Petrol vs Diesel Cost Debate

DGJsaver

Bongedone wrote: »

Have you heard of particulate filters ?

Have you heard of cars being over 5 years old ?

Pew_Pew_Pew_Lasers!

pault123 wrote: »

A 150 bhp Petrol (more horse power is needed in petrol for equivalent power) will do the 0-60 yet

Erm why would a 130bhp diesel engined car out-perform a 130bhp petrol engined car in a 0-60 race (presuming identical weights)?

DGJsaver

Bongedone wrote: »

Have you heard of particulate filters ?

"Diesel emissions from road transport are by far the biggest single cause of air quality legal breaches," says Simon Birkett, chair of the cross-party Campaign for Clean Air in London. He urges mayor Johnson and the government to take radical action to meet the demands of the new EU air quality directive, which is due to come into force very shortly and will require the UK to achieve much higher air quality standards for emissions of particulates by 2011.
"Unless the government sets, belatedly and soon, national standards for the abatement of emissions of oxides of nitrogen from older diesel vehicles of all main types, these vehicles must be banned from the most polluted parts of London if the UK is to comply with air quality laws," Birkett says. He wants to see all car advertisements show, in grams per kilometre, the emissions of the hazardous oxides of nitrogen and particulate matter, as well as carbon dioxide emissions.


From ;

http://www.guardian.co.uk/environment/2008/may/14/carbonemissions.climatechange


As i said , not everyone rides around in the latest models...

BillScarab

pault123 wrote: »

From a second hand buyers point of view I have to disagree with buying petrol.

Say I want to buy a car, I have a budget in mind say £3000. I look at all my options at this price, I don't see a petrol for £3000 and then think "oh i would prefer a diesel I'll put my budget up to £5000 because it cost that much more originally!"

I find a diesel for £3000 simple.

The difference though is Torque. Bucket loads of Torque. The car pulls at 2000 revs to a degree a petrol could only dream of. Changing down a gear isn't required for overtaking like a petrol, simply put foot down and the Turbo kicks in. The refinement of a modern diesel engine is stunning, after driving a vw/audi TDI engine petrol's feel very clumsy.

The biggest difference in a second hand diesel vs a petrol is performance overall. A 130 bhp 1.9 turbo diesel will do 0-60 in 8 seconds and pull on the motorway like a bullet train yet return a frugal 47-60 mpg.

A 150 bhp Petrol (more horse power is needed in petrol for equivalent power) will do the 0-60 yet with a lot more revs needed and return a pathetic 20-30 mpg.

Sorry but second hand buying a diesel wins.

For brand new car buying then I think your mad!

Modern diesels may be more refined than older ones but more refined than petrol engines? I think not.

Also I'm not sure why you think more horse power is needed in a petrol car for 'equivalent power'. Modern petrol engines tend to develop their power higher in the rev range so need revving more but power is power. Gearing may make a difference though.

Here's an exmpla to refute your strange claim.

Mazda 6 2.2D 182 Sport has 182 BHP 0-60 8.3 secs
Mazda 6 2.5 Sport (petrol) has 168 BHP 0-60 8.3 secs

The power outputs may actually be in PS not BHP but that's not relevant to the comparison.

The petrol also has a slightly higher top speed.

I would expect that the diesel may be quicker from 40-60 or similar due to the amount of torque it develops though.

pault123

Pew_Pew_Pew_Lasers! wrote: »

Erm why would a 130bhp diesel engined car out-perform a 130bhp petrol engined car in a 0-60 race (presuming identical weights)?

I didn't say it would out perform it, they will get similar 0-60' times - yet the diesel will win the torque race hands down. People tend to forget that it's torque and not brake horsepower that actually accelerates a car. Hence to match a 130bhp turbo diesels torque you need to get a higher rated 150bhp Petrol.

Bill i'm just a lover or diesel torque on tap at low revs, something petrol will never offer me.

MrsE_2

SlimTheBills wrote: »

Why should we buy diesel cars?

My DH does about 40k + per year, it works for him.

I bought a petrol because I only do about 6k.

BillScarab

pault123 wrote: »

I didn't say it would out perform it, they will get similar 0-60' times - yet the diesel will win the torque race hands down. People tend to forget that it's torque and not brake horsepower that actually accelerates a car. Hence to match a 130bhp turbo diesels torque you need to get a higher rated 150bhp Petrol.

Bill i'm just a lover or diesel torque on tap at low revs, something petrol will never offer me.

I drive them myself, the driving characteristics are more similar to the old traditional 8v petrols I used to drive in my youth. I'm still deabting whether my next car will be petrol or diesel though, I'll need to do some serious number crunching to see if petrol would be better financially.

pault123

BillScarab wrote: »

I drive them myself, the driving characteristics are more similar to the old traditional 8v petrols I used to drive in my youth. I'm still deabting whether my next car will be petrol or diesel though, I'll need to do some serious number crunching to see if petrol would be better financially.

Which engine do you have Bill?

DKLS

pault123 wrote: »

I didn't say it would out perform it, they will get similar 0-60' times - yet the diesel will win the torque race hands down. People tend to forget that it's torque and not brake horsepower that actually accelerates a car. Hence to match a 130bhp turbo diesels torque you need to get a higher rated 150bhp Petrol.

Bill i'm just a lover or diesel torque on tap at low revs, something petrol will never offer me.

Pickup is fine on a diesel, but I have found there is sod all in the midrange and not much more at the top end.
Moot point anyway for me, as the only diesel I enjoyed driving cost over 30k.

Will stick with my 330bhp Petrol motor, fuel economy is on the poor side, But get paid mileage so I don't feel the pain.

Pew_Pew_Pew_Lasers!

pault123 wrote: »

I didn't say it would out perform it, they will get similar 0-60' times - yet the diesel will win the torque race hands down. People tend to forget that it's torque and not brake horsepower that actually accelerates a car. Hence to match a 130bhp turbo diesels torque you need to get a higher rated 150bhp Petrol.

Bill i'm just a lover or diesel torque on tap at low revs, something petrol will never offer me.

Utter rubbish. You can have as much torque as you like, but it's horsepower that does the work, not torque. Dress it up however you like, but a 130bhp torquey diesel engine will never have as much power as a 131bhp petrol engine, and gearing aside it will never out-accelerate it, particularly as diesel engines tend to be heavier than their petrol counterparts.

The attitude you're displaying is the typical "I've got a new TDi engine, it'll out-accelerate a Ferrari". You're very much deluded. Remember, while your 'King of Torque' engine runs out of steam at 4000rpm, the petrol varient will be accelerating right up to 6000rpm with a much wider power band, and it won't require a turbo either.

For motorway trips, a diesel is usually a good choice - but for pure fun, it'll never ever be as good as a N/A petrol engine.