Engine Performance Unveiled: From Basic Principles To Advanced Insights

When you think about engine performance, the peak of an engine operating under a speed load and custom modifications comes to mind. Although engine performance can be referred to as such, the truth is engine performance is how well an engine performs under any kind of load especially regular cruising or driving operation. 

An engine’s performance is based on many factors, with each playing a key role in how your engine operates. This article will help you get a better understanding of the overall performance of your engine and create a baseline information hub on which you can build.

What you will learn:

Key Components of Engine Performance

Two critical metrics we use to explain the performance of your engine are Horsepower and Torque. Both can’t be separated, you can’t have one without the other, let me explain why by starting with torque.

Torque

Torque is the amount of rotational force your engine has to rotate your car’s wheels. The metric often used is ft-lb (foot-pound) because generally, you’re using a foot (12 inches) of leverage to exert a pound of force on something. Think of yourself tightening a screw with a foot-long wrench. Now if the Wrench was 2 ft long( 24 inches), double, you’re using 2-foot pounds of leverage on the screw. The force that you exerted to make that screw turn/rotate is called torque. 

Now it’s good to note that the amount of leverage available amplifies the amount of force exerted. For instance the longer the wrench the the more pounds of force you can exert on the screw. I used to have a 2013 VW CC and during maintenance and parts replacements, sometimes I would only have a small area to work with. I would go to Autozone to buy a ratchet with a longer handle that would allow me to have more leverage of force when working with limited space or very tight screws. 

Another thing to note is that it can be amplified in many different ways to get more force on rotation. For eg, if you were able to turn the 1-foot (12 inches) wrench with 2 pounds of force, it is still the same as exerting 1 pound with 2 ft of leverage—both equal 2-foot pounds of torque. Foot pounds is the metric we use to measure how much rotational force an engine or you turning a wrench produces. This is one aspect of engine performance. 

Horsepower

Another aspect of engine performance is horsepower. Remember I said torque is the twisting force exerted on the screw? Horsepower is how fast that rotation is happening. It is measured by work over distance. If it takes you 20 rotations to turn that wrench in one minute then that’s your horsepower output. It’s essentially how quickly your engine produces torque in a certain amount of time is how horsepower is derived. Horsepower encompasses distance, forces, and time, which is why you can use horsepower to tell how fast a car is based on its engine’s performance. 

Engine Efficiency and Fuel Efficiency

When your engine is running, it is going through a process of converting fuel into usable energy. Particularly for IC (internal combustion) engines this is what we call the combustion process. In the beginning, I mentioned engine performance is not only the speed load of the engine but also the cruising and even idling conditions. The combustion process is what happens in each of these conditions. It happens once the engine is started. 

Engine efficiency 

Most engines run on a four-stroke combustion process/cycle, where fuel is converted into mechanical energy. This means pistons move up and down in the engine block compressing and igniting an air and fuel mixture. The process starts with the first stroke moving downward. This stroke introduces the air-fuel mixture, and then the second stroke up compresses that mixture. The third stroke down is a result of the ignition or explosion of that compressed mixture, either by an electric spark or intense compression. The fourth stroke upward, pushes all the exhaust gases from the combustion out the cylinder, completing the four-stroke cycle. Each of these pistons is connected to a crankshaft through a connecting rod. Each stroke exerts a force on the crankshaft rotating it each time creating a rotational force we call torque, that gets converted into mechanical power. Great engine performance is how well this four-stroke cycle is being utilized in each style of driving. 

Fuel Efficiency

Using fuel most efficiently is also a part of engine performance. Fuel and air are mixed and compressed to create an environment in the cylinder for combustion to happen. This combustion is what ultimately gives power to the crankshaft. It is often referred to as the power stroke. In the air-fuel mixture, there is a ratio to which the fuel and air are burned for maximum efficiency. The ratio of air to fuel is  14.7:1. It is called the stoichiometric mixture of 14.7 grams of air to 1 gram of fuel. With this mixture, fuel is burned efficiently. However, it takes time for this ratio to burn off efficiently. When your engine is rotating faster this ratio now has less time to exist. To make up for this your engine introduces more fuel the faster it rotates. This is why your fuel consumption goes up the faster you drive. To maximize your fuel economy you would have to cruise at a speed that uses up a minimal amount of energy giving the engine enough time to maximize the air-fuel mixture ratio. For example, I drive a VW Tiguan, and cruising at 70 mph with the engine rotating just under 2000 RPMs returns me great gas mileage.   

