|
|
|
09-14-2010, 08:21 AM | #23 |
Captain
199
Rep 785
Posts |
I just found out from my tech that the N55's cast iron crank shaft is 3kgs lighter thank the N54 forged unit. (bmw tech manual) So I guess each has an advantage. Lighter is nice ultimately, but it wont have the resilience the forged one will...
__________________
991 Turbo
993 GT2 Outlaw |
Appreciate
0
|
09-14-2010, 08:25 AM | #24 |
enter macho title here...
12
Rep 150
Posts |
Going from 335 to 135-54 to 135-55...
The exhaust note is absolutely deeper. Stock, it's similar to the performance ex. On performance, after break in / learning, there is very small amount of initial lag, but the dct and your gearing choice mean that it just doesnt exist much. Press the sport button and it's just not there. The lower mid range is more punchy in the 55. The 54 is still pulling a bit harder above 6000. I'm getting 2-3 more mpg, but that will change over time I would guess. I understand how fragile ego's are around here, but I would not hesitate to call either engine bad. They're both fantastic and frankly it's a wash. Any one suggesting night and day difs or anything but incidental advantages (in either direction) are, IMO just full of themselves (no short supply round here). |
Appreciate
0
|
09-14-2010, 08:40 AM | #25 |
Colonel
382
Rep 2,067
Posts |
some dynos show less low end tq. I an find some dynos if you want, I think edmunds.
__________________
2020 X3MC
2009 135i: AW/CR Aluminum Trim, 6 speed, M-Sport, Premium, Heated Seats, Ipod, BMW Performance Pedals, BMW Performance SSK, BMW Performance Exhaust, BMW Performance Grills E93 M3 FSB |
Appreciate
0
|
09-14-2010, 09:15 AM | #26 | |
Banned
633
Rep 24,685
Posts
Drives: '04 330i ZHP
Join Date: Dec 2007
Location: Chicago Burbs
|
Quote:
This is one of the smartest things I've read on these forums in 3 years. |
|
Appreciate
0
|
09-14-2010, 09:23 AM | #28 |
Banned
633
Rep 24,685
Posts
Drives: '04 330i ZHP
Join Date: Dec 2007
Location: Chicago Burbs
|
we knew what you meant...
|
Appreciate
0
|
09-14-2010, 09:34 AM | #29 |
First Lieutenant
24
Rep 329
Posts |
forged vs cast, that's a huge cost savings for the n55 vs n54. not to mention forged is hell of a lot stronger. the lighter crank in the n55 would explain better perceived throttle response some have noticed compared to the n54. 7lbs or so less rotating mass is enough to notice on an engine of this size.
__________________
|
Appreciate
0
|
09-14-2010, 10:04 AM | #30 |
Banned
71
Rep 2,070
Posts |
I for one would like to see something in writing(reliable source) regarding crankshafts as opposed to some tech at a dealers word. He might be very well right but there are always alot of erroneous 'facts' that come from these types of informants.
|
Appreciate
0
|
09-14-2010, 10:32 AM | #31 |
First Lieutenant
24
Rep 329
Posts |
part numbers are different between the n54 and n55 crankshafts. pistons and rods are the same part number as far as i could tell. i'd be interested in seeing that true specs of the n55 crank.
__________________
|
Appreciate
0
|
09-14-2010, 10:59 AM | #32 | |
Banned
71
Rep 2,070
Posts |
Quote:
Does anyone know if the pistons and rods in the engines are forged? |
|
Appreciate
0
|
09-14-2010, 08:10 PM | #33 | |
Major General
890
Rep 7,047
Posts |
Quote:
How huge do you thing it is? The N55 has a much more advanced and costlier valvetronic system, compared to the now old tech throttle plate design. TS exhaust manifold takes greater design and build effort to create optimal airflow for the TS turbo. The more efficient, better design TS turbo may cost as much as the 2 smaller traditional turbos Weight reduction is no small thing, as most people complain of ever increasing weight. A cast crank saves weight and improves engine response. That's bad? Plus, less turbo plumbing. Sure, a forged crank is stronger, but we'll have to see if the cast unit actually posses any real problems. People are kidding themselves if they believe that a more advanced engine, which might actually cost less overall to produce, falls in the negative notion of "cost cutting". Reducing manufacturing costs while delivering a highly advanced engine is not "cost cutting" in the negative sense. It's pretty smart business. If the N55 actually sucked, then sure, it would be "cost cutting" gone wrong. But, that didn't happen. So, the negative comments are pointless. |
|
Appreciate
0
|
09-14-2010, 08:34 PM | #34 |
First Lieutenant
24
Rep 329
Posts |
a several hundred dollar cost reduction on a single part, multiplied by tens of thousands of units, multiplied by years upon years of model ranges equals a huge cost savings.
