N54 vs N55

[RPM90]

Originally Posted by 1SerieStud

Don't be so sure:

1) Turbochargers date all the way to many decades back, valvetronic is fairly new technology when compared to a turbocharger.

2) The single turbocharger has yet more innovative technology built into the system (twin scroll), which I am quite positive makes the turbocharger more expensive than a regular one.

So, mate a twin scroll turbocharger to valvetronic, and I can guarantee that due to newer technologies combined, you're looking at a more expensive setup. Regular twin turbo setups have been around for a while.

Plus the special manifold needed for the TS design.

I think the "more is more" mentality can skew things at times.
Just because there is 1 less turbo, I just don't see how that translates to "cost cutting" as some have said or implied.

If this engine were truly inferior it would be clearer, time will tell.
So far, it's quite an advanced design.

[1SerieStud]

Originally Posted by RPM90

Plus the special manifold needed for the TS design.

I think the "more is more" mentality can skew things at times.
Just because there is 1 less turbo, I just don't see how that translates to "cost cutting" as some have said or implied.

If this engine were truly inferior it would be clearer, time will tell.
So far, it's quite an advanced design.

+1....just wait until mods start to surface for this motor...looking back in time, the fastest, most powerful, greatest turbocharged setups are all single setups. And the ones that started off as twin setups (such as Supra's back in the 90's), all were converted to single in order to push big power and break the 600hp+ mark.

As you said, time will tell

[Milligan]

Forged crank is overkill on this car anyway. Both engines are the best in their class which makes them equal in my mind

[ILMOSTRO]

The troll is winning. You guys are fighting.

[clar]

I find it ridiculous that people are seriously entertaining the thought that cost cutting is the motive behind N55. The best way to cut cost would be to simply use N54 for another 5 years without spending huge amount of $ into researching a new engine that is the N55. Afterall, the R&D $ for N54 has already been spent. Cost cutting is when they use N54 for the upcoming 1M.

[mrcardio]

Originally Posted by clar

I find it ridiculous that people are seriously entertaining the thought that cost cutting is the motive behind N55. The best way to cut cost would be to simply use N54 for another 5 years without spending huge amount of $ into researching a new engine that is the N55. Afterall, the R&D $ for N54 has already been spent. Cost cutting is when they use N54 for the upcoming 1M.

This happens because people always want to believe they have the best thing available. When something new / better becomes available it devastates the ego.

[1SerieStud]

Originally Posted by mrcardio

This happens because people always want to believe they have the best thing available. When something new / better becomes available it devastates the ego.

I couldn't agree more with both of you!

[mrcardio]

This is interesting:

2011 BMW 335i sedan / N55

http://www.caranddriver.com/reviews/...dan-quick_test

C/D TEST RESULTS:
Zero to 60 mph: 4.8 sec
Zero to 100 mph: 11.7 sec
Zero to 130 mph: 20.7 sec
Street start, 5–60 mph: 5.5 sec
Standing ¼-mile: 13.6 sec @ 106 mph

"Our 2011 335i was just as quick as the twin-turbo car, reaching 60 mph in the same sprightly 4.8 seconds. The quarter-mile flew by in 13.6 seconds at 106 mph, 0.1 second behind the quickest twin-turbo sedan we tested. After the century mark, however, the new mill picks up steam, reaching 140 mph nearly a full second quicker".

[myke354]

ok after reading this thread i now feel like some brain cells have died...
r u guys kidding me ... first off these motors will never see any kind of power that would destroy a crank... so yes the n55 crank is lighter there for it has alot more going for it then the n54 does ... n54 crank will never be needed in this car..

now to the OP .. bottom line comes down to what ever motor u want.. the n54 is great so far the n55 still hasnt been cracked open yet to see how it likes mods..

but imho bmw failed... they should have fixed the fuel pump first rather then build a new motor..

[IMASINNER]

Originally Posted by 1SerieStud

let's cut cost and make a more modern engine combining valvetronic and twin scroll turbo technology which exhibits full torque 200 rpm's sooner than the n54. Doesn't sound like a cost cut to me

FYI - internals are still forged.

And Heeere Weeeeeeee Go!

[NYC6]

Forged cranks are alot harder to make and quite a bit more expensive. You gotta think BMW doesnt like to throw away money on parts that aren't needed. That would be failing business 101. Maybe they planned on turning up the power wick on the 54 all along. I'll be interested to see how the 55 engine handles big power when the tuners get it all figured out.

