Changing to a diesel

[Gers]

I'm about to take delivery of my first diesel car and am slightly worried about differences in driving style from the petrol car. I've searched the internet and got confusing information - some forums say it's no different, some say it's very different and some can't make their minds up.

Seems all to do with when to change gears????

Some up to date advice would be very welcome.

[Bongedone]

I have a diesel and not noticed a difference.

[Pew Pew Pew Lasers!]

I'm about to take delivery of my first diesel car and am slightly worried about differences in driving style from the petrol car. I've searched the internet and got confusing information - some forums say it's no different, some say it's very different and some can't make their minds up.

Seems all to do with when to change gears????

Some up to date advice would be very welcome.

There is nothing to worry about. Although diesel engined cars are very different to petrol engined cars, the differences aren't so great that they would cause you any problems.

Just make sure that when refilling you remember not to put petrol in.

[MX5huggy]

It will come naturally a diesel car operates at lower revs than a petrol so you change gear at lower revs but you change gear at about the same speeds. Your not going to do any damage by going bit high in the revs at the start.

[worried jim]

Just drive as you would normally and enjoy the mpg !

[cpdc1030]

On the Diesel car's i've driven I've noticed that the power seems to be either "on" or "off" - whereas with a petrol the power is variable depending on the revs. I.e. with a diesel there can be a huge surge in power between 1800rpm and 2200rpm, and little after that. I think that is related to the turbocharging. Whereas with a petrol the buildup of power is gradual and continues to increase up to the red line.

Depends on the model of course though.

[LandyAndy]

You'll probably find yourself changing gear less often as diesels have more torque at the sort of engine speeds most people use in everyday driving

[vikingaero]

Buy a misfuel gadget like the Caparo Rightfuel. Or if you have a Ford then chances are it has the misfuelling widget built in.

With a diesel you change up at lower revs than a petrol.

As the car will most probably be a turbo diesel don't forget to idle the car for 30 seconds before switching off after a hard run.

[Gers]

All most helpful - thanks!

Need a widget
Need to idle for 30 secs after a long run
Need to drive as normal
Don't need to move through the gears so much

Cheers!

:beer:

[AdrianHi]

If you are looking for maximum acceleration while overtaking the adjustment you need to make is changing up a gear at around 4000rpm at the latest and not trying to drive it to the red line which is around 4500-5000rpm. You will get more acceleration this way, most of the power is available 2000-4000rpm on a modern diesel though they are all quite different in response.
You need to exepriment and get to know how yours performs.

The 30 seconds of idling thing is rather outdated and not really neccessary on a modern intercooled turbo diesel using synthetic oils. A short period of gentle driving before shutting the engine off will suffice.

[Ebe Scrooge]

As has been mentioned, you can afford to be quite a bit lazier with gear-changes as there's a lot more torque available. Acceleration may be less than you're used to, so be careful with overtaking manouvers until you're used to it. Having said that, a lot of the modern diesel engines can give petrols a run for their money, I was amazed the first time I drove my brother's diesel.

I don't know how fastidious you are about servicing, but if you do nothing else then change the oil regularly. Although not to be recommended, diesels can take a far amount of neglect, more so than a petrol, but the one thing they are fussy about is their oil. And you'll probably find the recommended oil change interval is a lot shorter than you're used to.

[AdrianHi]

In recent years there has been a switch to synthetic long life oils, diesel fuel is a bit cleaner than it used to be, end result diesel oil change intervals are as long if not longer than petrols now.
My diesel works on condition based servicing and can go anywhere from 18,000 to 23,000 miles between oil services depending on how it is used.
In the quest to control emissions on diesels there are all sorts of compromises and bits of kit added to achieve this along with leaps in performance which conspire to make the modern diesel less reliable than diesels of old and current petrol engines.
Diesel Particulate Filter (DPF) the latest.
With all these measures regular open road driving is a must for long term health.
I heard recently that Skoda will no longer sell a diesel car fitted with a DPF to Taxi drivers who spend all their time in town, it kills the DPF quickly. On most cars the service life of a DPF is reconned to be 70-100K miles, so save up the £700-£1500 for it's replacement.

[Dave101t]

my diesel (6 speed) is almost as lazy as an automatic, hardly ever change gear in town!
lower revs too but apart from that, no real difference.

[harveybobbles]

On most cars the service life of a DPF is reconned to be 70-100K miles, so save up the £700-£1500 for it's replacement.

