GM mid sized sedans to only be offered with 4 cylinders
09-03-10, 04:21 AM
#106
Pole Position
Of course I'm not implying that 8 cylinders are more efficient than 4 cylinders, but there are occasions when they can be more efficient. Highway driving is one of these occasions, and I wouldn't be surprised if a Camry fared same or better if you stuffed the 4.6 V8 into it instead of factory's 2.4 4cyl. People already get 30mpg highway in the LS460, so if you stuffed this drivetrain into the lighter, smaller Camry it would fare even better.
Another situation is aggressive driving. With a smaller engine, you will have to floor it more and push it harder, and in the end your fuel economy will be pretty miserable, vs a big engine that doesn't have to break a sweat to be driven aggressively. A good demonstration of that would be Top Gear's test where V8 M3 got better fuel economy than a hybrid, gutless Prius. The Prius was driven all out around the track by Stig, and JC stayed right on his *** in the M3, and got about 2mpg better efficiency.
Back on the topic of GM discontinuing V6 engine in favor of turbo fours, I think its a bad decision on many levels. Here are my reasons:
1) People who are economy minded and do not want to spend a lot of money on a car, will buy a regular non turbo four.
2) There are people who do not care about power, and do no drive aggressively, but buy the V6 (or more) purely for the refinement and smoothness. GM will simply lose these customers. And believe me, this is a good percentage of customers.
3) There are people who buy the V6 engine because they like to drive aggressively, and i4 doesn't provide them with sufficient performance. They will have to buy the turbo fours instead, and it is my strong belief that when driven aggressively, a turbo four will deliver far worse efficiency vs NA V6.
What Mike (1sicklex) said really makes sense. If they are so efficiency concerned, they should be investing more in hybrids. A turbo four will probably carry a 3-4k price premium over NA four, so if they sold a hybrid four with the same price premium, that would make more sense. They would actually accomplish better fuel economy, and offset some of the nastiness of the four banger. When I drove the HS250 for instance, which is a hybrid four, the one thing that I liked about it is that the petrol engine shuts off when the car is stopped, so you don't get any of that crude four cylinder idling.
Another situation is aggressive driving. With a smaller engine, you will have to floor it more and push it harder, and in the end your fuel economy will be pretty miserable, vs a big engine that doesn't have to break a sweat to be driven aggressively. A good demonstration of that would be Top Gear's test where V8 M3 got better fuel economy than a hybrid, gutless Prius. The Prius was driven all out around the track by Stig, and JC stayed right on his *** in the M3, and got about 2mpg better efficiency.
Back on the topic of GM discontinuing V6 engine in favor of turbo fours, I think its a bad decision on many levels. Here are my reasons:
1) People who are economy minded and do not want to spend a lot of money on a car, will buy a regular non turbo four.
2) There are people who do not care about power, and do no drive aggressively, but buy the V6 (or more) purely for the refinement and smoothness. GM will simply lose these customers. And believe me, this is a good percentage of customers.
3) There are people who buy the V6 engine because they like to drive aggressively, and i4 doesn't provide them with sufficient performance. They will have to buy the turbo fours instead, and it is my strong belief that when driven aggressively, a turbo four will deliver far worse efficiency vs NA V6.
What Mike (1sicklex) said really makes sense. If they are so efficiency concerned, they should be investing more in hybrids. A turbo four will probably carry a 3-4k price premium over NA four, so if they sold a hybrid four with the same price premium, that would make more sense. They would actually accomplish better fuel economy, and offset some of the nastiness of the four banger. When I drove the HS250 for instance, which is a hybrid four, the one thing that I liked about it is that the petrol engine shuts off when the car is stopped, so you don't get any of that crude four cylinder idling.
09-03-10, 04:33 AM
#107
Here's where we disagree. By your analogy, installing an 8 liter, 800/800 HP/TQ engine into the LS would be economically beneficial because the engine could laze around at 90mph and barely sip any fuel. Physics says, you can't have your cake and eat it too. It is my belief that, up to a point, the smaller the engine, the more economical the car, regardless of size. It has been a fact for the past 100 years that manufactures, in order to create better fuel economy, install smaller engines into their cars, not larger ones. It's simple physics.
