BMW NA I6 vs. T I4?

[GTaudiophile]

I know how the normally-aspirated 3.0L I6 (old 328) and the new turbo 2.0L (current 328) differ on paper but can anyone tell me how they compare from behind the wheel?

The BMW NA I6 was simply a gem of an engine if you ask me and it saddens me that you can now only find it in North America on the outgoing 128i and 328i models. It's hard to believe this engine in its NA form will soon be gone from our shores.

 

[PhoKingGuy]

The N/A I-6 was a dog compared to the N54/N55, that being said it did sound quite good.

The 2.0T sounds like ass, but it does move quite a bit better than the old engine did, pick your poision.

 

[Throckmorton]

Bet the I6 gets better gas mileage in real world driving

 

[hans007]

My mom had a e90 328i and now has a f25 x3 with the n20. I have a f30 with the n20. I've driven her old 328 when she had it a few times...

The n52 3.0 i-6 had way way less power at low RPM so you have to get it to higher revs to make power so it generally will use a significant amount more gas. Its smoother and sounds smoother but that's about it. At cruising speeds it also uses more gas. I think if you like revving the engine etc the i-6 might have an advantage in "fun" but the i-4 turbo just makes a ton more power everywhere. It probably dynos in the 40 HP range higher...

I'd say other than the sound the new engine is better in every way. At idle the n20 sounds pretty diesel like though.

Good way to compare them is the 2011 vs 2012 528i which is one of the few cars that had the same engine on the same platform or the z4.

 

[iamwiz82]

I test drove an F30/N20 combo and was not impressed at all.

 

[Don Vito Corleone]

I have a 2006 330i and have been curious about the N20 as well. My car is not what I'd call fast, but it is noticeably faster than the many E90 328is I have driven - those cars always felt gutless to me. I think it's a shame that BMW is now out of the NA I6 business, though I certainly understand that forced aspiration is the way of the world nowadays. On paper the N20 sounds very impressive.

 

[Timorous]

I have a 2006 Z4 3.0si with the N52B30 engine and I really like it. It sounds great and it is really smooth. Capable of cruising along in 6th gear at around 30mph but also capable of hitting 70mph in 2nd.

 

[SpatiallyAware]

I have a z4m with the s54 and love it. I have put a good number of miles on a 335i and while it was fast, it just wasn't the same to me. I haven't driven the new 328 turbo motor.

Past that, the turbo BMW engines haven't been around long enough for me to completely trust them on my dime. The NA i6 are well known to be just about bulletproof.

 

[exdeath]

S54, N54/55 for me. Part of what makes a BMW is the straight 6.

 

[hans007]

S54, N54/55 for me. Part of what makes a BMW is the straight 6.

as much as a lot of bmw owners seem to say this but most BMWs sold in the world are i-4 and theres a lot of advantages to it. if anything its less weight hanging over the front end of the car and better weight balance (look up the weight distribution on the new 328 and 335 and you'll be surprised)

Not to mention the 2002 and E30 m3 and 318i in america. https://www.youtube.com/watch?v=ANv83OJk--4 (2 4 cylider cars)


makes a different noise, but if its lighter and makes more power, i'm generally for it. an n20 weighs ~60 lb less than an n52 while making more power and providing better weight distribution.

rumor has it the next z4 will be 4 cylinder only, so they can design it around the shorter engine which will let it handle better too

 

[Don Vito Corleone]

I have a z4m with the s54 and love it. I have put a good number of miles on a 335i and while it was fast, it just wasn't the same to me. I haven't driven the new 328 turbo motor.

Past that, the turbo BMW engines haven't been around long enough for me to completely trust them on my dime. The NA i6 are well known to be just about bulletproof.

I wouldn't go that far. The S54 has a pretty solid track record (I have one in my M3) but it is a very maintenance-intensive lump. I have an N52 in my 330i and had numerous VANOS solenoid failures when the car had less than 40K miles. These engines are not exactly competing with, say, the Nissan VQ when it comes to reliability. I would not assume the N20 won't be as reliable as the I6s - I expect it will.

 

[hans007]

I wouldn't go that far. The S54 has a pretty solid track record (I have one in my M3) but it is a very maintenance-intensive lump. I have an N52 in my 330i and had numerous VANOS solenoid failures when the car had less than 40K miles. These engines are not exactly competing with, say, the Nissan VQ when it comes to reliability. I would not assume the N20 won't be as reliable as the I6s - I expect it will.

