Tom W

I set a personal best in qualifying last weekend and wanted to spend some time to ensure I knew what I did right (and wrong) and to compare the driving in the 1:56 to more typical driving were I would turn closer to 1:58.

I'm not a pro driver or coach, just a guy trying to learn to go faster. I do have people ask what data system I use, why and what I think is most important. So, here's my analysis of a couple laps that were back-to-back and why one is faster than the other (and why I could go faster yet if I tried harder). I have a MoTeC because after a year with a Traqmate, I decided I liked the analysis and I would have the car built with only a MoTeC dash - no other gauges. I have a SDL and use i2-Pro for analysis. You can do essentially the same thing with a TraqMate.

These are two laps in qualifying at Thunderhill on Sunday. Track temp was 84 F during these laps (air inlet temperature). I drive a '92 964 that's been reduced to about 2440 lbs as I was running and it makes about 285 hp to the rear wheels.

Video of the two laps is here. The file name is SunQual and it's 318 Mb (I've not had time to reduce the size yet). It was created with TrackVision and has a data overlay. The 'MoTeC dash' in TrachVision isn't perfect, but it works well enough. And yes, the rear camera came loose but there wasn't anyone close behind so it's boring anyway.

The first plot shows the complete fast lap (lap 4), a 1:56.58, with the speed trace in blue. The slower lap (lap 5) was a 1:58.18 and it's in black. At the top is the variance - where I 'lost' time in the second lap and how much. The cursor shows a position in T10 where I'm at 68.4 mph in L4 and 62.3 mph in L5. Where I brake, and how hard, is shown in red for L4 and black for L5. Throttle position is green for L4 and black for L5.

So, the first shows most the data in a compact view. I was 'significantly' slower in T2 and through the 10/11/esses complex.

So, I looked at the lap in a bit more detail. The second plot shows T1 and T2 in detail. I get off the gas and onto the brakes sooner in L5 and I lose 0.2 sec immediately because of it. The video shows the tow truck on the right that distracts me. I stay 2 mph slower all through T1 and I'm on the gas fully sooner in L4. You can see I have commitment issues in L5 as I'm afraid to get back on the gas. I brake for T2 sooner and over slow (5 mph difference on entry) in L5. By the time I complete T2, I'm 0.6 sec behind.

The third panel shows T3 through T8. Not too much difference in the 2 laps. I over-brake for T3 in L4 and enter about 5 mph slower so I gain back 0.2 seconds here in L5. I commit to T5a better and get to full throttle in L5 better and carry 5 mph more speed into T6, but I'm on the brakes a bit longer and it hurts me a bit on getting to the apex. I get back on full gas faster in L5 and it halps gain back the lost speed. There is no significant difference through T7 and T8. I take T8 with a minimum corner speed of 104.5 in L4 and 104.9 in L5.

The fourth panel shows T9 through to the back straight (you can always see what's displayed by the track map in the lower right of the panel). I struggle with T9 and was working hard at carrying more speed through it last weekend. I am 3 mph faster in L4 than L5 and get on the gas faster in L4. After T9, I'm 0.77 sec slower in L5. I'm 6 mph faster in T10 in L4 than L5 and it has a big impact on speed into T11 and then I'm slower through 11. I'm distracted by the traffic that I'm closing on and about to have to pass. I get past two on the back straight. I never thought I was slowing at the time, but clearly the data show I was distracted. I'm now almost 1.6 sec slower.

The last panel shows T14/15 and the front straight. My line through 14/15 is less than ideal in L5 but it does not have a profound effect on the lap time. I'm slower to get to full throttle and it carries down the straight.

Tom W

Some other data analysis tables ....

I look at how well I do with consistency. The first two panels show the two laps previous for comparison. Lap 1 was the out lap under yellow. L2-L5 were at speed. I quit after L5 as I had already hit the 1:56 and was now running into slow traffic and I knew I would not get better.

The third panel is a visual of the plots with throttle position and brake pressure. I like it because it shows where I'm either not on the throttle or the brakes.

The fourth panel is a compilation of the section times.

So, I go back to Thunderhill in 10 days for a PCA race. I bet you can figure out what I'll be working on.

