Update: False. S55 engine has oversquare bore/stroke and shares "nothing" with N55!

[Boss330]

Originally Posted by mkoesel

Note that the V8 in the 458 is also an exemption as it makes more torque per liter than any other engine currently on the market.

If we go the route of subjectivity and look just at the "normal" non-performance cars out there with typical engines, I think we may indeed see a tendency for the under square engines to show slightly higher peak torque and at a slightly lower RPM than those with over square geometry. But, we are talking about an M engine here. Plus as swamp notes, road car engines are all so close to square, relatively speaking, that there is little variation in geometry to begin with.



For the record I still haven't been able come up with a truly compelling reason which is why I remain skeptical.

Just a question; You remain sceptical about the info that claims 89,6mm bore and 80mm stroke? (Which I also have said needs to be confirmed). So I also have a bit of sceptisism towards that

However I believe that the reasoning might be twofold (and this is just my private thoughts):

1: An oversquare engine will have better ability to produce torque higher in the RPM range and an undersquare engine will in the lower RPM range. Producing torque higher in the RPM range will yield more power. Low cost, durability, reliability, overall efficiency favor long stroke low RPM engines. High specific output, power to weight favor bigger bore high RPM engines.

2: A new block with larger bore spacing allows for larger bore in future versions of the S55. The short 80mm stroke also leaves plenty of room for longer stroke.

In short, the S55 could form the basis of a new generation of M engines, from the 3l M3/M4 to a 3,6-3,8l (for example with a 3,8l - 94mm bore and 91mm stroke) M5/M6 engine. All possible to accomodate within the S55 block, but not realistically in the N55 (you would need a 98mm stroke to get 3,7l from the N55).

[CanAutM3]

I am also eagerly anticipating official word from BMW regarding the S55 bore and stroke specifications. Until then, as interesting as they are, all our discussions here remains speculative.

For me, the potential of the S55 being a brand new bespoke ///M engine is one of the most exciting news about the F8X

[Boss330]

Originally Posted by CanAutM3

I am also eagerly anticipating official word from BMW regarding the S55 bore and stroke specifications. Until then, as interesting as they are, all our discussions here remains speculative.

For me, the potential of the S55 being a brand new bespoke ///M engine is one of the most exciting news about the F8X

Agreed!!!

That also implies that BMW M has a fairly strong position and solid budgets within BMW.

[swamp2]

Originally Posted by Boss330

Agreed!!!

That also implies that BMW M has a fairly strong position and solid budgets within BMW.

Unfortunately the position of BMW M within BMW is more visible through:

-M Sport models
-pseudo M models like the 1M (number in front of letter)
-M SUVs like X5M, X6M
-The coming new real M models such as the M2 and M4

However, I too remain thrilled that the M4 probably has a unique M engine. The flip side of that is that per BMWs cost and materials offensives (their exact word, not mine), the block/heads will undoubtedly be used on other models in the future. Thus it has little to no chance to be a truly M3/M4 specific M engine.

[Boss330]

Originally Posted by swamp2

Unfortunately the position of BMW M within BMW is more visible through:

-M Sport models
-pseudo M models like the 1M (number in front of letter)
-M SUVs like X5M, X6M
-The coming new real M models such as the M2 and M4

However, I too remain thrilled that the M4 probably has a unique M engine. The flip side of that is that per BMWs cost and materials offensives (their exact word, not mine), the block/heads will undoubtedly be used on other models in the future. Thus it has little to no chance to be a truly M3/M4 specific M engine.

1M is not a "pseudo" M model because of the number in front of the letter?

It would be sacriledge to call it the M1... The M1 is an icon and a production model based M car should not be named after the most iconic M car through history...

[mkoesel]

Originally Posted by Boss330

Just a question; You remain sceptical about the info that claims 89,6mm bore and 80mm stroke?

Yep.

However I believe that the reasoning might be twofold (and this is just my private thoughts):

Those are possibilities, yes. There are many others that have been presented in this thread as well. But so far, while there are many good ideas, nothing I've heard has been "truly compelling" as I put it in my last post.

How about this one for fun :

Suppose BMW is going back to the I6 for their top-tier engines (excl. V12). They will soon phase out the V8 family entirely and replace them all with big bore I6's. In other words, its a return to the days of the big-six/little-six, before the M60 V8 came onto the scene. Now do I believe that? No, not seriously. But it would be the sort of move that, in my mind, would need to be afoot to really justify a brand new I6 engine architecture. The thing is, the chances of the kick-off engine in such a lineup a) being just 3L and b) debuting in an M car, in my mind are approaching zero. Kind of neat to ponder though.

[solstice]

The S55 seems very similar to the N63 in terms of power and characteristics. Will this be the 550, X5/X6 50i,750 engine in the future?

