Honda 'End Of Discussion': Is The V6 Engine Inferior To The I4?

No, the V6 is more superior than the 4 cylinder, in terms of performance.However, because of the little difference in fuel consumption, which in my opinion can't be compared with the better performance, many Nigerians run away from V6 engine. The market is polluted with many stories about issues with the Honda V6 engine, hence the 'bad-mouth' in the market. I painfuly, sold a 2000 Accord V6 for N1.2m last week. Painful, in the sense that I would have made more money selling it in the US than in Nigeria. You win some you lose some!

I will advise you to go with the V6.Ever wondered why SUVs don't come with 4 cylinders.You will enjoy it if you maintain it well.

Nigeria is small for a V6 and not economical.  I don't know about a Honda but fort CAMRY's, you are better of with a 4 cylinder because it is easier to work on.  Engine is too conjested and components are hard to reach plus there are many mechanical issues being an "optimised" engine.  The V6 CAMRY is also a thirsty car. 

V6 don't outlast 4 cylinders in terms of wear.  Higher compression engines wear a lot faster than low compression engines due to compression and materials used in composition.  Honda's mechanical limit is about 130,000 miles.

Foremost, I did NOT read here and there to understand what I say.  I went to school and discipled engines, hotrodding and auto control systems and put together a pushrod engine, rebuilt a two CAM engine and electrical diagnostics in '05.  I later became active in SAE-I and have participated in a couple of seminars for tomorrows technology.  I got my first SAE certificate last December in powertrain essentials and design.  So, I know what I am talking about.  I don't mislead anybody; if I'm not sure, I'm not sure and I state it. 

The only difference between a four cylinder and a six cylinder is the degree to which they cycle.  To build an engine on the same scale will differ at engine cycle and displacement.  Determining displacement is [Bore² * 0.7854 * # of cylinders * Stroke] or using the Swept Volume Approach   = [((Bore/2) ²) (Stroke) п].   Another factor that determines the velocity (how fast) a car maintains or propels is the transmission and rear end gearing.  The 4 cyl will cycle every 180° while a 6 cyl cycles at 120°.

4-cylinder, 6-cylinder, …, x-cylinder are differentiated by the number of cylinder with different sizes of pistons and cylinders.  An engine size is determines by the volume of air that its pistons can displace in the cylinders.  To determine the wear specifications, you’ll need to know the engine size.  Cylinder bores in automotive engines range within 3.4 inches to 4 inches which is the size of the diameter of the cylinder across the cylinder.  When the piston strokes from tdc to bdc, the stroke is determined by the length of the throw of the rod journal which is called a crank throw.  A crank throw is one-half of the total stroke.  When an engine has a cylinder bore that is larger than its stroke, the engine is oversquare.  When the engine’s cylinder bore is less than its stroke, then it is undersquare.  With an oversquare engine, you have faster revving but you lack low speed torque.  With undersquare configuration, you have slower revving with a lot of torque at low speeds.  It doesn’t matter if it is 4 or 6 cylinders.  I do understand that there are two extra cylinders but it doesn’t guarantee you any performance if engine design is not intended for high output performance.

The compression ratio determines how much the air and fuel are compressed on the compression stroke as the piston tdc’s to bdc and vice versa.  A higher compression engine increases engine power and fuel economy.  In the process of combustion, potential energy pf the AFR (air fuel ratio) mixed is converted to thermal energy as well as kinetic energy.   

Pistons in low performance engines differ from low performance engines.  Low performance pistons are cast pistons which are porous grain in structure.  They aren’t strong enough materially and characteristically for continuous high revving use.  On the other hand, forged pistons are used in high performance engines and exactly 70% stronger than cast in material.  Heat dissipation is also greater but with bad wear characteristics wrt ring groves and pin bore characteristics.  Thermal expansion is at higher rates than the cast and also run at higher clearances.

