5250 High Performance Dyno Shop Blog

Engine Sensors | Race Cars & Street Performance Part 2

[fa icon="calendar"] Mar 27, 2017 8:30:00 AM / by Mike Wiener

Gauges Data AcquisitionStreet Performance or Race | Any modern vehicle is covered in sensors. These sensors measure temperature, pressure, electrical current, and movement.

Part 2 | A gauge is a way for us to turn these measurements into a visual scale for us to interpret. But there doesn't have to be one gauge for every sensor. In fact, there can be hundreds of sensors and no gauges.

When it comes to choosing what gauges you want in your car, first you need to find out what sensors are already installed from the factory, then you decide on what level of information you want to see. More isn’t always better.

  • Every car built today uses a system called CANBUS. This is a digital communications system that allows all the different components of a vehicle to talk to each other in binary code vs. individual wires for each function.

In a pre-CANBUS vehicle, if multiple computer system in the car wanted to know the outside temperature, they each had to have their own outdoor air temperature sensor.

This meant multiple sensors wired to different computers in different locations inside the vehicle. With CANBUS, there is only one outdoor air temperature sensor, but each computer in the car is able to access and share it's reading. This saves on materials and weight as redundancy is reduced.

This is an amazing opportunity for the aftermarket as we are also able to read and share the information from every sensor throughout the entire vehicle and display it on any digital device we want.

  • Instead of a gauge display with a single needle sweep, we have gauges with computer displays that can show the information from many sensors all at once.

Once you determine what sensors your car came from the factory with, you can decide if you want to use a digital gauge to display that data, or if you would rather have a traditional gauge that may be easier to read while driving.

Oil and Water Temperature as well as Boost and Oil Pressure can be read from the car's OBD system. Intake and Ambient air temperatures as well as tire pressures and temperatures can also be read and displayed.

One monitor that most factory cars do not come equipped with is a Wideband AIr to Fuel ratio sensor. The oxygen sensor that comes standard on most vehicles is designed to read ratios between 12:1 and 16:1. The accuracy of the sensor falls off very quickly outside of those ratios.

A wideband sensor used for tuning has a much wider range of 10:1 to 20:1. These sensors work by "pumping" air molecules from outside of the exhaust into the sensor and comparing that to the exhaust flowing over the sensor. An aftermarket wideband reacts to changes in the air to fuel ratio faster than a factory one and is much more accurate at the edges of it's range.

This allows for better tuning of the engine. Due to the fragility and sensitivity of these air to fuel ratio sensors, it is often a good idea to have 2 to compare to each other.

The temperature sensors all over the vehicle all work basically the same way., they are thermoresistors. They are made of a material that changes it's electrical resistance in response to a change in temperature.

These work very well until you get to really high temperatures like what you find in the exhaust. Exhaust gas temperature sensors, or EGT sensors work on a different principal called a thermocouple. Temperatures in the thousands of degrees would melt or permanently alter the characteristics of a thermoresistor.

A thermocouple is made of two metals that are bonded together. The two metals have a very high melting temperature and are not affected by the high heat. But as they heat up, a reaction between the two metals causes an electrical charge to be created. The higher the temperature, the greater the charge.

Pressures on a modern vehicle can reach into the tens of thousands of PSI. This is new territory as fuel injection system directly inject into the combustion chamber under the compression cycle. In a standard port fuel injection car, pressures rarely exceed 100psi and a carbureted car only sees triple digits in the oil pressure under cold starts. Fortunately, the same sensor technology can monitor this very wide range of vacuum to over 20,000psi.

From boost to oil pressure to fuel pressure, a transducer measures them all. A transducer is a device that converts physical movement into an electrical signal. These come in many different shapes and sizes and are all over a modern vehicle.

Street Race Performance gaugesThe last type of sensor measures movement. This may be rotational or linear. Rotational sensors keep track of cam and crank location to make sure fuel and spark timing are correct. Wheel speed sensors calculate road speed and ABS and Traction Control commands. Linear sensors calculate suspension location for air ride and cornering enhancements.

These sensors rely on magnets and ferrous timing wheels. Cam and Crank wheels are made up of teeth in a specific pattern. As the teeth pass by the sensor, they create an electrical spike that the computer can use to determine the location of the crank and camshafts or the speed of the wheels.


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Subscribe to our blog read Part 3 where I discuss how a race car utilizes these sensors differently than a street car and why your performance car could benefit. If you didn't get part one, click here.

Topics: Data and Gauges

Mike Wiener

Written by Mike Wiener