[Berduderunner]

Originally Posted by myke354

ok after reading this thread i now feel like some brain cells have died...
r u guys kidding me ... first off these motors will never see any kind of power that would destroy a crank... so yes the n55 crank is lighter there for it has alot more going for it then the n54 does ... n54 crank will never be needed in this car..

now to the OP .. bottom line comes down to what ever motor u want.. the n54 is great so far the n55 still hasnt been cracked open yet to see how it likes mods..

but imho bmw failed... they should have fixed the fuel pump first rather then build a new motor..

ahahaha

[angryBitz]

Everyone seems to be down on the single turbo in the N55, but its not an ordinary turbo, its a twin-scroll turbo. My understanding of a twin-scroll turbo is that it's fed by two exhaust inlets allowing it to spool faster so it can be larger without the extra turbo lag (like a twin-turbo). So in the end, I think the twin-scroll is comparable to the twin-turbo. However, one turbo sounds easier to maintain than two turbos.

Having said that... Didn't I read somewhere that the 1M coming out next year is going to have the N54 engine?

[myke354]

Originally Posted by angryBitz

Everyone seems to be down on the single turbo in the N55, but its not an ordinary turbo, its a twin-scroll turbo. My understanding of a twin-scroll turbo is that it's fed by two exhaust inlets allowing it to spool faster so it can be larger without the extra turbo lag (like a twin-turbo). So in the end, I think the twin-scroll is comparable to the twin-turbo. However, one turbo sounds easier to maintain than two turbos.

Having said that... Didn't I read somewhere that the 1M coming out next year is going to have the N54 engine?

u are 100% right on how it works now is one twin scroll as good as 2 single scrolls that is very up in the air..
think of it like this 2 small turbos will spool faster then 1 big turbo..

[angryBitz]

Originally Posted by myke354

u are 100% right on how it works now is one twin scroll as good as 2 single scrolls that is very up in the air..
think of it like this 2 small turbos will spool faster then 1 big turbo..

In terms of mass, each smaller turbo would have less mass to accelerate than the larger turbo. However, two smaller turbos delivering power to the engine would probably cause more turbulence due to variations in output/pressure compared to the single turbo... spool-time ultimately amounts to throttle response and throttle response is quoted to be better in the N55 - though I've never driven an N54.

My point isn't to say the N55 is better, but rather, I think they're much more the same than people think.

[myke354]

Originally Posted by angryBitz

In terms of mass, each smaller turbo would have less mass to accelerate than the larger turbo. However, two smaller turbos delivering power to the engine would probably cause more turbulence due to variations in output/pressure compared to the single turbo... spool-time ultimately amounts to throttle response and throttle response is quoted to be better in the N55 - though I've never driven an N54.

My point isn't to say the N55 is better, but rather, I think they're much more the same than people think.

ur point is very valid to a point .. yea 2 small turbos will have lass mass therefor move less air and make less power. now where i will tend to disagree is on spool times and this is something i would like to try myself.. the reason the n55 spool is better comes down to less mass in the crank witch can and does make a world of difference .. now i want to get my hands on a n55 crank and see if i can swap in to a n54 and see if my theory is right if so then im sure the n54 will spool the same as the n55 is not even faster witch is crazy cause 1200rpms is already very low

[angryBitz]

Originally Posted by myke354

ur point is very valid to a point .. yea 2 small turbos will have lass mass therefor move less air and make less power. now where i will tend to disagree is on spool times and this is something i would like to try myself.. the reason the n55 spool is better comes down to less mass in the crank witch can and does make a world of difference .. now i want to get my hands on a n55 crank and see if i can swap in to a n54 and see if my theory is right if so then im sure the n54 will spool the same as the n55 is not even faster witch is crazy cause 1200rpms is already very low

That wasn't my point and I'm not sure a lighter crank is going to affect spool times much.

By mass, I was referring to the amount of physical mass (weight/metal) needing to be accelerated in two small turbos vs one larger turbo. each smaller turbo will have less mass and spool faster, but I think the turbulence caused by having two compressors will cancel that out.

Regarding the lighter crank, i believe that will only affect engine speed, not spool-time. Spool time is affected by air turbulence, back pressure, turbo size, friction, etc...