Tom W

One other comment. Folk who don't know Thunderhill may wonder what's going on in T2 and T3. It's not as obvious from the data as it is on the video... My car has more push than desired in these turns and I throttle steer to help rotate the car. I'm working on the set-up to get a better balance.

Seth Thomas

Shoot me an email with the Motec file. I will look at it this weekend while I am at Mid Ohio coaching.

seth@seththomas.net

Van

You don't have those screen shots full size, do you?

2BWise

If you're using i2 pro you've got a mutlitude of options for analyzing data. The maths functionality is awesome. I suggest you look through your data and use the maths channels to create some custom channels. There are some very efficient ways to analyze the differences between these laps.

Tom W

Bill: I kept it simple here. I have many custom math channels to look at what I'm doing. The ASE book is a reference I carry with me to the track for every event. It's a question of what you are looking for - in this case the biggest mistakes are quite evident from the brake, throttle and speed channels and there was no need to look too much deeper to make the point.

Seth: I'd be happy to have you look at it - I'll send it tonight.

Van: I do have them, I just didn't want to paste a 1900 pixel wide piture into the thread so I re-sized them to 1024 max width. Send me a PM with your email and I'd be happy to provide them.

MJR911

Very cool, thanks for sharing Tom.

quickxotica

Tom - First of all, THANK YOU for sharing. I drive TH and use Traqmate, so this is a really nice window into the guts of a lap that is faster mine. I know am not using my data to its fullest potential... something I need to learn more about. I'll spend some more time pouring over the screenshots to learn what I can.

But first I have one really basic question: Why do you make each straight a stand-alone segment? When I create segments in Traqmate, I usually start a segment at the brake-point for a turn and then let it run all the way down the straight that follows and end it at the brake point of the next turn. I figure that makes it easier for me to see the effects of different techniques within a corner (because the effects will be magnified down the following straight). Or to look at it another way, I expect to be at WOT for the duration of the entire straight, so the only real difference from lap to lap should be solely dictated by the success/failure of my technique in the preceeding corner. (I hope that explanation makes sense.)

Why do you break the straights out seperately? What value do you gain from doing so? Sorry if this is dumb question.

Tom W

You can do it either way. If I break the straights into different segments, I find it it easier to look at the exit speed from the corner. That said, I noticed that my corner starts and stops got changed during my fooling around and are non-optimum. I usually like to end a straight/start a corner at the beginning of the braking zone and finish a corner once I'm past the exit and the wheel is back straight. Corner exit speed is then usually the max speed observed in the corner.

I've been racing for 3 years and have been using a data system for 3 years (1 with Traqmate and 2 with MoTeC). It was pretty obvious in the beginning that I was not very consistent and not getting on the throttle as soon as I could/should. Constantly reviewing the data helps drive that lesson home and make me work at doing it better. What's the difference between a 1:58 and a 1:56? - an average speed of about 1.5 mph at TH. If your speed in a corner varies by 4-5 mph each lap, your lap times will vary too. The data system helps me learn how fast I can go and when I go slower, why. That's what I then work on.

mark kibort

Thats great data Tom. Im curious as to what you did differently. Having a lot of time on the track in a car that is just a little slower, it will be interesting to see what the difference was. so, both runs were on the cool day. Most of my data is only timed data from the video and reference points. Ive only broke the laps ive done in to 3 segments, so its really crude. BUT, if I hit the apex of turn 8 at a specific time, i pretty know what my end lap time will be.

You have REAL similar specs to the BMW e30s and e36s that can run 2500lbs with driver and have 285rwhp on slicks. It would be interesting to see how their data compares.

EDIT:

I just did a quick review, but there is a huge differnce in how you come into turn 1. blue line is much later on the brakes and also same into 2. that alone will be a big difference in the end. again, just a quick review, but it looks like in all respects, the blue line is the faster lap all the way around. thanks again. This will be great for me on those same issues that will help me get down a second or so on my times there. we end up with our last race there for our season.
thanks again for the post!

