[The Berserker]

As the title states, I'm considering purchasing an F31 328i x-drive via ED. My intent is to keep this vehicle well beyond the 4/50 warranty period and so I'm interested in adding an extended warranty, either at time of vehicle purchase or later on. The conundrum is whether or not I should wait for the B48 motor to be available in the US - sounds like those builds will begin in July of 2016. Do the power gains alone justify waiting for this engine? I'm inclined to tune the N20 with Dinan (would this completely negate any/all extended warranty possibility?)... Are there any other changes or improvements that make it 'better' than the N20, especially given I intend to keep the vehicle for some time?

[the_phew]

Looks like fuel consumption is about 10% lower than the N20, and apparently the engine is much less noisy at idle. Those are the only major "real-world" differences that I've heard of.

You just have to weigh the improvements of the new engine versus uncertainty about its long-term reliability. IMHO, most automotive issues these days are not the engine itself, so that shouldn't be a chief concern. Even the disastrous N54 was doomed by the fuel pump, not the engine's internals.

[fusion0389]

Originally Posted by The Berserker

As the title states, I'm considering purchasing an F31 328i x-drive via ED. My intent is to keep this vehicle well beyond the 4/50 warranty period and so I'm interested in adding an extended warranty, either at time of vehicle purchase or later on. The conundrum is whether or not I should wait for the B48 motor to be available in the US - sounds like those builds will begin in July of 2016. Do the power gains alone justify waiting for this engine? I'm inclined to tune the N20 with Dinan (would this completely negate any/all extended warranty possibility?)... Are there any other changes or improvements that make it 'better' than the N20, especially given I intend to keep the vehicle for some time?

My opinion is to stay away from design changes for a couple years. BMW does a better job than most making sure bugs are worked out of the vehicles they put on the market. However, If you look at when the first F30 came out in 2012, there were changes to the platform to improve on it. Take for instance the change from a mechanical wastegate to the electronic wastegate. Thats just one example. The B48 platform could be perfect, but it could also have later revisions that work out bugs. Nobody can know for sure. What we do know is that the 328 with the N20/N26 has been out a while and that the kinks have been worked out. It has consistent performance and we generally know what to expect from it in the F30 platform since its been out a while.

Essentially it all comes down to a choice. Do you want to get something new with higher performance with the risk of having to deal with bugs or will you settle for something that has slightly less performance, but is tested tried and true? The N20\26 is as good as its going to get. We dont really have any real world reports on the B48. Personally I picked the F30 with the N20/26. I wanted some history behind the platform, i wanted to know what people loved and what people hated. This may or may not be the right decision for you, whatever you decide i wish you the best of luck!

[The Berserker]

Originally Posted by fusion0389

My opinion is to stay away from design changes for a couple years. BMW does a better job than most making sure bugs are worked out of the vehicles they put on the market. However, If you look at when the first F30 came out in 2012, there were changes to the platform to improve on it. Take for instance the change from a mechanical wastegate to the electronic wastegate. Thats just one example. The B48 platform could be perfect, but it could also have later revisions that work out bugs. Nobody can know for sure. What we do know is that the 328 with the N20/N26 has been out a while and that the kinks have been worked out. It has consistent performance and we generally know what to expect from it in the F30 platform since its been out a while.

Essentially it all comes down to a choice. Do you want to get something new with higher performance with the risk of having to deal with bugs or will you settle for something that has slightly less performance, but is tested tried and true? The N20\26 is as good as its going to get. We dont really have any real world reports on the B48. Personally I picked the F30 with the N20/26. I wanted some history behind the platform, i wanted to know what people loved and what people hated. This may or may not be the right decision for you, whatever you decide i wish you the best of luck!

Would you still have the same concerns given that the B48 is already available in Europe and will have been out for 12+ months by the time it's in the US spec F31s? Totally understand and agree with your points otherwise.

