[enotech]

I used to think that I understood how the model numbers work, but now I'm not so sure.

I thought that:
* The first number indicated the series (for example a 320i was a 3 series)
* The numbers after the first indicated the size of the engine (for example a 320i has a 2 litre engine, and a 318i had a 1.8 litre engine.
* The i/d indicated petrol or diesel.

The thing that's made me think that's all wrong was when I got my 330e. If my theory was correct, it'd have a 3 litre engine, but no, it's got a 2 litre engine.

Is there some consistency to the numbers?

[Vulpe]

The second number hasn't been accurate in a long time.

Currently as far as I can tell with the second number 2/3 is the 4 cylinder, 4 is the 6 cylinder and 5 is the V8

[rak299]

Your info used to be correct. Now, first number is the series, but after that, it doesn't mean much that makes sense. 320, 328, 330 are all 2-litre, 4 cylinder. Horsepower outputs vary. 340 has a 3-litre, 6-cylinder.

[Skyhigh]

Originally Posted by Vulpe

The second number hasn't been accurate in a long time.

Currently as far as I can tell with the second number 2/3 is the 4 cylinder, 4 is the 6 cylinder and 5 is the V8

As he said
I used to think the same (never been a BMW guy). I also used to believe in authentic engine sound before engaging with BMW and their fake "sound experience"

[stein_325i]

the second set of numbers (from my understanding) no longer represent engine size (they stopped that with the 325 and 525 e90/60 which had 3liter I6s) and started rating them at what their engine's output was equivalent to a naturally aspirated engine. For example a modern BMW 330i which has a 2liter turbo makes the equivalent to a naturally aspirated 3liter I6. The new 330i makes about 250hp and a 2006 330i with a NA 3liter I6 makes 255hp. Thus the new 330i is equivalent to the NA engine of an older 330i.

[IAmATeaf]

Originally Posted by Vulpe

The second number hasn't been accurate in a long time.

Currently as far as I can tell with the second number 2/3 is the 4 cylinder, 4 is the 6 cylinder and 5 is the V8

335i ?

[Kimoy]

following

[Skyhigh]

Originally Posted by IAmATeaf

335i ?

Key word - "currently"!
335i is no longer in production.

[HighlandPete]

Originally Posted by joshuastein55

the second set of numbers (from my understanding) no longer represent engine size (they stopped that with the 325 and 525 e90/60 which had 3liter I6s) and started rating them at what their engine's output was equivalent to a naturally aspirated engine. For example a modern BMW 330i which has a 2liter turbo makes the equivalent to a naturally aspirated 3liter I6. The new 330i makes about 250hp and a 2006 330i with a NA 3liter I6 makes 255hp. Thus the new 330i is equivalent to the NA engine of an older 330i.

Even with the original system, and the current numbering you illustrate, there are still anomalies. For example, the E39 540i was a 4.4+ litre, the E60 with the same capacity engine was a 545i.

Currently it seems markets and product placement, rather than output also influence the numbering. For example, the European 320d is renumbered a 328d for the US market. We've had a 325d in Europe, with more power output than the US 328d. 530d is renumbered a 540d, not for output, but again for marketing reasons.

[Billfitz]

Originally Posted by enotech

I thought that:
* The first number indicated the series (for example a 320i was a 3 series)

True.

* The numbers after the first indicated the size of the engine

They indicate the relative size of the price tag.

[Fuller]

Originally Posted by IAmATeaf

335i ?

335i is a 3.0 liter engine with output roughly equal to what a 3.5L na 6 cylinder is capable of.

This doesn't necessarily mean that the 335i driving experience is the same as with a car that has a 3.5L naturally aspirated 6 cylinder engine though. As you likely know, the turbo system noticeably changes the power delivery in the N54, N55, and now B58. The turbo engines can be, relatively, easily tuned to produce as much power as a naturally aspirated 5.0 to 6.2L v8 (approx 400hp and more).

As stated earlier in the thread though, the second number is mostly marketing and product placement, like any model number from any make. I don't think we can ascribe too much real world info or meaning to it, other than where bmw places it in their line up.

[Fuller]

Originally Posted by Billfitz

True.

They indicate the relative size of the price tag.

That's what the second number really correlates to.

[anotheran]

Originally Posted by Billfitz

True.
They indicate the relative size of the price tag.

