Are modern cars just too complicated?

[Derek Chevalier]

D_G said:

Derek Chevalier said:

D_G said:

If you buy a petrol engined car with just the basics I think new cars are still a good bet.

A modern direct injection petrol? As someone that had the misfortune to buy one of these, I would have to disagree. HPFP, coil packs, injectors, Nox sensors - it went back 8 times in four years for engine issues. And how do you get around the issue of carbon build up on the inlet valves?

I suspect you had a Mitsubishi GDi which was by far the worse direct injection petrol engine ever made. Most modern petrols are pretty good as the technology is well proven and the manufacturers are not needing to come up with new technologies to beat the emmission regulations (such as with diesels currently).

A 2008 BMW in fact. I am refusing to accept that it could possibly be better than the Mitsubishi unit! The technology certainly wasn't well proven for the N53/N54 engines.

[scarble]

There's no reason for it, GDI is way easier than uh.. DDI and we've been doing that for years.

[Derek Chevalier]

scarble said:

There's no reason for it, GDI is way easier than uh.. DDI and we've been doing that for years.

How do you avoid carbon build up on intake valves?

[thinfourth2]

Derek Chevalier said:

How do you avoid carbon build up on intake valves?

Stop making the engine breath its own farts would be a good start.

As my 1960 vintage cement mixer has direct injection and it don't suffer from carbon build up on the intake valves and it certainly ain't cutting edge technology

[scarble]

Derek Chevalier said:

How do you avoid carbon build up on intake valves?

How is GDI responsible for that?

thinfourth2 said:

Stop making the engine breath its own farts would be a good start.
As my 1960 vintage cement mixer has direct injection and it don't suffer from carbon build up on the intake valves and it certainly ain't cutting edge technology

Is it a petrol burning cement mixer?
Remember the by products from diesel combustion and SI petrol combustion are rather different.

[thinfourth2]

scarble said:

Derek Chevalier said:

How do you avoid carbon build up on intake valves?

How is GDI responsible for that?

thinfourth2 said:

Stop making the engine breath its own farts would be a good start.
As my 1960 vintage cement mixer has direct injection and it don't suffer from carbon build up on the intake valves and it certainly ain't cutting edge technology

Is it a petrol burning cement mixer?
Remember the by products from diesel combustion and SI petrol combustion are rather different.

They aren't hugely different

The difference is my 50 year old cement mixer doesn't breath its own farts

[scarble]

thinfourth2 said:

They aren't hugely different
The difference is my 50 year old cement mixer doesn't breath its own farts

It also doesn't pass modern emissions standards (and yes there are standards for off-highway equipment too)

[Prof Prolapse]

Derek Chevalier said:

Prof Prolapse said:

You can't fix it with some gaffa tape and a hammer anymore. But speaking in generalised terms you get more economy, power and reliability.

You are claiming that modern BMW petrol engines (for example) are more reliable than those of yesteryear?

Definition of generalize
verb

1 [no object] make a general or broad statement by inferring from specific cases: it is not easy to generalize about the poor

2 [with object] make (something) more widespread or widely applicable: attempts to generalize an elite education

[Derek Chevalier]

scarble said:

Derek Chevalier said:

How do you avoid carbon build up on intake valves?

How is GDI responsible for that?

http://www.thetruthaboutcars.com/2012/05/ask-an-engineer-gdi-problems-in-a-nutshell/

[Derek Chevalier]

Prof Prolapse said:

Derek Chevalier said:

Prof Prolapse said:

You can't fix it with some gaffa tape and a hammer anymore. But speaking in generalised terms you get more economy, power and reliability.

You are claiming that modern BMW petrol engines (for example) are more reliable than those of yesteryear?

Definition of generalize
verb

1 [no object] make a general or broad statement by inferring from specific cases: it is not easy to generalize about the poor

2 [with object] make (something) more widespread or widely applicable: attempts to generalize an elite education

Indeed we are generalizing. I don't see how engines of today are more reliable than the Japanese engines of the 80s.

[davepoth]

Certain complications do make the car better. But I have to wonder whether certain things really are necessary. Power seats on a small hatchback, for example, or tyre pressure monitors for non-run flat tyres. They add very little to the driving experience.

[Derek Chevalier]

Gaz. said:

Derek Chevalier said:

Indeed we are generalizing. I don't see how engines of today are more reliable than the Japanese engines of the 80s.

They probably aren't, but the difference is the emissions and economy. Toyota's 3.0TT engine from 1991 punts out 295g/km of CO2, NOx is 0.8g/km and it does about 23mpg combined in a 1500kg coupe, although it was also handsomely exceed 300,000 miles with routine servicing if the adverts for cars for sale in the USA are anything to go buy. A 2012 335i has 20bhp less, 30lbs.ft less but C02g/km is only 186 and is complaint with the latest emissions tests and under 0.1g/km for NOx.