Your theory of a 6 cylinder being more efficient in longetivity than 4 violates Heat Engines and the Second Law of Thermodynamics with respect to thermal efficiency and work in process of reversible isothermal compression at low temp, reversible adiabatic compression at low temp to high temp, reversible isothermal expansion at high temp to reversible adiabatic expansion from high temperature to low temperature (phases in a closed system).  The fact the pistons in a high output vehicle can withstand the tensile load at continuous high heat of the combustion process, there is enough stress/strain, wear is generated and in most cases elaborated. Higher compression engines run hotter than lower compression engines.  The irony in Honda's is it has only one heat or exothermic system (single enthalpy).  Would the engine still be in shape in a progressive state as its 4 cyl cousin?!  This is called Thermal Stress and Misfits or Prestrain.  This why some cars have blocks or heads that fracture.

Horsepower in a vehicle does not determine how fast your car goes.  As a matter of fact, it is used only 1% of the time you drive.  What determines your response is the amount of torque have and not horsepower.  You only need horsepower when taking off.  When you hot, you trade off horsepower for torque or torque for horsepower.  Horsepower really is the ideal “governor” to engine wear.  Torque doesn’t wear your engine.  The higher the horsepower in a vehicle, the shorter the longitevity and unforgiving if not engineered precisely. 

Ask any mechanical engineer or anybody that understands the discipline of continuum mechanics.  He will assert to all that I have said.  If I am wrong anywhere, please state it and reinforce with proof and not logic.  Logic is not acceptable in engineering. 

Honda's mechanical limit is 130000 miles.  It doesn't mean it wouldn't run but its designed for that span.  I will have to explain using terms of the Finite Element Method of major drivetrain components and I will not go there.  Toyota is the only japanese car that is designed 10 years or 250000 miles (although the new Camry and worse, the tundra defies the fact). 

Ivvie,
I was going to just let it go, however I have to say that you obviously do not have a true understanding of what you are saying. Either you lack real world experience or true technical understanding or both! The truth is most of the things you just said have no relevance to the argument and are just car techno-jargon, secondly a good half of it is misinformation and crap!!. It is always easy to spot people who read stuff and do not actually have full experience and knowledge. I interview, spot and fire people like that frequently in my line of business. Now, I do not need to start spelling out my credentials here or anywhere, a full understanding of Internal combustion and automotive engineering concepts and not a book knowledge means I do not need technical jargon to explain stuff, I will bring it down to the level of anybody. People are not idiots even if they do not know much about cars? Understanding the concept and relationship between Torque and Power and engine speed is one of the most difficult to grasp in automotive engineering and I see you don't have it. The constipated and illogical flow of your argument exposes your confusion – to put it nicely!.
Torque = in a car is measured in (ft Ib) foot pounds - this is known and defined as the spin or twist power in other words this measures the magnitude of energy delivered to twist the crankshaft. This could also be referred to as angular acceleration.
Horsepower (HP) = Is the rate of delivery of energy. It is measured as an element of energy for instance 1HP is equals to 33,000ft Ib/min. From this definition it is easy to see that there is a relationship between Horsepower and Torque. The Power output of an engine is expressed as its torque multiplied by its rotational speed. Simply put power is the rate at which energy is transmitted. Power = Torque x Rotational speed!!
When an engine outputs power, it transmits energy in two forms - both torque and Horsepower are generated, however Internal-combustion engines produce useful torque only over a limited range of rotational speeds. Essentially, engines are designed so that most of the torque is generated in the first 1000 - 3000 RPM's and that is where it is most needed to move the mass of a car with credible acceleration. Contrary to what you think, Ivvie, torque is the biggest contributing factor to acceleration. Once the mass of the car has acquired velocity then you have momentum which means that you need less torque and more horsepower to reach and maintain a higher rotational speed.
I have already given step by step and extensive explanation in my preceding statement about how wear occurs inside internal combustion engines. Now you say that my theory about 6 cyl vs 4 cyl rate of wear is wrong and I am going to quote what you said: 
What the heck are you talking about?? These verbose and ostentatious display of gibberish techno-jargon reflects a feeble minded attempt to appear technically vast and knowledgeable but it isn’t going to work here!.  Do you even have any idea what the second law of thermodynamics says?? What does this have to do with rate of wear?? - nothing!!.  For your information the second law of thermodynamics states that:  In the layman’s language this means that it is impossible to extract energy by heat from a high-temperature energy source and then convert all of the energy into work. At least some of the energy must be passed on to heat a lower-temperature energy sink. Thus, an engine with 100% efficiency is thermodynamically impossible. It is impossible to convert heat completely into work without loss of energy.  I see you using words like “Exothermic”, “Endothermic” and “Enthalpy” and you simply can’t explain how they affect an engine!. These are all heat related terms that have no bearing whatsoever on the argument you are trying to make. But since you have mentioned heat then I will educate you - most internal combustion engines waste about 36% of the energy in gasoline as heat lost to the cooling system and perhaps another 30% through the exhaust. The rest, 20-25% is used for motion and about 6% is lost to friction - that is what the second law of thermodynamic is about in this context!. Just so that you know – Exothermic refers to systems that give up latent heat and Endothermic is the opposite (it absorbs heat). Enthalpy is simply the heat content measured as the difference between the two!. I hope you get that. Now, you said: 


