BMW M3 / M4 Engine (S55): Deep Dive and Interview

[BMW M3 CRT]

Originally Posted by KennyPowers

no offense, but this post is ridiculous

the m3 isn't, never has been, and never will be a real sportscar. its well over 3000 lbs and is fattened up by a ton of luxury items.

Nope ... sorry, but you are ridiculous by making such an comment.
For BMW and the M-GmbH the M3 and M4 is clearly "their sportiest Sportscar" ... you are right that it is getting to fat over the generations, but its all the time defined from BMW as sportscar!

Originally Posted by KennyPowers

the m3 is also faster than most of its competitors because it is lighter and has a superior chassis and often times brakes. its not because the motor is more "tractable".

Then you are not fit in BMW M-GmbH history ... until now driveability is the main argument from the M-GmbH why their cars are so fast ... and the reasons are lighter, superior chassis and also important ... linear engine output

Originally Posted by KennyPowers

if that's the case, then why is the gt2 rs so damn fast and blows the doors off a gt3? shouldn't be the case since the motor is turbo and too powerful and not "tractable" according to you, no?

Simple answer ... because the GT2 plays in an totally different hp-class of cars than the GT3

Originally Posted by KennyPowers

fact is that modern turbo engines are not hard to drive on the track, even for novices like myself. my 997tt had zero lag problems, crazy driveability prolems or anything of the like. it basically felt like a really good chassis with a huge motor and great brakes.

BUT the 997tt is all wheel drive which reduces the negative impacts of high low-end-torque ... and its and fact that modern all-wheel-drive systems are getting better and better and the disadvantages of all-wheel-drive-systems on track are getting extremly smaller.

[ASAP]

Originally Posted by bradleyland

Well put. The GT2 vs GT3 is probably the best apples-to-apples comparison you'll find of a turbocharged vs N/A configuration in the same production chassis, and it destroys the argument that the tractability -- or lack thereof -- of a turbocharged engine makes a car slower around a track.

I agree with the speed comments but these are cars have a $100K difference in price so not exactly apples to apples. There is much more going on there than the engine.

[Black Gold]

Originally Posted by BMW M3 CRT

Nope ... sorry, but you are ridiculous by making such an comment.
For BMW and the M-GmbH the M3 and M4 is clearly "their sportiest Sportscar" ... you are right that it is getting to fat over the generations, but its all the time defined from BMW as sportscar!


Then you are not fit in BMW M-GmbH history ... until now driveability is the main argument from the M-GmbH why their cars are so fast ... and the reasons are lighter, superior chassis and also important ... linear engine output


Simple answer ... because the GT2 plays in an totally different hp-class of cars than the GT3



BUT the 997tt is all wheel drive which reduces the negative impacts of high low-end-torque ... and its and fact that modern all-wheel-drive systems are getting better and better and the disadvantages of all-wheel-drive-systems on track are getting extremly smaller.

BMW can call it whatever they want, but true sports cars don't have 4 doors and they aren't that heavy. a racing car doesn't have heated seats, nav, leather seats, back seats, etc...

Who says the new m3 wont be tractable except you? Your opinion is based on absolutely zero data to support your claims. The e9x m3, which I have tracked, is certainly not on the razors edge of traction out there. In fact, the worst part about it is the lack of torque coming out of corners and lack of straight line power. The stability and chassis are the best parts about it, and why its so easy and quick to drive.

What argument from BMW? Any company will always justify whatever they are doing at the time, that's just good business. The s55 powered m3 is claimed by BMW themselves to be half a second faster to 60, much faster to 1000m and has way more in gear acceleration. Its also 10+ seconds faster on the ring.

Considering average power, the s55 smokes the s65, and on the track, that's going to be an advantage whether you want it to be or not. We will find out soon enough.

The 997tt motor has no lag problems, or anything like that. Any fast car requires skill to drive, the faster the car, the more skill and balls required.

[Black Gold]

Originally Posted by ASAP

I agree with the speed comments but these are cars have a $100K difference in price so not exactly apples to apples. There is much more going on there than the engine.

What else is different about the gt2 and 3 except the engine in terms of performance? The rear track of the gt2 is slightly wider is all I can think of.

They basically have the same setup, except the gt3 is a little lighter.

[Black Gold]

Originally Posted by bradleyland

Do they weigh exactly the same? I thought the S55 was slightly heavier. Also, torque output has an impact on suspension tuning. These might seem like minor points, but chassis tuning is a holistic process. That's why so many tuner cars handle so poorly.

Regardless, the subtleties of chassis tuning aren't what would make the big difference. The difference in power between the S55 and S65 is enough for the S55 to come out on top, despite your claims that it is some kind of wildly uncontrollable beast. I think you're just so in love with the S65, you can't think rationally.

this

and the s55 is slightly lighter, I think 11 lbs. basically negligible.

