Anyone who thinks you need more cylinders to get more torque never rode a 500 Matchless single..
Observations regarding NA I4 vs V6 engines
- Thread starter The Critic
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another wikipedia article with links to other engine types
http://en.wikipedia.org/wiki/Engine_balance#More_than_two_cylinders
http://en.wikipedia.org/wiki/Engine_balance#More_than_two_cylinders
Originally Posted By: javacontour
I'd love to be able to get a 3-4L inline six in a sedan with RWD, but few of those are made today. I think BMW is pretty much one's only choice.
I have one in my '91 Toyota Cressida, but I'm not at all impressed with the motor. The rest of the car is outstanding though.
I'd love to be able to get a 3-4L inline six in a sedan with RWD, but few of those are made today. I think BMW is pretty much one's only choice.
I have one in my '91 Toyota Cressida, but I'm not at all impressed with the motor. The rest of the car is outstanding though.
Originally Posted By: John K
I think the VW TDI is renowned for a long flat torque curve that comes in around 1800 rpms.
Turbodiesels are outside the scope of this thread.
But with a few inexpensive mods, they can certainly keep up with most V6 gassers.
I think the VW TDI is renowned for a long flat torque curve that comes in around 1800 rpms.
Turbodiesels are outside the scope of this thread.
But with a few inexpensive mods, they can certainly keep up with most V6 gassers.
Why do vehicle manufacturers still make and use inline-4 engines? What possible advantage could an inline-4 engine (besides being easier and perhaps cheaper to make) have over a V4 engine?
Exactly. It's easier and cheaper than making a V4. They don't have to make complex manifolds, so their materails costs go down, and they're much easier to assemble and throw into a car.
Unless the "V4" is really a boxer engine, it's not going to be as balanced as an I4.
So I think the I4 is a reasonable decision given that while larger ones will need balance shafts, you have a much simpler engine block, with one intake and one exhaust manifold.
It's also easier to get longer intake runners in an I4 than a V engine, improving performance.
So I think the I4 is a reasonable decision given that while larger ones will need balance shafts, you have a much simpler engine block, with one intake and one exhaust manifold.
It's also easier to get longer intake runners in an I4 than a V engine, improving performance.
The weight and size of a V4 engine are lower when compared to a I4 engine, so they should have better fuel economy (from the lower weight and possibly the smaller size if that affects the vehicle's shape) than a comparable I4 engine.
I am really surprised that almost all of the 4 cylinder engines in vehicles are I4s. If I was buying a vehicle that has a 4 cylinder engine, I would want a V4 engine.
I am really surprised that almost all of the 4 cylinder engines in vehicles are I4s. If I was buying a vehicle that has a 4 cylinder engine, I would want a V4 engine.
Is it that big a difference if the engine is a DOHC made of aluminum.
So while the engine would not be as tall, it may have other components duplicated, negating much of the weight benefit.
I do recall that there wasn't much difference between the cast iron Zetec and the aluminum Duratec V6 in the Contour. Both engines were about the same on the scales.
So the question is, does the benefit of the boxer or V4 outweigh the costs?
Seems if it did, more car makers would already be using such engines.
So while the engine would not be as tall, it may have other components duplicated, negating much of the weight benefit.
I do recall that there wasn't much difference between the cast iron Zetec and the aluminum Duratec V6 in the Contour. Both engines were about the same on the scales.
So the question is, does the benefit of the boxer or V4 outweigh the costs?
Seems if it did, more car makers would already be using such engines.
Originally Posted By: The Critic
I guess a good engine example for my OP is the 2.4L 190HP I4 in the new 08 Accord EX, compared to the 3.0L 200HP V6 in the 98-02 Accord.
You are looking at only horsepower (not torque), and even at that, you are looking at MAX horsepower figures which are quoted at specific rpm, usually somewhere very high up - 7000 rpm. This tells you nothing about how much torque the engine produces across the entire rpm spectrum. Nobody revvs their engine up to 7000 in daily driving. Most cars will operate somewhere betw. 1500-4000 rpm. And in this lower range, a larger engine will generally produce more torque. You need to get a hold of and compare the torque curves for the respective engines in question - then it will become clear why one feels more powerful than the other. The max hp figure is pretty useless and it is only the marketoids that keep up this neverending fight for more horsepower. And without proper education, most consumers just blindly follow it, too.
