Petrol v diesel

TheShow

Hi,
any idea what the optimum milage is to warrant choosing a diesel engine over petrol.
Work commute is about 40 miles a day, but could be only 2 or three days a week in current situation. Weekends could cover probably up to 100 miles tipping around the place.

Running Diesel at the moment which is fine. Looking at a new car later in the year hopefully and with the more efficient engines these days just trying to cover all bases.

Thanks!

bazz26

It's not so much the amount of mileage as it is the type of driving done. In other words doing 30k km per year of mainly urban driving could be more detrimental to a diesel car than doing 10k km per year of mostly motorway driving. Short or constant stop/start journeys are not good for modern diesel cars.

TheShow

Commute from Blessington to Sandyford, mostly country roads and hill climbing with a bit of M50 thrown in for good measure.

GustavoFring

Micra > Alpina D3

Fact

:pac:

OP, you'd probably get away with a diesel but I wouldn't pay a premium for one since your fuel costs will be small.

ShadowHearth

:

I kind of I'm similar situation. I was thinking of diesel as my milage increased, but it did not increase so dramatically and it will still involve q lot small trips and city driving. On top of all modern diesels are money puts and there is not a single trouble free one thanks to egrs and dual mass wheels and then someone like audi who can't even do a damn oil pump to do its job.
I kind of more and more looking in to petrol engines. Just one rule too look in to when looking for petrol economical car - engine e size and power to weight ratio. A 1.6 petrol will do great mpg in something like focus, but it will completely horrible in mondeo.

sillysocks

That's interesting re type of driving. I'm very in-knowledgable about this stuff, but do you reckon a diesel would be suited if I do a commute twice a week of about 120km round trip, plus maybe a 250km round trip maybe once a month. Apart from that it's mainly short trips and school drops etc.

Stallingrad

sillysocks wrote: »

That's interesting re type of driving. I'm very in-knowledgable about this stuff, but do you reckon a diesel would be suited if I do a commute twice a week of about 120km round trip, plus maybe a 250km round trip maybe once a month. Apart from that it's mainly short trips and school drops etc.

If mainly short trips steer clear of diesel.

R.O.R

Herself has a modern diesel, and uses it to drive to and from work (6km each way), dropping / collecting the kids to Creche about halfway, so it's probably the worst type of driving you can imagine for a modern diesel.

We've had the car for 3 years now, done roughly 30,000km and not had any DPF issues - because we take for a good 1/2 hour at least run, every other weekend at the bare minimum. Usually 30 - 40 km Motorway spin and that seems to keep everything in check.

120km round trip twice a week and a 250km trip once a month should be more than enough to burn off the soot in the DPF.

R.O.R

Herself has a modern diesel, and uses it to drive to and from work (6km each way), dropping / collecting the kids to Creche about halfway, so it's probably the worst type of driving you can imagine for a modern diesel.

We've had the car for 3 years now, done roughly 30,000km and not had any DPF issues - because we take for a good 1/2 hour at least run, every other weekend at the bare minimum. Usually 30 - 40 km Motorway spin and that seems to keep everything in check.

120km round trip twice a week and a 250km trip once a month should be more than enough to burn off the soot in the DPF.

TRS30

R.O.R wrote: »

Herself has a modern diesel, and uses it to drive to and from work (6km each way), dropping / collecting the kids to Creche about halfway, so it's probably the worst type of driving you can imagine for a modern diesel.

We've had the car for 3 years now, done roughly 30,000km and not had any DPF issues - because we take for a good 1/2 hour at least run, every other weekend at the bare minimum. Usually 30 - 40 km Motorway spin and that seems to keep everything in check.

120km round trip twice a week and a 250km trip once a month should be more than enough to burn off the soot in the DPF.

Could you define modern please and make and model if you don't mind?

R.O.R

TRS30 wrote: »

Could you define modern please and make and model if you don't mind?

Volvo XC60 D5 - MY2010. 205ps Twin Turbo, 5 cylinder, 2400cc.

