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N55
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09-01-2009, 09:48 AM | #1 |
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N55
nono, the N55 with a single turbo is the successor of the N54. It delivers the same HP, the same torque (but at 100 RPM less) It is variable turbo (comparable to the turbo Porsche uses) eliminating the need of 2 small turbos. It has (even) less turbo lag, a better fuel economy and... it is cheaper to produce.
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09-01-2009, 09:50 AM | #2 | |
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09-01-2009, 10:01 AM | #3 |
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It is not variable and the N55 will have less torque. It still has a mechanical wastgate.
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09-01-2009, 10:08 AM | #4 | |
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The N54 and N55 will co-exist for sometime as the N54 is not leaving soon in current models but newer refreshes (not the 3) and new models will see the N55. The N55 has a dual scroll turbo and some nifty plumbing that actually increases the response. N55 also has valvetronic and some other features that I can't discuss at this time. In the end of the day the N55 will provide almost identical performance, save weight, decrease emissions, increase longevity and decrease cost per unit. The N54 while it is and will be a great motor it was never going to be a long term solution and was rather a stopgap that ended up being an overwhelming success. There will not be a twin turbo to replace the N54- a dual scroll single turbo is all that is needed to replicate that level of performance. Moving forward the BMW Group will use dual scroll (Twin Power in the EU) to emulate two turbos, and they have great success with this. I just drove the X5 ///M after my experience in the X6 ///M a few months ago- all I can say is that they have this turbo stuff down to a science and it is amazing. In the ///M motors they use 2 dual scrolls to emulate 4 turbos- great response, power and get the same MPG as the ///M3 with more power and a lot more weight. -M
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09-01-2009, 10:23 AM | #5 | |
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But how about the N54 from the current F01 740i (which has 326hp), will it be replaced with a 326hp N55 or with the regular 306hp N55 ? Or the F01 will use the N54 until the next major version of 7-series ? All this said, I can bet that the next M3 will not have a twin-scroll single turbo but it will have two turbos Being an I6 I don't believe the two turbos will be twin-scroll. And a twin-scroll twin-turbo V8 will be too much for an M3.
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Last edited by cstavaru; 09-01-2009 at 10:42 AM.. |
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09-01-2009, 10:47 AM | #6 |
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can a twinscroll turbo really replace 2 smaller ones?
As far as I undersood the only advantage of the N55 is that they combined gas pulses from different cylinders for fast spooling. In the N54 it is only possible to connect 1+2+3 and 4+5+6 ... but maybe with a custom made exhaust manifold it could be possible to do it on the N54... The same in the X6M engine... 8 cyl in 4 turbo inlet (2 dual scroll) the best should be 2 variable geometry turbo like in the 911 turbo... |
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09-01-2009, 01:27 PM | #7 |
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This motor will also reduce the cost to manufacture for BMW.
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09-01-2009, 06:54 PM | #8 |
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I drove the X5 M today and it is FAST!....atleast in regards to a suv
those turbos spool quick no matter were you are in the power band -Scott
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09-01-2009, 07:44 PM | #9 | |
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I am very well versed in the ///M turbo engine I have a good deal of time with it and have written on it extensively. The twin scrolls effectively are two single turbos in one housing, so they would not use two of them to replace the N54 as a twin turbo, there is something else that can be done. I am not at the stage where I can explain all of that in detail as far as the US market goes.... The ///M motor is effectively 4 turbos through the use of 2 dual scrolls. As far as the N54 with the HP bump that requires software and lots of cooling as we have seen in the 7er and now the power kit. The N54 while cleaner than many emissions wise is not where BMW needs or wants to be...
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09-02-2009, 04:24 AM | #10 | |
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http://www.bimmertoday.de/2009/05/26...szylinder-n55/ English Link: http://paultan.org/2009/05/27/new-bm...tronic-engine/ |
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09-02-2009, 04:24 AM | #11 | |
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http://www.bimmertoday.de/2009/07/15...ang-automatik/ |
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09-02-2009, 04:38 AM | #12 |
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Nice info !
