SundayDriver

I wonder if this guy is smart enough to start with the right tire pressure?
Ooh. Did I really say that.

Mike in Chi

"For those who are reading these posts, please do not beilieve the vast majority of what you are reading. Most of the comments are flat wrong and reflect an amazing level of ignorance/misinformation. "

For those reading this thread, Sunday Driver will be driving on a Saturday in 6 weeks for the National Championship at the SCCA runn-offs in a class of pure, purpose-built race cars. Isn't it amazing where an amazing level of ignorance/misinformation will take you?

In contrast, an amateur theorist was ready to sell his TT a few weeks ago because for some reason it didn't handle for **** when his tires where over-inflated by 10 lbs.

Please draw your own conclusions, after careful consideration.

Robert Henriksen

How many national championships did Miliken win behind the wheel of his own car? With his ability to come up with these theoretical models, he must have been a hellacious driver.

nman413

I cant wait for Haiku time

JackOlsen

These are my favorite two quotes of the past week on Rennlist.

One is true in a way the author didn't intend.

The other is just plain true.



The Haikus can't be far behind.

DJ

No Friction Circle?
Those scribbles are holy writ
Data rules, not skill.

bartman

Excuse my igonorance, I'm only a registered professional mechnical engineer (great, so now when I screw up at work, not only do I get fired, I get to go to go to jail too!!!!). The majority of posts seem to think that FC's are completely worthless, but wouldn't they at least provide some kind of baseline for comparison, i.e run the FC, do a mod, and then run again to see the delta? Am I missing something? I do agree that as a real world arbiter of performance it is highly limited, but there has to be some useful data there.

Adam Richman

"I've driven from one side of the track to the other, I've seen a lot of strange stuff, but I've never seen anything to make me believe there's one all-powerful circle controlling everything. There's no mystical friction circle controls my destiny."

Geo

What would it tell you and how?

First of all, the FC is strictly theoretical.

Second, FC plots don't relate to track positoin (i.e. where)

Third, who really gives a rat about max G besides Colorchange.

The reality is that you can gain so much more from traditional data acquisition that provices significantly greater amounts of data. It is linked completely to position on the track (and isn't one big scribble). It allows you to take sector times which is ultimately the goal, not g forces.

There are far better ways to acheive the ultimate goal of faster lap times.

RedlineMan

(Editor's Note - This is not a rant directed at Bartman. Read it rhetorically, please )

Yes, Bartman;

That would be a tremendous way of judging the effect of tuning or equipment changes, but how would you propose to do it? I mean, how would you then go out and drive the same exact plot on your FC? Same car position and angle, same turn in point and steering input, same g-load, same fuel load, same throttle application, same track temps, driver can't even take a freaking dump before the session.... you know?

If you miss the vaunted FC by a little bit, was it the miss or the mod that made the car do what it did, relative to your baseline? If you even COULD drive the perfect FC, it would likely be a fluke, and you might be driven to suicide trying to ever duplicate it again. You might hit it again, but with a completely different set of inputs. While you're lost in the quagmire of data, everyone else is having a blast... DRIVING!

I'm not an engineer. I'm merely the thespian; playing one in my shop every day, elbow deep in Porsches. I know that as a PE you are enjoined by cerebral indoctrination to uphold - or at least defend - the results of learned theory and calculation. We forgive you your studied inclinations. And yes, you are correct that there is merit in discussion of the FC... in the abstract.

What you are seeing here, as much as anything else, is a reaction to Color's insane reliance on data, and his insistance in its absolute efficacy, to teach himself how to drive. The rest of us have done it the old fashioned way; by driving. How bizzar is that?

When Great Grandpa grabbed your Dad by the seat of the pants and tossed him off the dock, he didn't shortly thereafter fling in a spread sheet showing the theoretical best way to cup the hands and stroke the water to keep oneself afloat. Is there value in learned instruction? Absolutely. However, we are all here today, so Dad must have done alright by his own instinct, eh?