[ASAP]

Originally Posted by KennyPowers

What else is different about the gt2 and 3 except the engine in terms of performance? The rear track of the gt2 is slightly wider is all I can think of.

They basically have the same setup, except the gt3 is a little lighter.

I'll be damned if Porsche is charging 100K for just a different engine. Another reason for me to hate them.

[BMW M3 CRT]

Originally Posted by ASAP

The Gt3 and GT3rs cost 1.5 x to 2 x an M3. They are much lighter cars and the engines are built on a completely different architecture with a completely different valve technology (one that costs double) as a Gt3 rs will cost nearly $140K usd.

I beleave you are misunderstanding me!
I don´t compare the GT3(GT3 RS) with an M3/M4 but with the other cars you listed.

Originally Posted by ASAP

I will ask a simpler question... in keeping with the NA motors, how could BMW have improved on the S65? Larger displacement? Honest question.

I don´t think more displacement is the only and the best way... I think the other improvement of the GTS engine (without the increased displacement!) woud bring an improved S65 in the 430 to 440hp / 430 to 450Nm range, which would be enough to be an costlier but performance wise good alternative to the S55 ... and this without changing the typical M engine characteristic.

[Boss330]

Originally Posted by BMW M3 CRT

Nope ... sorry, but you are ridiculous by making such an comment.
For BMW and the M-GmbH the M3 and M4 is clearly "their sportiest Sportscar" ... you are right that it is getting to fat over the generations, but its all the time defined from BMW as sportscar!


Then you are not fit in BMW M-GmbH history ... until now driveability is the main argument from the M-GmbH why their cars are so fast ... and the reasons are lighter, superior chassis and also important ... linear engine output

The M3 is a "sports saloon" and not a sports car

After completing its activities in Formula 1, Motorsport GmbH focused all its energy on touring car racing. And in 1986 this resulted in the birth of the BMW M3, a compact two-door sports saloon representing BMW’s first parallel development in series production and motor sport: The road version requiring a production run of 5,000 units within one year for recognition as a touring car was conceived for racing right from the start and tailored in virtually every respect to the regulations in Group A

http://www.m-power.com/_open/s/close...d=2978&lang=en

[Black Gold]

Originally Posted by ASAP

I'll be damned if Porsche is charging 100K for just a different engine. Another reason for me to hate them.

to be fair its not 100k more expensive, its more like 70k more

but yea, its true. then again, the engine does make like 600hp in a 3200 lb car

its a monster. it has slightly more luxurious things in it than the gt3 also. one thing it does have is standard carbon backed racing seats etc which are expensive options in the gt3. so like for like, maybe 50-60k difference.

[BMW M3 CRT]

Originally Posted by KennyPowers

this

and the s55 is slightly lighter, I think 11 lbs. basically negligible.

I also heared that the S55 is sllightly heavier than the S65 ... 205kg to 202kg.

But I also think that´s making no real difference!

[ASAP]

Originally Posted by BMW M3 CRT

I beleave you are misunderstanding me!
I don´t compare the GT3(GT3 RS) with an M3/M4 but with the other cars you listed.

In no way does this negate my comments.

I don´t think more displacement is the only and the best way... I think the other improvement of the GTS engine (without the increased displacement!) woud bring an improved S65 in the 430 to 440hp / 430 to 450Nm range, which would be enough to be an costlier but performance wise good alternative to the S55 ... and this without changing the typical M engine characteristic.

Same problem as above, the GTS was offered at a price of $150K... not a suitable price point for the class or for the largest market (USA).

[Boss330]

Originally Posted by KennyPowers

this

and the s55 is slightly lighter, I think 11 lbs. basically negligible.

Originally Posted by BMW M3 CRT

I also heared that the S55 is sllightly heavier than the S65 ... 205kg to 202kg.

But I also think that´s making no real difference!

BMW claims the S55 is 10kg lighter than the S65

[TeutonicFlight]

Originally Posted by GOLFFRR

awesome!

Plus 1

Amazing engineering here

[CanAutM3]

Originally Posted by KennyPowers

What else is different about the gt2 and 3 except the engine in terms of performance? The rear track of the gt2 is slightly wider is all I can think of.

They basically have the same setup, except the gt3 is a little lighter.

170hp difference

You cannot compare these two cars. Whatever the GT2 loses in tractability and ease of driving due to the turbocharged engine, it more than makes up for it with the additional power.