Not that I agree with it but I certainly understand the reasons.

I would like to see the tests redone when the cars have a few miles on, as I'm sure my BMW's economy has dropped dramatically as the dreadful engine has become clogged up. If I compare my 3.2 NSX engine to the 3.0 BMW, both with similar mileage, there is approx 60bhp difference, economy on a run is not too different, the BMW sounds like a diesel, throttle response, both when opening and closing the throttle is far worse.

I would rather pay the extra road tax.

[martin84]

Cars have never been 'simple.' I do think though the 90s was something of a sweet spot. Everything had fuel injection, reliable engines, cars could easily do 100k and more without problems and it was just before the obsession with co2 really took hold.

[Derek Chevalier]

martin84 said:

Cars have never been 'simple.' I do think though the 90s was something of a sweet spot. Everything had fuel injection, reliable engines, cars could easily do 100k and more without problems and it was just before the obsession with co2 really took hold.

Agreed

[Mermaid]

Derek Chevalier said:

martin84 said:

Cars have never been 'simple.' I do think though the 90s was something of a sweet spot. Everything had fuel injection, reliable engines, cars could easily do 100k and more without problems and it was just before the obsession with co2 really took hold.

Agreed

Reminds me of a E30 BMW 325i Touring i enjoyed for 200k miles.

[Scootersp]

Whilst cars keep getting 'improved' with the current drive being towards efficiency and low emissions the fundamental fact remains that they are all still 'just' internal combustion engines and the efficiency gains through advanced technology/electronics can only go so far.

I partially agree with the sweet spot 90's comments because as far as straight forward, get in and fire up and drive whatever the weather, whether the engine was cold/hot etc this was all fine. Ease of use and practicality wise little has changed for me past this point.

A 70's Cortina to a 2012 new focus, fine loads of mpg difference, the first focus almost 15 years ago to a 2012 one, next to nothing really is it?............and going ahead a decade it will be even less, it's diminishing returns, unless the weight of cars comes right down which seems unlikely given the equal push for safety.

So for me it's not so much they are too complicated more that any new technology comes with new parts and a learning curve and so a potential set of new problems with reliability/longevity and the 'gains' for the end user get less and less noticeable.

But you shouldn't stand still and I like to see innovation, I'm just quite content personally with the late 90's cars.

[scarble]

Derek Chevalier said:

http://www.thetruthaboutcars.com/2012/05/ask-an-en...

That's not a problem with GDI, that's a problem with EGR and purge/breather systems and issues with carbon build up on idle valves have existed since these were introduced in the 90s.
Sure GDI exacerbates the issue but that doesn't mean it is the cause of the problem. Of course there's no reason not to have direct and port injection, it works rather nicely actually.
More cars than you realise are DI, including pretty much all diesels and they don't all have carbon build up problems.
As for the article's assertion that GDI is super stressful for the poor widle injectors, well that's just bull.

[Derek Chevalier]

scarble said:

Derek Chevalier said:

http://www.thetruthaboutcars.com/2012/05/ask-an-en...

That's not a problem with GDI, that's a problem with EGR and purge/breather systems and issues with carbon build up on idle valves have existed since these were introduced in the 90s.
Sure GDI exacerbates the issue but that doesn't mean it is the cause of the problem. Of course there's no reason not to have direct and port injection, it works rather nicely actually.
More cars than you realise are DI, including pretty much all diesels and they don't all have carbon build up problems.
As for the article's assertion that GDI is super stressful for the poor widle injectors, well that's just bull.

I am not aware of a petrol non DI engine that suffers from carbon built up and power and efficiency loss, so unless someone tells me otherwise, it is an issue with petrol DI engines, which is why I will try and avoid buying another.

[scarble]

Derek Chevalier said:

I am not aware of a petrol non DI engine that suffers from carbon built up and power and efficiency loss, so unless someone tells me otherwise, it is an issue with petrol DI engines, which is why I will try and avoid buying another.

>Implying gunked up GDI, idle valves and breathers don't cause poor tip-in response, efficiency and excess crank case pressure (resulting in a loss of power)

[Dr Doofenshmirtz]

robsa said:

But the governments little scam about climate change and emissions ensures highly complicated management systems, guaranteed vehicle turnover for the car industry etc etc.

Not really...
Cutting pollution from vehicles was about cleaning the air we breath.
Have you forgotten what it was like getting stuck behind a lorry belching out carcinogenic black smoke 20 years ago? or breathing in the sweet smell of carcinogenic leaded not completely burned petrol?