I guess a good engine example for my OP is the 2.4L 190HP I4 in the new 08 Accord EX, compared to the 3.0L 200HP V6 in the 98-02 Accord.
You are looking at only horsepower (not torque), and even at that, you are looking at MAX horsepower figures which are quoted at specific rpm, usually somewhere very high up - 7000 rpm. This tells you nothing about how much torque the engine produces across the entire rpm spectrum. Nobody revvs their engine up to 7000 in daily driving. Most cars will operate somewhere betw. 1500-4000 rpm. And in this lower range, a larger engine will generally produce more torque. You need to get a hold of and compare the torque curves for the respective engines in question - then it will become clear why one feels more powerful than the other. The max hp figure is pretty useless and it is only the marketoids that keep up this neverending fight for more horsepower. And without proper education, most consumers just blindly follow it, too.
Originally Posted By: javacontour
Is it that big a difference if the engine is a DOHC made of aluminum.
So while the engine would not be as tall, it may have other components duplicated, negating much of the weight benefit.
I do recall that there wasn't much difference between the cast iron Zetec and the aluminum Duratec V6 in the Contour. Both engines were about the same on the scales.
So the question is, does the benefit of the boxer or V4 outweigh the costs?
Seems if it did, more car makers would already be using such engines.
From what I have read, I have come to believe that V6 engines have technological advantages over I6 engines and I see no reason for such technological advantages to disappear when two of the cylinders are removed. If Chrysler was still the engineering company and Mercedes-Benz vehicles were still over-engineered, I would expect vehicle manufacturers to put the best things into their vehicles, but since both Chrysler and Mercedes-Benz are mass manufacturing garbage in comparsion to what they used to manufacture, I am highly skeptical of the notion that automobile manufacturers are willing to put the best things into their vehicles.
Is it that big a difference if the engine is a DOHC made of aluminum.
So while the engine would not be as tall, it may have other components duplicated, negating much of the weight benefit.
I do recall that there wasn't much difference between the cast iron Zetec and the aluminum Duratec V6 in the Contour. Both engines were about the same on the scales.
So the question is, does the benefit of the boxer or V4 outweigh the costs?
Seems if it did, more car makers would already be using such engines.
From what I have read, I have come to believe that V6 engines have technological advantages over I6 engines and I see no reason for such technological advantages to disappear when two of the cylinders are removed. If Chrysler was still the engineering company and Mercedes-Benz vehicles were still over-engineered, I would expect vehicle manufacturers to put the best things into their vehicles, but since both Chrysler and Mercedes-Benz are mass manufacturing garbage in comparsion to what they used to manufacture, I am highly skeptical of the notion that automobile manufacturers are willing to put the best things into their vehicles.
A V6 is a packaging solution. A V6 puts more power and torque into a small place better than anything else. That's the end of it's advantages. If it's possible to get by with a lower powered I4 then things get back to normal for maintenance. If you just pay for everything and don't care much about some extra expense and want the extra power then buy the V6. If you do your own maintenance you might like the I4 a lot better. There are some V6 maintenance tasks that will scare you away from doing things yourself.
Why are you comparing V6 and I4 engines? They do not have the same number of cylinders and they have different designs. Such a thing makes it impossible to compare whether benefits or drawbacks come from the design (V versus inline), the number of cylinders (4 versus 6) or a combination of the two.
If you pick the cylinder count to compare, you get the different designs as a confounding variable. If you pick the different designs to compare, you get the cylinder count as a confounding variable.
A correct comparsion would be a V6 versus an I6, a V4 versus an I4, a V4 versus a V6 or an I4 versus an I6. Confounding variables are eliminated in those comparsions, assuming all other factors (e.g. metals used, displacement or per-cylinder displacement depending on what is being compared, etcetera) are as common to each as possible.
If you pick the cylinder count to compare, you get the different designs as a confounding variable. If you pick the different designs to compare, you get the cylinder count as a confounding variable.
A correct comparsion would be a V6 versus an I6, a V4 versus an I4, a V4 versus a V6 or an I4 versus an I6. Confounding variables are eliminated in those comparsions, assuming all other factors (e.g. metals used, displacement or per-cylinder displacement depending on what is being compared, etcetera) are as common to each as possible.
Comparing a V6 to an I4 may be apples to oranges in a technical sense, but it is a very real comparison when a person goes to shop for a car. Often times, a manufacturer will package the same sedan body with both a V6 and an I4. Honda Accords and Toyota Camrys immediately come to mind, and many others.