TRS30

R.O.R wrote: »

Volvo XC60 D5 - MY2010. 205ps Twin Turbo, 5 cylinder, 2400cc.

Nice bit of kit.

sillysocks

R.O.R wrote: »

Herself has a modern diesel, and uses it to drive to and from work (6km each way), dropping / collecting the kids to Creche about halfway, so it's probably the worst type of driving you can imagine for a modern diesel.

We've had the car for 3 years now, done roughly 30,000km and not had any DPF issues - because we take for a good 1/2 hour at least run, every other weekend at the bare minimum. Usually 30 - 40 km Motorway spin and that seems to keep everything in check.

120km round trip twice a week and a 250km trip once a month should be more than enough to burn off the soot in the DPF.

Thanks for the reply. It's a new car we're thinking of buying, 161 reg, so hopefully will be ok!

TRS30

R.O.R wrote: »

because we take for a good 1/2 hour at least run, every other weekend at the bare minimum. Usually 30 - 40 km Motorway spin and that seems to keep everything in check.

One other questions.

Do you mean keeping it in say 4th to get the revs up over say 3K for at least 1/2 hour or just normal driving?

R.O.R

TRS30 wrote: »

One other questions.

Do you mean keeping it in say 4th to get the revs up over say 3K for at least 1/2 hour or just normal driving?

Just normal driving in 6th on the motorway, and it's far from giving it a hard run - pretty sure the big turbo very rarely kicks in when she's driving. Spin would usually be Drogheda to Swords/Blanchardstown and cruising about 110km/h, so engine just ticking over in 6th at that speed.

ofcork

I give my diesel avensis a 130 mile or so round trip once a week normal driving and its been faultless since i got it in nov 14.

Ron Burgundy II

Modern petrols are pretty efficient. Like Ford ecobost, VW TSI, Audi FTSI etc.

Roadtoad

Diesels and costs of replacing duel mass flywheels have to be taken into account too. One of the biggest and easily ignored costs.
(€1300 Ford Galaxy every 70k miles) had to do it twice. That would buy a lot of fuel.

Roadtoad

Diesels and costs of replacing duel mass flywheels have to be taken into account too. One of the biggest and easily ignored costs.
(€1300 Ford Galaxy every 70k miles) had to do it twice. That would buy a lot of fuel.

TRS30

Ron Burgundy II wrote: »

Modern petrols are pretty efficient. Like Ford ecobost, VW TSI, Audi FTSI etc.

I thought there were still questions around the long term reliability on small turbo charged petrol's, like Ford's 1.0 euroboost due to the heavy work load on such a small engine in a big car?

flatty

TheShow wrote: »

Hi,
any idea what the optimum milage is to warrant choosing a diesel engine over petrol.
Work commute is about 40 miles a day, but could be only 2 or three days a week in current situation. Weekends could cover probably up to 100 miles tipping around the place.

Running Diesel at the moment which is fine. Looking at a new car later in the year hopefully and with the more efficient engines these days just trying to cover all bases.

Thanks!

Truth be known, I'll never buy another diesel after reading some of the data on how bad the emissions are for air quality. I'm no major green, I have two sports cars, one a 3.8l, and one a 5, but my wife's pretty new volvo diesel makes me feel guilty. I cycle a lot, and when a diesel overtakes you, it burns your throat. Especially bad at the minute as there are a lot of older, higher mileage, filthy ones about that shouldn't pass an nct.
I wonder what we are poisoning our snappers with.
Iirc, diesel is bad enough that Paris are banning them completely, and London rattling up the congestion charge on diesel engines.
I think they are awful.

Stallingrad

I would agree, anyone who is in any doubt as to if it suits there needs (i.e. not huge miles) should buy petrol.

