Data logging has been around for decades and is used by almost every major racing team in every form of motorsports. But if you're one of those rare people who don't eat, sleep, and breathe racing, you might not even know what it is or how it works.
What the Competition
Doesn't Want You To KnowA data logger is a computer system designed to record just about anything and everything a vehicle, engine, transmission, or driver is doing when the vehicle is running. Any pressure, speed, temperature, voltage, throttle position, or even suspension action can be measured and recorded for you and your team to analyze after a test or race. Think of it like your very own personal chassis dyno, but instead of simulating what might happen in competition, you're actually gathering information about what is happening during competition.
On Project X, our new RPM Performance Products data logger will record what happens during each of its runs on the track. From there, we can decide which changes are appropriate for the engine and/or vehicle before its next run. | 
Typically, diesel enthusiasts monitor their engine's exhaust-gas temperature (EGT) in one location: at the flange, where the turbo mounts. What we commonly refer to as EGT should really be called "turbine-inlet temperature" instead. This number is just an approximation of the temperatures seen from all six (or eight) cylinders and tells us very little about what is happening in each individual cylinder. On Project X, we wanted to know how much heat (and thus power) each cylinder was producing. | 
With the ATS Diesel exhaust manifold off the truck, Randy McMahon drilled and tapped all six exhaust ports so we could monitor each cylinder's EGT independently. We'll use a seventh sensor (arrow) installed in the normal EGT gauge location to give us the turbo drive pressure. |
How it Works
When the driver wants to start gathering data, a button is pushed to turn the system on and it starts recording from every sensor in its system. When the driver is finished, a button is pushed again to stop recording. Next, a computer is plugged in to the data logger so the information can be uploaded in report form. The report will show everything that happened during the time of monitoring.
With the ATS manifold drilled and tapped, it was cleaned and reinstalled on the engine. Here, the RPM Performance Products EGT sleeves are installed. | 
McMahon bent all the temperature sensors to 90 degrees for a lower-profile mounting and a cleaner underhood look. | 
The wiring from the six EGT sensors was routed to the rear of the engine compartment. |
Racers can take the information and use it to tune the entire vehicle (not just the engine) to better prepare it for the next run or race. A data logger speeds up users' learning processes by telling them things about the vehicle that even the best experts could only guess at.
To check the intercooler's efficiency, an intake temperature sensor and pressure sensor were mounted on the Banks High-Ram intake. | 
To ensure all the data is relevant and usable, McMahon mounted his own crankshaft position sensor (to get engine speed). The data logger will also use a sensor to monitor the driveshaft speed so the vehicle's actual speed can be calculated. | 
McMahon then installed a sensor to monitor the compressor outlet temperature. |
Once the sensors were mounted, McMahon routed the wires to these breakout boxes. | 
Each sensor gets its own channel, and the breakout box permits the data logger to collect information from multiple sensors (or channels) at one time. | 
The breakout boxes were mounted on the firewall so the wires could be run inside the truck to the control unit. |
During testing or competition, the data can be uploaded to a laptop computer and graphed. Here, Greg Hogue checks the readouts after each run at the Texas Mile. | 
This is a screen shot of the 161-mph run from the data-logging unit. | |
Project X Gets A Data Logger
Knowing the importance of data logging from years of professional drag racing, Greg Hogue placed a call to Randy McMahon from RPM Performance Products to get a data-loggingsystem installed on Project X. RPM Performance Products has been installing data-logging systems on tractor pullers for years and was a natural choice for our diesel competition truck. McMahon drove out from Oklahoma and gave Project X a good once-over. He discussed the sensor requirements with Hogue and started putting together a system for the truck. McMahon's next visit was a week before the Texas Mile race, and he spent an entire day wiring the system. With the data logger now functional and in place, Project X was ready for the Texas Mile.