Geoffrey

Merry Christmas to you all, I hope everyone is able to spend time with family and friends, I know I will.

Next Saturday I pick up my new 92 C2 Coupe...Oh, but that's a different subject. This week I finally got back to my race car and removed the engine and transmission to look at the clutch since the Tilton multiplate product is new to me and I want to ensure its longevity. I also need to adjust the valves, change the engine mounted oil filter, and do a leakdown test on the engine. In the process, I ordered some additional sensors for the car, which I'll install in the next month.

String potentiometer - This sensor will be mounted in the driver's footwell and attached to the steering column. This will allow me to log the Driver's steering input which then can be coorelated to lat-G force as well having the channel differentaited to get steering acceleration which can be used to see how agressive the steering wheel is moved. It can also be used for a number of additional analysis functions.

Gyroscope - The gyro will show the yaw speed of the car. You can use a MoTeC math channel to integrate the channel and obtain the yaw angle which will show the angle of the corner, and you can differentiate it to get the yaw acceleration rate.

Infrared Tire Temp - Ultimately I am going to install 3 IR tire temp sensors per wheel to see tire temps in transient on the track which will help determine the vehicle setup. For now, I am going to install a single IR Tire Temp sensor in the chassis to log the track temperature which I can then correlate to the manually measured tire temps and pressures

Linear Potentiometer - I have 4 linear potentiometers which I will install on each shock. This allows me to produce shock speed histograms which can then be used to properly set up the adjustable shocks I have. From the 4 sensors, I can get over 60 pieces of information about the vehicle relating to forces, roll, pitch, aerodynamic, etc.

enjoy.

PS. The second Total 911 article is out.

earlyapex

Happy Holidays!

Congratulations on the Total 911 coverage!

38D

Way cool

Benton

Too cool Geoffrey. One day, I hope to know half as much as you do about cars.

OT, are you an engineer? How did you learn all of this cool stuff, including all the stuff you know about data acquisition?

Larry Herman

Are you going to make this a series too? It would be facinating to see what information you get, and how you apply it.

kgorman

I just read the first article. Fantastic stuff. I am also interested in how you use the data to tune.

95m3racer

Using IR for tire temps is tricky.

First issue to solve is you have to maintain constant distance from the tire, so you'll need a bracket that is attached to the hub that turns with the front wheels. You also need to assume its the surface tire temp, which usually does not tell you too much. You need core/cord temperature.

Something worth looking into is interior tire pressure sensors that you can log via motec an watch tire pressure changes (use a high hz value to see more definition in the data).

Steering pot will be a HUGE benefit to your existing data. Steering angle + TPS + Brake position sensor + brake pressure distribution + shock pots + ride height sensors + Tire temps/pressures, you'll need to hire a daq engineer to give you a hand at the track. By the time you decifer whats what in the data the weekend will be over

Looking forward to seeing how you mount everything Geoff. Happy holidays and have fun!


Oh and in regards to the comments on how he tends to use the data for making the car/driver faster...thats the tricky part. This is more data than most entry levle pro teams have in touring/gt series, so he's definitely going to have his hands full.

Data is useless by itself

SundayDriver

Actually, surface temps, in real time, are far more valuable than core temps. The reason that core temps are done is becuase the surface temp changes too fast to read in the pits. Geoffrey took the 3 day Claude Roulle class and knows what to do with the data. And you do not NEED a dedicated data engineer if you have the system set up in advance and know what to look at.

You are right about the bracket for front tires but distance is not the big issue there - it is that you will be reading different parts of the tire (or the air) as the wheel turns.

Geoffrey

I would like to find a cost effective tire pressure monitoring system that communicates via CAN so I can interface it with MoTeC. The ones I have seen are in the 6k range so I'm not ready to check them out yet. If you know of something, I'd be interested.

I would generally agree that the core temp of the tire is important, however, IR Tire temps can be extremely useful in understanding how hard each tire is working and how well you setup in general is working. By using the averages of the inner, center, and outer for an average tire temp. Then you can compare tires against each other in various corners to understand where to look in suspension setup when you see gaps between the tire temps. You can begin to look at how roll moment distribution effects the forces applied to the tires. By plotting tire temps against lat-g you can understand at what tire temp the grip is maximized.

With the IR tire temps, you are looking at relative information, not necessarily specific values. It helps to determint the appropriate tire pressure by using math channels available in the MoTeC as well as camber. You can also export the tire temp averages per lap to an excel spreadsheet and plot them as a graph which can give you indications about how the tire is wearing and how long it takes to get up to temperature or how the balance of the car may change due to temp (grip).

As valuable as I belive them to be, it wont' be until later next year when I get a chance to install them given their rather heafty price tag and the complexity of installation.

This car represents my pursuit in understanding race cars at a higher level and to be able to provide better services to my customers because I will have done it and will understand it in detail.

SundayDriver

Congrats and very cool. Which gyor are you going with? I am doing a tunnel floor so I don't think the budget will support 13 IR sensors but I think I am going to do 4 or 7 - depending on what will fit available channels. I hope the FM team will take the plunge for full IR.

Are you doing (or do you have) the Chasecam?

ps - I have not forgotten about my promise for math channels - I am working on that for you.

An interesting observation about data - We both learned a lot in Orlando - one of those things is clearly how little we really know compared to the experts who do this 24/7 for many years. Yet many folks get a simple system, use it for a few months and think they are the experts. I have been seeing a lot of posts about data from folks who clearly do not know what they don't know.

Geoffrey

I went with the 10mv/degree gyro from MoTeC since I am a dealer I didn't really consider much else as they are price competitive and their sensors work well with their systems.

I don't know if I'll get a chasecam or not. It was a very good demonstration they had at the PRI booth and looks interesting. Basically I'm too lazy for the video part.

sleder

Geoffrey, I've read your 1st article, you have assisted me on numerous occassions, and I just want to say you continue to keep me amazed! As Larry said, I hope you make this an ongoing series so we can all learn the value of data acquistion and how to use it for ourselves.
Happy Holidays!

DaMan-993TT

A good read on IR temp sensors can be found here:
http://www.omega.com/temperature/Z/IRTC.html

I found it was cost prohibitive to get the right kind of data out of IR sensors. To get the IMO data the same like a pyrometer you need 12 narrowband sensors.

Challenges are wirering 12 sensors, maintaining sensors, they get very dirty quick, and replacing damaged sensors, 3 in one season.

I have since ripped it all out and sold them on eBay.

924RACR

I'm glad to finally see someone else putting a steering angle sensor and yaw rate sensor together - will be interested to see how you find working with the data!

I agree on the video - it's fun and cool to share/show off, but can sure take a lot of time to tie it in to the full data experience, and that's still ultimately just a gee-whiz factor at the end of the day, for me...

Phokaioglaukos

I had the good fortune to draw Geoffrey as an instructor at WGI with a BMW DE. I did not know him, and I did not know his car or his skills. I learned a lot that weekend, and there are things he told me then (and in later e-mails!) that I am still thinking about. There are so many good drivers who are also good instructors in the BMW and PCA programs that I am so very fortunate. Geoffrey, Larry, Don, and so many others. This is more than a sport or activity--this is, as Keith Code is wont to say, "as good as it gets."

And what is really great about it is that it will get better. Better as my driving gets better. Better as I learn data acquisition. Better as I meet more of you on this thread.

Thanks, all.

Maybe this winter is still time to install simple data acquisition.