Next BMW M3 returning to inline six-cylinder engine
05-29-12, 07:13 PM
#46
Oh, so many comments to reply to.
I'll try to answer as many as possible.
Some have said that in-line sixes have slightly more power on their down stroke, and the V sixes have slightly less power on their down strokes.
However, they did not explain why.
I don't know why myself?
If this is true, then it is a small intrinsic advantage of in-line sixes.
Now, in-line sixes also have an extrinsic advantage - the configuration of the in-line six, allows the intake ports to be more vertical and straighter, enhancing the more efficient in-flow of air.
Some would call this the effect of the intake manifold, rather than the in-line six itself.
The in-line six does provide a better intake manifold design.
More later...
I'll try to answer as many as possible.
Some have said that in-line sixes have slightly more power on their down stroke, and the V sixes have slightly less power on their down strokes.
However, they did not explain why.
I don't know why myself?
If this is true, then it is a small intrinsic advantage of in-line sixes.
Now, in-line sixes also have an extrinsic advantage - the configuration of the in-line six, allows the intake ports to be more vertical and straighter, enhancing the more efficient in-flow of air.
Some would call this the effect of the intake manifold, rather than the in-line six itself.
The in-line six does provide a better intake manifold design.
More later...
05-29-12, 07:20 PM
#47
Oh, so many comments to reply to.
I'll try to answer as many as possible.
Some have said that in-line sixes have slightly more power on their down stroke, and the V sixes have slightly less power on their down strokes.
However, they did not explain why.
I don't know why myself?
If this is true, then it is a small intrinsic advantage of in-line sixes.
Now, in-line sixes also have an extrinsic advantage - the configuration of the in-line six, allows the intake ports to be more vertical and straighter, enhancing the more efficient in-flow of air.
Some would call this the effect of the intake manifold, rather than the in-line six itself.
The in-line six does provide a better intake manifold design.
More later...
I'll try to answer as many as possible.
Some have said that in-line sixes have slightly more power on their down stroke, and the V sixes have slightly less power on their down strokes.
However, they did not explain why.
I don't know why myself?
If this is true, then it is a small intrinsic advantage of in-line sixes.
Now, in-line sixes also have an extrinsic advantage - the configuration of the in-line six, allows the intake ports to be more vertical and straighter, enhancing the more efficient in-flow of air.
Some would call this the effect of the intake manifold, rather than the in-line six itself.
The in-line six does provide a better intake manifold design.
More later...
05-29-12, 07:29 PM
#48
Bore to stroke ratio definitely has an impact on power delivery, but it's hardly an "all about" sort of thing. The Nissan VQ30DE engines were extremely oversquare (3.66" bore x 2.89" stroke), yet the first version was best known for its "world class torque" and had a lousy top-end. The K version from 2000-2001 with a variable intake manifold and modified cams was a top-end beast. Many of Honda's engine's are undersquare yet they have lousy torque and good top-end. The fact is, for street/EPA legal engines, you can pretty much give engines any sort of powerband and power delivery characteristics that you want. The real differences that you might see with bore to stroke ratio considerations won't be seen until you're talking about race spec engines. Like Formula 1 engines. They have a 'formula' engine configuration in terms of V-8 or V-10 and displacement, but nothing is said about what their bore to stroke ratio should be, so considerable effort is put into studying this on these engines. Yes, there are significant differences as far as maximum achievable horsepower and mid-range torque, and also fuel consumption. And even on F1 engines, on most of the tracks out there the fastest way around the track is rarely if ever maximum possible horsepower. It's always about striking a balance. When we're talking about run of the mill engines we're not even remotely close to hitting these limits.
Perceived engine smoothness and refinement can be pretty subjective, but I've never driven or felt an engine that was more refined than the I-6 engines. The three 3.0L V6 cars I've owned were all pretty refined, but I haven't been overly impressed from a refinement and NVH perspective with almost any of the 3.5L class V6 engines. They're nice enough for normal driving, but flog them and I dislike the feel and vibrations that a lot of them make. The old Nissan VQ30DE was my favorite. Due to the high bore to stroke ratio keeping the piston speeds very low, it was super smooth and refined even at high RPM. I did accidentally leave it in 3rd gear on the highway once - was going to pass but then didn't and forgot - and was running north of 5000rpm and didn't even notice, it was that smooth.
Perceived engine smoothness and refinement can be pretty subjective, but I've never driven or felt an engine that was more refined than the I-6 engines. The three 3.0L V6 cars I've owned were all pretty refined, but I haven't been overly impressed from a refinement and NVH perspective with almost any of the 3.5L class V6 engines. They're nice enough for normal driving, but flog them and I dislike the feel and vibrations that a lot of them make. The old Nissan VQ30DE was my favorite. Due to the high bore to stroke ratio keeping the piston speeds very low, it was super smooth and refined even at high RPM. I did accidentally leave it in 3rd gear on the highway once - was going to pass but then didn't and forgot - and was running north of 5000rpm and didn't even notice, it was that smooth.
With that being said, these are older engines anyway. Nissans high output V6 engines today are rather harsh, while not Chrysler harsh, they are no match for Toyota/Honda when it comes to refinement.