This. You got X2 with 28i which is a detuning of the B48 in the 330i but not detuned as much as the 320i. Just tells ppl which is more powerful relative to another and which costs more $$ within their series.

[tex2670]

With the trend toward smaller turbo engines, car companies don't want their model numbers to "go down" or stay same with HP increasing. So they have abandoned the last 2 numbers being the engine size.

[upsidedownfunnel]

The second number is really just a relative power rating. Currently the 28-30 models are right around 250hp while the 35 models are about 300 and the 40 models are about 320-330hp. 50 seems to be about 450hp. An M prefix usually means a bit of a power bump as well (M850xi, M340, etc.).

Back when turbocharging wasn't common, engine displacement was a good indicator of relative engine output. A 3 liter engine could output about 50% more power than a 2 liter engine with some relative losses.

However, now with turbocharging and using modular components, engine displacement has very little to do with power output. Higher output engines still need strengthened internals and better fuel delivery systems, stronger transmissions, stronger diffs, and stronger shafts. So it really doesn't make sense to define a car by how much volume the combustion chamber displaces. It makes no sense. A 250hp 2.0l engine will need to cost more than a 200hp 2.0l engine even if they use the same block.

[Fuller]

Originally Posted by upsidedownfunnel

The second number is really just a relative power rating. Currently the 28-30 models are right around 250hp while the 35 models are about 300 and the 40 models are about 320-330hp. 50 seems to be about 450hp. An M prefix usually means a bit of a power bump as well (M850xi, M340, etc.).

Back when turbocharging wasn't common, engine displacement was a good indicator of relative engine output. A 3 liter engine could output about 50% more power than a 2 liter engine with some relative losses.

However, now with turbocharging and using modular components, engine displacement has very little to do with power output. Higher output engines still need strengthened internals and better fuel delivery systems, stronger transmissions, stronger diffs, and stronger shafts. So it really doesn't make sense to define a car by how much volume the combustion chamber displaces. It makes no sense. A 250hp 2.0l engine will need to cost more than a 200hp 2.0l engine even if they use the same block.

You just had to mention the letter "M" didn't you. Throwing around Ms not directly related to an m-car in a bmw forum is a good way to initiate a full fledge shit storm. All it takes is one M division zealot, and you'll at least receive a stern scolding. With any luck it'll stop there, and he won't recruit any followers for echo effect.

[kern417]

I understand not realizing that the numbers don't correlate to an engine displacement anymore, but the fact that some of you are aware and still think it is associated with something else is amazing. The numbers have nothing to do with engine displacement or "relative" power. BMW is dealing with the same thing that Mercedes and Infiniti are. Premium brands are stuck using numbers in their model designation because it is taken as a more luxurious name. The higher the number, the higher the engine output and more expensive the car is. That's it.

When they come out with the next set of engines all the numbers will bump up again and again and again. That is, until they max out the 3 digits like porsche did and silently start picking smaller numbers that they never used before. Currently saving for 2065 391i.

[upsidedownfunnel]

Originally Posted by kern417

I understand not realizing that the numbers don't correlate to an engine displacement anymore, but the fact that some of you are aware and still think it is associated with something else is amazing. The numbers have nothing to do with engine displacement or "relative" power. BMW is dealing with the same thing that Mercedes and Infiniti are. Premium brands are stuck using numbers in their model designation because it is taken as a more luxurious name. The higher the number, the higher the engine output and more expensive the car is. That's it.

When they come out with the next set of engines all the numbers will bump up again and again and again. That is, until they max out the 3 digits like porsche did and silently start picking smaller numbers that they never used before. Currently saving for 2065 391i.

Wait, first you say it has nothing to do with "relative" power, then you say that "the higher the number, the higher the engine output". Do you know what "relative" means? lol.

It absolutely does have to do with relative engine output. Obviously as time marches on the numbers get higher. That's why I said relative. It's not a definitive horsepower figure, I never said it was.

[kern417]

Originally Posted by upsidedownfunnel

Wait, first you say it has nothing to do with "relative" power, then you say that "the higher the number, the higher the engine output". Do you know what "relative" means? lol.

It absolutely does have to do with relative engine output. Obviously as time marches on the numbers get higher. That's why I said relative. It's not a definitive horsepower figure, I never said it was.

I'm talking about saying that -35i means it makes about as much power as a 3.5L engine, etc.

Edit: I see what I did when I went back through I referenced the wrong post. Mixup on my part.