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Before I start, I will preface this by saying I’m an AiM dealer and data analysis is as deeply embedded into my post-session routine as lubing the kart’s chain.
You should decide whether you want to spend your time becoming a better karter, or building a better data logger. I’m not doubting your skills as an engineer, but AiM and other companies sell products which will fit your needs with analysis software that’s already built and should be wholly adequate to almost any karter out there. You can buy a Mychron 4 and GPS unit for $650 retail, and find them here used for less.
As far as tire temperatures go, karts aren’t like cars and formula cars. You’re not going to follow the same rules setting up a kart as you would a formula car or tin top.
The first sensor you need is a GPS unit. While it doesn’t quantify your inputs as a driver, it identifies the product of your inputs. You’ll be able to compare lap over lap, corner over corner.
Once you have the GPS and you have a couple bucks sitting around, buy the MyChron expansion, which allows you to connect 0-5v sensors to the MyChron.
There are differing opinions on what analog sensors are necessary, but the following is my opinion, including the order. I realize that budgets are finite which is why I order these in what I perceive to the most important first.
1.) steering sensor
2.) single axis accelerometer (used for lateral G)
3.) <span style=”line-height: 1.5;”>throttle position</span>
4.) Brake pressure
5.) Front wheel speed (either side)
Steering sensor is huge, as your input there has a large impact on your laptimes. It will give you great insight into how you are steering. You can also x-y plot the steering sensor against GPS lateral G to gain an understanding of the oversteer/understeer condition of the kart in any given corner, or an overall bias in one direction over the full lap.
The single axis accelerometer gives you an extremely accurate way to identify oversteer understeer condition when aligned so values run in the same direction as the GPS lateral G data. This is done with a math channel.
Throttle pos and brake pressure give you more qualitative insight into how you are driving each corner. Combined with steering input, this is how you will come to understand what is causing the time gain or loss through each corner that the GPS unit will uncover.
Front wheel speed (only need 1, side doesn’t matter) lets you do some cool stuff after your race using math channels in race studio.
For instance, you can use a complicated math channel which, using GPS lateral G, identifies the direction and radius of the corner your kart is in/leaving, then corrects the wheel speed sensor’s reading (which is only on one side) to reflect vehicle speed. Once you have your vehicle speed, you can compare that to the speed you are driving the rear axle at (RPM/gear ratio * tire rollout / 60 * .6818) to observe wheelspin as you get back into the gas off the corner. Rumor is that the upcoming logger will have the same capability of on-board math channels like the current automotive loggers do.