[markymark34]

Originally Posted by Fox530

I had the 330d on my shortlist - until I drove it. I was expecting it to be some sort of rocket powered 60mpg car from the way people go on about it but frankly my thoughts are as per my first post in this thread. It's a great tool for doing a job - covering 20-50k a year economically - but its otherwise devoid of much entertainment and once you get over the 'con' that is the turbo surge making you think its quicker than it really is (Remember it is rate of change in acceleration that gives you the sensation of speed, not actual acceleration which gives you actual increase in speed), it's not quite the weapon people think it is.

I'd be interested to try a 335d, mind, as that is far more comparable to the 330i power wise.

Hmmm not sure on a 330d not really being that quick. Define not that quick? In the real world it isnt far off my e46 M3 and remapped its at least a match and definitely as quick as my scooby STI (in a straight line anyway) If that isnt quick i dont know what is. A 335d is nearly as quick 30-70 as a Porsche 911 Turbo and i can reassure you significantly faster than a 330i.

Ps im not having a go or defending diesels (I hate diesels) but having owned/driven over 100k in 330is, 330ds, 335ds, 335i i feel im in a decent position to comment.

[Racing Teatray]

Originally Posted by Fox530

How are you finding the economy of your 135i v the 330d? The figures suggest the 330d should be some 17mpg better - is it?

Not quite but still a gratifying improvement. The 135i averaged 27mpg (mix of urban and motorway) and would do 31mpg on a run. So far the 330d averages around 38mpg in the same conditions and will do 44mpg on a run.

As another comparative, for my annual ski trip to the Alps and back, four up with four sets of skis on a ski-rack on the roof and a full load of luggage at a sustained 80-90mph, the 135i managed an ouchsome 20 mpg whereas the 330d gave a much more palatable 34mpg. Not least because the 3-series has a usefully bigger fuel tank than the 1-series so you stop much less frequently.

[Vaheed1]

Fox530: I'm not quite sure which way you're going with this thread. You're giving the impression that you don't like diesels, yet have come here for advice on them? You've (in your own, respected, opinion) defended the 30i to the hilt from the off - yet came here for advice on the diesel cars. Personally, I reckon you're taking the shizzle.

You claim that turbocharging is a " 'con' that is the turbo surge making you think its quicker than it really is" - You want to try telling that to a Veyron owner or a 911 Turbo owner. Have you even driven a turbo charged car, like you claim? a Porsche 997 T will do 40-60 mph in 1 second - and 50-70 in probably less. Can you name a N/A car that will give you such performance?

If you want excitement and noise - buy a Porsche or AMG merc - not a 3.0 six cylinder.

[Fox530]

Originally Posted by Vaheed1

Fox530: I'm not quite sure which way you're going with this thread. You're giving the impression that you don't like diesels, yet have come here for advice on them? You've (in your own, respected, opinion) defended the 30i to the hilt from the off - yet came here for advice on the diesel cars. Personally, I reckon you're taking the shizzle.

I didn't come here for advice on diesel cars, I'm not the original poster of this thread?

You claim that turbocharging is a " 'con' that is the turbo surge making you think its quicker than it really is" - You want to try telling that to a Veyron owner or a 911 Turbo owner. Have you even driven a turbo charged car, like you claim? a Porsche 997 T will do 40-60 mph in 1 second - and 50-70 in probably less. Can you name a N/A car that will give you such performance?

Whoa, slow down. You've completely misunderstood my point. I've nothing against turbocharging at all, I was merely explaining that the turbo surge you get gives you the impression the car is faster than it is - because of the differing rate in change of acceleration you get when the turbo kicks in. I wasn't saying turbo cars are not fast!

Maybe a poor choice of words on my part but I've definately got nothing against turbo cars.

But the way the power is delivered means if you have two identically performing cars but one is turbocharged, the turbocharged one will 'feel' faster if you see what I mean. The turbocharged car always feels quicker because of the kick you get.

[Racing Teatray]

Not necessarily.

There's definitely no mistaking the forced induction in the 330d simply because you can easily catch it off-boost in too high a gear.

By contrast, the twin-turbo N54 engine in my 135i felt naturally aspirated - the flexibility in sixth was astounding for a turbocharged engine.

[Fox530]

I loved the 335i I drove - like you say it doesnt feel turbocharged at all. It feels like a naturally aspirated engine and IMHO is all the better for it.

[SO8]

Originally Posted by Fox530

I loved the 335i I drove - like you say it doesnt feel turbocharged at all. It feels like a naturally aspirated engine and IMHO is all the better for it.

... and yet I didn't like the 335i engine in a Z4 35i as it felt breathless at higher revs - so I just went for a diesel which I was expecting from the off to be dead beyond 4500 rpm

[Racing Teatray]

Does a Z4 35i have the old N54 engine (original 335i/135i and, in breathed-on form, the Z4 35iS and 1 MCoupe) or the newer N55 engine?

There isn't much in the upper rev-range of a standard N54 it's true but it definitely has better low-rev tractability than the 330d engine (perhaps the twin-turbo 335d is better in this respec). By contrast the N54 in the 1 MCoupe, whilst not exactly a typical M-car high-rev screamer like the E92 M3's V8, has much more going on at the higher end of the rev range than a normal 135i/335i.