05-29-12, 07:53 PM
#49
I don't have much of an experience with Nissans VQ30DE engines, except back in 98 or 99 my parents had a Qx4 powered by one of those (I think), and as far as I can remember it performed worse than a 96ish 4Runner they had prior to it, which was also a 3.0 V6. On the other hand, my wife once owned a 97 J30, and she says that car was a beast off the line.
With that being said, these are older engines anyway. Nissans high output V6 engines today are rather harsh, while not Chrysler harsh, they are no match for Toyota/Honda when it comes to refinement.
With that being said, these are older engines anyway. Nissans high output V6 engines today are rather harsh, while not Chrysler harsh, they are no match for Toyota/Honda when it comes to refinement.
I've never tested their current 3.7 V6.
And everytime, their suspension is too hard and jittery, so I gave the Maximas a miss...
05-29-12, 08:04 PM
#50
The intake port kind of looks like a "lobster"???
From the main entry in the center, the manifold then curves to the 6 V-configured cylinders.
Thus, the air travels a little more tortuously in a V engine, than in an in-line six.
So this is said to explain one of the reasons why the in-line get's its extra bottom end punch.
For example, in recent times, the old 2003-10 530i 3.0 naturally aspirated in-line six out-powers not only the 2005-12 GS300 3.0 60 degree V6, it also out-powers other 3.0 60 degree V6's too like the 2002-2007 Accord 3.0 V6.
Meanwhile, the Benz 3.0 90 degree V6 in the 2002-09 E300 and 2000-07 C300 is by far the worst for bottom end torque.
Mind you, once the Benz 3.0 90 degree V6 winds up, there is tons of top end torque.
It's just the bottom, where the BMW in-line six is punchiest, while the 90 degree Benz V6 is the worst, with the Lexus and Honda 60 degree V6's in between....
05-29-12, 08:22 PM
#51
...
I've driven pretty much every car that competes with GS/IS350, except the new Audis, and I can honestly say that Lexus engine is simply best in class. Silky smooth, rocket like acceleration with very good response through entire range of rpm. I'd love to see Lexus bright high power V8/V12 models, and maybe experiment with turbos, but there's nothing wrong with their current V6.
I've driven pretty much every car that competes with GS/IS350, except the new Audis, and I can honestly say that Lexus engine is simply best in class. Silky smooth, rocket like acceleration with very good response through entire range of rpm. I'd love to see Lexus bright high power V8/V12 models, and maybe experiment with turbos, but there's nothing wrong with their current V6.
It is by far the smoothest and quietest six that I have ever driven.
Has anyone driven back to back, a 3.0 six that is smoother and quieter than the 2005-12 3GS300 six???
Theoretically, the in-line six is more harmonically balanced than the V6 in both primary and secondary vibrations.
However, in reality the 2005-12 3GS300 3.0 60 degree V6 is the smoothest and quietest on the market.
I do find the competing 2003-10 BMW 530i 3.0 in-line six considerably punchier down the bottom end.
But the Lexus 60 degree V6, despite its secondary imbalances, and uneven numbers of cylinders per bank, and hence front to rear rocking couple - the Lexus 60 degree V6 is smoother and quieter than the BMW in-line six.
Another advantage of the V6, is that the engine is much more compact, with much more room left for cabin length.
Notice how the new 5 and 3 Series are very large and long externally?
Yet internally, both BMW's lack the cabin length and legroom of the E Class Benz!
That in-line six robs the car of length!
Thus, I can live with my 2005-12 3GS300's lack of bottom end punch, for a smoother and quieter engine, and a longer cabin.
The 3.5 in the latest 4GS is nice too.
More powerful, but not as smooth nor quiet.
The 3.5 has greater reciprocating mass, so it's not as smooth...
Last edited by peteharvey; 05-29-12 at 08:40 PM.
05-29-12, 08:37 PM
#52
...
With Mercedes it was long overdue, as their 90 degree V6 was just horrible and unacceptable for premium vehicles. But where are you getting the info on MB inline six engines? They just introduced their new 60 degree direct injected V6 for MY2012 vehicles. I've never hear anything about their plans for an inline six.
With Mercedes it was long overdue, as their 90 degree V6 was just horrible and unacceptable for premium vehicles. But where are you getting the info on MB inline six engines? They just introduced their new 60 degree direct injected V6 for MY2012 vehicles. I've never hear anything about their plans for an inline six.
Now Fiat owns Chrysler, so they intend to use the same 60 degree V6 in their range of Alfas and Lancias.
Me thinks that Benz wants to distance itself from Chrysler, Fiat, Alfa and Lancia!
Benz has already approved of bringing back the in-line six for 2015!
There are many articles on it.
Here are some:
http://www.worldcarfans.com/11110253...amily---report
http://www.autoguide.com/auto-news/2...zing-plan.html
http://editorial.autos.msn.com/blogs...3-275fd6eb5068
http://rumors.automobilemag.com/repo...795.html?ti=v2
http://www.caradvice.com.au/143292/m...t-six-engines/
That's enough; 4 in a row. I better not bore people with anymore of my posts...
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