With a smaller engine, you can only run it so hard so that it can only consume so much fuel per unit air...
depending on weight, aerodynamic efficiency of the vehicle, rolling resistance, and such, there is an ideal size engine per vehicle, as far as fuel consumption is concerned...
it seems one of the best ideas around right now might be how some vehicles cut fueling to some cylinders - this gives you power when you need it, but fuel economy when you need it as well...
09-03-10, 07:34 AM
#108
Lexus Fanatic
City/suburban driving is a biggest portion of modern driving in the US, which is why the EPA city rating resembles the mileage that most people get with most cars. And big engines are not the most fuel-efficient in those conditions. 90mph cruise conditons are not normal operating conditions.
09-03-10, 09:26 AM
#109
Nope, its called cylinder deactivation, and its utterly useless. It shows 1-2mpg improvement, and thats probably more or less a manipulated result. When you stop injecting fuel into some of the cylinders, the other cylinders have to work twice as hard to run an air pump. Additionally, fuel serves as a lubricant, and the deactivated cylinders are incurring more wear.
09-03-10, 09:34 AM
#110
Here's where we disagree. By your analogy, installing an 8 liter, 800/800 HP/TQ engine into the LS would be economically beneficial because the engine could laze around at 90mph and barely sip any fuel. Physics says, you can't have your cake and eat it too. It is my belief that, up to a point, the smaller the engine, the more economical the car, regardless of size. It has been a fact for the past 100 years that manufactures, in order to create better fuel economy, install smaller engines into their cars, not larger ones. It's simple physics.
We're talking reasonable size engines here, and only for certain situations. While your belief that the smaller the engine, the more economical the gar is generally true, it is not always the case. If you stick a small four cylinder into a large heavy sedan or truck, it will possibly return worse economy than a V8.
09-03-10, 12:22 PM
#111
Lead Lap
Join Date: Jun 2006
Location: MD
Posts: 4,511
Likes: 0
Received 0 Likes
on
0 Posts
IF (?) that's the case, then Buick needs to update their website.....it still shows the CXL AWD with the 3.0L. (the AWD is an option only on the CXL trim-level).
http://www.buick.com/vehicles/2010/l...=tabHighlights
LaCrosse CXL AWD
Engine Power 3.0L DOHC SIDI V6
Transmission 6-speed automatic, electronically controlled with overdrive, Driver Shift Control
http://www.buick.com/vehicles/2010/l...=tabHighlights
LaCrosse CXL AWD
Engine Power 3.0L DOHC SIDI V6
Transmission 6-speed automatic, electronically controlled with overdrive, Driver Shift Control
09-03-10, 02:11 PM
#112
Nope, its called cylinder deactivation, and its utterly useless. It shows 1-2mpg improvement, and thats probably more or less a manipulated result. When you stop injecting fuel into some of the cylinders, the other cylinders have to work twice as hard to run an air pump. Additionally, fuel serves as a lubricant, and the deactivated cylinders are incurring more wear.
Got an idea then - two 4 cylinder engines, separated by a clutch - one 4 cylinder engine runs all the time (or similar to some pseudo hybrid technology, the engine stops when the vehicle is stopped, but is available as soon as the pedal is pressed), and the second engine starts up and comes online as soon as it is needed... would be an interesting concept for sure...
09-03-10, 03:04 PM
#113
Lexus Fanatic
09-03-10, 07:38 PM
#114
Lexus Fanatic
Join Date: Jan 2005
Location: A better place
Posts: 7,285
Likes: 0
Received 0 Likes
on
0 Posts
A lot of misconceptions and inaccurate information in this thread.
Apples to apples, with all other variables being equal, a naturally aspirated four cylinder or turbo 4 cylinder will never be as smooth or refined as a 6 cylinder engine. Again, this is all other things being equal except the engine design. Even the highest quality 4 cylinders cannot match a high quality 6 cylinder in refinement or smoothness. This is by design, and this is where physics come into play. Oh and as for Honda 4 cylinders, I've never found any Honda 4 cylinder to be as smooth as a good V6 engine. Modern Honda 4 cylinders may feel smooth when new, but that is heavily due to the engine mounts absorbing a lot of harshness and vibration. Modern Hondas go through engine mounts quite quickly. Once the engine mounts deteriorate, then you can easily feel the vibration and harshness from Honda's engines. I've felt it on plenty of modern Hondas, even models with the J-Series V6.
As for fuel economy, some modern V6 engines can get fuel economy close to, if not equal to many naturally aspirated and turbo model 4 cylinders.
