135i: N54 vs N55 - My Humble Opinion

[Mr Rooty Von Tooty]

I posted this in another thread:

"The engine internals are the same except the N54 has a forged crank. You'll notice the M235/240 & M2 all have a forged crank.

You can read about the difference between a single scroll and twin here:

http://dsportmag.com/the-tech/twin-s...-great-divide/

How much difference does the twin in the N54 make over the N55? Good luck in figuring that one out."

I was on the freeway today, and I had a chance to open it up. BTW, I have the M-Sport with DCT and the software upgrade to solve stalling and engine surge. Also Michelin A/S 3s.

This car runs like a rocket. The power comes on quickly and smoothly, and the DCT happily administers it. There is absolutely nothing this car or engine needs to improve its performance. It can frighteningly quick bury the speedometer needle.

The suspension gives a firm but supple ride except when you run into some bad pavement. The handling is first rate, so the suspension too doesn't need any improvements.

I doubt the M2 would impress me more than this car. It already has everything.

[HyeWarrior]

^Agreed

After the car warms up, Sport mode completely eliminates any kind of lag. Car drives as if should imo in Sport mode

[1smokehouse]

Originally Posted by Mr Rooty Von Tooty

I posted this in another thread:

BTW, I have the M-Sport with DCT and the software upgrade to solve stalling and engine surge.

Which software upgrade if I may ask? PPK? I have the same car on its way to Guam and will arrive at the end of the month.

[MightyMouseTech]

Dackelone

Dackel had posted a great BMW Technical bulletin showing all the differences between the N54 and N55. Dammit, I can't find it right now.

[Mr Rooty Von Tooty]

Originally Posted by HyeWarrior

^Agreed

After the car warms up, Sport mode completely eliminates any kind of lag. Car drives as if should imo in Sport mode

I have never used the Sport Mode or paddles! Why bother?

[Mr Rooty Von Tooty]

Originally Posted by 1smokehouse

Which software upgrade if I may ask? PPK? I have the same car on its way to Guam and will arrive at the end of the month.

You have to search around. I have written several posts describing this software update. BTW, it took nearly a day to do. It transformed the car into a truly great drive!

[Dackelone]

Originally Posted by MightyMouseTech

Dackelone

Dackel had posted a great BMW Technical bulletin showing all the differences between the N54 and N55. Dammit, I can't find it right now.

Mighty I think your thinking of these pdf's...

2007 Engine Tech: How the N54 works (must read!!!)
http://www.e90post.com/forums/showthread.php?t=38856

N55-guide-BIMMERPOST.pdf
http://www.bimmerpost.com/goodiesfor...BIMMERPOST.pdf

Originally Posted by Mr Rooty Von Tooty

I doubt the M2 would impress me more than this car. It already has everything.

The M2 impressed me, and I also have a N54, albeit "tuned" with 380PS and 520Nm. This past September Artemis was kind enough to let me drive his M2 thru the Bavarian Alps. I was really impressed with the car's handling and smooth power delivery - even at high rpm's. Sure it was a little bit down from my 135i's power level... but what really impressed me most about Artemis 's M2 was how well it handled and how much grip the front of the car had under turn in. The M2 is a very entertaining car - more so than a 135i or M235i. The M2 loved being driven hard into the twisties - and I am thankful for Luke allowing me to drive his M2 that day.

I also fell in love with the M-Performance Exhaust Luke's M2 has. Its the cherry on the M2's driving package/performance/envelope.

[tock172]

Originally Posted by Mr Rooty Von Tooty

I posted this in another thread:

"The engine internals are the same except the N54 has a forged crank. You'll notice the M235/240 & M2 all have a forged crank.

You can read about the difference between a single scroll and twin here:

http://dsportmag.com/the-tech/twin-s...-great-divide/

How much difference does the twin in the N54 make over the N55? Good luck in figuring that one out."

The N54 does have a forged crankshaft, but the N55 in the M235i uses steel alloy (our cars get cast iron), and the S55 uses hardened steel alloy. I'm guessing the N55B30T0 in the M2 uses either steel alloy or hardened steel alloy.

Originally Posted by atr_hugo

- The single turbo on the N55 is getting an exhaust pulse every 120 degrees of engine rotation, the two turbos in the N54 receive an exhaust pulse every 240 degrees of engine rotation - the N55 'feels' like it is smoother in acceleration to me, almost like what I've experienced with a V-12

Recall that the N55 makes use of a single, twin scroll turbo. Each scroll is plumbed to an individual bank of 3 cylinders. This, in conjunction with the Valvetronic allows for a lower torque peak and less lag. The N54 uses two individual turbos, each one being fed from a bank of 3 cylinders as well. Regardless, there's still lightly more lag and a less linear power band because the system is slightly less efficient.



The biggest thing for me when I made my decision was reliability and maintenance. My 1-series is my 7th BMW and I wasn't in the mood for something I would need to wrench on. So far, the N55 has been an excellent engine that easily makes more power in stock form that I'll ever need. (But I'm still itching for Dinan S2 software).

