Diesel or Petrol?
- Thread starter pepsilol
- Start date
To bring this back to relevance, I've just got back in after using my new V8 Petrol Discovery 3 for the first day in 'proper' usage. Absolutely worlds apart from where I've come from in all scenarios, but the effortless power of a big displacement V8 and an Auto box is absolutely dreamland.
I'm getting out of the car, more thinking I've been for a pleasant stroll, rather than that I've driven somewhere in stressful traffic.
With the radio off, I could be sat in a library, its lovely. Calm, peaceful, relaxing... everything. I'd imagine a Range Rover is another step up in quality from this.
Unless they do a lovely refined one with smooth power, get a petrol.
I'm getting out of the car, more thinking I've been for a pleasant stroll, rather than that I've driven somewhere in stressful traffic.
With the radio off, I could be sat in a library, its lovely. Calm, peaceful, relaxing... everything. I'd imagine a Range Rover is another step up in quality from this.
Unless they do a lovely refined one with smooth power, get a petrol.
You are several replies behind - I stated it earlier:
I had checked the official BMW technical data before I replied.
Nobody is discounting the x35d as a very good engine - it's one of the best diesel engines offered in any car. However, to reduce the entire experience of a petrol and diesel engine to a fraction of a second in acceleration figures and fuel economy ignores too many important factors. I have never, ever come across a diesel engine of any design, capacity or age that's as smooth as even the old M54B30 in my 330i - and that includes the latest from BMW.
The noise from an x35d engine is also very different to a petrol noise. It doesn't have the same excitement, partly due to the lack of rev range further amplified by the fact the engine's note barely changes in pitch or volume from 2000 to 5000 RPM. You basically have an engine that produces a satisfying growly buzz when you are pushing on.
If we are comparing a 335i to a 335d for elements of reasonable merit:
335d Pro
Better fuel economy
Better power nearer the 'day-to-day' powerband - quicker access to faster acceleration without going all out
335i Pro
Better sound
More exciting driving experience
Smoother and more refined, especially under low loads, plus no DPF regens (that intentionally misfire the engine)
There aren't really any other tangible differences.
Rilot was mad for selling his Range
Guess what.....The mrs has now decided that an auto wasn't so much of a problem afterall and that I can have another Rangie......FFS........
I'll leave it for the minute though. The CR-V is actually pretty good and in the summer I'll be in the S2000 more anyway.
Maybe next year I'll re-visit the Rangie with a late L322 5.0 SC.
<Likes>
This really is not the case. For starters the 335i/d engines you're comparing - the 335i has a single turbo whereas the 335d has twin turbos.
There is a reason >99% of all diesel engines have a turbo fitted whereas perhaps <10% of petrol engines have a turbo - and that is, that diesel engines are dog slow until you do fit a turbo whereas petrol engines.. aren't. Sure, you can fit a turbo to a petrol engine and it will go like stink but you don't have to, to get reasonable power out of it.
Take something like the S2k 2L petrol producing ~240bhp IIRC. This is a petrol engine without a turbo/supercharger etc, and I can't think of a single diesel 2L engine that produces as much power even with a turbo.
It's a valid point that diesels provide better fuel economy but this is due to a number of reasons - notably that there is more energy per litre of diesel than per litre of petrol - and again due to diesels having turbos while petrol counterparts often do not. This means the car can cruise without the turbo spooling up, in which state it is essentially a lower-powered engine consuming less fuel, vs the non-turbo where it is always a 'higher-powered' engine. Hence the rise now in small 1.0L or 1.2L turbo petrol engines for small city cars, many of which comfortably produce <120g/km CO2.
The downside of course with using a turbo is added expense and added risk of failure, both of which add to the total cost of ownership and eat into the fuel savings. Clearly there are also other, diesel specific things and diesel-biased things which can go wrong as well like DPFs or DMFs/injectors etc.
DPFs for example currently get a bad rep perhaps partially because they are a new technology introduced in the past 10 years. Catalytic converters had their fair share of teething problems when they were introduced as well but these are now very robust and I expect DPFs will go down the same route.. but they are not yet there.
Performance delivery is really, really not linear in turbo engines. They give a shove of fairly low down torque and then not much else for the rest of the rev range. n/a engines are far more linear in their performance delivery and still are nothing like an electric motor in smoothness.