[Black Gold]

Originally Posted by CanAutM3

170hp difference

You cannot compare these two cars. Whatever the GT2 loses in tractability and ease of driving due to the turbocharged engine, it more than makes up for it with the additional power.

that's the point. M3 CRT is going nuts saying that turbo motors are not "tractable" and they lose their drivability. I am saying that no, they don't in well sorted cars. they are a lot faster as they should be

he is grasping to anything that will make the s65 look better than the s55

[coloradoe92m3]

Wow you guys so angry

[i001947]

Is BMW still using plastic turbine propellers in the Turbine Housings? There have been numerous issues in the 335Xi with plastic propellers cracking due the heat.

[IMrMark]

Originally Posted by i001947

Is BMW still using plastic turbine propellers in the Turbine Housings? There have been numerous issues in the 335Xi with plastic propellers cracking due the heat.

Not sure the answer, but the photo in the OP seems to show something that looks nice and metallic... god I hope it is.

[ASAP]

well now we can ask the guy from abu dhabi anything we need to lol

[swamp2]

A couple of points to add/clarify:

Yes average power is important and it must be considered when trying to understand a vehicles performance. That being said, peak power is still a darn good predictor of overall performance. Also, along those lines, the benefits of more power at rpms which are not seen during WOT contests are irrelevant to the level of performance (basically below 5k rpm in the S55). Should be obvious but it seems to continue to be overlooked.

Also along that line of reasoning keep in mind this tradeoff. Those who prefer engines with an ability to produce a lot of power at low rpm (often sacrificing an ability to do so at high rpm - much like S55 vs. s65) love to talk about the benefit of not having to venture in to "aggressive" driving at high rpm. Well, yes and no. The dyno plots intrinsically assume a WOT condition with boost being pretty well maximized. Thus you can't fully enjoy "lazy driving" at part throttle AND simultaneously enjoy this large gap shown between the power curves.

[Boss330]

Originally Posted by swamp2

A couple of points to add/clarify:

Yes average power is important and it must be considered when trying to understand a vehicles performance. That being said, peak power is still a darn good predictor of overall performance. Also, along those lines, the benefits of more power at rpms which are not seen during WOT contests are irrelevant to the level of performance (basically below 5k rpm in the S55). Should be obvious but it seems to continue to be overlooked.

Also along that line of reasoning keep in mind this tradeoff. Those who prefer engines with an ability to produce a lot of power at low rpm (often sacrificing an ability to do so at high rpm - much like S55 vs. s65) love to talk about the benefit of not having to venture in to "aggressive" driving at high rpm. Well, yes and no. The dyno plots intrinsically assume a WOT condition with boost being pretty well maximized. Thus you can't fully enjoy "lazy driving" at part throttle AND simultaneously enjoy this large gap shown between the power curves.

Good points. It's no use at a track to have tons more power below 5000rpm, if you allways keep revs above 5000rpm (which I understand is your point as well).

I'd just like to add that when in Sport and Sport+ mode the wastegates are closed during part throttle driving, keeping the turbos spinning (pre tensioned in BMW speak). This means that the engine should feel much more alert and closer to a WOT scenario than it does in Normal mode. I suspect that the S55 will feel much stronger than the S65 even during "non WOT but partial throttle", especially when in Sport and Sport+ mode.

According to BMW the S55 makes 270Nm unboosted (that would be at fairly low load conditions then). The S65 makes a maximum of 400Nm during WOT conditions. The S55 and S65 might not feel all that different during part throttle condition when just running "on the motor" (unboosted).

Where the S65 needed to be tuned (cams, intake runner length etc) for high end power (ususally at the cost of low down torque), the S55 should be able to have been tuned for low end power and torque "on the motor", as boosting provides the power the S65 needed RPM to make.

All the above just my "thinking out loud" thoughts here

[FogCityM3]

Thx! also a tuned FBO M3 will produce about 7.5%-8.0% more bhp in the upper rev ranges vs stock. Stock E90/2 CRT and GTS, stock new M3/M4, and FBO E9x M3 are likely to have fairly close performance on a track (but in that order by a few secs between each).

Originally Posted by CanAutM3

Here you go:

I agree with you, 1st gear will pretty much useless for maximum acceleration due to traction limitations. I am guessing that such a short gearing is necessary to maintain drivability and decent acceleration in day-to-day puttering around when the engine is not on boost.

I also agree that comparing the two engines power charts as a function of RPM is pretty much useless because it does not factor in the gearing. I plotted the max available engine power vs road speed for DCT optioned F8X and E9X on the graph below. From 35mph to 155mph (2nd gear and up on the F8X), the F8X produces an average 423hp compared to the E9X that produces 391hp. That is 8% more (not considering any underrating of the S55). It is not negligible, but not as much as the graph in the interview leads one to believe.