ColorChange

The victor was never in question. Fishman ... "you da man!"

Fishman is in a race so he may have had issues. I am using his fastest lap in session 3, Saturday during an enduro race where he was driving an unfamiliar car so he would be even better in his car on a clear track (not good for me). He is driving a race prep 944S2, I am in a 600hp 911tt on Michelin PS2’s. You can't compare real accurately, different cars, different days, etc., but I think you can still learn.

Let’s look at the data.


1a. Wholly throttle batman! The car accelerates like a rocket. I dusted a Z06, viper GTS, Lotus Esprit like they were standing still. Even race prep cup cars didn’t stand a chance. But as far as driving goes, big deal: anyone can stomp the throttle – but is sure is fun!

1b. I brake earlier because I have to. I brake harder than Greg. You can see I either lightened up on the braking because I hit the hooks too early or I had a bad double clutch downshift (probable as I was having trouble with my short sifter - slop).

1c. Greg’s has ***** and I don’t! It looks like (from other turns) we can pull an equal lat g max even though he is on race rubber, but I have bigger tires, so, he just went in hotter and took his car to the limit. I’m a coward.

1d. This higher lat g load (and lower mass car) results in a much higher turn speed for Greg, 85 versus 77 mph.

2a. Greg says “Welcome back Tim, where’ve you been?” I am real close to Greg on turn 2 (yeah I know, blind squirrel …). Good job for me.

2b. He got on the throttle a little earlier than I did as I put in an ever so slight lift that I don’t think I needed.

3a. We are very similar through turn 3. My higher speed means I build lat g’s sooner and I peak a little higher than he does, again due to my higher speed.

4a. We take a different line through 4. Greg brakes earlier, is on the throttle earlier, while I brake deeper and harder, and get on the throttle later. This is somewhat of an example of different lines for different hp/weight cars as the graph shows, where I am faster coming in and slower out but, when you plot the data as a function of time, my speed advantage coming in disappears and you see that I am slower through the apex and track out so I could still be over braking too late. When we look at g-sum you will see I did very well but may have been on the wrong line.

5a. OK Greg got out the big turn 1 stick and pummeled me ruthlessly again. I get destroyed through the 5-6 combination. I am still too timid in taking my car to the limit on these high speed turns. He pulls about a 0.1 or more lat g’s higher through here than I do.

5b. I brake a little too much here and overslow for the entry.

5c. When you combine Greg’s higher lat g’s, with the lighter car, this translates into about 7mph difference. I suck.

6a. + 6b. Same thing as turn 5. Greg’s pulls higher lat g’s and I did a throttle lift that was completely unnecessary; chicken sh*t!

7a. Well, as Greg welcomes me back to the race, again, I do OK in turn 7. We pull equal lat g’s but you can see, Greg is slower in the turn but on the throttle sooner. His line is faster and he drove it better (higher g-sum).

7b. Appears to be a case of I cam into the turn to fast and could not get on the throttle soon enough. I’m faster on entry, Greg is quicker on exit. He wins this one.

8a. I do pretty well in 8. I pull a little higher lat g’s but Greg’s lighter car is still faster. You can see where I am purposefully trying to lift off the throttle to get my car to rotate (fighting push) as I go around the turn.

8b. I over braked the turn again. Damn! It is easy to see on the g-sum plot but you can also see the speed difference in the early part of the turn where Greg kills me.

9a. I think I actually beat Greg on entry here! Yea!!!! Unfortunately, he buries me on the rest of the turn. I pull higher lat g’s and come in faster to 9, but then I chicken out as we go through the rest of the turn.

9b. I brake harder on entry because I am gong faster coming in but you can see I trail brake on entry and beat Greg on the entry.

10a. Now the man with courage destroys the chicken sh*t pup! The big lat g drop is a slight off camber drop as you drift out to the pit exit area and it scares me as the wall is coming up close. Greg fears nothing!

10b. Look at how much smoother Greg is with his throttle modulation. I’m all over the place searching for the limit. Then at track out it’s bye bye with the right foot.

Here is the g-sum plot.



Yes, I have now proven that:

1. Fishman is hot shoe
2. I suck
3. The throttle covers a multitude of sins

924RACR

Nothing like some good hard data to show slow-in/fast-out wins the day! I've just been re-hashing my own old data in preparation for this weekend's racing (Waterford Hills), and revisiting that concept myself. Funny part was that last I went out, I made a conscious plan to not overdo the braking - never went beyond 0.8g decel - since I didn't have any competition, and yet even so I found many instances each lap where I overdid braking, either too late, too hard, or too long! As easy as I was on the brakes, I still overdid it.

Just like they say - Brakes? Who needs 'em! They just slow you down anyway!

As for the above data - I wouldn't be so harsh on yourself about lateral g's, especially considering the tire difference... I can show countless of my own laps with higher lateral g's and slower lap and segment times anyway...

Sanjeevan

C.C. I want to thank you for sharing this with us, I found it VERY informative, and I certainly learned a lot.

