Petrol vs Diesel
Author
Discussion

romeogolf

Original Poster:

2,112 posts

148 months

Tuesday 17th June 2014
quotequote all
At what annual mileage do you think a modern diesel bought today becomes more economical than an equivalent petrol engined car?

I drive ~20k per year and currently have diesel, but wondering if it's worth switching back to the green pump next time around? Mostly motorway miles (70 mile round-trip commute down A31/M27/M271 from Bournemouth into Southampton).

Edited by romeogolf on Tuesday 17th June 14:48

Rawwr

22,722 posts

263 months

Tuesday 17th June 2014
quotequote all
5,000,000,000,000 miles.

funkyrobot

18,789 posts

257 months

Tuesday 17th June 2014
quotequote all
Modern petrols can be quite economical. I suggest you take a look at some vehicle mpg figures (but please take these with a pinch of salt) and see how they fare.

Boxer87

46 posts

147 months

Tuesday 17th June 2014
quotequote all
70 mile commute?? Stick to a diesel! Much much better economy!

Smoother drive on motorway with diesel. More torque available to easily overtake. And upward of 40mpg on most diesels.

funkyrobot

18,789 posts

257 months

Tuesday 17th June 2014
quotequote all
Rawwr said:
5,000,000,000,000 miles.
Engine would just be run in, innit mate!

romeogolf

Original Poster:

2,112 posts

148 months

Tuesday 17th June 2014
quotequote all
Boxer87 said:
70 mile commute?? Stick to a diesel! Much much better economy!

Smoother drive on motorway with diesel. More torque available to easily overtake. And upward of 40mpg on most diesels.
Well, 35 each way, but yeah 70 miles round-trip. It's been a very long time (6 years) since last owned a petrol ...!

IanCress

4,409 posts

195 months

Tuesday 17th June 2014
quotequote all
There's no 'magic' number. It depends on MPG, fuel prices, servicing and tax costs, difference in price between the petrol and diesel model, depreciation when you come to sell it...

Some petrol models are achieving over 50mpg these days, which along with cheaper fuel prices probably gets pretty close to the running costs of the diesel. And they don't sound like a tractor, which is a bonus.

Edited by IanCress on Tuesday 17th June 14:54

aarondbs

883 posts

175 months

Tuesday 17th June 2014
quotequote all
Boxer87 said:
70 mile commute?? Stick to a diesel! Much much better economy!

Smoother drive on motorway with diesel. More torque available to easily overtake. And upward of 40mpg on most diesels.
Much smoother...doubtful...unless comparing apples (6 cyl diesel) with oranges (4 cyl petrol)and even then not necessarily

More torque available not necessarily and would depend on gearing surely

I've driven diesels for years and some great petrols.

kambites

71,462 posts

250 months

Tuesday 17th June 2014
quotequote all
It's a completely unanswerable question, it could be anything from 500 miles to 50k miles depending on exact usage.

gizlaroc

17,251 posts

253 months

Tuesday 17th June 2014
quotequote all
A3 1.4tfsi vs 2.0tdi the turbo petrol is the sweeter to drive and cheaper to run.

However, most will compare their 150bhp 4 cyl diesel with their 260bhp 3 litre petrol designed 15 years ago and tell you diesel is far more economical.

Boxer87

46 posts

147 months

Tuesday 17th June 2014
quotequote all
aarondbs said:
Much smoother...doubtful...unless comparing apples (6 cyl diesel) with oranges (4 cyl petrol)and even then not necessarily

More torque available not necessarily and would depend on gearing surely

I've driven diesels for years and some great petrols.
Just to give 1 example:

Audi 1.9TDI - 230 lb/ft torque
Bmw 325i petrol - 200 lb/ft torque

Granted the bmw has more horsepower naturally. But diesels have short power bands. Ideal for overtaking. (If in correct gear, same for a petrol though)

xjay1337

15,966 posts

147 months

Tuesday 17th June 2014
quotequote all
gizlaroc said:
A3 1.4tfsi vs 2.0tdi the turbo petrol is the sweeter to drive and cheaper to run.

