S55 vs N54

[ASAP]

I may be starting the most dangerous thread on this forum but at least it's in the right section. To start... stock for stock; there is no need to compare these motors; in fact it would be silly as the S55 has 130 more HP and way more TQ.

Some facts-

S55/N54

Both Twin Turbo (albeit it's still debatable as to what turbos the S55 has and how they have been modified), The N54 has Td03's as we all know.

Both 3.0L Inline 6 Motors

The rest are build material and quality differences that at these power levels may be considered negligible. Open deck vs closed deck and so forth, so forth.

The main and most telling difference is usable powerband and revability of the motor. The N54 redlines at just under 7K but the turbos lose steam past approx 5900-6000 RPM.

The S55 Redlines at 7600 rpm but has its peak usable power from the high 5000s to the low 7000s which is a huge difference.

We all know the N54 is extremely tunable and was even chosen as being good enough by BMW M to power the 1M. Stock turbo and with all boltons the engine can easily produce upwards of 440 WHP on E85 / Meth and upwards of 390-400 WHP on pump gas. We do not yet know the tuning capabilities of the S55 for many reasons (undisclosed turbo, potentially uncrackable ECU and so forth).

How will these motors compare at similar power levels? Discuss

[Vectors2final]

Closed deck.

[AYEDEE]

No wars started from this thread thank god

[ASAP]

Originally Posted by Vectors2final

Closed deck.

Yes but that's a design feature that has nothing to do with the performance of the motor and never comes into play until obscene amounts of HP. A guy just dyno'd an open block N54 at 750 whp with no issues. On these block designs, I don't see it being an issue until you almost hit 1000 whp. The pistons will long disappear before any of those issues.

[Vectors2final]

True, but it has been a staple in many aftermarket upgrades. Even south of 500hp.

I'm sure that the "track ready" cooling system should help a bit. I'm not sure on the definition of "precision direct injection" that makes it different from the like.

[ASAP]

I think the 2 largest items are the turbos and the headroom available and the RPM advantage that the S55 has. Outside of that; it's all a wash.

[Patronus86]

I think one point few people, except maybe the op, are willing to acknowledge is that the S55 was developed from the N55 which in turn was developed from the N54....the S55 is based off of the technology and methodologies used in the N54.

According to BMW engineers and some of the initial reviews, the S55 has corrected some of the major issues of the early N54 models (cooling, fuel feeding, and a wider torque/hp band). So there is no denying that the S55 seems to be a significant step up from its predecessors.

However, it would have been nice if BMW had made the S55 a more unique engine instead of retooling and reworking it from the N54/N55 baseline. I like the idea of inline 6's on M4's, but maybe if they had built a new engine with greater displacement, even more hp, this car would likely have a lot more character in the engine department...the autocar review and others agree that everything about the new M4 is awesome, except the engine.

Everyone acknowledges the S55 is a solid engine, but it doesn't seem to have the sound, high-end grunt and red-line performance that past BMW's have had.

[Vectors2final]

I think that's where the problem lies.


A lot of people felt that the previous models were too geared towards the top end of performance, rather than the down low to mid range performance of the F8x. It's more real world and enjoyable. Revving to 8000 plus isn't ideal and sometimes impossible.

I guess you could have both, but at the sacrifice of cost.Thats more or less why they retooled this platform. Tried and true with potential for more.

That leaves the division of those who want top end, and those who like bottom end midrange performance.

Once a tune is figured out for this thing... jesus.

[ASAP]

Originally Posted by Patronus86

I think one point few people, except maybe the op, are willing to acknowledge is that the S55 was developed from the N55 which in turn was developed from the N54....the S55 is based off of the technology and methodologies used in the N54.

According to BMW engineers and some of the initial reviews, the S55 has corrected some of the major issues of the early N54 models (cooling, fuel feeding, and a wider torque/hp band). So there is no denying that the S55 seems to be a significant step up from its predecessors.

However, it would have been nice if BMW had made the S55 a more unique engine instead of retooling and reworking it from the N54/N55 baseline. I like the idea of inline 6's on M4's, but maybe if they had built a new engine with greater displacement, even more hp, this car would likely have a lot more character in the engine department...the autocar review and others agree that everything about the new M4 is awesome, except the engine.

Everyone acknowledges the S55 is a solid engine, but it doesn't seem to have the sound, high-end grunt and red-line performance that past BMW's have had.

The cooling benefits are a step up no doubt. Everything else you said seems to be some sort of pointless opinion.

[Patronus86]

Originally Posted by Vectors2final

I think that's where the problem lies.


A lot of people felt that the previous models were too geared towards the top end of performance, rather than the down low to mid range performance of the F8x. It's more real world and enjoyable. Revving to 8000 plus isn't ideal and sometimes impossible.

