Quote:
Originally Posted by sois
Hmmm, I have driven both as well and is quite clear to me that the N54 is a lot more responsive (less lag) and is generally quicker. I was able to modulate a 6sp N55 a bit better than an automatic N55 (dreadful compared to an N54 automatic). However, the 6spd N54 walked on the 6spd N55. This discrepancy is made quite clear by BMW with the new 335is coupe and cab (fitted with the N54 engine and listed with 320hp and 332tq). These are the values N54 engine owners suspected were more realistic all along. The N55 stock does not possess the output that the stock N54 engine possesses and this has been confirmed with more realistic dyno tests.
From what I have read and having driven cars with both engines and auto/6spd combos this is as clear as day to me (the superior quickness/responsiveness of the N54). However, they are both fantastic engines and the N55 I suspect is much more economical and easy for BMW to handle (I believe the N55 runs cooler as well). I can only imagine how many buyers think they are getting the same engine though (twin turbo versus twin scroll terminology...). Clever marketing.
Anyway, Cheers!
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Interesting once again, given the lack of evidence/credibility. I'm not about to turn this into a "you say this, I say that argument", but allow me to address a few things:
1) The N54 engine on the 335is has a completely different tune than the standard N54 engine, because it actually includes the power package that BMW offers through its performance line. So, the 320hp and 332tq that you are referring to have nothing to do with "true" N54 engine power and prior underrating - what this means is that, even the 335is itself may possibly be underrated at these numbers and could indeed be making even more power than claimed thanks to better cooling and a better tune.
2) There is no way that the N55 is experiences more lag than the N54. Not only does BMW claim full torque achieved at 200 rpm's sooner with the newer engine, but I have actually compared them back to back. 2 turbo's to spool versus 1; new twin scroll technology, etc...it is a more advanced engine which achieves equal power and apparently more effortlessly while still improving gas consumption. There is nothing that your butt dyno can type on here that will disprove that, specially with BMW standing behind it. I highly doubt they are in for false advertisement either!
3) Lastly, I can't vouch for auto vs. manual because I have never owned an automatic car, and I refuse to for the time being, however, I hear that DCT mated to the N55 is incredibly quick, and not just that, but also quicker than the N54 car. In 6 speed, I do not know what you're talking about in terms of the N54 walking the N55. My car feels faster than the N54 I drove, and again, at the very least, it achieves full torque quicker which common sense will indicate that it will propel the car faster.
Again, you're entitled to your opinions just like I am to mine, but your statements have no credibility behind them other than "you drove them." At the very least I am citing BMW factual information, and this lovely video shows us how underrated the N55 engine is when it's dynoing so close to its crank rated power.
Cheers!
Edit: I forgot to touch on this part of the subject, but I'm very sure that most people going for the 2011+ models are well aware of the fact that the car has a single turbo now. Somehow I get the impression that you were making it sound like twin has an advantage over single, however, I come from long history with turbocharged applications and I can tell you that the greatest forced inducted machines out there are either running single turbos, or have been converted at one point or another from twin to single. Just look at the greatest supra's and rx7's out there...all converted to single and for multiple reasons: 1) less moving parts = less maintenance, 2) 1 turbo = cooler engine than 2 turbo's, 3) 1 single turbo is more efficient than 2 turbo's, and I'm sure I could keep going. I was actually very happy to know this and made me inclined to getting my 2011 over the left over 2010 that was sitting on the lot. It sounds better, gets better economy, has better/newer technology, and makes the same amount of power. By the way, sit tight and watch when aftermarket companies start developing for this engine - it's been proven throughout time that single turbo setups have a lot more potential than twin turbo setups when it comes to generating higher amounts of power than stock configuration.