Add to that the fact that superchargers are way more inefficient that turbos as they are essentially 'always on'.
Turbos on diesels work so well due to the innate exhaust pressure being able to spool turbos without any delay (and maybe more reasons too?).
It is definitely the case that manufacturers are squeezing smaller engines with better tuning and forced induction. The liberal use of turbos allows for excellent performance stats, yet also the ability to deliver great emissions and MPG returns on the regulation testing.
As indeed I mention - but that doesn't alter the point I'm making which involves comparing diesel/petrol engines on the market at the moment, which in practical terms for most second hand cars means diesel = turbo, petrol = n/a.
Once petrol turbo'd engines are as common as muck, it will be interesting to compare real world mpgz between your typical 2.0TDI and 1.2-1.4TSI making similar amounts of power.
Well there has been a huge shift (in my eyes).
We have Petrol engines getting more economical, and Diesel engines getting more powerful.
I'm primarily talking BMW here - i'd be willing to go out on a limb and say that the investment they place in the continual engine development and refinement beats most other mainstream manufacturers hands down.
I had a 335i which could do 39MPG on a long run. That staggered me for a twin-scroll turbo 3 litre petrol; i'd have expected mid 20's at best! Similarly, the 3L diesels were a shock too when I saw the performance specs. It felt like a disservice to the x35d engine that it receives virtually no hype or attention from the media.
Definitely other actual reasons. Do only diesels have innate exhaust pressure?
Forced induction works well on diesels primarily because you can use significant levels of boost with no danger of detonation, which would be a problem on petrol engines. They still suffer from some lag, though with the very small and efficient turbos used on modern car engines it's not a major problem.
Soldato
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So we need stickers not saying 'powered by fairy dust' but powered by sooty dust. Matthew Corbett won't be pleased!
![[TW]Fox](/data/man-of-honor/2009.png){kind=avatar}
Is this some sort of bizarre diesel v petrol fight where 0-60 times are the only key judge of a cars performance?
Seems like RedvGreen is self-justifying his F30 330d purchase, I think the entire universe now has the memo that he has an F30 330d and likes it, it's in every thread.
The bottom line remains - diesel is a financial compromise. It really is that simple. We'd almost all pick petrol if money wasn't in the way.
No bias - I very much suspect my next car will be a 530d. Will it be because diesels are proper wicked and better than petrols? No, it's because nobody bothered to buy a 530i and almost nobody a 535i and I couldn't afford to order a brand new 530i whilst they were still in the range nor order a brand new 535i now.
If money wasn't in the way there is no way I'd pick a diesel BMW (as this argument appears to have gone 335i v 335d) over a petrol one. Why would you?
Seems like RedvGreen is self-justifying his F30 330d purchase, I think the entire universe now has the memo that he has an F30 330d and likes it, it's in every thread.
The bottom line remains - diesel is a financial compromise. It really is that simple. We'd almost all pick petrol if money wasn't in the way.
No bias - I very much suspect my next car will be a 530d. Will it be because diesels are proper wicked and better than petrols? No, it's because nobody bothered to buy a 530i and almost nobody a 535i and I couldn't afford to order a brand new 530i whilst they were still in the range nor order a brand new 535i now.
If money wasn't in the way there is no way I'd pick a diesel BMW (as this argument appears to have gone 335i v 335d) over a petrol one. Why would you?
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Superchargers are for performance and fun, not mpgz
And sound. A turbo sounds like it has flatulence but a supercharger just sounds horny and rude.
I can't see me ever buying a diesel unless it was transport for work. It's just wrong.
EDIT: Sadly turbochargers are the future as they are certainly efficient.
[TW]Fox;25660412 said:
Last I checked, I have a 330D not a 335D which is what we were discussing here
I am not justifying my purchase; however my purchase really opened my eyes to BMW diesels being awesome all-rounders.
As you say, if Petrol was cheaper than it currently is, then MPG/range really doesn't matter at all. There'd be no reason to consider Diesels except for emissions (which would primarily be a business concern or avoiding first-year-showroom tax).
Glad you are liking it, they make every other car seem totally rubbish don't they (the Range Rover is another step up too) Rilot was mad for selling his Range
It's like driving round in your lounge
I'd imagine the range is a bit more drawing/billiards room