[nicknaz]

Originally Posted by the_phew

Even the disastrous N54 was doomed by the fuel pump, not the engine's internals.

Lol, by doomed you mean, runs great and is great for modding after latest versions of fuel pumps and injectors are installed?

I daily drove an N54 car for 3 years and yes I had those parts replaced, but it was very hassle free. sorry if you had a bad experience with one; I agree it would suck if you were one of the early owners who had to trouble shoot at the start in the E90 335 days

OP, personally, I would wait for the updated engine and also to see if there any bugs in the updated power steering or other systems that need to be ironed out.

[fusion0389]

Originally Posted by nicknaz

Lol, by doomed you mean, runs great and is great for modding after latest versions of fuel pumps and injectors are installed?

I daily drove an N54 car for 3 years and yes I had those parts replaced, but it was very hassle free. sorry if you had a bad experience with one; I agree it would suck if you were one of the early owners who had to trouble shoot at the start in the E90 335 days

OP, personally, I would wait for the updated engine and also to see if there any bugs in the updated power steering or other systems that need to be ironed out.

BINGO!!! This is what im trying to say, the early owners are the poeple who had to deal with the troubleshooting. Most dealers are idiots so that leaves the owner to do lots of calling, researching, etc to help get their brand new car fixed. If you wait a couple years, you'll be able to easily search the strengths and weaknesses of the B48.

[fusion0389]

Originally Posted by The Berserker

Would you still have the same concerns given that the B48 is already available in Europe and will have been out for 12+ months by the time it's in the US spec F31s? Totally understand and agree with your points otherwise.

Yes I would still wait, most manufacturers are going to a "global" parts bin where powertrains and assocated components are shared across markets. Even though the physical hardware is "the same" the software is modified to suit the local regulations. There are many different variables here. Emissions control systems may also vary depending on the market. When a new engine is dropped in, other things are tweaked too.

Please dont take this as "NEW STUFF IS BAD" because its not! I will eventually turn in my 328 N20/26 for a 330 B48, but i'm ok waiting a few years for any bugs to come out. I dont have the time or patience to have to deal with the troubleshooting hurry up and wait process. I'd rather let someone else do that work for me, that way BMW can implement the fix before my car is even built

[ynguldyn]

My main takeaway from the B58 training doc was that it's going to be a hell of a job to fix any major issue with this engine. The cooling system is basically brand new and significantly more complex than anything that came before it, timing chain in the rear of the engine could mean engine pull for any VANOS and/or head work, engine block itself ha to replaced if it has any issues. B48 is not going to be different, because it's basically 2/3*B58. If you're buying with the expectation of paying your own money for repairs, get the N20 now.

[nürburgring]

As a fellow F31 owner, I have one suggestion. Make sure you order your wagon with the M-Sport package. It's worth every penny, including the sexy steering wheel.

[ynguldyn]

Originally Posted by nürburgring

As a fellow F31 owner, I have one suggestion. Make sure you order your wagon with the M-Sport package. It's worth every penny, including the sexy steering wheel.

Track package is more important.

[fusion0389]

Originally Posted by ynguldyn

My main takeaway from the B58 training doc was that it's going to be a hell of a job to fix any major issue with this engine. The cooling system is basically brand new and significantly more complex than anything that came before it, timing chain in the rear of the engine could mean engine pull for any VANOS and/or head work, engine block itself ha to replaced if it has any issues. B48 is not going to be different, because it's basically 2/3*B58. If you're buying with the expectation of paying your own money for repairs, get the N20 now.

I found it interesting that the B58 document tries to advertise how they built this engine from existing parts when in reality its all pretty much brand new. Not much on the engine is interchangable with any other platform. This engine shares design similarities with other platforms, but thats as close as it gets. Now if you're planning on leasing then i'd say who gives a crap since you'll turn it in before warranty coverage is up. The worst thing you'd experience in a lease is being put in a loaner while its getting fixed.