Most of the time, the V6 will be of larger capacity than the I4, but commands a price premium, higher fuel consumption and servicing costs. However, the V6 will be smoother to drive and torquier and would be a better match to an automatic transmission. Horsepower numbers may be fairly close, but not torque figures, unless the I4 is turbocharged or supercharged.
Technologically, both V6s and I4s are fairly close. You can get both with variable valve timing, high compression, excellent engine management systems... the list goes on. The V6 powerplants are usually heavier, but the engineers also work hard to reduce weight on them wherever possible such as composite intake manifolds, aluminium accessory mounting brackets etc. I also have a feeling that a V6 engine will usually have a higher "development budget" compared to an I4, seeing that the V6 is often viewed as a more premium engine.
Most of the time, the V6 will be of larger capacity than the I4, but commands a price premium, higher fuel consumption and servicing costs. However, the V6 will be smoother to drive and torquier and would be a better match to an automatic transmission. Horsepower numbers may be fairly close, but not torque figures, unless the I4 is turbocharged or supercharged.
Technologically, both V6s and I4s are fairly close. You can get both with variable valve timing, high compression, excellent engine management systems... the list goes on. The V6 powerplants are usually heavier, but the engineers also work hard to reduce weight on them wherever possible such as composite intake manifolds, aluminium accessory mounting brackets etc. I also have a feeling that a V6 engine will usually have a higher "development budget" compared to an I4, seeing that the V6 is often viewed as a more premium engine.
Originally Posted By: ShiningArcanine
From what I have read, I have come to believe that V6 engines have technological advantages over I6 engines ...
This piqued my interest. What technological advantages are you citing here? An I6 has more main bearings, and is much better balanced than a V6. It only has one cylinder head (and one head gasket), only requires one set of cams (assuming OHC), and can use a shorter timing chain (again, assuming OHC).
The only technical disadvantages I can see are that a longer head, cam, and crankshaft might be more prone to warpage or breaking but it doesn't seem like that's been a huge problem historically.
As stated above, clearly the V6 has great packaging advantages, but I'm curious as to what technological advantages you see here.
From what I have read, I have come to believe that V6 engines have technological advantages over I6 engines ...
This piqued my interest. What technological advantages are you citing here? An I6 has more main bearings, and is much better balanced than a V6. It only has one cylinder head (and one head gasket), only requires one set of cams (assuming OHC), and can use a shorter timing chain (again, assuming OHC).
The only technical disadvantages I can see are that a longer head, cam, and crankshaft might be more prone to warpage or breaking but it doesn't seem like that's been a huge problem historically.
As stated above, clearly the V6 has great packaging advantages, but I'm curious as to what technological advantages you see here.
One advantage of a V6 over an I6 is more even cooling. So one might be able to get more performance out of a V6 due to more even temperatures throughout the engine.
Perhaps on the other side of that, faster warm up of a V6 engine, as there is less mass to heat up, compared to the typical I6 engine, so one would expect a V6 to go into closed loop operation quicker.
Perhaps on the other side of that, faster warm up of a V6 engine, as there is less mass to heat up, compared to the typical I6 engine, so one would expect a V6 to go into closed loop operation quicker.
Originally Posted By: javacontour
One advantage of a V6 over an I6 is more even cooling.
Why is that? Doesn't that, to a large extent, depend on the design of the cooling system itself?
One advantage of a V6 over an I6 is more even cooling.
Why is that? Doesn't that, to a large extent, depend on the design of the cooling system itself?
I can see how even cooling would be easier in the V6 given that in an I6 the coolant has to go further to get from the radiator to the back of the block, so maybe the back of the engine runs slightly hotter than the front?
So more even cooling and potentially faster warm up (due to likely decreased mass) sound like decent advantages, but in my mind those don't give the V6 the lead, especially given the single head and set of cams advantage the I6 has.
When it comes down to it, both of the thermal advantages mentioned here are advantages that come from shape and packaging. Are there any real mechanical advantages to a V6 over an I6? (I realize this is a slightly different question from my earlier one).
So more even cooling and potentially faster warm up (due to likely decreased mass) sound like decent advantages, but in my mind those don't give the V6 the lead, especially given the single head and set of cams advantage the I6 has.
When it comes down to it, both of the thermal advantages mentioned here are advantages that come from shape and packaging. Are there any real mechanical advantages to a V6 over an I6? (I realize this is a slightly different question from my earlier one).
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