I've replaced/blasted/jet washed them with mileage circa 50,000. Such a shitty idea really! Peugeots are THE worst ones going! nothing is cheap about running a deisel these days. the money you save in fuel will be put towards replacing the DPF and/or the DMF...!

The main thing to watch out for is getting the right fuel in..!

[Gers]

:eek:

Am not a taxi driver so shouldn't have to worry about that. Getting a brand new Vauxhall Meriva 1.7 CDTi and will concentrate on getting the black stuff in and not the green stuff!!

Thanks for all the techie stuff...:confused: but as long as I can change gears up and down without too much of a problem I hope to be OK!

[MX5huggy]

black stuff in and not the green stuff!!

Be extra carefull if you end up at a BP station they have some blue pumps !!

[Pew Pew Pew Lasers!]

All most helpful - thanks!

Need a widget
Need to idle for 30 secs after a long run
Need to drive as normal
Don't need to move through the gears so much

Cheers!

:beer:

The widget is only useful if you're forgetful.

You don't need to idle, just drive smoothly without flooring the accelerator for a minute or two before you arrive at your destination.
Stick to whatever gear gives you the most power at whatever speed you're doing - the same as you would in any other car.

[MJAllen88]

As said before, there isnt really much difference apart from that they don't rev as high and the power is delivered on a set rev band, rather than gradual power increases all the way up the revs like on a petrol.

I think diesels have been given amazing attention in the last few years due to the economical and environmental issues we've had. Diesel engines are now slightly less likely to give lovely respectable cars the etiquette of a transit van like they used to :).

Still noisey and the vibrations in your car can send shivers down your spine, but once you get used to the rev bandings, you can prevent this and you'll be surprised at the lovely, punchey drive they provide :)

[thescouselander]

You'll probably find yourself changing gear less often as diesels have more torque at the sort of engine speeds most people use in everyday driving


I would say its just the opposite. You have to change gear more often in a diesel because the power is delivered over a very narrow rev range. You'll really notice this when the red line quickly approaches in the middle of an overtaking manouvre.

If I way to buy a diesel it would have to be an automatic for this reason.

[kittie]

DPF is actually a big problem across a whole range of diesel engines. I only did my research on it today after lack of regeneration on our car caused warning lights to come on and hence a 5 hour visit to the garage

I actually ordered another car two days ago and was able to change the engine today away from a 1.6 dpf. Totally unsuitable for us as we do about 8k a year and mostly short runs. We were never initially told about DPF. I have read about people having lots of trouble with the new DPF engines, in spite of regular motorway driving

Do the google searches before going diesel

[olly300]

DPF is actually a big problem across a whole range of diesel engines. I only did my research on it today after lack of regeneration on our car caused warning lights to come on and hence a 5 hour visit to the garage

I actually ordered another car two days ago and was able to change the engine today away from a 1.6 dpf. Totally unsuitable for us as we do about 8k a year and mostly short runs. We were never initially told about DPF. I have read about people having lots of trouble with the new DPF engines, in spite of regular motorway driving

Do the google searches before going diesel

You mean this: http://www.theaa.com/motoring_advice/fuels-and-environment/diesel-particulate-filters.html

[Rallydriver]

I would say its just the opposite. You have to change gear more often in a diesel because the power is delivered over a very narrow rev range. You'll really notice this when the red line quickly approaches in the middle of an overtaking manouvre.

This is true in certain situations. Given the average driver (vast majority) who drives a petrol never takes it into the top of the rev range then it probably will be quicker for them, bear in mind these drivers don't usually overtake anything going quicker than a tractor.

For a driver used to using the full rev range of a petrol engine then it will require planning of the manouvre which is not natural to them and possibly an extra gearchange.

The science bit. (simplified alot)
With a petrol engine, the fuel is ignited by a spark. That spark is timed to ignite the fuel so it burns at the correct time to push the piston down. As the revs of the engine increase, the spark needs to happen earlier in order for the fuel to be burning at the correct time to push the piston down. This is known as ignition advance.
Essentially this means that at higher revs the power from each stroke stays more constant but because there are more power strokes the engine creates more power.

With a diesel, the fuel is ignited by the diesel/air mixture being squashed by the rising piston (compression ignition). So ignition happens at a set time in the cycle no matter what the engine speed is. Therefore, as the engine speed rises, each power stroke produces less power. Hence a diesel engine runs out of steam as the revs rise.

Simplified alot to be understood, I know there are flaws in the explanation but they make it easier to understand the basic concepts.

No doubt one day someone will manage to advance the ignition on a diesel, lets hope they manage it before the oil runs out. lol.