BGB Motorsports

I haven't yet watched the video and if I had the actual Motec files it would be a bit easier because I could scroll over the data. I'm sure someone else might have some better input, as I've never driven a Porsche around Thunderhill. We have however run the 25 Hour race there for the last 5 years, nearly winning overall last year and I love the track. It's one of my favorite in North America and I've also stayed at Holiday Inn Express several times before so...

Your faster lap has a higher rate of entry speed but you follow it up with much earlier throttle application, almost everywhere. There's a fine line between "fast in" and "too fast in." It’s no good to carry additional entry speed if you physically cannot go to the throttle because you've missed the apex or throttle application point due to too much understeer or oversteer (depending on your car's natural tendency to give up front grip or rear grip when overdriven). If you can’t go back to full throttle when you want to, there’s no point in carrying that much entry speed. You can see in the data that in T3 thru T7 the time variance doesn't change because you're switching back and forth between the two styles. In one of the turns (5 or 6) you have more speed through the middle but you can’t pick up the throttle. Zero change to the overall difference between those corners.

Thunderhill has very long faster corners and if you walk the track you'll notice that the exits of those corners are much more uphill than you'd think. If you carry speed in and you don't go sooner to power, you'll lose all that momentum at the exit. The exits of T1, T2 and T10 (i think it's 10... the fast left hander at the bottom of the hill before the slow left hander for the esses) are very much uphill and you're not losing your momentum because you're going back to power harder and sooner. Another good thing you’re doing is that In the corners where you're going deeper, your brake traces shows that your initial brake pressure in T1 and T2 is greater in lap 4 than in lap 5. You're cognizant of the fact that you're going deeper and you're following it up with more initial brake pressure or greater overall brake pressure. T1 doesn't go down exactly that way but you still apply greater overall brake pressure so as not to miss the turn-in point.

Any time you exit a corner that’s uphill, you HAVE to carry as much speed through the middle but not too much that you can’t get on the gas. I try and drive all corners like that but uphill corners hurt you twice as much because you’re going uphill. Every bit that you overslow or every foot you hesitate to go to power, your time gained will suffer.

John

SundayDriver

I saw a couple of things in the data -and agree that with the files, much more could be learned.

Fast lap had harder, later braking (in general) and earlier throttle that you tended to keep up. One other notable item is that at the very end (S/F) of the fast lap, you slowed much earlier than at the start of that lap. Had no effect on the fast lap but killed the following lap from the very beginning.

As a reference, when I started using MoTeC, I hired a data engineer with Indy car experience to help me interpret the data. One interesting tidbit I learned is that the elapsed time from when you come off throttle until you achieve max braking pressure is a good measure of braking skill and aggressiveness. Pros usually take 0.15 seconds for this. I was usually around 0.20. You could drag the cursor in the live data to measure what you are doing. I sense that you have gains to be made there.

Also, do you look at the oversteer/understeer data from MOTEC? While not very precise, it is a pretty good indicator of what the car is doing. I also found the roll and pitch were good to look at if you have suspension travel data. You can better understand if you are keeping the car balanced.

Personally, I also would look at inverse corner radius. That is an indication of how smoothly you are getting the car around the corners.

mark kibort

Good points, especially the uphill corner exit advice. However, being uphill and banked, alows for a slightly higher entrance and cornering speed, as you can then trust the uphill and banking to keep more traction on the exit, with applying the throttle earlier as well.

Tom W

I will post the MoTeC .ld file to the same spot as the video later tonight for any that want to play with it. I'll also post the full sized screen shots there too for those who are not adept at i2-Pro.

The great thing about MoTeC is you can do some much with it. The downside is it takes time to learn and then do it. I do have shock pots and I do look at the oversteer/understeer, shock histograms and calculated fron t and rear down force, etc. I'm just not that proficient yet. My MoTeC dealer (Dave Ferguson/Veracity Racing) has helped get me going, i just need more lessons (and the time it takes to utilize what I might learn). At the moment, my approach is more along the lines of fixing the bigger driver problems and then start working on the more finesse issues. I agree completely that a faster transition to the brakes and better brake control would help (I've reviewed what's on the Optimum G website), that isn't going to help much if I'm woefully inconsistent in my braking points and entry speed control. I did just add triple-adjustable shocks and am working to get them set-up properly too.

Anything you guys supply that helps me learn is a plus.