Speed Secrets: Keeping Your Car Healthy

By Ross Bentley

December 09, 2014

These week, data guy Matt Romanowski writes about how to use your data system to help you monitor the health of your engine. As he so accurately points out, it's difficult to work on improving your driving when your engine isn't working! - Ross
Many times when we data guys start thinking about the data we collect from our car, we jump immediately into what the driver is doing and how we can make them faster. An important thing that should really always be checked first is the health of the car! If we can't keep the car running out on the track, it won't matter how good the driver is.
Many of the new data systems that talk to the car through the CAN bus (the communication system in new cars which allows the different computers to talk to each other) will give all sorts of engine metrics and information, but even in old cars with minimal sensors, we can learn something. One of the first things to check is the battery voltage. Most systems, even the most basic GPS-based ones, will give you a recording of the voltage that powers it. This should always be above 12 volts and really around 13. I've found a lot of failing alternators in the middle of a practice session that, when replaced, allowed the team to go on and finish the race instead of being a DNF.
If you have more sensors or a connection to the car’s computer, you'll have many more things to check out. Figuring out how to look at the data can be one of the challenges. If you have the ability to make a chart with your system, sometimes that is the easiest way to display the info. A quick look through the minimum and maximum values can tell you a lot about how a system is performing. Graphing the data, especially over an entire session, can tell you a lot about how, or even if, a system is reaching some sort of equilibrium. 
You can look at oil pressure. Is it steady or does it have lots of quick jumps? Does it rise steadily with RPM? Does it stay at a consistent level through corners and braking or does it start to drop? All of these are things to check out to see if there is a problem with the system, filter, pick up, or other engine problems.
You can check out oil temp. How long does it actually take your car to get up to temp on the first run of the day? I bet you will be surprised! Does the oil temp find a plateau or seem to just keep increasing and increasing? Is the max temperature the oil reaches acceptable for your oil and engine? If it's a cold day, does your car get hot enough?
The same thing can be done for coolant temps. Does the engine warm up quickly? With the high performance demands put on many newer cars, is the radiator and cooling system up to the task of your track driving? Lots of people across Florida, Texas, and California have had to add extra radiators to keep their cars cool during the hottest part of the track season. 
In modern cars, transmissions have started to overheat. Older cars that are driven hard can have the same problem. Just added a limited slip differential to your car? This is definitely something you'll want to keep an eye on.
For cars with more sensors, you can check things like fuel pressure, crankcase pressure, lambda readings (air/fuel), MAP (Manifold Absolute Pressure) and many more things. Some of the systems will also have a simple channel that will show when a check engine light is on. With some creative and more advanced work in the data analysis software, you can create similar alarms on your own. These are a great way to make looking at the engine data very easy and fast, so you can get back to making the driver faster!
I've included a couple sample graphs to give you some ideas of what to look out for as you're doing your engine analysis. The first one, for the fuel pressure, is very obviously bad. You can see the wide constant variation and the overall downward trend of the fuel pressure. This car was having a number of problems in the fuel system, including issues with the pump and fuel tank pickup. 
The next graph shows a transmission that is working its way to a serious overheating problem. You can see that the upward trend isn’t stopping and is climbing to over 225 degrees F. Sometimes you might find that a cooling system - whether the problem is the engine coolant, oil, or transmission - is not robust enough and won't allow the system to find a temperature range to stabilize in. This is certainly one of those cases!
So, while this won't necessarily make you faster, it will help you to keep the car on the track longer and more consistently. Remember, as Rick Mears said, "To finish first, you must first finish."
- Matt Romanowski
Twitter: @trailbrakematt
Website: www.trailbrake.net
Exerpted from Ross Bentley’s Speed Secrets WeeklyFor more tips and additional articles on the art and science of racing, click here to subscribe 
Also be sure to check out Ross Bentley's book, Ultimate Speed Secrets: The Complete Guide to High-Performance and Race Driving.