E90Fleet..what's the N51 all about?

STE92VE · 03-22-2007, 02:55 PM

Since discovering my E92 will have the N51 SULEV engine, I've been researching the crap out of it and really have not come up with any solid answers as to how it will perform compared to the N52. This is what I've got so far.

N51 Overview
In order to comply with SULEV requirements, the N51 is another variant of the N52
engine. There are various measures to meet the EPA/CARB standards, some of which
are familiar from the previous SULEV (M56) engine.
Some of the SULEV measures for the N51 include:
• Near engine catalyst with additional underbody catalyst
• Secondary air system
• Optimized combustion chamber geometry in cylinder head
• Modified piston crown for lower compression
• Plastic valve cover with integrated crankcase vent valve and separator (from N52KP)
• Stainless steel fuel lines with threaded connections
• Radiator with “Prem-air” coating
• Throttle system - EGAS08 carried over from N52KP
• Airbox with Activated carbon filter for EVAP control
• Purge system pipes are made from “optimized” plastic

Maybe you can shed a liittle light on whether there will be any noticeable differences regarding HP, torque, MPG or reliability issues as to the N52. Thanks!

E90Fleet · 03-22-2007, 03:12 PM

I can add the following info:

The N54 and N52KP meet ULEV II requirements for 2007. There are not many
changes to the emissiom systems on these engines. The N54 engine has 2 underbody
catalysts in addition to the “near engine” catalysts already in use from the N52.
The N51 engine, however, is a SULEV II compliant engine which meets the 2007
requirements. In addition to the 5 exisiting SULEV states of California, New York, Maine,
Massachusetts, and Vermont - four states have been added for 2007. These states
include, Connecticut, Rhode Island, Oregon and Washington State.
The N51 emissions measures include:
• Secondary Air System with mini-HFM
• Radiator with “Prem-air” coating
• Lower compression ratio (10:1) via modified combustion chamber and pistons
• Underbody catalyst in addition to “near engine” catalyst
• Activated carbon air filter in air filter housing
• Steel fuel lines with threaded fittings and sealed fuel tank
• Crankcase ventilation system integrated into cylinder head cover
• Purge system piping made from optimized plastic

The N51 engine uses the designation - “N51B30M0”. This
engine is SULEV II compliant with 230 horsepower.

E90Fleet · 03-22-2007, 03:13 PM

This table may help aswell:

STE92VE · 03-22-2007, 03:38 PM

That table makes the comparison very clear. Would the lower compression ratio mean that you can run 87 octane and get the same performance as the higher compression N52 which needs 91?

E90Fleet · 03-22-2007, 03:41 PM

Quote:

Originally Posted by STE92VE

That table makes the comparison very clear. Would the lower compression ratio mean that you can run 87 octane and get the same performance as the higher compression N52 which needs 91?

It could probably accept a lower octane, but you may find its gives you a worse gas milage and lower performance.

Best see what the manual reccomends

STE92VE · 03-22-2007, 03:48 PM

Good idea! I'll post my experience after delivery. Thanks!

canucklion · 03-22-2007, 03:49 PM

Fleet, you're unreal

danimal · 03-22-2007, 05:57 PM

Now I get what all the cries of "I wish fleet were here" were about. Glad you are back.

Can I hijack this thread for a second to ask about my engine (engine code = N52B30AE)? I was told by someone at my dealer that the only change from prior N52's is a "revision in fuel management," which apparently translates to a 1 mpg improvement in the EPA highway cycle.

Can you verify this? Is this just a minor tweak to the ECU or...? Any info you have would be great.

Thanks & welcome back (even though I wasn't here when you left

),

-Dan

teknochild · 03-22-2007, 06:02 PM

Quote:

Originally Posted by STE92VE

That table makes the comparison very clear. Would the lower compression ratio mean that you can run 87 octane and get the same performance as the higher compression N52 which needs 91?

i doubt that, its .7 diffrence, most of the low octane engines are around 8:1

STE92VE · 03-22-2007, 06:15 PM

As E90Fleet said, whatever the recommended octane is, that's what I'll use. What's the sense of getting the Ultimate Driving Machine if I'm going to treat it like a Toyota!

LEDZEP · 03-22-2007, 06:19 PM

Quote:

Originally Posted by canucklion

Fleet, you're unreal

Nope. I pinched him once. He's real.

SteveMD · 03-22-2007, 06:21 PM

Hmmm...the N51 doesn't have the three stage manifold?

E90Fleet · 03-22-2007, 06:31 PM

Quote:

Originally Posted by danthman

Now I get what all the cries of "I wish fleet were here" were about. Glad you are back.