Factors Affecting Engine Performance

Engine Design and Operation

When an engine is designed it is made with temperature in mind. From the materials used to the oil galleries and coolant pathways forged, it is all a part of maximizing temperature for the best possible combustion process. The optimal engine operating temperature is from 190-220 degrees Fahrenheit. Your engine stays in this range because it was designed to. It is designed with oil and coolant passageways to keep your engine cool and lubricated during the combustion process. Engine oil keeps your engine from having metal-on-metal contact which decreases excess heat, friction, and wear. Coolant keeps your engine from also overheating by keeping stable temperatures around the cylinder walls. This prevents these areas from getting too hot, which increases pre-ignition, which wastes fuel and ultimately leads to engine failure. Pre-ignition is when the fuel ignites before its time. This ultimately decreases engine performance, to where the fuel is wasted and the preferred amount of energy from the power stroke is unattained. This can cause serious damage to the engine. 

Transmission Influencing Engine Performance

Your transmission regulates the power that you’re engine produces. Whether it’s an automatic or manual transmission, each gear adjusts the engine’s speed, ultimately dictating the car’s speed. You can control how fast your engine revs to control whichever driving style you prefer. Higher revs allow you to utilize max horsepower and torque to have optimal power when needed. In comparison, lower more steady revs give your engine a chance to utilize the fuel more efficiently. The lower the gear the higher the revs. The higher the gear the lower the revs. Unless you pushing the car full load. 

Tires

Tires are the main contact from the car to the road which means it is the main way we feel the engine performance of a car. If you have new tires, old tires the wrong tires, or the right tires, it all impacts the way you feel the engine performance. Old or worn-out tires can make your engine do more work than it needs to. Whereas new tires will let you feel every bit of performance possible. Tires provide transaction which is key to telling what your horsepower and torque figures are in some cases. When you put your foot to the floor on the accelerating pedal, you feel the forces push you back in your seat. What you feel is the torque forces due to the tires on your car. Tires influence how your car or engine performs in hot, cold, wet, icy, snowy, muddy, or rocky terrains. There is a tire for each of these scenarios, so having the right tire to match matters more than you think. Tires help us to understand engine performance physically.  

Maintenance For Engine Performance

Maintenance relates to engine performance in a way that it sustains the level of performance your engine produces. There are a few things to keep up with and be aware of that are considered proper engine maintenance.

• Engine oil – checking the level and color of your engine could mean the difference between poor or great engine performance. If your engine oil is no good that means your engine is working harder than it should to keep up with running. Bad engine oil can cause wear and excess friction which can ultimately lead to engine failure. 
• Coolant –  Checking your coolant level is also very important. Coolant keeps your engine from overheating. In the engine bay, there is usually a reservoir showing your coolant and its level. There is a min and max line on that reservoir and the coolant level should be between that. Anything above the max line or below the min line will require your extra attention. Refer to the car’s owner’s manual to know when to change your engine’s coolant. 
• Air filter – Air flow is one of the most important things when it comes to engine performance. Your engine wouldn’t run without air otherwise. So it is important to check and keep up with maintaining a clean air filter. This ensures your car gets the optimal amount of clean air to the engine for combustion. 
• Electrical – Your car battery is the source of all the electronics in the vehicle including parts like the ECU, that impact the performance of your engine. Batteries typically last 4 – 5 years, so it is a good idea to stay on top of how good your battery is. It is also good to make sure there aren’t any loose connections around or on your battery connectors. Spark plugs are another key piece that is vital to engine combustion. Replacing worn spark plugs and coil packs can not only maintain engine performance but also prevent engine damage. 

Role of Engine Oil in Engine Performance

Lubrication and Friction Reduction

Having great engine oil contributes immensely to your engine performance. Engine oil prevents metal-on-metal contact reducing friction, which reduces wear and further engine damage. Engine oil viscosity is also an important factor for you to know when changing your oil. Your engine was tested and developed on a specific engine oil so always refer to the owner’s manual for your engine oil viscosity and oil change interval. Some manufacturers recommend different grades of oil depending on the time of year. The environment impacts the liquids in your engine such as the engine oil so the right viscosity for the right time is important. Synthetic engine oil is the best there is currently for your engine. It has more stable molecules for engine temperature change and an array of options for specific engine types. Getting the right engine oil for your car can return better gas mileage, and is a preventative measure in maintaining engine performance.      

Advanced Technologies Enhancing Engine Performance

When your engine is being developed, manufacturers tune and program the engine’s computer for the best possible performance from said engine. In this modern era, your engine characteristics are controlled by an ECU (Electronic Control Unit) computer. The ECU controls airflow, fuel injections, ignition timing, transmission, and a bunch of other aspects of your car and engine. The ECU is running multiple calculations every second for the benefit of your engine’s performance. The ECU is also calibrated on specific characteristics of your engine parts. Whether it’s a specific size of the air intake pipe or a different size turbo the ECU has sensors that feed that information to it maximizing those characteristics. Your car has an OBD 2 port where a mechanic can connect to your car’s ECU to run diagnostics or reprogram your car for better performance. 