Now in pure car-speak (engineering lingo aside), torque is that part of an engine output that will propel you from 0-60 in a few seconds however, anybody that knows cars knows that there is a power curve or power bandwidth within which all engines operate optimally. Which means, depending on how the engineers choose to design and tune the powerplant, there will be a trade off between maximum horsepower and maximum torque. There are obviously other factors for the engineers to consider such as purpose or function of car, transmission delivery method, final drive ratio, gearing ratio and the mass (weight) of the vehicle. As speed builds torque output peaks out and diminishes while horsepower continues to build to the peak of the engine’s power delivery curve. Thus, it is ultimately horsepower that take you to a car’s top speed and partly what enables a car to have mid-range to top-end performance!. This is why say a Bulldozer or CAT engine delivers marginal horsepower ratings but incredibly massive torque (the engine is designed to push, pull or move objects supporting loads of immense proportions, it is however not designed for speed).  However, a sports motorbike engine (e.g Honda CBR 1000FF or Suzuki GSX-R Hayabusa) isn’t tuned for great amounts of torque but it does deliver incredible horsepower for high-end  delivery because they where designed for speed with less mass and load consideration. A car's engine usually has to find a careful balance between the two depending on its purpose.
Now we could go on and on with this argument but I think I have said enough for one day. If you want to understand why engines wear – read my preceding statements. Wear is caused by only one thing Friction!! (which is a direct consequent of motion under load of course – that is why changing your engine oil frequently is so important!).  Your final statement says: I am totally at loss for words when I hear people get grandiloquent and bombastic, using technical terms without a clear understanding as to the meaning! The quoted statement above is such a load of sh*t, where is your information from?, can you show me one technical attestation to back up your Honda claims. Hondas are being used by millions of people all over the world and without going any further they will be the first to tell you that you do not know what you are talking about. "Finite element method of major drivetrain components" - what a load of crap!! - every mechanical device in the world has a finite life expectancy. Anyone reading your statements will see that there is no clear understanding and thought process being expressed. It is just hot air!!

just had to say u guys are educated, don't still know anything about auto

Now i know i did not miss anything by not reading Mechanical Engineering.
Everything I need is right here, on this page

Midas, Ivvie,
Fire on ! Grandiloquently !

I love mechanical engineering and I do FEA every single day to be proficient.

@Seun
"End of Discussion" is the Honda Accord 2003-2005 models

I understand that the 2006 version is known as "The discussion continues"

What is all these grammer just because someone wanted an advice?  And now you guys have succeded in confusing the poor guy the more.  Anyway @poster, just go to berger and you will see people who will be more willing to help you instead of these two show offs. 

Chei!!! The Discussion don turn to car!! 


S I E N A!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Where You dey now

Abeg come 'End this physicscussion'

Seun your banning power has been rendered impotent if you don't tell how many cylinder it is and its Rpm and Bhp 

At least i don learn now!!  No be so

Ivvie  and Midas02. Both of you are missing one important aspect of technical arguments!!!