[FieldingMellish]

FWIW, I drove a pre-LCI 330d today, back to back with a pre-LCI 330i. There was really no comparison between them. The 330d is a great car, of course, but for me it just didn't have the wow factor, which the 330i had in spades. After much flip-flopping, I now know my original instinct was best. The bad news was they didn't like my offer on the 330i. In fact they so disliked it that they didn't even counter offer. But at least I am certain now what car I want.

[Fox530]

Originally Posted by FieldingMellish

FWIW, I drove a pre-LCI 330d today, back to back with a pre-LCI 330i. There was really no comparison between them. The 330d is a great car, of course, but for me it just didn't have the wow factor, which the 330i had in spades.

This is exactly what I did and exactly what I found as well. I guess its hard to put into words what was wrong with the 330d because honestly, there is nothing wrong with the 330d, it's a brilliant car, but.. it isn't a 330i.

I guess the 330d is a crushingly competent business tool whereas the 330i is... just different.

[willhollin]

Thread Closed

[SteveC]

[QUOTE=Fox530;9301398]I had the 330d on my shortlist - until I drove it. I was expecting it to be some sort of rocket powered 60mpg car from the way people go on about it but frankly my thoughts are as per my first post in this thread. It's a great tool for doing a job - covering 20-50k a year economically - but its otherwise devoid of much entertainment and once you get over the 'con' that is the turbo surge making you think its quicker than it really is (Remember it is rate of change in acceleration that gives you the sensation of speed, not actual acceleration which gives you actual increase in speed), it's not quite the weapon people think it is.


Acceleration is by definition a rate of change (speed with time), so what you're saying is that "its the rate of change of the rate of change that makes you think its fast"

Lets look at a real world situation where acceleration (rate of change of speed) is key....overtaking

To measure overtaking prowess, manufacturers typically use the the 4th gear roll-on test (the time it takes to go from 50 - 75mph in 4th gear)

If you compare a 330d with a Z4M, for example the 'd' has 245hp and the 'M' 343hp and 125kg less weight, however in a 4th gear roll-on the 330d is slightly faster than the M. Why is that? Its because the 'd' power and torque curves are far stonger at lower revs. Nail the throttle in both cars and while the 'M' is building some revs, the 'd' is long gone. So its no con...the 'd' is damned fast. Of course, by the end of the test, the 'M' car has hit its power band and will catch and pass the 'd' in a shriek of rapidly building revs.

So back to your terminology, the 'd' actually has a lower 'rate of change' of acceleration than the 'M' car. The 'd' sets of very quickly and maintains a steady rate of acceleration, while the 'M' is well out of its power band so initially sets of quite slowly by comparison before it finally hits it 'ohmygod' stride.

So, in the crucial overtaking test, the 'd' actually feels faster because it has greater initial acceleration and the 'M' feels initially slower because you have to wait longer for serious power to kick in.

In a 'd' if you're sitting at a reasonable distance behind a car waiting to overtake, you better be careful to move over before you nail it, otherwise it would be easy to get a lot closer a lot faster than you expect.

Ultimately a Z4M accelerates a lot harder than a 330d, but its the d's instant strong acceleration that make its feel fast

In summary, there's no con. What makes a car feel fast is its rate of acceleration and the 330d feels fast because it is.

[Fox530]

Originally Posted by SteveC

Acceleration is by definition a rate of change (speed with time), so what you're saying is that "its the rate of change of the rate of change that makes you think its fast"

Thats what I said by saying 'rate of change in acceleration' not just rate of change'. You get a surge of power at one point - whereas with, say, the Z4M in your example the power builds linearly all the way up the rev range.

The 330d, with a 0-60 of 6.7 seconds in pre LCI Coupe form, is not as fast as a Z4M, which is considerably quicker, unless you don't drive the Z4M Properly - the S54 engine in the Z4M isn't designed for you to nail it in 4th gear at 50mph. Thats not how it works. Do that, and it'll be as slow as a 330d will be if you nail it in 2nd whilst the engine is doing 4500rpm.

Select the correct gear for the Z4M, and it's gone. And nothing this side of a remapped 335d is going to be in with a chance.

[SO8]

I owned a Z4M Roadster up until 10 months ago .... I would not go back from my LCI 330d ... It's ok if you can afford or have the space for two cars but I just didn't gel with it. For me the power delivery was too linear. Thrash it and it is very quick with a lovely noise .... but I found it was more suited to a track and I have more fun from my 330d - crucially - for the journeys I am doing. No, I don't get the thrill ... but it ticks more boxes. They are just totally different beasts doing totally different things. I do need another quick convertible though

[Fox530]

Originally Posted by SO8

They are just totally different beasts doing totally different things.

This I do agree with

I think your personal circumtances dictate which is the best choice.

[SteveC]

Originally Posted by Fox530

Thats what I said by saying 'rate of change in acceleration' not just rate of change'. You get a surge of power at one point - whereas with, say, the Z4M in your example the power builds linearly all the way up the rev range.