( S55 rpm estimates from dyno and tach. )
N63: 4,395*cc, 402*hp @5500-6400, 440*lb·ft@1750-4500, 7000 rpm redline
S55: 3,000 cc, 430 hp @6000-7000, ~400 lb·ft@2000-5500, 7500 rpm redline

I would think dyno charts from both engines will look very similar with a slight shift of the curves to higher rpms for the S55

[jstnstr]

probably not

[turbolag]

No.

Because this is a M engine.

[solstice]

Originally Posted by turbolag

No.

Because this is a M engine.

It would of course be renamed and probably lose the turbo pre-pressurizing function and have rpm lowered to be able to swap to cheaper materials here and there. It would make a good base though as I think mkoesel already touched on.

Btw I recently ran an N63 equipped 750iL at 13.3s/109.4 mph at the strip from standstill and idle rpms with one attempt. Similar power delivery should be pretty fierce in a 3500 lbs car even if the engine characteristic is not very exciting in itself.

[gman36]

Originally Posted by solstice

The S55 seems very similar to the N63 in terms of power and characteristics. Will this be the 550, X5/X6 50i,750 engine in the future?

( S55 rpm estimates from dyno and tach. )
N63: 4,395*cc, 402*hp @5500-6400, 440*lb·ft@1750-4500, 7000 rpm redline
S55: 3,000 cc, 430 hp @6000-7000, ~400 lb·ft@2000-5500, 7500 rpm redline

I would think dyno charts from both engines will look very similar with a slight shift of the curves to higher rpms for the S55

Your question is a little vague. I think in your case for the question asked, the n55 would be a I6 version of an N63... With the only similarity being a twin scroll turbo. The S55 is by far nothing compared to an N63 and N55 if the thought stirs about.

[gman36]

Thank you! This N55 same as S55 crap is pretty annoying...

[solstice]

Originally Posted by gman36

Your question is a little vague. I think in your case for the question asked, the n55 would be a I6 version of an N63... With the only similarity being a twin scroll turbo. The S55 is by far nothing compared to an N63 and N55 if the thought stirs about.

I was mainly looking at the similarities in power and characteristics. If the power curves are very close in shape and level the N63 could give us a good idea of how the S55 will feel and generate power across the rpm range.

Secondly the similarities could make for a good downsizing replacement for the V8s in the standard cars and SUVs with some minor changes to lower cost. The rpm does not need to run to 7500 for the standard cars for example.

[aus]

More likely to be the block for the N55 replacement.

.

[aus]

Originally Posted by swamp2

Unfortunately the position of BMW M within BMW is more visible through:

-M Sport models
-pseudo M models like the 1M (number in front of letter)
-M SUVs like X5M, X6M
-The coming new real M models such as the M2 and M4

However, I too remain thrilled that the M4 probably has a unique M engine. The flip side of that is that per BMWs cost and materials offensives (their exact word, not mine), the block/heads will undoubtedly be used on other models in the future. Thus it has little to no chance to be a truly M3/M4 specific M engine.

Agreed. I'm thinking N55 replacement with a single twin scroll turbo.
Almost no way it stays excusive to //M.

Originally Posted by gman36

Thank you! This N55 same as S55 crap is pretty annoying...

Then BMW shouldn't have called it the S55. Not really sure why they did that when it's a different block.

.

[solstice]

Originally Posted by aus

More likely to be the block for the N55 replacement.

.

You don't think the N55 will be replaced with a spiced up N20? I.e a 4-banger.

[aus]

Originally Posted by solstice

You don't think the N55 will be replaced with a spiced up N20? I.e a 4-banger.

BMW has LONG history of I6 engines. I just don't see them abandoning all that history. Besides, you can't put a 4 banger in a 7 series in the US, and it can't be the only engine in a 5/6 series.

Besides, the I4 sounds pretty bad and isn't smoothe enough for the higher end cars.

.

[solstice]

Not the only engine if this new N63 level I6 replace the V8s. Maybe the 7 gets a hybrid to complement this six and no I4. Lots of options

[swamp2]

Originally Posted by Boss330

1M is not a "pseudo" M model because of the number in front of the letter?

It would be sacriledge to call it the M1... The M1 is an icon and a production model based M car should not be named after the most iconic M car through history...

Sure the naming factor is related to the legacy of the M1. Rumor I heard though was that focus groups preferred M1 but the BMW Board made the final call on the name. However, the 1M is a "special" (literally less than special) M car in many ways. No other M car has been made from such a parts bin type of approach. BMW developed the car in record time (and I'm sure at record low cost as well). Some passionately call it a true M car, others don't. Of course I am the big, bad jealous M3 owner in the latter camp...