Quote your references as you make your arguments. That way other mechanical engineers like me  that appreciates your angle of reasoning can check up your reference and better understand you point of view in addition to the fact that references gives more substance to your arguments.

Dpresident,

I am sorry the entire purpose for your starting this thread has gone to the dogs!. The answer to your question was adequately answered in the first few entries.

Ovvie,

Earlier you said:

Then after I had educated you and you had gone back to do some more reading, you now said:

Well, are you going to keep changing your mind about what you think torque and horsepowers are responsible for??. Cos last time I checked the fundamental laws of physics and mechanics hadn't changed.

It is ok for you to continue to blow hot air! I personally feel a little too old and too busy for this, however my dialogue with you has led me to an inevitable but interesting conclusion - you are one of those guys who is more interested in appearing good rather than getting some real knowledge and correction. Nothing you have said so far makes much sense nor do they support your arguement. Anybody could cut and paste from physics textbooks but the actual test is in the sound understanding and logical presentation of what you know. Much of your statements are incoherent gibberish being thrown out there in a tirade of misguided and bombastic pomp!! Lets face it - you know squat! - you are either a wannabe or you are still in school. Hopefully, someday you will read your statements and have a hearty laugh!

I still look forward to you presenting us here with some credible proof and attestations alluding to your claims about Honda engines being designed for only 130,000 miles and Toyotas for 250,000 miles. And for the records, textbooks don't always cover one's ineptitude but modesty does! Have a nice one.

@Midas

There are 4 processes in a heat engine that constitute a cycle.
Wknet = [1 to 2]ΣpδV + [2 to 3] ΣpδV  + [3 to 4] ΣpδV  +  [4 to 1] ΣpδV or
Wknet = [1 to 2]∫pdv + [2 to 3] ∫pdv + [3 to 4] ∫pdv + [4 to 1] ∫pdv with [x to x as integrating from to].

I defined the heat engine as four individual processes represented by a particular circumstance by which the engine is operating between two temperature regions as hign and low as heat transfer changes from high to low and vice versa. 

2nd Law of Thermodynamics
I don’t know where you got your second law of thermodynamics from.   I will state the law and explain it.  The 2nd law states that no heat engine can produce a net work output by exchanging heat with a single fixed-temperature region. 

What this tells you is that there is a restriction placed on heat engines.  Heat added Q_add and heat rejected Q_rej must be nonzero.  All required for a heat sink is to be at 0 Kelvin.
η_T = (1 – (T_L/T_H) * 100
as T_L = 0.  It is impossible to reach 100% efficiency because heat rejected must be 0.  You will need a PMM2 to convert 100% of heat to work.

Now you are referring to entropy in the definition of the 2nd law.  Entropy is abstract because it seems not to relate to a basic experience because it is a measure of unavailable energy in a system.  The greater the entropy of a system, the less available is that system for doing work or transferring heat.  In mechanics, as the system increases in volume it can perform work but also has a reduced capability to perform other work.

That is just by the side

What I was driving at was with this process in place with two different materials during a combustion phase, the materials involved will react differently to heat.  Piston made out of forged iron and a cylinder block made of aluminium the tensile load the piston withstands differs greatly and uneven to the block.  The surface and subsurface contact at extreme temperatures with the four processes in place causes abrasions.  The reaction is slower in low compression engines. 

In reference to what I meant by Honda’s mechanical limits, the easiest way to explain it is that it peaks out at approximately 130,000 miles.  That is pretty much high compared to many that peak out at 50,000 miles.  I won’t explain any further on that because it is another field entirely and you will have to be thought at conferences or seminars. 

Obua, I am not wrong and I covered nothing with theory.  I interchanged disciplines in an applied manner because its the only way to explain myself. 

What did you state?  I am not in ASE nor do I have such a certification.  These are trivial and cannot use solvers without having these principles understood.  In the industry, to prove this, CAA, CAE and FEA is used and I think the matching analysis would be engine design consideration with the appropriate PD.

My point is that high compression engines wear quicker due to work, higher heat and different materials.  I had use those terms to explain my point.  I did not state that any engine was inferior but a con of the V6 engine to the 4 cyl.