No matter the data available, driving will always be done where the rubber meets the road and the hands grip the wheel. That's where theory goes out the tailpipe!

RedlineMan

Oh...

And Sunday;

In six-weeks time, may your ingnorance be at its Zenith!

SundayDriver

Not completely worthless, but worth far less than other ways of viewing the same data and pretty much worthless as a tool to develop as a driver.

The FC will tell you pretty major things, but it is the combination of car/driver/track. The highly respected book by Milliken & Milliken (some of us really have read this, can spell the author's names and credit both authors) makes the point quite clearly that it shows the overall system. The examples in the book tend towards a comparison of 2 F1 cars 5-6 years apart or a race drvier vs. street driver. They clearly show the vast differences.

BUT, for driver development, the g vs lap time (or position) is far better because you can see where you are on the track for the g event. You can also overlay throttle, brakes, steering, moon phase or anything else you think is important. The g-g graph just doesn't show you much in this regard.

For tuning a given car, let's start with the premise that the car is close to working right. If not, then the driver can feel this, big time, and no data is needed to tell you it is ill handling. So with a car that is pretty close, what would you do with g-g data? Most changes will improve one things and hurt another at this stage. But the g-g graph will tend to hide this unless you have helped left handers and screwed up right handers. Even here, the strip chart trace will show the same thing, only better.

If all you have is a hammer, then the whole world looks like a nail. If all you have is a g-g graph, then that is a great tool to you. BUT, all data systems today, offer much better tools than the g-g- graph. So, my position is that it is pretty much worthless when considered within the range of tools we have available for tuning the car and developing the driver. So directly answering your good question about it having at least some useful data, I would say yes, there MIGHT be a case where it makes some sense, but usually not the best choice and in all cases there is something to be learned but it is not the best tool to use to learn that thing.

The reason for this thread and comments is because we occasionally get someone who feel that the g-g graph is the be all end all. This time around it is ColorChange - last time it was GhettoRacer. Neither could ever support their positions about that tool. Color simply says read Miliken (sp) and it will be clear. Well I read it long ago and continually refer to it and I don't see anything in that text that supports his assertions.

SundayDriver

Thanks. It will be my first time to do the run-offs and I am really looking forward to it. We have a lot of very fast cars (I have one of them) and a bunch of very fast young drivers (I miss the mark there). But it is the only opportunity to run a race with that many cars in the same class, all to ourselves. For me, it is all about how many cars I can beat and the camaraderie of the group.

924RACR

Mmmm... I am an engineer, Mechanical by training, specializing in Vehicle Dynamics (though admittedly of a different sort than the Ross Brawns et al of this world), and spend far more time than I'd care to admit in fully-instrumented cars doing nothing but taking data, analyzing it, and re-running with revised tuning. But I try not to admit it too often - if for nothing else than the fact, or at least my perception, that engineers seem to be one of the least humble groups of professionals out there!!! I try in fact to bring up that qualification only when it directly applies to the discussion at hand - ABS/TCS/ESP systems.

Beyond that, I'm still a mid-level racer trying to learn how to improve my (on racetrack) driving ability from the data I gather, and have a difficult enough time trying to boil down two simple channels enough to draw conclusions! Just evaluating AY and speed on one track (Waterford Hills) are challenging enough, for me. When I get more sensors hooked up (I'm going for yaw rate and decel, plus maybe throttle and steering if I feel like working up a steering angle sensor), I'll really be swamped by the noise.

As a personal aside, if anyone else out there has their own data from Waterford and/or would be interested in looking at mine and giving feedback, I'd be happy to send my data (AIM system). I've only had one weekend on track with data, so still am working my way into it.

Mark - good luck at the Rub-Offs! (spoken like a true IT driver!

Robert Henriksen

Colorchange Race Team
engineer will drove the car
All the way to last