[The Berserker]

Thanks for the feedback guys, really good input. Starts to feel like the N20 is possibly the more economical choice for a less than short-term vehicle, even if it is down on power a bit compared to the B48.

[SCMike]

Originally Posted by nürburgring

As a fellow F31 owner, I have one suggestion. Make sure you order your wagon with the M-Sport package. It's worth every penny, including the sexy steering wheel.

Originally Posted by ynguldyn

Track package is more important.

Yes to both: ZMP + ZTR = getting impatient for its arrival. Mine is currently on board the Eurasian Highway docked at Baltimore - several more days until the F31 is back on terra firma in Charleston.

[ynguldyn]

Originally Posted by SCMike

Yes to both: ZMP + ZTR = getting impatient for its arrival. Mine is currently on board the Eurasian Highway docked at Baltimore - several more days until the F31 is back on terra firma in Charleston.

Mine got offloaded on the 17th.

It's a race!

[nürburgring]

F31 > F30

[the_phew]

Originally Posted by nürburgring

F31 > F30

If only they would offer 6MT and/or RWD. Then again, they probably sold all of 200 E91s in that configuration. I regret not making it 201!

[ynguldyn]

Originally Posted by nürburgring

F31 > F30

But F32 < F31.

That's German math.

[Emilim]

Originally Posted by The Berserker

As the title states, I'm considering purchasing an F31 328i x-drive via ED. My intent is to keep this vehicle well beyond the 4/50 warranty period and so I'm interested in adding an extended warranty, either at time of vehicle purchase or later on. The conundrum is whether or not I should wait for the B48 motor to be available in the US - sounds like those builds will begin in July of 2016. Do the power gains alone justify waiting for this engine? I'm inclined to tune the N20 with Dinan (would this completely negate any/all extended warranty possibility?)... Are there any other changes or improvements that make it 'better' than the N20, especially given I intend to keep the vehicle for some time?

I've actually thought about this too when I placed my order earlier this year. In the end, I feel the output figures were too similar to justify waiting another whole year. Any actual differences will likely be too small to notice in normal daily use and it becomes a subjective decision based on what you think is more important: proven and tested tech vs. the newest and latest thing.

[canukgtp]

Well coming from a 335 sedan and E92 M3...I can say I'm very happy with the stock power in my F31...for everyday around the city and hwy, it's fantastic with great fuel economy...I'll be honest that I'm considering a tune just to make things a little more lively, but even the small power gains of the B48 would make me want a tune...so as others have said, proven track record of the N20 is probably worth making the jump now.

That being said anybody have a BMS stage 1 or something similar they want to sell me and ship to Canada hahaha!

[ynguldyn]

Originally Posted by ynguldyn

My main takeaway from the B58 training doc was that it's going to be a hell of a job to fix any major issue with this engine. The cooling system is basically brand new and significantly more complex than anything that came before it, timing chain in the rear of the engine could mean engine pull for any VANOS and/or head work, engine block itself ha to replaced if it has any issues. B48 is not going to be different, because it's basically 2/3*B58. If you're buying with the expectation of paying your own money for repairs, get the N20 now.

Well, I have to follow this up with a correction.

B46/B48 is a more conservative design than B58. It still has an air-to-air intercooler mounted underneath the radiator, and it still uses a traditional thermostat.

[fusion0389]

Originally Posted by ynguldyn

Well, I have to follow this up with a correction.

B46/B48 is a more conservative design than B58. It still has an air-to-air intercooler mounted underneath the radiator, and it still uses a traditional thermostat.

Even if that is true, alot has changed. Its still very different from the previous design and we dont know what the weak points are going to be. Its a complex engine that has alot of potential for great performance. For me its just a waiting game to see what the real life experiences are.

[englishguy84]

Came across this thread looking for more technical information about the B46. Seems like so far, so good as far as problems go for the new engines, with the caveat that the location of some key components meaning that I'd still be more comfortable with an N20/55 outside warranty