N52 had a problem where the head bolts snap since they are aluminum . Has something to do with the magnesium block and not being able to use steel bolts.

 

[Don Vito Corleone]

N52 had a problem where the head bolts snap since they are aluminum . Has something to do with the magnesium block and not being able to use steel bolts.

Huh - never heard of that and have certainly not experienced it, knock on wood.

 

[iamwiz82]

I wouldn't go that far. The S54 has a pretty solid track record (I have one in my M3) but it is a very maintenance-intensive lump. I have an N52 in my 330i and had numerous VANOS solenoid failures when the car had less than 40K miles. These engines are not exactly competing with, say, the Nissan VQ when it comes to reliability. I would not assume the N20 won't be as reliable as the I6s - I expect it will.

Agreed, the S54 requires valve adjustments every, 30-40,000 miles. That's off the deep end of common maintenance for 99.9999% of Americans.

 

[hans007]

Huh - never heard of that and have certainly not experienced it, knock on wood.

I am not sure how often it happens . I guess i only remember reading about it since it seemed so odd. Its not like every car it happens like say the hpfp issue on the n54

 

[SpatiallyAware]

Agreed, the S54 requires valve adjustments every, 30-40,000 miles. That's off the deep end of common maintenance for 99.9999% of Americans.

I hear this a lot, but honestly I think it's a travesty to have the 'car geekness' of wanting an s54 yet not do the valve adjustment yourself.


It is incredibly easy. Skill-wise it's no more difficult than changing brakes, perhaps a bit more time consuming. Coming from the motorcycle community where people have no problems loosening/lifting cams to get a shim out I was VERY surprised to hear how many people won't touch their s54.

 

[SpatiallyAware]

I wouldn't go that far. The S54 has a pretty solid track record (I have one in my M3) but it is a very maintenance-intensive lump. I have an N52 in my 330i and had numerous VANOS solenoid failures when the car had less than 40K miles. These engines are not exactly competing with, say, the Nissan VQ when it comes to reliability. I would not assume the N20 won't be as reliable as the I6s - I expect it will.

You can get a rebuilt vanos for less than $300 nowadays for non M cars, M cars are $1300... Completely reasonable considering how long the newer setups last.. And yes there are some odd issues, even the s54 has the cam gear bolts and the very old ones had some oil supply issues.

The huge difference here is that BMW (tends to) stand behind their products. Cam bolts, vanos, HPFP, subframes.... Historically BMW admits there is some issue and provides a method to correct it.


And comparing this to the VQ and it's major issues is crazy..

The VQ (all of them, but HR motor in particular) has well-known major oil consumption issues, none of which were admitted by infiniti. Years ago I almost bought a g65 6mt, but after reading horror story after horror story of 3 quarts of oil required in 3000 miles being "normal" by infiniti I instead focused on the m45.... Until finding out that the nissan small v8 has far worse issues than the v6.

In ~2010 (the m45 had been out 5 years) literally not one person on their forums had gotten 100k out of their motors. Almost all had major oil consumption issues including catastrophic failure, complete with black smoke from burned oil and fried/wet catalytic converters. Nissan claimed that this was all "normal", that it was a performance engine and you have to go into it with realistic longevity expectations. 100k miles! Rofl..


Google nissan oil consumption and read up on it... I could understand it if they all were like this, but in a single production run, one motor will burn very clean and the next motor is using 1qt per 1000 miles. Totally unacceptable.


And again... The s54 is hardly maintenance intensive.... The only thing different than any other engine is the valve adjustments, which is a 6 hour DIY job if you really take your time. All you need is a fan wrench and little magnet to get the shims out, take them to an indy shop or dealer and swap them out. It's not the big deal that many claim, even if you have to pay an indy shop maybe $800 every two years.

 

[Don Vito Corleone]

I hear this a lot, but honestly I think it's a travesty to have the 'car geekness' of wanting an s54 yet not do the valve adjustment yourself.


It is incredibly easy. Skill-wise it's no more difficult than changing brakes, perhaps a bit more time consuming. Coming from the motorcycle community where people have no problems loosening/lifting cams to get a shim out I was VERY surprised to hear how many people won't touch their s54.

I bet less than 5% of S54 owners (probably less than 1%) do this work themselves - the risk/reward ratio doesn't favor newbie mechanics messing around inside such a complicated engine.

 

[SpatiallyAware]

I bet less than 5% of S54 owners (probably less than 1%) do this work themselves - the risk/reward ratio doesn't favor newbie mechanics messing around inside such a complicated engine.