Beyond that, I was turned off by the fact that the N54 is based on the M54 design. I owned two E46 330i's and I think the M54 is a great engine, but not when it has 2 turbos, an intercooler and direct injection (which doesn't like our gasoline) added on to it. How many revisions of injectors has the N54 had now?

[davis449]

Beyond that, I was turned off by the fact that the N54 is based on the M54 design. I owned two E46 330i's and I think the M54 is a great engine, but not when it has 2 turbos, an intercooler and direct injection (which doesn't like our gasoline) added on to it. How many revisions of injectors has the N54 had now?

LOL! The only reason I was willing to take on a N54, as I have, is because I will not own the car past the warranty expiration...

[tock172]

Originally Posted by davis449

LOL! The only reason I was willing to take on a N54, as I have, is because I will not own the car past the warranty expiration...

Funny, I don't plan on keeping my N55 after the warranty is gone either. Perhaps not even that long.

[1smokehouse]

Originally Posted by Mr Rooty Von Tooty

You have to search around. I have written several posts describing this software update. BTW, it took nearly a day to do. It transformed the car into a truly great drive!

Found your thread... I'm getting the PPK after it arrives, hopefully it will fix any issues it may have.

Thanks!

[squeedle]

I must be evaluating some different metric than most of you, because the two models definitely felt very different to me. And even to my wife in the passenger seat. The main difference I felt was accelerating from very slow speed or from a dead stop. The N55 just seemed to wait and wait to be sure I wanted to go fast before it kicked in. The N54 was just like, "sweet, let's go".

Wish I could ride along with some of you guys to get your take in real-time. If anyone's in the SF area and feels like having an enthusiastic passenger, please PM me.

And, just to reiterate, I wish I preferred the N55. It definitely seems to be the more reliable of the two. I went into all this expecting to like it more, or at least about the same. So there's that, for whatever it's worth. I am convinced it's the "smarter" buy. But it just didn't make me smile.

[Esteban]

Originally Posted by Mr Rooty Von Tooty

I have never used the Sport Mode or paddles! Why bother?

Cause it makes the car more fun than it already is!

[The Wind Breezes]

Putting the car into auto-shift mode feels so weird. Paddles most times, sequential stick occasionally.

[Esteban]

Originally Posted by The Wind Breezes

Putting the car into auto-shift mode feels so weird. Paddles most times, sequential stick occasionally.

Agree about auto-shift. Never use it. Manual mode + sport button with the DCT is a blast!

[Mr Rooty Von Tooty]

The cast crank on the 135i would be the major reason I'd leave this engine stock. In any case, I just wouldn't want more power, since I can't see any advantage to it besides removing tread from the rear tires. I also notice that for an additional 20 HP, BMW upgrades the cooling system and something else which I forget. That to me is a warning to leave things alone!

As for the M2, assuming I traded my car, I'd need to add around $35,000 to make the purchase. That would make a sizable impression on my wallet. Perhaps in another 7 years or so, I might make a grab for one? In any case, I'd never get rid of a satisfying ride. In fact, I hardly bother to drive my Mercedes since getting this car!

[davis449]

Originally Posted by tock172

Funny, I don't plan on keeping my N55 after the warranty is gone either. Perhaps not even that long.

Funny, I had a high deductible, covers-all warranty on my N55 and the big driving force behind my trading the 1er was I didn't want to keep getting repairs done at just under my deductible all the time...

[ianc]

but what really impressed me most about Artemis 's M2 was how well it handled and how much grip the front of the car had under turn in. The M2 is a very entertaining car - more so than a 135i or M235i

Dack, remind me again; have you done the M3 bits on the front of your car? I know you did M3 RSFB's, but can't remember if you tweaked the front at all. It really helps...

ianc

[Esteban]

Speaking of the M2, would love to test drive one to see what it's all about, but my local dealer doesn't have one, nor does any dealer in my area. Will have to wait a bit, I guess.

[swagon]

Originally Posted by Esteban

Speaking of the M2, would love to test drive one to see what it's all about, but my local dealer doesn't have one, nor does any dealer in my area. Will have to wait a bit, I guess.

That's weird. Pretty sure there must be at least a dozen of BMW dealership in LA, no?

I did not get the chance to drive it hard on some twisty roads, but I really liked the M2, as well.

[Esteban]

Originally Posted by swagon

That's weird. Pretty sure there must be at least a dozen of BMW dealership in LA, no?

I did not get the chance to drive it hard on some twisty roads, but I really liked the M2, as well.

Don't live that close to LA, and also, I HATE LA. I avoid it like the plague! Will wait for something closer to come in my area.

[Esteban]

PS - and even if I did go to LA, where would I drive it? In LA's congested traffic? Yeah, that sounds like tons of fun. Seriously, traffic sucks out there. No thanks!