4-Cylinder engine vs 6-cylinder engine – car talk (1) – nigeria gas monkey live


It is very hard to generalize but if you must do, with all things being equal, a 4 cylinder engine will consume less fuel and will be less complicated. Some manufacturers simply lump out 2 cylinders to make a lower cylinder equivalent. This is true with some BMW models (E60 M5 V10 and E9X M3 V8).

I think you should focus on a particular Make then you can decide. For example, Audi’s 2.0T is more developed and offer you more “everything” per liter than the discontinued 3.0 V engine. With BMW, the Inline 6 engines are probably better than the old 4 cylinder engines but BMW now has a great 2.0 liter 4 cylinder turbo that will replace most inline 6s. BMW’s inline 6 is actually their bread-and-butter until the arrival of the new 4 cylinder because they use it across every model (X5, X3, 528, 530, 330, 325, 328, 128) and the engine is known for its balance/smoothness.

Once you decide on a particular Make, the next thing to consider is the weight of the car. A very heavy car like 5 series, E class, S class, 7 Series, mid-sized SUV will struggle with a naturally aspirated 4-cylinder engine because of low torque. A turbo 4 cylinder might offer enough torque to move a huge car but it will have a very weak top end. For example, it will take forever to accelerate over 100 MPH which is needed on US highways. Imagine trying to overtake a trailer traveling at 80 mph, you step on your gas and it takes eternity for it to respond:-) In the US, luxury cars can never sell with a 4 cylinder engine (even 6 cylinders won’t sell very well), which is one of the reasons Acura’s top of the line RL failed. But things are starting to change with the introduction of turbocharged 6 cylinder engines.

No matter how good an I4 engine is, it can never eliminate engine vibration at high rpm. Unlike V6 engine that will smoothly rev beyond 7000rpm or the red zone. The balancer shaft on most of the V6 does the work of eliminating engine vibrations, even when clanking the engine. If you doubt me, place your hand on a car bonnet with V6 engine and have someone clank or start the engine for you. Come back and tell us your findings.

Once you get on the wheel of any V6 and hit highway, you wont give a damn about the propaganda of fuel economy of V6. The manuovering and road handling of V6 car on hiway gives one so much fun and relaxation. In fact, you will be gigling like a girl till you hit your final destination

About the crap about high cost maintenace of V6. Keep listening to the Clowns that call themselves mechanics in Nigeria. V6 engines have proven to be very durable. A V6 engine, if properlly cared for, can exceed 800,000 km before need for engine rebuild. The extra 2 cylinders reduces the stress on the engine been cause by the added load on the engine such as A/C, power steering pump and long distance drive.

Both engines are fundamentally different. The difference between the 4 and a 6 cylinder is its powerstroke. A V6 is inherently a defective engine. You cannot match a 4 cylinder to a 6 or 8 or 12 no matter how much power per piston or per litre. The inertia load on the pistons are greater and you have greater dynamic at RPMs. Same as lower cylinders against higher (V6 against V10). In some cases, you may get away with it if the power/torque overwhelms the greater cylindered car due to other factors. In a circuit, yes but linear acceleration — it will be inconclusive. Don’t get me wrong, there are cars that out-perform cars with more cylinders but inertia and dynamic loads will be greater with more rotating and reciprocating mass at the rods while the higher cylindered vehicle will do similar performance with a lot less load.

All the reasons given for choosing a 6 cyl over 4 cyl are correct but actually outdated. In short it used to be a power issue (HP), torque, stillness etc. The flip side was that you knew that you would pay more on fuel and possibly repairs. Nowadays auto manufacturers are discovering that with the latest technology a 4 cyl accommodates and make the 6 cyl an expensive alternative. There are 4 cyl with lots of HP, incredible torque ( torque is that ability to move force, so when you are climbing a hill or accelerating while in a high gear) etc. A good example is BMW and MB who have adopted this in many models of their 5 series and E Class respectively. Not to mention that they are good for the environment ( exhaust ext). I doubted a bit at first, but I have an E class 2010 and I was shocked at the performance and the fuel efficiency though its a diesel, is sick ( I get 17-18 KM per liter) and push the pedal on the highway (120+km). Torque is crazy. The dealer showed me the new S Class, yes you guessed it with 4 cyl. I test drove it and couldn’t believe it. Who would have believed that you could make a S Class using a 4 cyl. technology means we can achieve more using less.

Power (hp) = Torque (ft.lb) * [(RPM (*1000))/(5252)] From this relationship, you can see that power is solely based rpm and torque. In other words, power is proportional to torque at any given rpm. On the flip, Torque (ft.lb) = [((5252 * (Power (hp))) / RPM (*1000)] In other words, less torque as RPM climbs. This is the engineering conclusion that you cannot generate torque when climbing a hill on high gears.

Lowering the gear sends torque to the wheels and upshifting gives rpm to the wheels. Whenever you upshift, torque to the wheels drop. This is the reason why you have to downshift to a lower gear for passing. You are basically "conjuring" torque to the wheels as you build acceleration in favour of RPM. You cannot upshift and gain torque.

Engine to the S Class is denoted as peak horsepower/torques which is useless to the average and a substantial percentage of spirited drivers. There isn’t any innovation there. What M B is passing across is that the S Class is heavier and enough torque to overcome the frictional and gravitational forces so that it is still benzy. It is still an internal combustion engine. You cannot match the diesel to the lower displaced V8 of the same class. It just doesn’t have the power. All Benzes are torquey. This is why passing is effortless and better performance at the top end (except for the v6’s gassers).

The automotive industry does not reflect the technologies of today. As a matter of fact, it is a lot behind. Same with computers and wireless and the wireless technologies that are out to the main public. If you are really interested in ground-breaking technology and what’s up currently, look into the Oil and Gas sector/industries. The automotive is just a profit-making ground. Few companies are into innovations in the automotive but the real innovations in the auto world are from private individuals, not the major auto companies. Re: 4-cylinder Engine Vs 6-cylinder Engine by uchenageme( m): 9:41pm On Oct 31, 2011