I guess you could have both, but at the sacrifice of cost.Thats more or less why they retooled this platform. Tried and true with potential for more.

That leaves the division of those who want top end, and those who like bottom end midrange performance.

Once a tune is figured out for this thing... jesus.

I don't really know how much more hp and torque a tune can wring out of the S55...BMW M division has essentially already tuned this thing and have taken a N54/N55 type motor to its max. If we are talking about turbo swaps and bigger intercoolers and meth, than yeah anything is possible. A simple tune though is unlikely to add much simply because I don't think there is much leeway in the safety and efficiency specs of this engine.


I do think BMW M cars, though still usable as daily drivers, have always had a bias, however slight, towards performance. Like I said before, everything about the new M4 speaks of performance, though still usable...everything but the engine.

It's a high-tech and extremely well-built engine, but I think BMW could have pushed themselves a little bit further in that department.

[Patronus86]

Originally Posted by ASAP

The cooling benefits are a step up no doubt. Everything else you said seems to be some sort of pointless opinion.

Go readup about the N54 and N55 engines then come back to me. Whether or not you like my "opinions" the S55 engine was based off of those earlier engine models.

I'm sorry you find that inconvenient...

[ASAP]

Originally Posted by Patronus86

Go readup about the N54 and N55 engines then come back to me. Whether or not you like my "opinions" the S55 engine was based off of those earlier engine models.

I'm sorry you find that inconvenient...

Thats a fact. Your opinions start on the 3rd paragraph.

[Patronus86]

Originally Posted by ASAP

Thats a fact. Your opinions start on the 3rd paragraph.

You stated everything I said, except the bit about cooling, was pointless opinion...so that's why I defended what I said about the origins of the S55 engine.

I agree the 3rd paragraph was my opinion, but I felt it was relevant to the topic of this thread (n54 vs S55).

[ASAP]

Originally Posted by Patronus86

You stated everything I said, except the bit about cooling, was pointless opinion...so that's why I defended what I said about the origins of the S55 engine.

I agree the 3rd paragraph was my opinion, but I felt it was relevant to the topic of this thread (n54 vs S55).

So what led you to believe that I would deny the correlation between the N54/N55/S55?

[Patronus86]

Originally Posted by ASAP

So what led you to believe that I would deny the correlation between the N54/N55/S55?

Really? I have already answered that...I responded to this post from you:

Originally Posted by ASAP

The cooling benefits are a step up no doubt. Everything else you said seems to be some sort of pointless opinion.

When you said "everything" I interpreted that to mean everything and not just the 3rd paragraph. Why are you still arguing about this?

Also, my post was my supportive of what you were saying originally and yet I get a blatantly hostile response from you...you really know how to show your gratitude.

[ASAP]

Originally Posted by Patronus86

Really? I have already answered that...I responded to this post from you:

When you said "everything" I interpreted that to mean everything and not just the 3rd paragraph. Why are you still arguing about this?

Also, my post was my supportive of what you were saying originally and yet I get a blatantly hostile response from you...you really know how to show your gratitude.

Nobody is being hostile, I am just trying to keep this near 100% technical if possible.

[tooch]

Theres a 2.5 l engine I believe it's an audi outputting 525bhp so i believe theres still room left in this motor for at least another 100hp without anything to major.The building materials in the new engine are way better than what they had for the n54/n55 something like 60% new parts that are unique to the s55

[ASAP]

A fun video is coming everyone's way. Sit tight

[///M ARMY]

Its still a new platform, it will take time to see if full potential in action for the F8x. The N54 is great motor and tunable, to early to say about the S55. I personally feel that the car will max out around 550whp on stock turbos.

[A418t81]

Originally Posted by ASAP

A fun video is coming everyone's way. Sit tight

Not at all surprising. The N54 was an auto, and was completely FBO including meth. Those cars all dyno 440+ whp and 460+ wtq on Terry's dyno. The F8X doesn't make that kind of power stock. A simple stage 1 JB4 will turn the tables though.

[ASAP]

Originally Posted by A418t81

Not at all surprising. The N54 was an auto, and was completely FBO including meth. Those cars all dyno 440+ whp and 460+ wtq on Terry's dyno. The F8X doesn't make that kind of power stock. A simple stage 1 JB4 will turn the tables though.

Well, to be 100% fair... an RB car is an even fairer comparison as the turbos are sized and flow very identically. A stock turbo N54 isn't even the same class of motor. It was done to demonstrate an all out stock turbo N54 vs a stock S55. Stock for stock, obviously we wouldn't be having this discussion.

[TurboSid]

N54 has no where to go but upgraded turbos.

S55 is just getting started

I'm not hating, i was an n54 guy a week ago, but this isn't the e90/92 M platform... they were N/A so they didn't have much room to make power without going F/I.