Z-man

Tim:
You are comparing apples and oranges, but still an interesting comparison. You're comparing your DE times against someone in an enduro. An enduro driver typically don't be at the max g-sum as long as someone in a sprint race. Let me explain:

Let's say that a racecar corners the best at a slip angle of somewhere between 10 and 15 degrees.
Let's also say that you get two drivers: one who can consistently run at a 10 degree slip angle through the corners, and one who can consistently run at a 15 degree slip angle. Now, put them in an enduro. The 15-degree driver is going to produce a greater g-sum in the beginning of the race, and theoretically, he would pull away from Mr. 10-degree racer. HOWEVER ultimately, our 10-degree racer will have the upper hand as the race progresses. Why? Because he is using less slip angle, the 10-degree slip angle driver is putting much less wear and tear on his tires! Initially, he will have a lower g-sum, but his g-sum will not fall off as early as the 15-degree slip angle guy. In the end, his average g-sum will be greater than the 15-degree slip angle driver. (For further reading on this, check out: Speed Secrets Ross Bentley)

I suspect that if Mr. Fishman were running a sprint race, you would see a slightly different (and perhaps more agressive) g-sum plot.

-Z-man.

SundayDriver

Seems to me there are a few very good lessons here. First though, let me say thanks for posting this data. It is interesting and useful. But, you create an extra challenge by having to do this with two different cars. I really suggest you get someone like Greg to drive YOUR car so you get even better comparison data.

Others, and myself, have said that speed comes in three steps; line, exit speed then entry speed.

Line - You say your line is pretty good. I would like to hear if Fishman thinks you have it down well and are consisent. The data can't really tell us all that much.

Exit Speed - I think you say a few times that he is beating you here. The data pretty clearly shows that. It looks to me like you are leaving seconds on the table by not maximizing your exit speeds. If you do have the line down pretty well, then Exit Speed is what you should be paying the most attention to, at this stage.

Entry Speed - Again, you state more than once in your analysis that you entered too fast. Tim, you are making some very common mistakes in this area. Mistakes that others have told you that you are making and you have insisted that entry speed with deep (trail) braking is important to your progress. The data does not support your earlier assertions.

I think your analysis of your own performance is pretty accurate. I also think your analysis contradicts many of the things your argued earlier.

G Data
What, if anything, can you learn from the G-Sum that the speed trace does not tell you? I don't see anything. However, I see a number of details that the speed trace indicates that are hidden in the G-Sum. For example, G-Sum shows you get an early win in T9, as you say. Does that mean you then made an error and gave it back, or was the error taking the entry speed at the expense of the exit? Not knowing the exact corner (I've only been there once) the data makes me suspect you let the car get out of balance and suffered for that choice. Fishman gave up early speed in favor of balance and was able to use all the car in places you could not. I am truly interested in any lessons you think that G-Sum provides that are not equally or better seen with the speed trace.

Finally on G data, how do the 2 FC's look? Is there anything to be learned there that is not better seen with speed traces?

I think you are on the right track. I also think you can learn better from your data using speed data, rather than g's. But, if you can show me where g data is better, I would gladly admit it is better and use it myself.

Again, thanks for posting. Good stuff.

Larry Herman

Ok, here's where I am the novice. CC, for me and the other DAS impaired, would you explain what each line means. I figured out the speed line, but am not sure what the other colors represent.

Brian P

While this might be true when looking at an entire race, I've found very little difference when looking at best lap time between an enduro racer and a sprint racer. In other words, if you look at the best lap time for a given class, it's about equally likely that that time came from a sprint racer as it is from an enduro racer. My analysis comes from looking at all of the results of PCA club racing.

I suspect the difference is that the enduro racer might do that best lap just a couple of times during the racer. The sprint racer might do that best lap nearly every lap.

Jim Child

I was chasing Greg nose to tail during most of his enduro stint, and I can assure you that we were both running as hard as we would in a sprint race.

Greg Fishman

Tim,
I take it you used our hypothetical best lap between when making a comparison?
Just curious what the difference in overall lap times were.

Also, this was my first time ever to drive a race prepped 944S2. I used to own a 944S2 cab many moons ago though. Also this was a practice session that allowed for a co-drivers to drive in preparation for the enduro.

Z-man

Nice. So much for theories.

Ok: I'll be burning my Ross Bently book tonight!

-Z.

Jim Child

Don't do that! Just keep in mind that a PCA enduro is only 90 minutes, and not really comparable to the 12 and 24 hour endurance races that Bently was probably referring to.

Brian P

I thought Ross was giving an example of three different drivers.

Driver A might have a certain grip level at a 15% slip angle. Driver B would have the same grip at a 10% slip angle. Driver B would win most races for the following two reasons:

1) His tires are being worked less hard, so they will last longer.
2) Mistakes by driver A (i.e., going too fast) would cause him to lose grip and become more likely to spin. Mistakes by driver B would actually cause him to gain more grip and go faster.

However, driver C might be driving at the optimum slip angle of 12.5% (btw, pulling numbers out of thin air here, don't try to use them unless you enjoy drifting contests). His tires would last long and he would be carrying more speed through the turns.

Greg Fishman

Yes, sir. I was running hard as I could, every turn, every lap. I had to drive hard to stay in front of you, after your pit stop. Car was going away due to a problem in the alignment (no negative camber in the driver's side front) and I couldn't finish the race.
Anywho, this section was from the day before the enduro's practice session.

Professor Helmüt Tester

That's not an 'enduro'...that's a 'warm-up session'.

Z-man

Don't worry - I was just kiddin' But thanks for the clarification.

So then how long is a squirt race? (Er: I mean a SPRINT race)?

-Z-man.