Performance Chips In Engine Performance

Performance chips are technical pieces of code you can buy, that plug into your car’s ECU to reprogram for better performance. However, it won’t work unless you’re changing out physical parts. The manufacturer has already programmed your ECU for the best possible performance from the stock parts. Unless you’re changing out these parts for better-designed parts, or bigger parts, the performance chips won’t work. Once you start swapping out parts then you would need a performance chip/ECU tune to reprogram for those specific parts taking actual advantage of the change. 

Turbocharger In Engine Performance

Turbochargers can heavily influence your engine performance. Your engine uses an air-fuel mixture to make power. A turbocharger condenses more air and sends it to your engine for more power. However, an ECU tune could reprogram the amount of fuel mixed to take better advantage of the extra air being introduced. Engines that are already equipped with turbos from the factory have already been tuned by the manufacturers for this. However, if a bigger turbo was swapped out for the stock one then the ECU tune/reprogramming comes in handy.  

Real-Time Adjustments for Dynamic Performance

With all the innovations in the modern era of cars more and more cars are coming equipped with real-time adjustment modes that recalibrate your car for specific scenarios. It’s like your car has a brain (the ECU) and you can manually switch its mindset to deal with specific tasks. Our environment has many different terrains you can come across when driving. You have snow, gravel, mud, rocky, wet surfaces and you can be going up a hill. All of these terrains can affect your traction making it hard for your car to perform well and safely. A lot of cars come equipped with 4-wheel or all-wheel drive systems, and transaction control systems, all of which can be adjusted further for specific terrains. Modes like snow and off-road modes adjust the engine parameters to maximize the engine performance, impacting your tractions for the best possible result. 

The Environmental Impact and Emissions

Your engine burns air and fuel to make power, but it is not a complete burning process. There is an exhaust after combustions which exits the car exhaust pipes. This exhaust is called emissions. Emissions harm the environment and are also harmful to human health. The government has imposed regulatory compliances so vehicles don’t ruin the environment or make it deadly for us. As a result, your engine is fitted with an emissions system that includes various parts. One of which is a catalytic converter which greatly reduces the harmful chemicals that would come out of the exhaust pipe. The catalytic converter essentially sifts through the combustion gases converting them to less harmful gases. This is another aspect that your ECU monitors which ultimately affects your engine performance. 

Conclusion

Although when we think about engine performance we think about only speed, now we can see it’s much more than that. From the ECU to tuning to the catalytic converters, engine performance entails how your engine is made to run often time to be the most efficient maximizing good gas mileage, and lessening harmful emissions. You can always swap out parts and tune your car for better performance but keeping up with maintenance is also equality if not more important than that. There is a reason the term “well-oiled machine exists”. 

FAQs:

What factors influence engine performance the most? 

Factors that influence engine design are:

• Engine design – There are multiple engine designs and setups that maximize engine performance in multiple ways. Whether you drive a commuter car to maximize fuel efficiency or a sports car the maximize speed and handling, the very design and material choice of engine parts such as camshafts, crankshafts. Pistons, air intake, exhaust manifold, etc. influence your results in either direction. 

• Maintenance – Maintaining your engine’s parts is one of the most important factors that affects your engine’s lifespan which influences the performance of your engine. The type of oil and the oil change interval is a very important way to reduce wear and tear on your engine parts and cost in the long run. You can refer to your owner’s manual for oil and oil change information including basic checks you can you every 6 months or so to avoid expense and increase engine longevity. 

• Fuel Quality – Your engine burns fuel to move/run/make power. The quality of fuel being burned in your engine is important to how your engine will perform. Bad fuel can result in higher emissions, systems error/check engine light, or extra unwanted material building up in your engine’s cylinder, which causes other problems for other engine parts. 

How does regular maintenance affect engine performance?

As your engine operates, it experiences wear. Parts get used and need to be replaced or cleaned. As parts wear and air, oil, and filters get dirty or clogged, it’s good to replace and clean these parts. These parts are essential to the good operation of your engine and can negatively affect your engine performance if left uncared for. Regular maintenance allows for the upkeep of these parts ensuring a longer lifespan and consistent performance of your engine. 

Can engine performance affect fuel efficiency? 

For your engine to perform it uses fuel. Your engine burns fuel to operate. Depending on the type of performance your engine is made for, whether it’s for commuting or sporty driving, the fuel being burnt releases energy. This fuel can either be burned in the most efficient way to maximize the amount of fuel your gas tank has or burned in the most energy-efficient way to get the most power from your engine. Either way, depending on the type of engine you have, it has a direct impact on the use of fuel being used. 

What are common signs of reduced engine performance? 

Common signs of reduced engine performance are:

• Excessive oil consumption 

• Bad gas mileage 

• Check engine light 

• Engine speed is limited 

• Less responsive accelerating pedal 

• Rough Idle