Some here in this thread claim that a turbo 4 gets great economy as long as you drive lightly. The same thing applies to 6 cylinders; you can get great fuel economy in a V6 by driving lightly.
As for GM, I am not surprised by this and it seems like an "I give up" attitude at GM. Using some advanced technologies (mostly not including forced induction), it is possible to get exceptional fuel economy from a V6 engine without a lot of added cost.
I hope the new EPA fuel economy guidelines are more realistic in terms of highway driving. The current standard for highway driving is not satisfactory. Sure it's a standard, but it's inaccurate and gives false hope to a lot of people because a lot of these models that have great highway ratings under the current EPA system do not do so great in real-world highway speeds (above 65 mph).
Apples to apples, with all other variables being equal, a naturally aspirated four cylinder or turbo 4 cylinder will never be as smooth or refined as a 6 cylinder engine. Again, this is all other things being equal except the engine design. Even the highest quality 4 cylinders cannot match a high quality 6 cylinder in refinement or smoothness. This is by design, and this is where physics come into play. Oh and as for Honda 4 cylinders, I've never found any Honda 4 cylinder to be as smooth as a good V6 engine. Modern Honda 4 cylinders may feel smooth when new, but that is heavily due to the engine mounts absorbing a lot of harshness and vibration. Modern Hondas go through engine mounts quite quickly. Once the engine mounts deteriorate, then you can easily feel the vibration and harshness from Honda's engines. I've felt it on plenty of modern Hondas, even models with the J-Series V6.
As for fuel economy, some modern V6 engines can get fuel economy close to, if not equal to many naturally aspirated and turbo model 4 cylinders.
Some here in this thread claim that a turbo 4 gets great economy as long as you drive lightly. The same thing applies to 6 cylinders; you can get great fuel economy in a V6 by driving lightly.
As for GM, I am not surprised by this and it seems like an "I give up" attitude at GM. Using some advanced technologies (mostly not including forced induction), it is possible to get exceptional fuel economy from a V6 engine without a lot of added cost.
I hope the new EPA fuel economy guidelines are more realistic in terms of highway driving. The current standard for highway driving is not satisfactory. Sure it's a standard, but it's inaccurate and gives false hope to a lot of people because a lot of these models that have great highway ratings under the current EPA system do not do so great in real-world highway speeds (above 65 mph).
09-03-10, 10:26 PM
#115
Lead Lap
Join Date: Jun 2006
Location: MD
Posts: 4,511
Likes: 0
Received 0 Likes
on
0 Posts
And the AWD 3.6L model is rated for 16/26, which isn't all that great, considering the bar that Audi has raised for AWD vehicles. However, the 3.0L was only rated for 16/25.
09-04-10, 08:49 AM
#116
Lexus Fanatic
Apples to apples, with all other variables being equal, a naturally aspirated four cylinder or turbo 4 cylinder will never be as smooth or refined as a 6 cylinder engine. Again, this is all other things being equal except the engine design. Even the highest quality 4 cylinders cannot match a high quality 6 cylinder in refinement or smoothness. This is by design, and this is where physics come into play. Oh and as for Honda 4 cylinders, I've never found any Honda 4 cylinder to be as smooth as a good V6 engine. Modern Honda 4 cylinders may feel smooth when new, but that is heavily due to the engine mounts absorbing a lot of harshness and vibration. Modern Hondas go through engine mounts quite quickly. Once the engine mounts deteriorate, then you can easily feel the vibration and harshness from Honda's engines. I've felt it on plenty of modern Hondas, even models with the J-Series V6.
I hope the new EPA fuel economy guidelines are more realistic in terms of highway driving. The current standard for highway driving is not satisfactory. Sure it's a standard, but it's inaccurate and gives false hope to a lot of people because a lot of these models that have great highway ratings under the current EPA system do not do so great in real-world highway speeds (above 65 mph).
The city EPA figures, on the other hand, may be another story. Because of the high traffic congestion and stop/go driving in and around major cities (especially my D.C. area, which is second only to SoCal in traffic density) it is often not easy to get the EPA city figures.
But weather tends to make a big difference, too. The warmer it is, and the drier the roads are, the better MPG you will get, in general.
Thread
Thread Starter
Forum
Replies
Last Post
LexFather
Car Chat
15
05-15-09 09:16 PM