[mkoesel]

Originally Posted by aus

Agreed. I'm thinking N55 replacement with a single twin scroll turbo.

The N55 replacement will share the architecture of the new B38 three cylinder. The S55 is likely to see use in models such as an X3/X4 M or Z3/Z4 M. Other possibilities exist such as, just for example, a super car with hybrid drivetrain in the 600hp+ output range.

Almost no way it stays excusive to //M.

I strongly suspect that it will, just like all M-built S* motors have. Well, there is the Z8, but that would fall under my super car point above. This engine won't find its way into normal series cars.

Originally Posted by swamp2

Sure the naming factor is related to the legacy of the M1. Rumor I heard though was ...

Regardless of how we may each feel about it and how we may categorize it (which is wandering a bit off topic if we are being honest), let's not forget that the 1M was a one-off product, not the beginning of a whole new line of M cars planned deliberately to be executed on a tight timeline with a comparably small budget.

There is the new M Performance vehicles though, which would fit into your list of types of M branded vehicles in your earlier post. As we know, these are products that typically sit just above the M-Sport trim line in the overall picture, borrowing heavily (almost entirely) from the aesthetics of that line rather than using M-proper aesthetics, and mechanically offering mostly minor tweaks from the top tier series car which they sit just above. The new M235i, however, does at least add an LSD which is a popularly requested feature for a non-M-proper car.

[Romo]

Originally Posted by swamp2

Sure the naming factor is related to the legacy of the M1. Rumor I heard though was that focus groups preferred M1 but the BMW Board made the final call on the name. However, the 1M is a "special" (literally less than special) M car in many ways. No other M car has been made from such a parts bin type of approach. BMW developed the car in record time (and I'm sure at record low cost as well). Some passionately call it a true M car, others don't. Of course I am the big, bad jealous M3 owner in the latter camp...

I really do like your comments and the way you back it up with scientific evidence.

But I do disagree, with all due respect, about your 1M opinion.

Yes the 1M is parts bin, yes it is a tweaked N54, but tweaked by ///M, yes it has an E92 chassis/brakes/wheels, yes they did it for cost effective reasons only, but hell yes what a car has been produced. That is not only my opinion, but the whole automotive industry and all world wide carmagazines/journalists.

It is totally irrelevant if this car is a real ///M car or not, (but 99% of all people who had the chance to drive/own one, say it is utterly ///M) this car is by far the best bimmer I have ever driven (did own E46 M3, E92 M3) only a E46 M3CSL will match this car in driving fun, overall speaking I dare to say the 1M is the best fun car ever made by BMW ( real ///M or not)

Yes there was little time for development, yes it was made and produced by a little group off enthusiasts, but they made the whole BMW board proud, this car was a revelation to the world, once again was made crystal clear what the potential off the BMW brand was, this car will be one for the history books. It is living history as we speak !

All future ///M cars will always be compared to the 1M, as it was really the beginning of a new era.

[Boss330]

Originally Posted by Romo

I really do like your comments and the way you back it up with scientific evidence.

But I do disagree, with all due respect, about your 1M opinion.

Yes the 1M is parts bin, yes it is a tweaked N54, but tweaked by ///M, yes it has an E92 chassis/brakes/wheels, yes they did it for cost effective reasons only, but hell yes what a car has been produced. That is not only my opinion, but the whole automotive industry and all world wide carmagazines/journalists.

It is totally irrelevant if this car is a real ///M car or not, (but 99% of all people who had the chance to drive/own one, say it is utterly ///M) this car is by far the best bimmer I have ever driven (did own E46 M3, E92 M3) only a E46 M3CSL will match this car in driving fun, overall speaking I dare to say the 1M is the best fun car ever made by BMW ( real ///M or not)

Yes there was little time for development, yes it was made and produced by a little group off enthusiasts, but they made the whole BMW board proud, this car was a relavation to the world, once again was made crystal clear what the potential off the BMW brand was, this car will be one for the history books. It is living history as we speak !

All future ///M cars will always be compared to the 1M, as it was really the beginning of a new era.

Sometimes the result is greater than the sum of the parts. And the best things sometimes happens by accidence. The result is what the car should be judged by, not the process leading to it's birth.

If the most important part of calling something "true M" is by the process of creation, and not by the end result. If the first is the case, then "true M" has more of a image and "poseur" meaning IMHO. What should matter is how the car drives, feels, gives feedback and if it's is a fast and enjoyable sports car.

If M make a car that is one the greatest driver cars in their history, who cares if they used parts that already were developed for the M3 or other cars? I get that a "bespoke" M3 might be perceived as a "purer" M, by the fact that it's been developed more substantially by M. But if the result of that development is carried over to the 1M, and that ends up being a more involving/"better" drivers car, what's not to like...