It seems that the N55 has 8% better fuel consumption, lower emissions, maximum torque is reached 0.5 seconds earlier and maximum torque begins 100RPM earlier. Looks like a winner...the only problem is tunability. I am not sure that piggyback can be used to tune a Valvetronic engine. Flashes most likey.
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09-02-2009, 04:41 AM | #13 |
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are the N55 mpg and torque better thanks of the valvetronik or the twinscroll turbo?
I would say that a N54 with valvetronik would be as good as a N55 but more expensive to build. I saw in the german description of the engine that even the turbo lag Is reduced in the N55… after the mess on the N54! Easy they don’t have wastegte rattle to fix on the N55… so no lag introduced by the DME Another money aspect, I think BMW switched from Mitsubishi (N54) to garret turbo in the N55, these are the same as the ones used in the X6//M... large scale economy???? |
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09-02-2009, 04:59 AM | #14 |
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looking at the pictures of N55:
there is a MAF air flow meter in the duct between filter and turbo, is it good or bad? the DME is bolted on the engine block near the trottle body intercooler is bigger, X6 style is the HPFP the same crap as the N54? any improovement to use Ethanol fuel? |
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09-02-2009, 09:46 AM | #15 | |
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Less lag w/ n55 thanks to plumbing and twin scroll. I will be covering this motor in great depth like I did with the turbo ///M motor When I am given the go ahead. Just note that the N54 is not going to disappear over night, the N52 in higher output guise still exists in the X3 and X5 even though it left the 3 series. There are also new 4 cylinders and 3 cylinder hybrids in the not so distant future. Emissions and MPG improvements with similar performance to the current offerings. Efficient dynamics at its best! -M
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09-02-2009, 10:05 AM | #16 |
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Great write up for the X6//M !!!
Hope you will provide the same in depth detail for the N55 Do you think that upgrading the N54 with a single twinscroll turbo (maybe with the OEM N55 one) and refining the DME software, the N54 coud perform as good as the N55? I don't care about MPG and emissions, only turbo lag, torque and HP are interesting... |
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09-02-2009, 10:40 AM | #17 |
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Still, we must not forget that by using twin-scroll instead of twin-turbo, a degree of freedom is lost. The two gas flows are no more independent because the scrolls share the same axle (right ?). The banks of cylinders operating on the two flows must be perfectly matched, otherwise different gas flow speeds on the two separate airways could alter the engine behaviour negatively.
Also, I believe the twin-scroll turbine is quite a lot more expensive than a single-scroll. I don't know if on the N54 both turbos break at the same time usually, but if you have to replace a turbine on the N54 it will be probably much cheaper than on the N55. I am very curious if the next M3 (which I believe will be an inline 6) will use a single twin-scroll turbo or 2 classic ones...that will be the moment where we will see if the twin-scroll technology is just for cost or for performance.
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09-02-2009, 11:02 AM | #18 |
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The N54 will always be down on the N55 in stock form due to the presence of valvetronic on the N55. Tuneability is a whole different story.
In theory, one could change the exhaust manifold(s) on the N54 to run a single dual-scroll turbo and get (essentially) identical results to the current twin turbo setup. |
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09-02-2009, 12:04 PM | #19 |
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Twin scroll is not literally like two turbos.
If you want to use the 'old' term for a turbo (turbine supercharger), then yes, there are two turbines. (I.E. a double turbine hot-side). There is still a single compressor (normal cold-side). (Not a bad thing). It makes a little bit of difference, but I've never seen any numbers to suggest a twin scroll would dramatically change anything over a single scroll. It's more like one of those 'every little bit helps' sort of things. -scheherazade |
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09-02-2009, 01:26 PM | #20 | |
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The advantage of the single turbo twin-scroll vs. twin setup would be the reduction in the amount of plumbing...and with the twin scroll setup you would be able to take advantage of the exhaust pulses to help reduce lag and use the exhaust flow more efficiently. I'm curious as to why they would go back to a MAF rather than a MAP system. Any thoughts? |
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09-02-2009, 02:53 PM | #21 |
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Apparently it does. The lack of a throttle body and thus the unrestricted airflow to the engine at all times contributes to better power delivery (or at least this is what they say in the N55 press release).
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