[LEDZEP]

N51 is the California emissions engine. N52 is the "regular" engine. Both are 3.0 litre and both produce 230 HP in the 328i.

[piezo]

Make sure you check out the attachments in this thread:

http://e90post.com/forums/showthread.php?t=38856

Unfortunately, there's not much in there about the N51; lower compression, additional cat, etc. No power or economy specs though...

[STE92VE]

Originally Posted by piezo

Make sure you check out the attachments in this thread:

http://e90post.com/forums/showthread.php?t=38856

Unfortunately, there's not much in there about the N51; lower compression, additional cat, etc. No power or economy specs though...

Thanks...this is more info than I've seen until this point:
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

[luckyu]

Originally Posted by piezo

Make sure you check out the attachments in this thread:

http://e90post.com/forums/showthread.php?t=38856

Unfortunately, there's not much in there about the N51; lower compression, additional cat, etc. No power or economy specs though...

Thanks for posting that! Great information.

[Lassaxi]

So does anyone know how BMW decides who gets which engine? I'm in MA, and I know that MA follows CA emissions standards. Does that mean I will automatically get an N51 in my 328xi?

[dmichael]

Originally Posted by Lassaxi

So does anyone know how BMW decides who gets which engine? I'm in MA, and I know that MA follows CA emissions standards. Does that mean I will automatically get an N51 in my 328xi?

Lassaxi, now that you have your car did you check you VIN to see if you have an N51 or N52? If yes, which is it?

I am in MA too and about to order a car, I will certainly ask about my ability to specify a N52 over an N51. Seems to me though that if MA follows CA standards (first I've ever heard of that, wonder how new it is), BMW has no choice but to comply 100%. HP difference is significant between these 2 engines.

I test drove a 328xi today with manual trans and I have to admit, I was totally underwhelmed by its power. Got me thinking it was an N51. I may have to order from Nashua, NH.

[STE92VE]

Originally Posted by dmichael

Lassaxi, now that you have your car did you check you VIN to see if you have an N51 or N52? If yes, which is it?

I am in MA too and about to order a car, I will certainly ask about my ability to specify a N52 over an N51. Seems to me though that if MA follows CA standards (first I've ever heard of that, wonder how new it is), BMW has no choice but to comply 100%. HP difference is significant between these 2 engines.

I test drove a 328xi today with manual trans and I have to admit, I was totally underwhelmed by its power. Got me thinking it was an N51. I may have to order from Nashua, NH.

I'm the one that started this thread and since taking delivery, any questions or doubts about the N51 have been put to rest. There is no difference in HP between the N51 & N52 engines and therefore it is certainly not a significant one as dmichael states in his post. Where did you (dmichael) get your information from?

I am totally satisfied with the performance of the N51 engine and it met or exceeded the expectations I had.

[LACA335i]

Originally Posted by STE92VE

I just checked the VIN I just received and it was coded for the N51 SULEV engine (California emmisions). Car is status 150, start of production...I immediately called my dealer and told him that is not what was ordered. Check your VIN to make sure you are getting what you want.
I'll keep posting my progress as this goes on.

where do u check it .. give me the link

thanks you

[matt_435xi]

Originally Posted by STE92VE

I'm the one that started this thread and since taking delivery, any questions or doubts about the N51 have been put to rest. There is no difference in HP between the N51 & N52 engines and therefore it is certainly not a significant one as dmichael states in his post. Where did you (dmichael) get your information from?

I am totally satisfied with the performance of the N51 engine and it met or exceeded the expectations I had.

scuba did you do your CDV yet? i did with hyperM3, the slight change has me happy.

[dmichael]

Originally Posted by STE92VE

There is no difference in HP between the N51 & N52 engines and therefore it is certainly not a significant one as dmichael states in his post. Where did you (dmichael) get your information from?

Further up on this thread someone said the N51 HP was in the 170-190 ballpark. Thats about what it felt like to me in the 328xi sedan with 6spd Manny.

My daily driver is an 04 Saab 9-5, it has a turbo and produces 250hp. by comparison the 328 felt a lot slower than I am used to, which I did not expect, given only 20 HP difference. Possibly its the turbo that makes this an unfair comparison. My butt dyno tells me the BMW will eat the Saab's dust off the line. The BMW is still a great car and I won't judge is on its quickness alone, since it has many other great qualities. I may still end up buying one, but I was expecting it to be quicker than what it is. The over all impression is that the car feels heavy. N51 may very well have 230, but the Saab must be quite a bit lighter, giving it a much better power to weight ratio.

[STE92VE]

Originally Posted by matt_335Ci

scuba did you do your CDV yet? i did with hyperM3, the slight change has me happy.

Nope, still driving with OEM CDV. It kind of makes driving with the clutch effortless. I like it that way for now!

Are you planning to join us regarding my PM of 6/12/07?

[STE92VE]

Originally Posted by dmichael

Further up on this thread someone said the N51 HP was in the 170-190 ballpark.

Originally Posted by Lassaxi

I had read previous specualtion that the N51 would only produce in the ballpark of 170-190 hp. Does anyone know if this is true?

This is what was written and it's true for the 2.5L versions. The 3.0L versions are rated at 230.

Originally Posted by LACA335i

where do u check it .. give me the link

thanks you

You can either check your VIN or look on the front of your engine block.

Originally Posted by STE92VE

Digits 4-7 of your VIN are AG model codes..here are the codes:
http://jon.bimmerfest.com/bulletins/...rder_Guide.pdf

[dmichael]

Originally Posted by LACA335i

where do u check it .. give me the link

thanks you

Digits 4-7 on your VIN, what do they say?
Cross check that with the official 2007 MY ordering guide that is linked somwhere in this thread.

Here it is;
VC73 = N51,
VC93 = N52

Come to think of it, its sort of silly to think that they can get away with advertising a given power rating for a given model, and then come out with lower power version and blame it on EPA regs. If they are forced to do it thats one thing, but they would always have to disclaimer it in literature and advertising and display the lower rating.

Sorry for waking up this thread without getting confirmation that the power is not lower for N51's.

[STE92VE]

Originally Posted by dmichael

Sorry for waking up this thread without getting confirmation that the power is not lower for N51's.

No problem at all. I'm sure there are 100's of folks out there who have the N51 and either don't care or don't realize that they have it. In a way it makes me feel good that I have it and that I'm doing my share to decrease emissions. Some of the points you made regarding the performance with your Saab v. the 328 were valid. Now if you put yourself into the 335i, that's another ballgame!
Good luck with whatever you decide. :rocks:

[VIZSLA]

Another reason to check your VIN. When I went to pay for my car the credit union had the wrong VIN on its docs. Sales manager said it was for a Jeep! A quick call to the C/U cleared things up and the check was accepted but it could have been a major hassle and delay.

[dmichael]

Originally Posted by STE92VE

In a way it makes me feel good that I have it and that I'm doing my share to decrease emissions.

As long as the power is the same and its better for the environment, whats not to like and why is BMW bothering to make 2 versions of the same engine? That's what I'd like to know. Why not send the N51 to every state. I did read that N51 uses 2 catalytic converters as opposed to 1 for the N52, which might explain things. Some cats can be quite expensive to replace. Volvo charges $1200 for my S70. I imagine BMW's ain't cheap, so multiply that by 2. Ouch.