N20 vibration question

Looking at this article:
http://www.bmwblog.com/2011/06/02/bm...hes-in-canada/

"The N20 is quite smooth. Equipped with balance shafts and high quality engine mounts, the 2.0 liter four manages to suppress vibration to a large degree."

The key is that the vibration is suppressed, unlike the I-6 where it is naturally cancelled. So, being no expert in this stuff myself, an OCD question comes to mind...would the vibration get worse with age because of wear and tear of the components used to suppress the vibration?

Originally Posted by mr_clueless

Looking at this article:
http://www.bmwblog.com/2011/06/02/bm...hes-in-canada/

"The N20 is quite smooth. Equipped with balance shafts and high quality engine mounts, the 2.0 liter four manages to suppress vibration to a large degree."

The key is that the vibration is suppressed, unlike the I-6 where it is naturally cancelled. So, being no expert in this stuff myself, an OCD question comes to mind...would the vibration get worse with age because of wear and tear of the components used to suppress the vibration?

doubt it...i drove the N20, its not as smooth as the i6, obv... but lots of power and very nice

Originally Posted by mr_clueless

Equipped with balance shafts and high quality engine mounts, the 2.0 liter four manages to suppress vibration to a large degree.

As do all modern 4-cyl. engines.

NVH is well mastered these except for the "N" - noise.

Not that it does make too much of it. It is about quality. If not up to 6 cyl., I can tell you that the Audi 2.0T makes a nicer and sophisticated noise than the N20. At least in the X1.

Vibration is there as soon as the rev gets high. I don't think they have come up with an effective way to cancel the vibration at high rev band, not yet.

I think it is easier to manage the noise, more padding to insulate the cabin, if all other efforts fail.

audi 2.0t vibrates like **** above 4000 The n20 was much smoother imo

How does **** vibrate?

Originally Posted by raleedy

How does **** vibrate?

At the Brown Note frequency.

Originally Posted by justinnum1

audi 2.0t vibrates like **** above 4000 The n20 was much smoother imo

No, it doesn't. Stop exaggerating. I've driven plenty of VAG 2.0T equipped cars over the years. They don't vibrate like a POS.

I can say this for those who are curious about a well-balanced 2.0 liter 4-cyl vs. a "naturally balanced" 6-cyl engine:

my Honda's 2.0 liter 4-cyl engine, after 114k miles on it, revs more smoothly at 8000 rpms than my "naturally balanced" flat six porsche engine at 6000 rpms.

There is nothing unusual about a super smooth 4-cyl spinning to 6000, 7000, or 8000 rpms. Honda's been doing it for years in their f20, f22, and k20 series engines. I own a k20z3 (which was the first one in which Honda added a SINGLE balance shaft).

People put too much emphasis on the "natural balance" of an engine. . It's not like Ferrari v12s, Porsche flat sixes, Subaru H6's, and BMW inline sixes have been able to use solid motor mounts - no, they still dampen engine vibration through the use of rubber. And when you go to a harder or solid motor mount, you get NVH penetrating the cabin. Even in all those designs deemed "naturally balanced".

BMW's 2.0 may feel smoother at 6500 rpms than those who have owned inline six engines in the past. BMW has been known to build a beautifully smooth inline six, but there is a myth perpertuated by the brand-snobbish that says you can't get the same smoothness outside of an inline six (or otherwise naturally harmonically correct engine).


P.s. It may have been smooth, but my recent test drive of an x3 with the naturally aspirated 3.0 left me thinking that it was one of the worst sounding engines I'd recently heard from inside the cabin. It's mostly sound tuning nowadays anyway.

Originally Posted by AutoUnion

No, it doesn't. Stop exaggerating. I've driven plenty of VAG 2.0T equipped cars over the years. They don't vibrate like a POS.

Thats your opinion. Mine is above 4000rpm the audi 2.0t feels very unsettled. Maybe its the extra weight of the audi, idk...but the n20 felt slightly more refined.

Originally Posted by JoeFromPA

I can say this for those who are curious about a well-balanced 2.0 liter 4-cyl vs. a "naturally balanced" 6-cyl engine:

my Honda's 2.0 liter 4-cyl engine, after 114k miles on it, revs more smoothly at 8000 rpms than my "naturally balanced" flat six porsche engine at 6000 rpms.

There is nothing unusual about a super smooth 4-cyl spinning to 6000, 7000, or 8000 rpms. Honda's been doing it for years in their f20, f22, and k20 series engines. I own a k20z3 (which was the first one in which Honda added a SINGLE balance shaft).

People put too much emphasis on the "natural balance" of an engine. . It's not like Ferrari v12s, Porsche flat sixes, Subaru H6's, and BMW inline sixes have been able to use solid motor mounts - no, they still dampen engine vibration through the use of rubber. And when you go to a harder or solid motor mount, you get NVH penetrating the cabin. Even in all those designs deemed "naturally balanced".

BMW's 2.0 may feel smoother at 6500 rpms than those who have owned inline six engines in the past. BMW has been known to build a beautifully smooth inline six, but there is a myth perpertuated by the brand-snobbish that says you can't get the same smoothness outside of an inline six (or otherwise naturally harmonically correct engine).