R.O.R

flatty wrote: »

Truth be known, I'll never buy another diesel after reading some of the data on how bad the emissions are for air quality. I'm no major green, I have two sports cars, one a 3.8l, and one a 5, but my wife's pretty new volvo diesel makes me feel guilty. I cycle a lot, and when a diesel overtakes you, it burns your throat. Especially bad at the minute as there are a lot of older, higher mileage, filthy ones about that shouldn't pass an nct.
I wonder what we are poisoning our snappers with.
Iirc, diesel is bad enough that Paris are banning them completely, and London rattling up the congestion charge on diesel engines.
I think they are awful.

Keep kidding yourself that buying a new Petrol rather than a new Diesel is helping the environment and future generations.

http://www.transportenvironment.org/sites/te/files/publications/GDI%20Briefing_final_T&E.pdf

Won't be too long until PPF/GPF are required on Petrol cars, then no ICE engine will be suitable for Start/Stop city traffic

flatty

R.O.R wrote: »

Keep kidding yourself that buying a new Petrol rather than a new Diesel is helping the environment and future generations.

http://www.transportenvironment.org/sites/te/files/publications/GDI%20Briefing_final_T&E.pdf

Won't be too long until PPF/GPF are required on Petrol cars, then no ICE engine will be suitable for Start/Stop city traffic

I always buy used. I am specifically talking about inhaled microparticles. I presume Paris and London have done an odd fact check. Petrol cars don't routinely make me gag whilst cycling.

Elemonator

bazz26 wrote: »

It's not so much the amount of mileage as it is the type of driving done. In other words doing 30k km per year of mainly urban driving could be more detrimental to a diesel car than doing 10k km per year of mostly motorway driving. Short or constant stop/start journeys are not good for modern diesel cars.

Been doing a lot of town driving and motorway driving/commuting in my diesel. No problems with any of my cars since 2007 when I switched to diesel. It's a blue motion engine if that makes any difference.

bazz26

Elemonator wrote: »

Been doing a lot of town driving and motorway driving/commuting in my diesel. No problems with any of my cars since 2007 when I switched to diesel. It's a blue motion engine if that makes any difference.

Your motorway driving may well be sufficient to allow the DPF to do it's job. Also alot of diesel cars may not have had DPFs fitted before 2011 when they became mandatory on all diesel cars sold in Europe.

TRS30

Roadtoad wrote: »

Diesels and costs of replacing duel mass flywheels have to be taken into account too. One of the biggest and easily ignored costs.
(€1300 Ford Galaxy every 70k miles) had to do it twice. That would buy a lot of fuel.

Is having to replace the dual mass flywheel a given on all diesels?

Nonoperational

flatty wrote: »

I always buy used. I am specifically talking about inhaled microparticles. I presume Paris and London have done an odd fact check. Petrol cars don't routinely make me gag whilst cycling.

Have London and Paris banned Euro 6 diesels?

TRS30 wrote: »

Is having to replace the dual mass flywheel a given on all diesels?

Nope.

1jcdub

TRS30 wrote: »

Is having to replace the dual mass flywheel a given on all diesels?

No or happens on all engines. Worst thing to do I'd drive in low rpm mode. It caused a lot of vibration through the transmission which caused the DMF to fail prematurely

dr.fuzzenstein

Roadtoad wrote: »

Diesels and costs of replacing duel mass flywheels have to be taken into account too. One of the biggest and easily ignored costs.
(€1300 Ford Galaxy every 70k miles) had to do it twice. That would buy a lot of fuel.

Do you dragrace it? But maybe it's a heavier car. 2006 Cmax, every 250k km and if you go to a good indy, around the €700 mark. Might even have been less.
There is a lot of pub talk about "Ah yeah, dem diesel be needing injectors, DMFs and DPFs every other week, costs thousands a year!"
Not always true. Research is needed when buying any car.

shietpilot

dr.fuzzenstein wrote: »

Do you dragrace it? But maybe it's a heavier car. 2006 Cmax, every 250k km and if you go to a good indy, around the €700 mark. Might even have been less.
There is a lot of pub talk about "Ah yeah, dem diesel be needing injectors, DMFs and DPFs every other week, costs thousands a year!"
Not always true. Research is needed when buying any car.