However, most will compare their 150bhp 4 cyl diesel with their 260bhp 3 litre petrol designed 15 years ago and tell you diesel is far more economical.
A mapped TDI 170 is only just slightly slower than my 2.0 TFSI GTI (decat and intake so probably around 210bhp) . Yet can get 60mpg where as the very best I can manage is 42 and that's driving like a nanny.

Both have pros and cons. I've owned a heavily tuned TDI and would go back to one in a heartbeat.

elliotff

174 posts

169 months

Tuesday 17th June 2014
quotequote all
I have just come back from a road trip in my Fiesta ST2. Averaged 35.6 miles over 1400 miles. I think it depends on what you like to drive.

xjay1337

15,966 posts

147 months

Tuesday 17th June 2014
quotequote all
Boxer87 said:
Just to give 1 example:

Audi 1.9TDI - 230 lb/ft torque
Bmw 325i petrol - 200 lb/ft torque

Granted the bmw has more horsepower naturally. But diesels have short power bands. Ideal for overtaking. (If in correct gear, same for a petrol though)
Not really a fair comparison

2.0 TDI makes 237lb ft torque @ let's say 2000rpm
The BMW would make 200lb ft torque @ let's say 3500... so it's making it 50% more often... to get equivalent performance of a petrol/diesel you need to divide the BHP by about 0.75.... that being said mid range (Eg 30-50 etc) the TDIs punch well above their weight.

DanielJames

7,543 posts

197 months

Tuesday 17th June 2014
quotequote all
I should go back to a diesel I know it, I just can't say farewell to my E36 yet.

BoostMonkey

579 posts

214 months

Tuesday 17th June 2014
quotequote all
This might help or not, but it sounds like a do a similar type of millage at 55 miles a day.

Latest Skoda Octavia 2.0TDI - 61mpg
BMW M235i 3.0ltr - 34mpg
Polo GTi 1.4TSI - 47mpg

Same journey, take your conclusions from that if its helpful.


DanielJames

7,543 posts

197 months

Tuesday 17th June 2014
quotequote all
That's crazy MPG from the Octavia.

I've got a scary theory that manufacturers are making cars just to last a couple of years these days with how strung they are. Be interesting to see how many of the cars are still going like the old 1.9PD engines do.

romeogolf

Original Poster:

2,112 posts

148 months

Tuesday 17th June 2014
quotequote all
BoostMonkey said:
This might help or not, but it sounds like a do a similar type of millage at 55 miles a day.

Latest Skoda Octavia 2.0TDI - 61mpg
BMW M235i 3.0ltr - 34mpg
Polo GTi 1.4TSI - 47mpg

Same journey, take your conclusions from that if its helpful.
Wow, quite a difference there.

SuperchargedVR6

3,138 posts

249 months

Tuesday 17th June 2014
quotequote all
Boxer87 said:
70 mile commute?? Stick to a diesel! Much much better economy!

Smoother drive on motorway with diesel. More torque available to easily overtake. And upward of 40mpg on most diesels.
Or up to 40mpg if it's a 335d smile

I can think of a couple of comparable petrol vs diesel where it makes little sense to have the petrol:

BMW 330d (or a 335d if you want more thump) vs MK5 Golf R32. 45mpg(35mpg) vs 25mpg (real life averages)

BMW 123d vs MK6 Golf GTI. 50mpg vs 30mpg (").

The BMWs are at least a match performance wise and arguably handle better, but clobber the VWs in terms of mpg.

In terms of real world commuting where it's all about instant punch to get one up on the other toner salesmen, diesel makes the most sense. If it's a long open road where you can wring it out, petrol every time.




romeogolf

Original Poster:

2,112 posts

148 months

Tuesday 17th June 2014
quotequote all
Honestly getting "one-up" on the next car isn't an issue to me. I set the cruise control to 72mph and stay left for majority of the drive. I like a bit of punch for slip-roads and pulling on in small spaces, though.