is it better to be fast in or fast out? I could zero in on that one area of the course and see the pros and cons as well as the difference in time splits for each attack. Sometimes I was really suprised and found something like an entire half second in one small section of the course. In order for this to work you have to be driving consistently though. I run a lot of courses and study a lot afterwards and so have built a pretty big catalog in my brain. When walking I can recognize parts of things I have seen and studied before so my first run tends to be much better than it was in the past. I have more of it figured out before I get to the starting line the first time and I don't tend to make big changes in attack anymore.

Geez also reassures me about some things. There is one particular place we run a couple times a year where I always seem to get creamed. I didn't know if it was me tanking it everytime or the car. I didn't think it was me but hey, I don't know everything. Geez shows me that without a doubt my tires had far less grip on that surface compared to my Hoosier shod competition whereas on other surfaces the difference was much smaller. I could see my cornering ability drop considerably on that surface (guys I respect agree that without a doubt the Victoracer doesn't work on that surface. The Hoosier cars always run away).

My fiance just finished her first full season and though she doesn't really study this much she can see where I'm really creaming her just by looking at the trackmaps. The good news is her driving is pretty consistent as her "good" days and "bad" days are not nearly as different as she thinks IMO. If you're consistent you can consistently improve; you just have to have a plan. The car has scared her before when it did something she didn't expect and that makes here timid. I've been there. Lately she has at least shown she can catch the car if it tries to get away so I'm trying to convince her to be more aggressive. She's proven she can control the car so she needs to push her limits. She doesn't have the experience but I'm trying to teach her how to focus in on how the car feels. She doesn't notice a difference many times when I make a change to the car even though it I insist the car is 200% better. Her brain is not tuned to a fine enough resolution yet when it comes to feedback from the car. I ride with people and I'm sitting there thinking "This guy is on his way to losing it!" but they themselves don't recognize it until after it happens. It's not that they're stupid but they literally don't notice, their brain hasn't tuned into that channel yet. I think when you really get the hang of it you don't drive the car by just watching where you are going, you drive it with what your hands and butt feel.

I'm still amazed at times when I see someone do what I thought couldn't be done. It's great; I smile. There is some little thing they are doing that I am not and that allows them to pull off this "impossible" result but I can't figure out what they are doing different. Geez is helping me figure out what the consequences of my actions are.

Umrswimr

That's good info, Damon... I found very similar results when I ran in the rain earlier this year. Tread makes a HUGE difference.

redrotorR1

Well, let's just look at the numbers here.

11% improvement in Left G's.
6% improvement in Right G's.
Relatively same numbers in Accel G's.
34% improvement in Braking G's.

Qualitatively analyzing the Geez plots, your braking zones are shorter and the transition spots show more aggressive driving. My guess is that 60% of the improvement is in the tread and the other 40% is from increased driver confidence. The problem with R-compounds and rain is that you never truly know where the limit is. You're always creeping up on it and then overshooting.

I wish I had one of these things at Nationals. My first run two runs on Topeka concrete were like being a auto-x newbie again. Had I known how much more aggressive I could've been, I could've lopped off even more time .... and popped into the top 10.

DamonB

Those numbers you're looking at are max G. What you have to keep in mind was my ability to transition was much quicker on the street tires in the rain. Therefore I can approach max G much more quickly and hold it for a longer distance on the course before I must change direction again. Just looking at the peak G readings makes you think the difference wasn't as big as it actually was. On the race tires in the wet I had to drive the car very gingerly and tip-toe everywhere, I concentrated on building all braking, turning and acceleration forces very gently. This course was actually ridiculously slow so driver confidence wasn't a problem, all my concentration was on trying to get the tires to the limit without slipping.

IMO 90% of the time improvement was strictly due to the street tires' ability to grip better. We all certainly get faster with more chances at the course but in this case that wasn't it, I felt the course was "simple".

DamonB

Here are the same two runs from the wet that are pictured above. On the left was the fastest run on race tires, on the right the street tire run that was 2.5 seconds quicker. I have included graphs of lateral acceleration and transition rate for each run as well. Look at the instant numbers posted at the top right of each pic. What's interesting to note is that at that point in time usage is the same on both runs; 80%. This area of the course is accelerating out of a slow right hand turn and slightly uphill into a left handed kink. The usage rate is low on both because of turbo lag out of the corner; it was lugging there. Elsewhere on the course I was able to accelerate at higher rates so Geez is grading me lower here (Geez assumes your max acceleration rate elsewhere should be the same here as well). At that instant the transition rate on race tires was 2.3 g/sec and on street tires 2.8 g/sec. Also notice the huge difference in speeds at that instant. On street tires I not only went through the corner faster, I could also accelerate more aggressively on the way out.

The real key to why the street tires were so much quicker is the friction circle graphs. Notice on street tires how I was able to blend my acceleration and turning as well as my braking and turning where on the race tires that is practically non-existent. The fact that I could be speed up and slow down the car while also cornering is the reason the street tires produced such a drastic change in lap time, not so much that the street tires just had higher maximum values. On race tires the transition limits were so much lower I could not make the car do more than one thing at a time.