Yeah my Focus is sitting at 216k km and the release bearing doesn't sound too great to be honest :pac:

It will be a nice enough post for the DIY thread though €410~ will get me a SACHS DMF, clutch and a new release bearing. Ugh, not looking forward to this job at all :rolleyes:

70k sounds an awfully short time for a DMF though. I think it will be more down to:
- Driving in too high a gear labouring the engine and causing extra vibrations
- Starting issues like a sticky starter, slow cranking speed from a bad battery
- Remap putting extra load on the flywheel as the flywheel is designed for stock engine power
- 90%+ city driving

dr.fuzzenstein

shietpilot wrote: »

Yeah my Focus is sitting at 216k km and the release bearing doesn't sound too great to be honest :pac:

It will be a nice enough post for the DIY thread though €410~ will get me a SACHS DMF, clutch and a new release bearing. Ugh, not looking forward to this job at all :rolleyes:

70k sounds an awfully short time for a DMF though. I think it will be more down to:
- Driving in too high a gear labouring the engine and causing extra vibrations
- Starting issues like a sticky starter, slow cranking speed from a bad battery
- Remap putting extra load on the flywheel as the flywheel is designed for stock engine power
- 90%+ city driving

It will last a few more km's, I remember mine being noisy when I went off the gas, it went on like that for ages. Dangerous game though
You get 6.6l/100km on your Focus? That's 42 mpg, mine gets 48.7 at the moment, that's 5.8l/100 km. (your sig) That can't be right. When I got that consumption, a hose between the intercooler and air intake of the engine had split. Not even my ham-fisted, lead-footed GF manages that kind of figure. Sum Ting Wong.

shietpilot

dr.fuzzenstein wrote: »

It will last a few more km's, I remember mine being noisy when I went off the gas, it went on like that for ages. Dangerous game though
You get 6.6l/100km on your Focus? That's 42 mpg, mine gets 48.7 at the moment, that's 5.8l/100 km. (your sig) That can't be right. When I got that consumption, a hose between the intercooler and air intake of the engine had split. Not even my ham-fisted, lead-footed GF manages that kind of figure. Sum Ting Wong.

Heavy foot man, heavy foot :pac:

I got a few 5.9 l/100 km runs when I drove gently but 9/10 if I have the choice between driving gently or putting the foot down and bombing it I choose the latter

She's booshting fine so it can't be any split hose :P

The J Stands for Jay

R.O.R wrote: »

Keep kidding yourself that buying a new Petrol rather than a new Diesel is helping the environment and future generations.

http://www.transportenvironment.org/sites/te/files/publications/GDI%20Briefing_final_T&E.pdf

Won't be too long until PPF/GPF are required on Petrol cars, then no ICE engine will be suitable for Start/Stop city traffic

Sounds like plug in hybrids will be the way to go. BMW have an interesting looking one on the way.

R.O.R

McGaggs wrote: »

Sounds like plug in hybrids will be the way to go. BMW have an interesting looking one on the way.

That's not going to solve the issue. Most of the time, they are still going to be run by a direct injection petrol engine, with the battery assisting.

TRS30

1jcdub wrote: »

No or happens on all engines. Worst thing to do I'd drive in low rpm mode. It caused a lot of vibration through the transmission which caused the DMF to fail prematurely

When you say drive in low rpm mode, what level are you talking about? I will usually drive in the highest gear possible that will keep the rev's under 2K as I thought this saved a bit on fuel.

shietpilot

TRS30 wrote: »

When you say drive in low rpm mode, what level are you talking about? I will usually drive in the highest gear possible that will keep the rev's under 2K as I thought this saved a bit on fuel.

Under 2000 RPM, e.g 1500 RPM is fine. I often drive at such engine speed.

If you try and drive at a constant speed at say 1100 RPM you will hear the engine struggling (labouring) and you will most certainly feel some vibration. This is a killer for the DMF.