E90Post
 


European Auto Source
 
BMW 3-Series (E90 E92) Forum > BMW E90/E92/E93 3-series General Forums > Regional Forums > UK > Petrol VS. Diesel - some fun figures



Reply
 
Thread Tools Search this Thread
      10-16-2012, 12:13 PM   #1
xPETEZx
Lieutenant
United Kingdom
8
Rep
560
Posts

 
Drives: BMW 325i SE 6MT (E90 LCI)
Join Date: Oct 2012
Location: London

iTrader: (0)

Post Petrol VS. Diesel - some fun figures

Hey!

So this topic is more of a information share, and see what others thoughts are.

Before buying my car, I was endlessly going back and fourth between a 325i and a 320d.
In the end the n47 timing chain failures and possible DFP issues with short journeys along with a good deal on a 325i swung it in the petrol favour.

However, I keep asking myself if I made the right decision in terms of fuel cost, so put together a sheet to run some numbers.

Here some figures:

Advertised MPG: (Going to use these for my calculations, in the absence of what kind of figures I would achieve in a 320d)
320d: 59
325i: 39 (My actual is 31.7)

Cost per litre:
d: 1.429
i: 1.359

Cost per mile:
d: 9p
i: 13p

Tax per year:
d: 100
i: 195

Rough difference in purchase cost:
1500 - 2000

Given the 4p difference in cost per mile, how many miles need to be covered to make up the difference?
1750 / 0.04 = 43750 Miles

So, taking into account an annual mileage of 10,000 it would take me 4 years to make up the extra cost in fuel. (provided the ratio between petrol and diesel stays the same)
For each year, I also need to add on another 95 extra for tax.


I guess this just confirms what everybody says about needing to do 12-15k a year or more to make back that extra initial price in a reasonable time frame.

Recently I also got the itch to consider swapping my 325i for a 330d. (Plus about 5k-6k) and to make that cost back and given the 330d is not as effiecent as the 320d, would have taken 300k miles!!* )

*330d by my calculation of 49MPG, would cost just 2p less per mile. So 6000 / 0.02)
Appreciate 0
      10-16-2012, 12:26 PM   #2
Kerr
Brigadier General
Scotland
46
Rep
3,723
Posts

 
Drives: 08' 335i Coupe
Join Date: Dec 2010
Location: Aberdeen

iTrader: (0)

We've had similar threads on here comparing others cars.

The conclusion from many when comparing the 335i to the 335d, is buy the car you prefer to drive.

There really isn't any cost between the two overall.
Appreciate 0
      10-16-2012, 12:38 PM   #3
Flood
New Member
Flood's Avatar
United Kingdom
1
Rep
13
Posts

 
Drives: E92 325 se
Join Date: May 2012
Location: Kilmarnock

iTrader: (0)

Been through the same, and glad I chose the 325i.

You would also need to reduce the diesel mpg as I doubt anyone gets 59 in real life, possibly 45-50 mpg. I actually average approx 34 mpg out of my 325
Appreciate 0
      10-16-2012, 01:17 PM   #4
BanziBarn
Lieutenant Colonel
BanziBarn's Avatar
34
Rep
1,789
Posts

 
Drives: BMW 330D E90 LCI Msport
Join Date: Sep 2009
Location: London

iTrader: (0)

I chose my D based on how it drove rather than the cost to run as I only do 8k miles per year.

But actually, that's not 100% true becuase in terms of the "performance feel" it was between the 330d and 335i, not the 330i so that's where it gets a bit complicated! The D was cheaper to buy, insure, fuel and tax compared to the 335 so despite my low milage, I didn't need to worry about making up the purchase price premium of the diesel, because it was actually cheaper to buy!

As diesels get better and better the decision making process is going to be incresingly based on the drive as well as the economics I think.
__________________
Black 330d E90 LCI M Sport Saloon Auto. Privacy Glass, Cream Leather, 6FL, I-Drive/Nav/Bluetooth, Alpine hifi upgrade.

http://www.e90post.com/forums/picture.php?albumid=2148&pictureid=44259
Appreciate 0
      10-16-2012, 01:34 PM   #5
Rudz
Major
Rudz's Avatar
United Kingdom
15
Rep
1,008
Posts

 
Drives: E92 335i LCI MSport
Join Date: Feb 2012
Location: Brighton

iTrader: (2)

how did you arrive at that calculation though

320D - 10k miles, 55MPG, @ fuel prices you've mentioned it would cost 1180 to run 10k miles

325i would cost 1930 to run 10k miles @ 32MPG

That's 750 more per year in fuel costs plus additional road tax, you'll recoup in 2 years mate ? the residuals of a diesel is better than a petrol ? @ 10k miles a year, I still feel diesel's are better
Appreciate 0
      10-16-2012, 01:43 PM   #6
xs2man
Captain
xs2man's Avatar
9
Rep
604
Posts

 
Drives: 2013 F11 530d M-Sport
Join Date: Jun 2012
Location: Scotland

iTrader: (2)

You can't take the absolute difference in purchase costs into account when you do these calculations though. When its time to sell the car, the diesel will still be worth more than the petrol, so you will recoup a lot of that cost at that stage.

