BMW M3/M4 s55 Engine RPM Redline Projections via Technical Sound Analysis

[US///M3]

Wouldn't the small tubines/scrolls choke the tuned N55 above 7,000rpm?

[Ezio]

Originally Posted by Boss330

No, it's only 600rpm apart... Or 7,8%

Hardly worlds apart...

The E30 M3 S14 engine had a rev limit of 7300rpm

The E36 M3 S50 engine had a rev limit of 7200rpm

The E46 M3 S54 engine had a rev limit of 8000rpm

The E9x M3 S65 engine has a rev limit of 8300rpm

Never heard much complaint about low rev limit on the prevoius straight engine M3's before...

You really don't see the flaw on your statement do you ?

let me help you out, its the year 2013. at the time of those engines, they "more" high revving. This new 2014 M3 will have a lower rev limiter than a 2002 BMW M3.

also 600RPM is a lot, nice try though.

[M3_WC]

Originally Posted by aajami

Hi Boss330,

I appreciate the thoughtful feedback! It's certainly interesting to see the science behind it.

Per my original disclaimer, though, I was referring simply to the emotion of driving a high-revving engine vs. driving one with a lower redline. Or put another way, when I had my S2000, there was a world of difference between how the car felt and sounded (and how both made me feel) when I would hold the RPMs at 7,000 vs. when I'd hold them 8,000 and at 8,900. The same goes for the M3: 7K RPM feels a certain way -- and 8,000 feels like something else altogether.

Source: My unscientific brain.

This

[Boss330]

Originally Posted by aajami

Hi Boss330,

I appreciate the thoughtful feedback! It's certainly interesting to see the science behind it.

Per my original disclaimer, though, I was referring simply to the emotion of driving a high-revving engine vs. driving one with a lower redline. Or put another way, when I had my S2000, there was a world of difference between how the car felt and sounded (and how both made me feel) when I would hold the RPMs at 7,000 vs. when I'd hold them 8,000 and at 8,900. The same goes for the M3: 7K RPM feels a certain way -- and 8,000 feels like something else altogether.

Source: My unscientific brain.

Which is why I was surprised by the article I found, because my brain functions like yours... Not sure how big a difference 7700rpm vs 8300rpm will be though. And it's a 6cyl vs 8cyl, so totally different frequencies as well (8cyl has 1 more combustion per revolution 8/2 vs 6/2)

[khanyam4]

Originally Posted by FogCityM3

Wow..incredible! only on M3 board could you get such innovative thinking and quality content!

agreed for the most part.

[kgaler]

Newbi question: At the risk of being slightly off topic.... why does it matter if it redlines at 8K vs something like 7200?

[strati1]

Originally Posted by swamp2

I'm a recovering physicist and recovering engineer. Now I sell engineering software.

Wow, that sounds credible to me. Thank you sir.

[Doctor///M]

"...and the new M3 will have one of the best engines we have ever done." - Friedrich Nitschke

that's all I need to know :-D

Thanks for sharing this analysis. Science rules!

[Brosef]

Originally Posted by Boss330

No, it's only 600rpm apart... Or 7,8%

Hardly worlds apart...

The E30 M3 S14 engine had a rev limit of 7300rpm

The E36 M3 S50 engine had a rev limit of 7200rpm

The E46 M3 S54 engine had a rev limit of 8000rpm

The E9x M3 S65 engine has a rev limit of 8300rpm

Never heard much complaint about low rev limit on the prevoius straight engine M3's before...

tough to settle for a hamburger after you've had steak.

[Boss330]

Originally Posted by Ezio

You really don't see the flaw on your statement do you ?

let me help you out, its the year 2013. at the time of those engines, they "more" high revving. This new 2014 M3 will have a lower rev limiter than a 2002 BMW M3.

also 600RPM is a lot, nice try though.

600rpm is 30Hz, not a lot in my book But I appreciate that to many, it's emotionally a big deal not to have a redline over 8000rpm...

And, yes the redline is going "the wrong way" compared with the S65. My comparison was just to show that a 7700rpm redline isn't that different from previous gen M3 engines. And even though it might be redlined some 300rpm under the E46 M3, the S55 will have way more power... I know which I prefer given the choice of 300rpm more or 100+ hp more...

I wouldn't mind if BMW had stayed NA either, but I suspect (or at least hope ) the new M3/M4 will give the competition something to think about.

[Boss330]

Originally Posted by Brosef

tough to settle for a hamburger after you've had steak.

Agreed, that's why I'd rather have superior performance than 600rpm's extra... If you can't have both 8300rpm and better performance in the same package I mean...

I suspect the E9x M3 will be like a burger performancewise compared with the F80

[dcleminson]

Originally Posted by solstice

Nice!