The 330d, with a 0-60 of 6.7 seconds in pre LCI Coupe form, is not as fast as a Z4M, which is considerably quicker, unless you don't drive the Z4M Properly - the S54 engine in the Z4M isn't designed for you to nail it in 4th gear at 50mph. Thats not how it works. Do that, and it'll be as slow as a 330d will be if you nail it in 2nd whilst the engine is doing 4500rpm.

Select the correct gear for the Z4M, and it's gone. And nothing this side of a remapped 335d is going to be in with a chance.

Hi there,

I was actually paraphrasing what you said, so of course we're in agreement on that point.

Judging by your reply, I don't think you quite grasped the point I was making.

The LCI 330d does o-60 in 6.1 seconds, the Z4M 5.0 secs (and probably considerably quicker according to actual roadtests), so no disputing, the 'M' is the quicker car by a good margin.

In the 50-75mph 4th gear roll-on test, the 'd' needs 4.9 seconds, while the 'M' needs 5.0 (a function of being in too high a gear, as you correctly state). However that's not the point...the point is they both need around 5 seconds, so we can compare their power delivery style to see which 'feels' fastest

The 'M' is massively out of its power band, while the 'd' is on song. In a side by side roll-on, the 'd' would pull out a considerable lead, while the 'M' was building revs. But once revving, the 'M would haul in the 'd' and pass it going considerable faster. By definition then, if the 'M' starts out accelerating slower yet ends up faster, it has the greatest change in its rate of acceleration. Its rate of acceleration is also then by definition not linear but exponential, given that its rate of acceleration increases with revs.

So, according to your initial statement, the M should feel faster, because it has the greatest change in the rate of accleration. However it doesn't...it feels slower compared to the d's roll on acceleration, because the 'd' is there from the get go, while the 'M' is stuggling for revs. Its the 'd' that has the linear acceleration (a uniform rate of increase in speed) whereas the 'M' has an exponential increase in speed) i.e a distinct powerband...fast from 2500 rpm, blistering from 4000rpm

In the 330d LCI there's not really a discernable powerband and you really need to be below 1200rpm to catch it 'off turbo'. So the reason the 'd' feels fast is not because of a turbo initiated change in the rate of its acceleration (the 'M' has a far greater change in my example)... the reason it feels fast is because it accelerates hard, pretty much instaneously and linearly from low revs. In short, it goes from gentle suburban cruise to M-eater in the blink of an eye and that's why people buy it. It works brilliantly in the real world

Cheers

[kaishang]

> Its rate of acceleration is also then by definition not linear but exponential, given that its rate of acceleration increases with revs.


It's not exponential acceleration either, it is just non-linear over the speed range in question.

Exponential means (some constant)^(some power).

[Fox530]

I think we are talking at cross purposes, or perhaps we both mean different things by 'linear'.

The turbo on the 330d gives you a surge that makes it feel fast, a N/A engine is lacking in this surge and therefore by comparison often feels slower than it is. This is why a lot of people like turbo engines, they enjoy the kick you get from most of them.

I have not driven a 330d LCI so I cannot comment on its acceleration. The 2008 330d I drove though certainly didn't go from suburban cruise to Motorway speed 'in the blink of an eye'. It left me quite dissapointed because of all the hype that surrounds them. It certainly wasn't slow, and easily had 'enough' performance, but it wasn't quite the tarmac terrorist many owners would have you beleive.

[SteveChester]

I've got a preLCI 330d, had it remapped via Evolve, big brakes and non runflats and I can't fault it at all.

Embarrasses lots of boy racers at the lights..............

[absidian]

Hi all, to be fair, I think this debate is rather one-sided because there just aren't enough 330i models around, let alone their owners to tell you how special the 330i really is.

As an enthusiast, don't let carbon and road tax policies dictate what "a good car" should be for you.

330D vs 330i = Head (best compromise) vs Heart (what you actually want)?

I have been in the same situation and made the right decision with a 330i M Sport. Coming from several BMW's and other fast german+italian marques, I can really honestly tell you the 330i comes tops in equivalent-category comparisons.

Pls don't get me wrong about diesel, I have an even faster 3L turbo diesel sport saloon in my garage too (0-60 in 6 secs). I still prefer the 330i most days - it has that EMOTIONAL CONNECTION and driver-adjustable balance that is missing in most td's.

Surely easier-to-drive does not make a good car, otherwise we'd all be in a Honda/Toyota by now?

[HighlandPete]

Originally Posted by absidian

330D vs 330i = Head (best compromise) vs Heart (what you actually want)?

^ +1

It is why so many have the diesel.

I drive a 330d, after the indulgence of a petrol V8 540i, and it was definitely a 'head' decision.

I'm considering getting an F11 touring, tried the 530d and the 535i F10. The diesel is the practical car to purchase, but to be fair I'd have the 535i and the twin scroll turbo'd engine as the preferred choice, for engine feel and smile factor. So sweet and refined, and some revs if you want them.

HighlandPete

[RichJ]

When the 330i works it is a really good engine and a great all rounder in terms of noise, economy, emissions, power etc.