Learn me Data acquisition - autocross

I hope the GRM brain trust can point me in the right direction. I’ve searched the magazine and forum archives, and the info I found is either pretty old, or doesn’t really address my questions.

I finally got my project up and running and have been having a blast at the local autocrosses. It has become abundantly clear that as bad as my car fabrication skills are, my driving skills are worse. I’ve heard from numerous people, and various things I’ve read that data loggers can provide a wealth of info, and really help you see where your shortcomings are, as well as experiment with different techniques in a section and learn which one works better.

There are a variety of systems I’ve read about in the old threads, and looked at the websites. I’ve seen lots of conflicting info and some company websites are pretty out of date. If this is covered somewhere please let me know.

Are there any of the data systems that work especially well for autocross? It seems some don’t work well on courses where you don’t get back to a set starting point. What other issues do you have in using them for autocross? How do they start and stop times? Also, this will be much more feasible if i can split it with my dad, are any easy to switch between cars? Do any work well, or not well with megasquirt controlled cars?

I’ve seen some with video, and some without. How much useful info comes from the video vs. the gps/accelerometer data?

What are the pro’s and cons of the GPS systems vs. accelerometers?

How do you best utilize the data?

watching this with interest.

The Race Capture Pro is pretty "grassroots" friendly. Start and stop can be triggered by some kind of activity from the car (like high-rpm launch detection), or just a button on the unit.

http://www.autosportlabs.com/

Ooooh, price has gone up a bit...should have got in on the crowdfunding like me

Oh and ECU integration is pretty much a non-issue unless you're depending on an OBD2 interface for sensor readings, in which case you'd be SOL with any aftermarket ECU.

Oh BTW the really cheap and easy option is to use a smartphone app. This gets you accelerometer readings, GPS coordinates, some have video integration (just saves you having to match up your video and data manually), and some have an OBD2 interface for sensors as well. The data won't be the best quality due to the crappy accelerometers and GPS receivers most phones have, but if you just want something basic for cheap that's an option.

I'm kind of surprised that a MS style job hasn't been done. There are some really cheap microprossesors out there, which can be put together with a whole host of sensors- fast gps, 3 axis accelerometers, 3 axis rotation, and other inputs.

I was going to do that and use with an older verion of this- http://www.racechrono.com/ but I lost interest in racing.

The RCP is the "MS style job" of the data logging world. Even better since it's properly open source (libre) hardware & software.

Can the race capture be synced to video? I saw some that had side by side run viewing, that seems really useful, anyone know which ones do that?

GameboyRMH wrote: The RCP is the "MS style job" of the data logging world. Even better since it's properly open source (libre) hardware & software.

yes and no. Yes that it's open source, but no- it's not a assemble yourself kit.

Taking a step back, I'm sure there are some useful things to learn in an autocross from data - I've even logged data in TraqMate during autocross events. However, I don't think it's nearly as useful as in road racing.

The problem is that you generally only get a few runs on any given autocross course, so it's not like you can really try lots of different lines or stop to analyze your data in the middle of an event. Also, in the limited number of runs you get, you will probably still be figuring out the best path through the cones right up to your last run, and it will be obvious when you get it wrong. You won't need a data log to tell you "oh, hey that slalom worked much better with a lower entry speed", etc.

Additionally, you already get your time slip for every run so you know if you were faster or slower than the previous runs. Data logs can break this down into smaller time segments, but in autocross the course is so short that you don't really need to break it down much more.

IMO, there's not a lot of use for data in this situation. You'll be much better off just getting more practice, focusing on learning how to read the course and riding with other drivers/having them ride with you.

Where data might be more useful is in car setup. Recording max later G, timing runs through a 'practice' slalom, etc can help you set up the car, but I don't know that it's worth investing in a full data logging system for this.

The part of tuning your car is a big reason I'm interested. My homemade Frankenstein has lots of room for improvement, and I'm hoping this will help me pinpoint it.

Also, I know I have an overall time, but if I was trying to find the best line in one area it would be nice to be able to separate it from the rest of the course.

I think another reason I'm interested is my region is small, and no one really has anything that compares to my car, so I'm at a loss for where to start kmproving both driving and setup

icaneat50eggs wrote: What are the pro’s and cons of the GPS systems vs. accelerometers?

FYI, I think most of the nicer systems have both GPS and accelerometers. One issue I've had in my limited logging of autocross data is that the GPS data is not really accurate enough for such small courses. I would see my runs shift relative to eachother on the overlays (this is using TraqMate). This makes it very hard to compare runs base on distance covered etc, and the way TraqMate separates the course into split times the shift in the overlays would mess up the split times. Other/newer systems might do this better. The TraqMate I used for this was really old (maybe 7 years old)?

icaneat50eggs wrote: Can the race capture be synced to video? I saw some that had side by side run viewing, that seems really useful, anyone know which ones do that?

All of them do that if you line up the video manually in post-production (using some 3rd party software like Race Render). Some have camera integration where it starts the camera recording when you start logging, or vice-versa. Some of the smartphone apps integrate with the smartphone's camera, like Harry's Lap Timer.

The RCP can be integrated with a GoPro2 using a DIY cable.

I'm actually looking for the kind of anti grassroots. I want real easy plug and play and great tech support

In reply to icaneat50eggs:

there have been a lot of advertisers in recent GRM's for that.

Just got home and am bendin pages now. I just wondered what everyone's experiences had been

There's autocross and then there's AUTOCROSS. Are you doing 3 short run SCCA stuff or 8-12 run local car club autocross?

With the 3 run stuff I can't believe you can get anything worthwhile out of it, but if you're running many, many runs then you might be able to make the comparisons.

In reply to icaneat50eggs:

I've seen people here post about Trackmate,

(just keeping your thread up in the list... )

We usually get at least 8 official runs In addition I try to get one or two with a good driver behind the wheel.

And it is scca

I saw a lot of people using solostorm in Lincoln. I'm tempted to try it. It seems to be good for reviewing between runs.

I second solo storm. One of our local hot shoes gave s little demonstration. I was impressed. If you know what you are doing, you can review your data between runs.

carguy123 wrote: There's autocross and then there's AUTOCROSS. Are you doing 3 short run SCCA stuff or 8-12 run local car club autocross? With the 3 run stuff I can't believe you can get anything worthwhile out of it, but if you're running many, many runs then you might be able to make the comparisons.

Anyone want to she'd some light on this comment about scca vs real autocross? What's with the 3 runs comment?

In reply to icaneat50eggs:

In most of the regions with really big SCCA membership, there are so many people turning out for autocross events that there's only enough time for everyone to make 3 or 4 runs during the day. IMO, those types of events really emphasize past experience, and the drivers' ability to memorize the course, think far ahead, and recognize common course features and the best way to attack them.

With such few runs, it will be fairly obvious where you need to improve and what you've done wrong on previous runs and data review is probably not terribly useful.

Most non-SCCA events have far more runs and you can probably learn the course enough and get clean enough runs that data might be somewhat useful for improving.

icaneat50eggs wrote: Anyone want to she'd some light on this comment about scca vs real autocross? What's with the 3 runs comment?

At the top level SCCA events (nationals, tours, etc) you only get 3 runs per day. This is partly because they have high attendance, and partly because the event is run more rigorously. Cars always run in the same order, assigned grid spots, every cone is numbered and the precise ones knocked down are recorded for each run, etc etc. Doing all that stuff slows the event down vs the typical local event.

Apparently some people have forgotten they started doing this to have fun

In reply to icaneat50eggs:

I tend to agree with this. If having fun is your only goal though, I would forget about data and spend the money on more seat time.