P.s. It may have been smooth, but my recent test drive of an x3 with the naturally aspirated 3.0 left me thinking that it was one of the worst sounding engines I'd recently heard from inside the cabin. It's mostly sound tuning nowadays anyway.

idk about that, the N52 is butter smooth, the sound is nothing special, i agree with you there. I was just really surprised with the N20. The torque was cazy, reminded me of my 335 It did not feel as smooth as the N52, but offered great performance above 5000K.

Originally Posted by raleedy

How does **** vibrate?

Kinda like jello, doesn't it?

Originally Posted by JoeFromPA

I can say this for those who are curious about a well-balanced 2.0 liter 4-cyl vs. a "naturally balanced" 6-cyl engine:

my Honda's 2.0 liter 4-cyl engine, after 114k miles on it, revs more smoothly at 8000 rpms than my "naturally balanced" flat six porsche engine at 6000 rpms.

There is nothing unusual about a super smooth 4-cyl spinning to 6000, 7000, or 8000 rpms. Honda's been doing it for years in their f20, f22, and k20 series engines. I own a k20z3 (which was the first one in which Honda added a SINGLE balance shaft).

People put too much emphasis on the "natural balance" of an engine. . It's not like Ferrari v12s, Porsche flat sixes, Subaru H6's, and BMW inline sixes have been able to use solid motor mounts - no, they still dampen engine vibration through the use of rubber. And when you go to a harder or solid motor mount, you get NVH penetrating the cabin. Even in all those designs deemed "naturally balanced".

BMW's 2.0 may feel smoother at 6500 rpms than those who have owned inline six engines in the past. BMW has been known to build a beautifully smooth inline six, but there is a myth perpertuated by the brand-snobbish that says you can't get the same smoothness outside of an inline six (or otherwise naturally harmonically correct engine).


P.s. It may have been smooth, but my recent test drive of an x3 with the naturally aspirated 3.0 left me thinking that it was one of the worst sounding engines I'd recently heard from inside the cabin. It's mostly sound tuning nowadays anyway.

I am not familiar with the kind of very high revving 4 bangers you are talking about, but for the common 4 bangers and V6s, none could be revved above 5,000 without crapping out, because they are not designed to rev high. Those turbo 4s have low end power, not at the high end.

As far as the N52 engine sound, I agree the stock engine sound is nothing to brag about at all. Many of us use intake mods to improve the sound.

Unfortunately vibration cannot be "improved" by the users. Besides, some of the vibrations are not from the engine, but turbo, or intake, or exhaust, or a combination of those.

When I test drove a 335i, I felt more vibration at the high end than the 328i, but I knew the vibration was from the turbo and the more aggressive exhaust in the 335i.

Drove a Z4 35is and a 335is too, they had even more "vibration" because of the much more aggressive exhausts.

DTC,

I agree with you that some vibration is from exhaust/intake tuning - you feel that on all cars based upon their tuning.

As a side note: You do not feel vibration because of a turbo (FYI, they are far more balanced than the typical engine - they have to be, they have essentially zero-tolerance for internal vibration considering their turbine speeds and proximity to the housings). And, beyond that, the turbo is essentially mounted to the engine - so you are feeling vibrations coming through the engine itself.

You should definitely go give an s2000 a test drive (f20/f22 engine, 8000-9000rpm redline stock) as well as a 2006-2010 Honda Civic SI (k20z3 engine, 8000 rpm redline stock). They are jerky in terms of on/off throttle, and they are noisy through lack of sound-deadening, design, and just that they are noisy engines. But they are silky smooth at any engine rpm within their redline. These are 2.0 to 2.2 liter 4-cylinder engines who are, essentially, 10 years old in design.

Anyway, my point here is simply more a note that inline sixes and flat sixes are not some sort of miracle-workers in NVH. In fact, the engine design commentary ignores the power pulsing to the flywheel - which is smoother in a v8 and needs to be damped in 4-cyl & 6-cyl engines. The power pulsing in 4 & 6 cyl engines is a source of NVH that needs to be "handled".

Joe, thanks for the info.

I didn't mean vibration from the turbine, rather other turbo air flow process, though I am not in a position to guess.

I consider the cars you mentioned above more suited for the enthusiasts than the BMW 3s equipped with the N/A I6 engines.

It takes some enthusiasm to want to rev the engine to 6000 in order to get it go fast, naturally more enthusiasm is needed to want to kick it up to 8000 to go fast, and endure all the discomfort at the same time.

For me N52 strikes a balance. But I do admire people like you who go around at 8000 rpm.

Enthusiasm, or simply the engine lacks significant power below that level

My honda is the equivalent of a regular civic until 5800 rpms (at which point it switches to a 2nd cam). At 6000 rpms, I'm making the same power as a 335i makes at 3000 rpms. At 8000 rpms, I'm making the same power as a 335i at 4000 rpms. So I need to rev it from 6000-8000 to get the acceleration available to a 335i owner in a more readily accessible RPM range, 3000-4000.

Anyway, I'm extremely sensitive to engine vibrations and have learned alot about what makes them and what avoids them. I own a 2008 Subaru Legacy GT 5-speed, which has a primarily balanced engine through it's flat-four design (secondary imbalances exist and are addressed with a harmonic balancer). It's one of the least "balanced" engines I've ever owned. The porsche flat six loves to rev and is smooth, but not as smooth as a BMW inline six (imho). But then, the Honda 2.0 is smoother than either the flat four or flat six engines I own.

I've learned alot about what makes an engine balanced and smooth - and at the end of the day, I can't judge an engine on design alone anymore.