How to quickly and easily find speed from those data traces

J.G.
By J.G. Pasterjak
Apr 15, 2024 | data, Lap Times, Data Traces | Posted in News and Notes | Never miss an article

Photography Credit: Chris Tropea

All the squiggly lines in the world mean nothing if you’re not taking the time to decipher them and turn that info into a plan.

Who has time to analyze all that data? Not many of us, that’s who. 

But you can find time with even the quickest of glances and the simplest of data systems. Don’t let data overload convince you …

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Comments
gunner (Forum Supporter)
gunner (Forum Supporter) GRM+ Memberand Dork
7/28/23 2:04 p.m.

Ah, this article will help me finally be able to interpret some of the squiggly lines during practice in assetto corsa. My climb from backmarker to mid pack is all but assured! (Insert evil maniacal laugh here)

MockingbirdRacing
MockingbirdRacing New Reader
7/28/23 2:28 p.m.

Wow this really helps understand the data trace. Just spent lunch looking at some recent laps and in the data can see where I left time along with every shift point and lift for curb bashing. Now I understand a bit more and can compare more than just lap times and entry and exit speeds. Thanks for the article.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
8/1/23 12:10 p.m.

now i need a way to record data

and a running car to generate data

:-(

ETM
ETM None
8/4/23 1:50 a.m.

What other channels would you suggest to log besides speed and distance that could help detecting those mistakes and take advantage of those tenths of seconds needed to beat my fastest lap time? 

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
8/4/23 11:47 a.m.
ETM said:

What other channels would you suggest to log besides speed and distance that could help detecting those mistakes and take advantage of those tenths of seconds needed to beat my fastest lap time? 

IME, the speed trace over distance is the single most important data trace, you pretty much always start with this trace for identifying problem areas to focus in on.

The next tier of traces in importance are the driver inputs -- throttle position, brake pressure, and steering angle.  TPS is usually pretty easy to get on anything made in the last 30 years, and of the other two brake pressure is way more important than steering.  Once you've identified problem areas in the speed trace, you go to these traces (along with the accompanying video) to identify the reason for the problem.  Abrupt brake release, throttle too soon, throttle choppy, etc.

Pretty much every other trace after that is for addressing specialized problems.  If you've got a CAN bus car then getting engine data is usually pretty easy, and having temps, pressures, RPM, etc is nice if you're ever chasing an engine problem.  Wheel speeds are sometimes useful for understanding ABS or differential behaviour.  Ambient air temp is nice if you're comparing two runs from different days and want to see if that might account for power differences down the straight.

ShinnyGroove (Forum Supporter)
ShinnyGroove (Forum Supporter) Dork
8/4/23 12:02 p.m.

The real power with the data is if you csn compare your lap to a reference lap from a faster driver in the same car.  That is where throttle position and brake pressure channels are really useful.  Faster drivers usually brake later, brake less, and are on the throttle more. A time plot comparing your lap to the reference lap is nice; you can see specifically which parts of the course are costing you the most time. The other big thing is to get good video and integrate with data overlays if possible. Once you home in on a particular corner to improve, the video is a critical tool. 

JG Pasterjak
JG Pasterjak Production/Art Director
8/4/23 12:08 p.m.
ETM said:

What other channels would you suggest to log besides speed and distance that could help detecting those mistakes and take advantage of those tenths of seconds needed to beat my fastest lap time? 

Aside from a speed/distance, you can learn a lot from a friction circle, particularly about how you're transitioning from acceleration/braking into and out of corners. Just a quick glance at a G cloud will show you whether your trail braking or progressive throttling needs attention.

As for additional inputs, I'll agree with codrus on the throttle trace. Typically the throttle is going to match up pretty well with the speed trace, but you can find a bit more info, particularly from mid corner on, by looking at the throttle application.

Brake trace is also great, and arguably more important than throttle trace, but frequently harder to come by as a lot of ECUs don't give you easy acces to brake pressure readings. But if you have access to it, it's a great channel to add.

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