Can I hijack this thread for a second to ask about my engine (engine code = N52B30AE)? I was told by someone at my dealer that the only change from prior N52's is a "revision in fuel management," which apparently translates to a 1 mpg improvement in the EPA highway cycle.

Can you verify this? Is this just a minor tweak to the ECU or...? Any info you have would be great.

Thanks & welcome back (even though I wasn't here when you left

),

-Dan

Hi

The engine in your 328i is a N52KP ( also known as N52N )

It has a number of improvements over the original N52

the table I posted above shows lots of the changes between the original N52 and the N52KP

here are some of the changes aswell:

• New engine management (MSV80)
• New HFM (digital)
• New throttle - EGAS8 with magnetoresistive position feedback
• Plastic valve cover with integrated crankcase vent valve and oil separation
• Stronger connecting rods
• Exhaust valve stem increased to 6mm
• New electric water pump (2nd generation)
• Lightweight camshafts (hydroformed)

STE92VE · 03-22-2007, 06:34 PM

Quote:

Originally Posted by SteveMD

Hmmm...the N51 doesn't have the three stage manifold?

Neither does the N52 in the 230HP version which is what the 328i has:

The N52KP will be available in three versions as follows:
• N52B30O1 - High Output version with 260hp
• N52B30M1 - Medium Output version with 230hp
• N52B30U1 - Possible future application with 215hp

E90Fleet · 03-22-2007, 06:40 PM

Quote:

Originally Posted by SteveMD

Hmmm...the N51 doesn't have the three stage manifold?

No, because its only available in the lower 230hp output

The N52KP in the 328i also doesnt have it, just like the USA 325i didnt

But the high ouput N52KP model in the X3 3.0si does

danimal · 03-22-2007, 06:44 PM

Quote:

Originally Posted by E90Fleet

The engine in your 328i is a N52KP...

U :rocks:

-Dan

munda007 · 06-07-2007, 04:12 PM

I also got N51 in my 2007 328i.
Does the dealer has to disclose that the car is a SULEV? and not a regular 328i? I see some dealer websites and they post the car as a SULEV.
Should I be worried with N51 in my car?
Thanks guys !! and E90Fleet U rock man!!

Bram335 · 06-07-2007, 04:17 PM

Thanks for always providing useful and valid information. I recently registered but I had been browsing the forum for a while. The information you provide is unreal. I salute you my friend...

dmboone25 · 06-07-2007, 04:23 PM

He has CRAZY info on the E9X's. Wow.

STE92VE · 06-09-2007, 07:54 AM

Quote:

Originally Posted by munda007

I also got N51 in my 2007 328i.
Does the dealer has to disclose that the car is a SULEV? and not a regular 328i? I see some dealer websites and they post the car as a SULEV.
Should I be worried with N51 in my car?
Thanks guys !! and E90Fleet U rock man!!

No & No.....So far no issues with the N51 except I'm getting great gas mileage!

yessir! · 06-10-2007, 09:37 PM

hi all, very long time lurker but this is my first post. first off, e90fleet, your posts are always very informative and i have learned quite alot.

second, how would i go about finding out which engine i have in my car? i have an april 07 production e92 335, and it was ordered from a non-sulev state but shipped to the state where i live, which is one of the 4 new sulev states. i've searched but maybe i'm not looking in the right place. finally, any sarcifice in peformance for the added fuel efficiency?

thanks all!

E90Fleet · 06-11-2007, 06:13 AM

Quote:

Originally Posted by yessir!

hi all, very long time lurker but this is my first post. first off, e90fleet, your posts are always very informative and i have learned quite alot.

second, how would i go about finding out which engine i have in my car? i have an april 07 production e92 335, and it was ordered from a non-sulev state but shipped to the state where i live, which is one of the 4 new sulev states. i've searched but maybe i'm not looking in the right place. finally, any sarcifice in peformance for the added fuel efficiency?

thanks all!

