+1 Ouch! the motor industry would be horified to hear you calling NVH an emerging science when they have been spending millions on the subject since the early sixties. Certainly agree that huge strides have been made in recent years. The Germans & good old Toyota Lexus probably lead the way in recent times in real world cars

 

Having owned an M111 powered car since it was new in 2002, I wonder where all the vibration in yours is coming from, Glyn. The only thing you hear in ours is the sound of the supercharger and the exhaust. Personally, I think it is cool. Is it louder than most people would like at 4.5k rpm? Sure. But so is a 911.

All I can say is that driving BMW v-8 and I-6 engines regularly, and a Honda four cylinder of recent vintage as well, that the M111 is absolutely fine, with a sportier feel and sound than the v-8 in the BMW or the I-4 in the Honda.

Also, having spoken to many Mercedes techs (at some of our local club gatherings and DIY sessions), I've yet heard one of them say anything other than the fact that the M111 is a solid, durable, well engineered motor. While I personally have driven and think the 271 is a great engine, most of them have told me they would prefer a 111 because it is far more durable, in terms of what they see everyday at the dealer.

Here's one other thing, based on my long experience with German cars: If NVH is your primary concern, buy Japanese. Almost no German car can match the smoothness of a Honda v-6 or I-4, or Lexus v-8, for example, because the tolerances in those motors are tighter. The problem is the rest of the car is not as solid, but that's a different discussion. Someone who is looking for the best in class NVH in a German car? That tells me they don't know German cars that well, especially a Mercedes.

 

Thanks for the reply. I'm sure it's sincere. You do not understand NVH in it's entirety. It is all encompassing and how every component of a car reacts with all other components - The Japanese without doubt do a good job with engines. More so Toyota/Lexus than Honda in THIS measure. Before you climb down my throat Honda make wonderfull engines - they are just more raunchy than a Lexus, even their wonderful V6. Modern NVH problems have little to do with tolerances in engines. They are all pretty tight. They have a lot to do with intake noise, primary engine noise (less of a problem in modern designs), balance, exhaust noise and it's interaction with ALL of the rest of the car.

NVH issues are how, as an example, the sound, frequency & amplitude of the intake system reacts with the primary frequency & it's harmonics of the gearbox - and that with the diff - and that with the tyres - and that with the exhaust - and that with the all the body components etc. Then there is absorbsion of noise by the various components of a car to add to the mix. So your comment "The problem is the rest of the car is not as solid, but that's a different discussion." is not valid. The German's do hugely well in total NVH engineering with (now I'm going to be shot) Audi probably leading by a short head. At the same time the new Lexus GS450h Hybrid that I had the pleasure of driving the other day is a stunning example of good NVH engineering. While there is vast commentary on detailed NVH engineering our local CAR magazine published an article on NVH engineering 101 for us ordinary citizens that I have scanned with their permission to give you a flavour - It is by no means exhaustive but a good start - Sorry I'm picky but vibration analysis, it's interactions and destructive ways have been a subject of study for me over many years in the industrial sphere of my job. This has probably been futher enhanced by my interest in High End Audio although the connection might be hard to understand by those with no interest in the subject.

Read this - then we can discuss briefly if you wish - I don't want to irritate the moderators. We need them for proper & usefull control of this forum.

I've said what I intend about the M111 and I'm unrepentant & I quote "If you want me to say that the M111 is a tough & durable if slightly crude affair with poor NVH engineering that was easily modded I'm more than prepared to say that - hows that?"

On reliablitity - once modified (optimised?) I'll bet the M111 is no more reliable than the already optimised M271 driven similarly. Fuel has a lot to do with M271 ills. Your Gasohol does not help as it only really increases Research Octane not Motor Octane.

And hey! - if the M111 contribution to NVH problems doesn't bug you then lucky you. They bug a lot of others - owned one - never again! I now drive a V6. Please enjoy your car.

 

Your doing as well as my C320. I don't worry about atmospheric conditions though.

 

Gee, thanks for the info. Do you think if I read it I will be as smart and well informed as you are?

You do realize, I hope, that you come across as a patronizing ***, and if your reading skills were as well developed as your ego you would understand that my statement about engine tolerances was not meant to be an all-encompassing explanation of NVH, but rather just a single point of consideration.

In the interim, thanks for reminding me that the internet is a great place to find yet further proof that a little bit of knowledge is a dangerous thing. You would be well served to better utilize your time on the internet somewhere else maybe -- perhaps attach your "backgrounder" to your resume and send it to Mercedes? Heck, they don't know anything about building motors or NVH, and I am sure they could use help. You sound like the candidate for whom Mercedes has been searching.

 

Thank you

 

This is great. A new way to fall out with someone you've never even met. For my point of view if you want to drive a car that feels like it was built in someones shed you don't buy a Mercedes. Only the most generous person would say that the M111 was a good engine for Mercedes. Great for putting in something else, but not a quality marque like Mercedes.( I'm thinking of a piece of plant machinary or a rock crusher) The only 4 cyl Merc worth a damn was the 190e cosworth and then you wanted performance. I seem to remember the manual gearboxes took a bit of getting used to. That's another argument for another day. If you want to drive a car with class, comfort and performance you buy a Mercedes, but not one with a M111 engine in it.

 

Emerging instead of static, perhaps?

I will not argue with the great amounts of money spent on NVH in the past. However, I think only recently have we started to see great results.

Example, virtually all 4-cylinder engines in the 1980's and into the 1990's suffered from poor balance, second-order vibrations, and resonant frequencies. They made harsh sounds and were generally rough-running.

You could feel these engines vibrating through the steering wheel, or almost any place on the body. Noisy drivetrains and vibrating body panels often added to the racket. Manufacturers addressed this problem with more cylinders in the engines, especially on more expensive cars.

These days, most four cylinder engines are smooth and quiet (except some basic economy cars). This did not happen by accident, nor did it happen cheaply. The M271 engine benefitted from this newer technology.

 

You have given nothing to substantiate what you say. Waste of a post. But hey, at 3 posts, you are going to need to get some count.

Funny part is that you talk about performance? Where is the performance in the C240?

I'll happily continue to drive my C230 with the M111.

E

 

+1 Oh! absolutely agreed in all respects

 

With respect - the number of posts has nothing to do with the quality of posts'. Post number 1 could be more profound and informative than the greatest post by the oldest vet on the forum!

You have the weirdest way of measuring things

If post count is important to you then this sensible quote by Drex who qualifies by your measure, and I might say by many more important ones, should RESONATE with you

"The main reason they made the m271 was to adhere to the consumers that would complain about the m111 being too "noisy" and "rough." What that did, in turn, was limit the capacity of what any enthusiast could do with the m271 engine without A LOT of money to put into very custom power modifications."

Consumers in Europe, Africa, Middle East, Asia Pacific, Australia etc. & I dare say a lot in the Americas, did not like this engine one bit and Benz had to respond to their customer's complaints

 

this tells me you based this literally upon your "long experience with german cars." research, or educating one's self on the matter, would reveal japanese cars are commonly engineered to encorporate error, and allow greater tolerances than european vehicles. however, this is also one of the regarded reasonings for the reliability of japanese vehicles.