Are you confused by common automotive parlance? Do you read Car and Driver and feel confused? This article will go over some basic car and engine specifications and terminology in order to help clear up the confusion. The next time someone talks about what type of engine they have in a particular car, you’ll know exactly what they’re talking about.
What the “V” in V6 Means
You often hear people talking about V6 or V8 engines (if you hear them talk about V4 engines, smile to yourself, because they don’t know what they’re talking about, as such an engine does not exist). So what exactly does the “V” in V6 stand for? It actually doesn’t stand for anything-it means just that-V. The V in V6 or V8, or even V10 refers to the geometric arrangement of the cylinders and pistons. When viewed from the front of the engine (in front of the car for a rear wheel drive car and from the side of the car for a front wheel drive one), the cylinders will form a V. If this information is confusing to you, read how a car engine works to get a clearer picture.
If the engine has four cylinders, they are arranged in a straight line. If you read the engine specs for a four cylinder, you will never see “V4.” The specifications will usually say I4, which is short for inline 4. If you viewed the engine from above the hood and connected the tops of the cylinder, an “I” would be formed. There are also inline 6 and 8 cylinder engines. Inline 8 cylinder engines were common with older model cars but I6 engines are still available today. Sometimes, people will car inline engines “straight,” which means the same thing as inline.
The other cylinder arrangement is a “flat” arrangement, but they aren’t common. In a flat arrangement, the range of motion for each piston is parallel to the ground, and each cylinder bank (say a bank of 2 for a four cylinder engine) is 180 degrees from each other (think of a V6 engine with the vertex angle being 180 degrees).
Difference Between a Turbocharger and Supercharger
You’ll hear a lot of people talking about turbo engines. Many people don’t know that a turbo is simply an ancillary engine component that uses the exhaust from your engine to spin a turbine that powers a compressor that blows more air into your engine, allowing it to consume more fuel and deliver more power. A supercharger does the same thing but the compressor is driven directly by your engine (usually connected by a belt). A turbocharger delivers more power when the engine is working at higher speeds (i.e., higher RPMs) while a supercharger produces a more even power boost throughout the RPM range. The exact details of how a turbocharger work and how a supercharge works are more complicated, but you get the idea.
What the 4.0 Means in a 4.0 Liter Engine
When you hear someone talk about a 4 liter engine, they are referring to the displacement, or volume, of all cylinders. Technically, engine displacement is the sum of the difference between top dead center cylinder volume and bottom dead center cylinder volume for all cylinders (the swept path of each piston as it moves up and down). The displacement is directly proportional to the number of cylinders, as there are generally more cylinders with a larger displacement. For example, a 4.0 Liter engine would either be a large six cylinder engine or a small 8 cylinder one.
The displacement of engines in American cars was formerly designated by cubic inches. If you hear someone talk of a 350, or 318 engine, that number is the displacement in cubic inches. To convert cubic inches to liters, divide cubic inches by 61. To convert liters to cubic inches, multiply liters by 61. Hence a 350 engine would have a displacement of about 5.7 liters (350 divided by 61).
Another displacement unit found in smaller engines (e.g., motorcycles) is cubic centimeters, or “cc.” To convert cc to liters, divide by 1000. Hence, 1300 cc is equivalent to 1.3 liters.
Difference Between Big Block and Small Block
When hearing people discuss older engines, you’ll often hear them talking about a “400 big block” or “350 small block.” The big or small in these terms are just referring to the external dimensions of the engine as one would see if the engine were removed from the car. An engine can have the same displacement (or power even) and be big or small block. I could not find a specific dimension that is used to strictly define either so saying big or small block is a pretty vague demarcation.
Rear Wheel, Front Wheel, 4 Wheel, and All-Wheel Drive
Cars come with all these options. There are different handling and driving characteristics of each and basic engine configurations that are common to each option.
Rear wheel drive (RWD) cars have the back wheels pushing the car along. Most race cars have RWD because, during cornering, the driver can still steer if the wheels break loose and, in straight acceleration, a car tilts back, giving more traction to the rear wheels. Most luxury cars have RWD because it offers a more comfortable, balanced ride compared to front wheel drive. The reason for this is complicated, but you can hear a very good explanation here if you’re so inclined.
Front wheel drive (FWD) cars have the front wheels pulling the car along. The engine in these cars is rotated 90 degrees when compared to the engines in rear wheel drive bars. If you’re unsure of whether a car is front or wheel drive, pop the hood and inspect the orientation of the engine. If the long dimension of the engine is parallel to the front axle, it’s a front wheel drive car. Front wheel drive cars are safer to drive in the snow and rain than rear wheel drive cars because there is more weight over the drive wheels, offering better traction.
Four wheel drive (4WD) cars are different from all wheel drive (AWD) in that four wheel drive is an option from rear wheel drive while all wheel drive drives all wheels on all surfaces continuously. Actually, there are some cars that offer “full time four wheel drive,” which differ from all wheel drive in that there is four low and four high modes. Four wheel drive, low, is the mode that offers significant off road driving capability.
Automatic versus Manual
If someone says 5-speed or 6-speed, they are referring to a car that has a foot clutch and manual gear shift. Newer automatic transmissions have 5 or 6 gears, but they are never referred to as 5 or 6 speed. Manual transmission is also called “stick shift” or “manual.” Older cars with manual transmissions sometimes have a column shifter so referring to them as stick shift would be technically incorrect.
Many modern automatic cars offer a manual (though clutchless) shifting mode. This is referred to as Manumatic or by another proprietary name depending on the manufacturer. Manumatic lets the driver shift gears without worrying about a clutch. This feature is found on sporty cars that have an automatic transmission.