The 335i is a N54

There is only one type of engine for it

The N51 is one of the the 328i engines

03-22-2007, 02:55 PM	#1
STE92VE STEVIL Empire 218 Rep 6,297 Posts Drives: Fast Join Date: May 2006 Location: Long Island, NY iTrader: (0)	E90Fleet..what's the N51 all about? Since discovering my E92 will have the N51 SULEV engine, I've been researching the crap out of it and really have not come up with any solid answers as to how it will perform compared to the N52. This is what I've got so far. N51 Overview In order to comply with SULEV requirements, the N51 is another variant of the N52 engine. There are various measures to meet the EPA/CARB standards, some of which are familiar from the previous SULEV (M56) engine. Some of the SULEV measures for the N51 include: • Near engine catalyst with additional underbody catalyst • Secondary air system • Optimized combustion chamber geometry in cylinder head • Modified piston crown for lower compression • Plastic valve cover with integrated crankcase vent valve and separator (from N52KP) • Stainless steel fuel lines with threaded connections • Radiator with “Prem-air” coating • Throttle system - EGAS08 carried over from N52KP • Airbox with Activated carbon filter for EVAP control • Purge system pipes are made from “optimized” plastic Maybe you can shed a liittle light on whether there will be any noticeable differences regarding HP, torque, MPG or reliability issues as to the N52. Thanks! __________________ 2007 E92 328i 6MT-Space Gray/Black Dakota/Gray Poplar w/heated seats-PCD 4/27/07 (SOLD) 2009 E90 328i xDrive 6AT-Space Gray/Oyster Dakota/Dark Burl Walnut w/ZPP,ZCW,Xenons-ED 4/17/09 - Redelivery 5/30/09 (SOLD) 2014 E84 xDrive28i 8AT-Alpine White/Black Nevada/Silver Matte w/ZMV,ZLP,494 - DD 3/14/14 (SOLD)
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03-22-2007, 03:12 PM	#2
E90Fleet Lieutenant General 1312 Rep 10,185 Posts Drives: BMW Join Date: Apr 2005 Location: South Africa iTrader: (0)	I can add the following info: The N54 and N52KP meet ULEV II requirements for 2007. There are not many changes to the emissiom systems on these engines. The N54 engine has 2 underbody catalysts in addition to the “near engine” catalysts already in use from the N52. The N51 engine, however, is a SULEV II compliant engine which meets the 2007 requirements. In addition to the 5 exisiting SULEV states of California, New York, Maine, Massachusetts, and Vermont - four states have been added for 2007. These states include, Connecticut, Rhode Island, Oregon and Washington State. The N51 emissions measures include: • Secondary Air System with mini-HFM • Radiator with “Prem-air” coating • Lower compression ratio (10:1) via modified combustion chamber and pistons • Underbody catalyst in addition to “near engine” catalyst • Activated carbon air filter in air filter housing • Steel fuel lines with threaded fittings and sealed fuel tank • Crankcase ventilation system integrated into cylinder head cover • Purge system piping made from optimized plastic The N51 engine uses the designation - “N51B30M0”. This engine is SULEV II compliant with 230 horsepower. __________________ BMW if you are reading, I need a job, Please.
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03-22-2007, 03:13 PM	#3
E90Fleet Lieutenant General 1312 Rep 10,185 Posts Drives: BMW Join Date: Apr 2005 Location: South Africa iTrader: (0)	This table may help aswell: Attached Images __________________ BMW if you are reading, I need a job, Please.
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03-22-2007, 03:38 PM	#4
STE92VE STEVIL Empire 218 Rep 6,297 Posts Drives: Fast Join Date: May 2006 Location: Long Island, NY iTrader: (0)	That table makes the comparison very clear. Would the lower compression ratio mean that you can run 87 octane and get the same performance as the higher compression N52 which needs 91? __________________ 2007 E92 328i 6MT-Space Gray/Black Dakota/Gray Poplar w/heated seats-PCD 4/27/07 (SOLD) 2009 E90 328i xDrive 6AT-Space Gray/Oyster Dakota/Dark Burl Walnut w/ZPP,ZCW,Xenons-ED 4/17/09 - Redelivery 5/30/09 (SOLD) 2014 E84 xDrive28i 8AT-Alpine White/Black Nevada/Silver Matte w/ZMV,ZLP,494 - DD 3/14/14 (SOLD)
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03-22-2007, 03:48 PM	#6
STE92VE STEVIL Empire 218 Rep 6,297 Posts Drives: Fast Join Date: May 2006 Location: Long Island, NY iTrader: (0)	Good idea! I'll post my experience after delivery. Thanks! __________________ 2007 E92 328i 6MT-Space Gray/Black Dakota/Gray Poplar w/heated seats-PCD 4/27/07 (SOLD) 2009 E90 328i xDrive 6AT-Space Gray/Oyster Dakota/Dark Burl Walnut w/ZPP,ZCW,Xenons-ED 4/17/09 - Redelivery 5/30/09 (SOLD) 2014 E84 xDrive28i 8AT-Alpine White/Black Nevada/Silver Matte w/ZMV,ZLP,494 - DD 3/14/14 (SOLD)