that was my point, nothing more. my only other point was i thought it was interesting that the part changed from motor to motor. a forged crank was a point of interest in the n54 press release in '06/'07, which obviously was something bmw thought the motor needed then. "Crankshaft The cast iron crankshaft is retained for the N52KP and N51. To accommodate the increased power output of the N54, the crankshaft is forged steel."
__________________
Last edited by scs; 09-14-2010 at 08:49 PM.. |
Appreciate
0
|
09-14-2010, 10:21 PM | #35 | |
I'm just a cook
24
Rep 971
Posts |
Quote:
Still no one has provided hard facts that the N55 crank is not forged. |
|
Appreciate
0
|
09-15-2010, 01:49 PM | #38 |
Brigadier General
181
Rep 4,038
Posts |
I like he n55 better personally.. stock vs stock but if i wanted a 450 race car i would choose the n54 its definitely proven itself.
my n55 makes some pretty sick sounds for a tune only car |
Appreciate
0
|
09-15-2010, 02:04 PM | #39 |
First Lieutenant
24
Rep 329
Posts |
no worries man, i wasn't intending on getting attacked either. i was just responding to the different crank between the two motors.
__________________
|
Appreciate
0
|
09-15-2010, 04:20 PM | #40 |
New Member
2
Rep 15
Posts |
|
Appreciate
0
|
09-15-2010, 05:07 PM | #41 |
Lieutenant Colonel
102
Rep 1,552
Posts
Drives: '19 M2C | '20 100AE ND2
Join Date: Dec 2009
Location: Phx, AZ
|
Your friend is wrong.
__________________
2019 M2C - Alpine White - 6MT
2023 Supra 6MT - Deposit and Wait |
Appreciate
0
|
09-15-2010, 08:14 PM | #42 |
Lieutenant
69
Rep 460
Posts |
N55 sounds deeper and throatier than the N54 due primarely to the midpipe exhaust not having cats as found on the N54, and only has one cat on the downpipe instead of two as on the N54 (for obvious reasons).
As engines go, with full catle$$ exhausts on both, I doubt they would sound all that different. As for valvetronic vs twin turbo, I'm pretty sure that two turbos cost more than a single unit mated to valvetronic. |
Appreciate
0
|
09-15-2010, 08:26 PM | #43 | |
Brigadier General
184
Rep 3,939
Posts |
Quote:
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. |
|
Appreciate
0
|
09-15-2010, 10:02 PM | #44 | |
Major General
890
Rep 7,047
Posts |
Quote:
You made a statement of fact, and I asked how much the difference would be. The statements I made after asking you to clarify your comment, was intended towards the general topic and not specifically at you. I should have been more clear. To your point again; I know that a forged piece costs more than a cast piece. But, BWM choose to save money in one area for a reason, and then choose to spend it somewhere else for a reason. Saving costs on manufacturing, while still delivering a great product, simply doesn't add up to "cost cutting", as I stated. Going with a cast piece may prove to be a mistake in the long run, or BMW has since discovered a costlier forged piece wasn't necessary for the N55. Cost savings on any one item shouldn't be made outside of the whole, imo. BMW still have to produce this engine at a price point, so they spend less on one thing and more on another. No attack intended, just discussion. Last edited by RPM90; 09-15-2010 at 10:11 PM.. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|