Well, like I said, $800 every two years/25k miles (if you aren't capable of taking off a valve cover and using feeler gauges) is definitely not "maintenance intensive".

 

[Don Vito Corleone]

Well, like I said, $800 every two years/25k miles (if you aren't capable of taking off a valve cover and using feeler gauges) is definitely not "maintenance intensive".

I'd say it is, given that the overwhelming majority of road car engines don't require something similar. I am not bothered by it - you have to pay to play - but it's an unusual requirement.

 

[SpatiallyAware]

I'd say it is, given that the overwhelming majority of road car engines don't require something similar. I am not bothered by it - you have to pay to play - but it's an unusual requirement.

Unusual sure, a "caveat" yes... But "maintenance intensive" it is not, especially compared to any other car in this class.

Trust me, I really understand the pay to play mentality but $800 every couple years is not it when compared in relation to tires, fluid changes, etc that you would have to put on any performance car.

Pretty much all cars in these categories require synthetic oil, special trans fluid, all of the rest of the maintenance is the same except for the feared valve adjustments.

 

[hans007]

You can get a rebuilt vanos for less than $300 nowadays for non M cars, M cars are $1300... Completely reasonable considering how long the newer setups last.. And yes there are some odd issues, even the s54 has the cam gear bolts and the very old ones had some oil supply issues.

The huge difference here is that BMW (tends to) stand behind their products. Cam bolts, vanos, HPFP, subframes.... Historically BMW admits there is some issue and provides a method to correct it.


And comparing this to the VQ and it's major issues is crazy..

The VQ (all of them, but HR motor in particular) has well-known major oil consumption issues, none of which were admitted by infiniti. Years ago I almost bought a g65 6mt, but after reading horror story after horror story of 3 quarts of oil required in 3000 miles being "normal" by infiniti I instead focused on the m45.... Until finding out that the nissan small v8 has far worse issues than the v6.

In ~2010 (the m45 had been out 5 years) literally not one person on their forums had gotten 100k out of their motors. Almost all had major oil consumption issues including catastrophic failure, complete with black smoke from burned oil and fried/wet catalytic converters. Nissan claimed that this was all "normal", that it was a performance engine and you have to go into it with realistic longevity expectations. 100k miles! Rofl..


Google nissan oil consumption and read up on it... I could understand it if they all were like this, but in a single production run, one motor will burn very clean and the next motor is using 1qt per 1000 miles. Totally unacceptable.


And again... The s54 is hardly maintenance intensive.... The only thing different than any other engine is the valve adjustments, which is a 6 hour DIY job if you really take your time. All you need is a fan wrench and little magnet to get the shims out, take them to an indy shop or dealer and swap them out. It's not the big deal that many claim, even if you have to pay an indy shop maybe $800 every two years.

I had these type of issues with an Audi. Oil burn , black smoke, fried cat. Failed injector. Audi said it was normal for 3 years and now if you birch and moan a lot they will replace your engine maybe. With probably another bad one since lots of the ea888 has this problem.

BMW might take care of issues faster historically or maybe they just have less of them but then again its different issues. Oil burn won't immediately stop your car and dealers will tend to "its normal" you probably on any make but a blown HP FP will or a bad oil pump on say an e46 m3 and they will definitely scramble to fix it . Cooper s owners I know have some oil burn problems and have complained for years. and i've heard 550i F10 owners are getting oil burn on the 4.4 V8 and dealers have been saying the usual "its normal".

 

[Railgun]

as much as a lot of bmw owners seem to say this but most BMWs sold in the world are i-4 and theres a lot of advantages to it. if anything its less weight hanging over the front end of the car and better weight balance (look up the weight distribution on the new 328 and 335 and you'll be surprised)

I am...it's exactly the same...

2013 is 51.1/49.9 F/R (BMW)

2007 is....51/49 F/R (R&T)

This is the 335...

 

[Railgun]

The N/A I-6 was a dog compared to the N54/N55, that being said it did sound quite good.

I don't even know why you're comparing the two. Of course the NA is going to be slower...

 

[hans007]

I am...it's exactly the same...

2013 is 51.1/49.9 F/R (BMW)

2007 is....51/49 F/R (R&T)

This is the 335...

well obviously, those both have the same engine.

i meant, the 328 with th 2.0t vs a 328 with the i-6.

given the differing body styles its probably more fair to look at the weight balance of the e89 z4 or f10 528i since those cars had both engines.

2012/13 328i has a 50/50 weight distribution. it wouldn't have that if it had the i-6.