Here's a pretty clean audio of the only production I6 turbo M car, it's in cabin but it would be interresting to see what top rpm the SW spits out.

4:24 and 4:28 for example seems like possible redline shifts.
( if you watch the whole thing you will also see two M3s showing who the daddy is )

Awesome video.. The only cars asserting themselves over the M1 were the M3's...

[FogCityM3]

LOL

Originally Posted by khanyam3

agreed for the most part.

[ProbyOne]

Originally Posted by swamp2

Thanks. Although it is quick to do I don't want to analyze video after video. Anyone can do this with a plethora of free audio tools on any OS. A quick analysis of this one though around 4:24 indicated a much lower peak rpm than the 7000 rpm redline. The method is absolutely not 100% robust for all recordings but the baseline cases of the dyno runs completely convinced me that it can work. I suspect one reason here is simply the fact of internal vs. external audio. It's no doubt the design of passenger vehicles is to drown out a significant portion of engine and exhaust noise.

I also tested a few different dyno runs for various cars before convincing myself that it would work. With the right equipment it would be a pretty good way for racing teams to keep an eye (ear?) on the competition

I didn't have any good audio software on the computer and resorted to matching frequency by using this tone synthesizer http://www.philtulga.com/tone.html. Obviously Audacity is much more accurate with clear audio... I expected to be within ~5-10 Hz based on matching a few other cars really well.

I have a new appreciation for hitting the rev limiter on the dyno. We need someone to get out there with a good mic and radar gun

[StealYourFace]

I love all the sour pusses on this board hahaha. Some forum guy made an assumption based on something that is proven to be true within a margin of error and everyone bashes the guy, no to mention the car that isn't released and just about promises to be unconditionally awesome.

Cover the tach, lie about the weight, tell them it's naturally aspirated and said sour pusses will say it's the best thing since canned beer.

[darmawaa]

It's easy for a turbo engine to rev 8000rpm, Mc laren already did that.
What we need is low end torque (peak torque start @1500 rpm) AND 8000rpm redline.
Mc laren peak torque start @3000 rpm

[Mangler]

Originally Posted by Brosef

tough to settle for a hamburger after you've had steak.

I know. After the e30 they have all been mutton.

T

[Mangler]

Originally Posted by ProbyOne

I also tested a few different dyno runs for various cars before convincing myself that it would work. With the right equipment it would be a pretty good way for racing teams to keep an eye (ear?) on the competition

I didn't have any good audio software on the computer and resorted to matching frequency by using this tone synthesizer http://www.philtulga.com/tone.html. Obviously Audacity is much more accurate with clear audio... I expected to be within ~5-10 Hz based on matching a few other cars really well.

I have a new appreciation for hitting the rev limiter on the dyno. We need someone to get out there with a good mic and radar gun

There's a free app called RTA. It s a 1/3 octave RTA and it will give the the entire spectrum of frequencies of whatever the source it.

T

[OrangeCrush]

Thanks Swamp! Well done!

[zuggerat89]

Originally Posted by StealYourFace

I love all the sour pusses on this board hahaha. Some forum guy made an assumption based on something that is proven to be true within a margin of error and everyone bashes the guy, no to mention the car that isn't released and just about promises to be unconditionally awesome.

Cover the tach, lie about the weight, tell them it's naturally aspirated and said sour pusses will say it's the best thing since canned beer.

Sour pusses is right!

Every journalist on earth said the E46 M3 exhaust note sounded like garbage when it first came out, everyone whined about the rasp. Now it's loved, go figure.

This car, like past generations, will be amazing, and just like in past generations, the car will sound amazing [at high revs].

[mkoesel]

The S50B30 was limited to 7200RPM, the S50B32 upped that to 7600RPM.

At any rate they have been steadily pushing the state of the art and increasing max RPM since the very first M3, and that's largely why there have been no complaints in that area. This will be the first time they go back the other way for the M I6. Note that I am not suggesting the engine will be inadequate for this reason.

Originally Posted by Boss330

No, it's only 600rpm apart... Or 7,8%

Hardly worlds apart...

The E30 M3 S14 engine had a rev limit of 7300rpm

The E36 M3 S50 engine had a rev limit of 7200rpm

The E46 M3 S54 engine had a rev limit of 8000rpm

The E9x M3 S65 engine has a rev limit of 8300rpm

Never heard much complaint about low rev limit on the prevoius straight engine M3's before...

[Kuwen]

Originally Posted by zuggerat89

Sour pusses is right!

Every journalist on earth said the E46 M3 exhaust note sounded like garbage when it first came out, everyone whined about the rasp. Now it's loved, go figure.

This car, like past generations, will be amazing, and just like in past generations, the car will sound amazing [at high revs].

E46 noises are some of my favorite sounds on the road. The key is sounding unique / special, and from what we've seen/heard, is where we're headed (imo).