[RPM90]

Originally Posted by myke354

ur point is very valid to a point .. yea 2 small turbos will have lass mass therefor move less air and make less power. now where i will tend to disagree is on spool times and this is something i would like to try myself.. the reason the n55 spool is better comes down to less mass in the crank witch can and does make a world of difference .. now i want to get my hands on a n55 crank and see if i can swap in to a n54 and see if my theory is right if so then im sure the n54 will spool the same as the n55 is not even faster witch is crazy cause 1200rpms is already very low

The crank will make some difference in terms of the engine being able to build rev quicker, which would also translate to exhaust pressure building quicker as well. However, the crank isn't the only reason here, it is one factor/ingredient in the mix.

The TS turbo has specialized "tuned" manifold designed to feed the TS at low and high rpm, so that is another factor in how fast the turbo can spool.

Then there is valvetronic, which should have the potential to reduce 'pumping loss' as the engine doesn't have to fight the added restriction of a throttle plate.

All of those contribute a little bit in N55 design, which results in a slightly more efficient engine of the same displacement and equal power.
Efficiency is a major motivator in designing the N55, not "cost cutting".
If in fact the N55 cost less to build than the N54, then that a very good thing for BMW in terms of business and profit, considering the N55 has succeeded in producing what BMW sought to get, which is near equivalent performance in a higher efficiency engine.
If the N55 sucked, then it would a fail.

Still, does anyone have the numbers on how much it costs to build an N54 compared to an N55?
Until we get that, we can't really say much about the true costs to build.

[angryBitz]

Originally Posted by RPM90

Still, does anyone have the numbers on how much it costs to build an N54 compared to an N55?
Until we get that, we can't really say much about the true costs to build.

Why does the cost of the engine matter?

If the cost of the N55 turned out to be 1/2 of the N54, would it really matter? The only reason cost cutting would matter to the consumer is if quality were reduced to a point where we might break it due to mods and we don't really know that yet. So I say forget $$$ and lets get some N55 guinea pigs hooked up with some mods. My car is at 915 miles today. When I hit 1500, I'm going to get an oil change and then I'm going straight to Vishnu - but I'd love it if someone else did it first!

[jwalk135]

(This is the most war inducing thread haha. for the record I love 1 series and both engines are great but....)I have a late N54 and that is quicker than an N55 which lets all face it, makes it better. 'Twin Turbo' just sounds better than 'Turbo' too. The power comes in at 100 revs less I think which is about 1 millimeter on the dial, does this warranty any excitement? no. It does have lower co2 emissions though but if you're bothered about that buy a 118i.

In all seriousness though they had to find a way of making the brilliant N54 more 'eco' for the green warriors and the N55 is a great solution, unfortunately the experience has been ever so slightly diluted. In the real world there probably isn't much in it (well maybe a bit) and as long as we are all carrying the 1er flag who cares.

ps I completely tore apart an R32 today and am pretty sure the 135 is good for 170mph easily if de restricted.

[jwalk135]

Trojan4evr summed it up! He has both and thinks they are both great.

[1SerieStud]

Lol correction: stock for stock the n54 is NOT faster than the n55. Also, there is a larger market of mods for the n54 platform which is why most modded n54's are quicker. It's just a matter of time as more parts are becoming available for the new platform.

Also, your reasoning behind the turbo setups is mediocre at best...picking twin turbo because it "sounds better than turbo" portrays a high level of ignorance. If you want to argue twin versus single, go talk to the supra and rx7 guys pushing 6, 7, 800+ hp by converting from twin (stock) to single turbo. A single big turbo is more efficient by being able to provide similar and/or greater amounts of power, with less moving parts (1 turbo versus 2), and therefore producing less heat. This also leads to less possible parts that could break, as well as weight savings.

Originally Posted by jwalk135

(This is the most war inducing thread haha. for the record I love 1 series and both engines are great but....)I have a late N54 and that is quicker than an N55 which lets all face it, makes it better. 'Twin Turbo' just sounds better than 'Turbo' too. The power comes in at 100 revs less I think which is about 1 millimeter on the dial, does this warranty any excitement? no. It does have lower co2 emissions though but if you're bothered about that buy a 118i.

In all seriousness though they had to find a way of making the brilliant N54 more 'eco' for the green warriors and the N55 is a great solution, unfortunately the experience has been ever so slightly diluted. In the real world there probably isn't much in it (well maybe a bit) and as long as we are all carrying the 1er flag who cares.

ps I completely tore apart an R32 today and am pretty sure the 135 is good for 170mph easily if de restricted.