Data Acquisition EFI Technology Logger

Proper harnessing is both an art and one of the most time consuming, pain in the ass things to do. It's not cheap or fun (well, some might think so), but in the end it's all worth it. Proper harnessing starts with proper wire, proper wire isn't what you get from Manny, Moe, and Jack. Wire will be of a multiple conductor type, that meets the following specs. Now, I know what you're thinking: "This stuff must be expensive right?" Wrong. Proper wire isn't very expensive. The typical recommended brand is Raychem Spec 44, or Spec 55 wire. Spec 44 and 55 wire is well insulated, lightweight, extremely durable, takes heat well, and consistent.

With your wire taken care of let's move onto the sleeving or covering of the wire. A large variety of brands are available; in fact, there's a huge amount to choose from. The two most common are Raychem NTFR and Raychem DR-25. There are a lot of misinformed customers out there who wholeheartedly believe if it doesn't have the silly yellow Raychem writing on it then it's not good sleeving. This is far from the truth, while Raychem's NTFR sleeving doesn't have pretty writing on it, it has superior abrasion resistance, slightly less heat resistance, but it costs quite a bit less. Either one is perfect for a race car harness. All connectors should be properly booted and epoxyed-no sense in sleeving a harness and then leaving it open where it's terminated.

Let's talk about terminating a harness. While some connectors you might be forced to use attach to the manufacturers component, there are some options.

Mil-spec connectors offer a great compromise for durability, serviceability, and cost. It's the choice that all the JDM boys use on their hard-parking firewall mobiles. Mil-spec connectors feature pin-type contacts that are easy to crimp, install, and remove. Best of all, they can be crimped solder-free. What's the point of adding a mil-spec connector if it just terminates to a factory connector on the other end?

Autosport connectors are any data acquisition/race car guy's dream. The connectors are known for their cool black anodized, lightweight aluminum housings and super-high density. They are your ultimate connection solution. While almost twice the price of mil-spec connectors, these are the best.

DTM connectors are probably the absolute best-bang-for-your-buck solution on the market. These connectors are cheap and easy to work with, and the best part of all is that they use mil-spec pins, which saves the crimp and solder time. They come in a large variety of configurations, including PCB mount.

Here are a few things to keep in mind when designing a data acquisition system:Design for the future. This usually doesn't cost more and will save you a huge amount of work down the road.

Design for ease of expandability. Be sure to always design an expandable system; you don't want to be ripping into a harness mid season looking for open channels.

Design for serviceability. When designing a system, keep in mind that it may need to be removed from the car for troubleshooting. Don't design some technological masterpiece that requires the car to be disassembled.

In our next installment, we'll visit the software part of our series and show you the power of data acquisition.

10-bit
0-1,024 bits
4.88mV per bit
This equates that for every 4.88mV change in the sensor output the logger will register 1 bit of engineering value change.

12-bit
0-4,096 bits
1.22mV per bit
This equates that for every 1.22mV change in the sensor output the logger will register 1 bit of engineering value change.

16-bit
0-65,653 bits
0.076mV per bit
This equates that for every 0.076mV change in the sensor output the logger will register 1 bit of engineering value change.