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03-22-2007, 03:49 PM	#7
canucklion pull my finger to get your kinder® surprise 148 Rep 10,455 Posts Drives: circles around you Join Date: Dec 2005 Location: Toronto, Canada iTrader: (9)	Fleet, you're unreal __________________
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03-22-2007, 05:57 PM	#8
danimal Captain 50 Rep 755 Posts Drives: '14 228i Join Date: Jan 2007 Location: San Diego, CA iTrader: (0) Garage List 2014 BMW 228i [10.00] 2007 BMW 328i Sedan [0.00]	Now I get what all the cries of "I wish fleet were here" were about. Glad you are back. Can I hijack this thread for a second to ask about my engine (engine code = N52B30AE)? I was told by someone at my dealer that the only change from prior N52's is a "revision in fuel management," which apparently translates to a 1 mpg improvement in the EPA highway cycle. Can you verify this? Is this just a minor tweak to the ECU or...? Any info you have would be great. Thanks & welcome back (even though I wasn't here when you left ), -Dan __________________ 2014 228i alpine white \| sport line \| 6-speed manual \| lighting package \| driver assistance package interior - black Sensatec \| aluminum & red trim
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03-22-2007, 06:15 PM	#10
STE92VE STEVIL Empire 218 Rep 6,297 Posts Drives: Fast Join Date: May 2006 Location: Long Island, NY iTrader: (0)	As E90Fleet said, whatever the recommended octane is, that's what I'll use. What's the sense of getting the Ultimate Driving Machine if I'm going to treat it like a Toyota! __________________ 2007 E92 328i 6MT-Space Gray/Black Dakota/Gray Poplar w/heated seats-PCD 4/27/07 (SOLD) 2009 E90 328i xDrive 6AT-Space Gray/Oyster Dakota/Dark Burl Walnut w/ZPP,ZCW,Xenons-ED 4/17/09 - Redelivery 5/30/09 (SOLD) 2014 E84 xDrive28i 8AT-Alpine White/Black Nevada/Silver Matte w/ZMV,ZLP,494 - DD 3/14/14 (SOLD)
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03-22-2007, 06:21 PM	#12
SteveMD Colonel 196 Rep 2,485 Posts Drives: 2016 F10 535i MSport Join Date: Dec 2005 Location: Raventown! iTrader: (3)	Hmmm...the N51 doesn't have the three stage manifold? __________________ 2006 E90 330i (retired) 2009 E90 335i (retired) 2012 E70 X5 50i M Sport (retired) 2016 F10 535i M Sport
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06-07-2007, 04:12 PM	#17
munda007 Registered 0 Rep 3 Posts Drives: e90 Join Date: Jun 2007 Location: wa iTrader: (0)	I also got N51 in my 2007 328i. Does the dealer has to disclose that the car is a SULEV? and not a regular 328i? I see some dealer websites and they post the car as a SULEV. Should I be worried with N51 in my car? Thanks guys !! and E90Fleet U rock man!!
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06-07-2007, 04:17 PM	#18
Bram335 First Lieutenant 17 Rep 302 Posts Drives: 335 AW Join Date: Jun 2007 Location: Toronto iTrader: (0)	e90 Fleet - I salute you Thanks for always providing useful and valid information. I recently registered but I had been browsing the forum for a while. The information you provide is unreal. I salute you my friend...
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06-07-2007, 04:23 PM	#19
dmboone25 Lieutenant General 4972 Rep 10,200 Posts Drives: 2024 Golf R / 2022 718 Spyder Join Date: Sep 2006 Location: Dallas, TX iTrader: (0) Garage List 2007 E92 328i [10.00] 2007 328i [10.00]	He has CRAZY info on the E9X's. Wow. __________________ Past rides: 2016 981 BGTS, 2020 MINI JCW, 2017 F80, 2015 981 CS, 2014 F22 235, 2011 E82 135, 2008 E82 135, 2007 E92 328, 2007 E92 328 (My lady drives an OG M2. So does my dad)
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06-10-2007, 09:37 PM	#21
yessir! New Member 0 Rep 5 Posts Drives: 2011 X6 5.0i Join Date: Jun 2007 Location: depends on the day... iTrader: (0)	hi all, very long time lurker but this is my first post. first off, e90fleet, your posts are always very informative and i have learned quite alot. second, how would i go about finding out which engine i have in my car? i have an april 07 production e92 335, and it was ordered from a non-sulev state but shipped to the state where i live, which is one of the 4 new sulev states. i've searched but maybe i'm not looking in the right place. finally, any sarcifice in peformance for the added fuel efficiency? thanks all!
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