And even then, you are not taking into account service costs. A 2.0 TDI will be cheaper to service than the 325i because it requires less oil, and will be covered by fixed price servicing, which the 325 wont be.

In reality, your 5k-6k isn't the real number you should be using either. Presumably that number comes from trading in your car against another. Which isn't the actual difference of the two models worth. The actual difference in that case would be better made between the selling prices of the two models, as trading in you are always going to loose out, regardless of if you were to go to a petrol or diesel. The bulk of that cost can be associated with your want / need to change, and shouldn't be taken into consideration in these calculations.

I did have some serious calculations to do before I bought my 335d, because my 2.0 TDI A4 was so terrible on fuel. It costs the same per mile in fuel as the 335d costs. The cost to change wasn't too bad, but that was the cost because I wanted to change. I also had to trade in a 3 month old motor for a 2 year old motor, a huge difference in miles (3500 against 17000), but better spec (slightly) in the BMW.

The only real way you can determine the difference between petrol and diesel is against actual fuel consumption figures. No other calculations should really be factored in. At a push you could pop tax differences in there, but they will be minimal compared to fuel costs anyway, so not really worth even considering.
__________________
530d M-Sport Touring.

Appreciate 0
      10-16-2012, 02:08 PM   #7
acerboo
Brigadier General
England
57
Rep
3,686
Posts

 
Drives: e92 335d lci
Join Date: Jul 2008
Location: kent

iTrader: (2)

run a 330i and a 335d even cpmparing to a 335i id go for diesel every time on driveability
Appreciate 0
      10-16-2012, 02:20 PM   #8
takumichinoku
Private
0
Rep
82
Posts

 
Drives: 335i
Join Date: Feb 2012
Location: UK

iTrader: (0)

You forgot about the all important sound test.
Appreciate 0
      10-16-2012, 02:29 PM   #9
Kerr
Brigadier General
Scotland
46
Rep
3,723
Posts

 
Drives: 08' 335i Coupe
Join Date: Dec 2010
Location: Aberdeen

iTrader: (0)

BMW claim to be "the ultimate driving machine".

I'm suprised how many people choose their car based on saving a relatively small amount of cash.
Appreciate 0
      10-16-2012, 02:35 PM   #10
rickyjones1209
First Lieutenant
rickyjones1209's Avatar
7
Rep
342
Posts

 
Drives: 2008 e92 335i
Join Date: Jan 2012
Location: Cheshire

iTrader: (1)

Diesel is for company cars, tractors, trucks and boats. Not premium German cars, especially not e92 and e93.

I fear I may be shot down with that one ha ha
__________________
Current - 08 e92 335i M Sport
Previous - 02 Renault Laguna, 04 Seat Leon Cupra R, 03 Subaru Impreza WRX, 01 Renault Clio 172, 98 Peugeot 106 Rallye S2, 94 Peugeot 106 Rallye S1
Appreciate 0
      10-16-2012, 05:00 PM   #11
xPETEZx
Lieutenant
United Kingdom
8
Rep
560
Posts

 
Drives: BMW 325i SE 6MT (E90 LCI)
Join Date: Oct 2012
Location: London

iTrader: (0)

Quote:
Originally Posted by Rudz View Post
how did you arrive at that calculation though

320D - 10k miles, 55MPG, @ fuel prices you've mentioned it would cost 1180 to run 10k miles

325i would cost 1930 to run 10k miles @ 32MPG

That's 750 more per year in fuel costs plus additional road tax, you'll recoup in 2 years mate ? the residuals of a diesel is better than a petrol ? @ 10k miles a year, I still feel diesel's are better

0.13 x 10,000 = 1300
0.09 x 10,000 = 900

Saving of 400. To make up the 1500 saved on purchase would therefore still take the 3~ years I calculated.


Either way, my figures are not 100%, they are little more than back of an envelope calculations.

I purposely left selling price out of all calculations because of the potential for variation.
I did however look at how much a 325i and 320d that are 7 years old (55 plates) would be worth.
Due to the massive variation in spec etc, its not entirely accurate but it really dosent look like the 320d holds it value much better than the 325i.
At the very least, that 1500 - 2000 gap difference now, gets smaller with age.
Appreciate 0
      10-16-2012, 05:15 PM   #12
Dave_3
Colonel
Dave_3's Avatar
Scotland
47
Rep
2,814
Posts

 
Drives: F32 430D sDrive Msport
Join Date: Oct 2006
Location: CH / SCO

iTrader: (0)

Garage List
Quote:
Originally Posted by rickyjones1209 View Post

I fear I may be shot down with that one ha ha
Fear not, the mountain of dead bodies from the last time that was mentioned will cushion your fall.



D.
__________________
Escort Mk1 RS2000 (2.1 2x44IDFS, BVH, Kent FR32, 5spd, 180 BHP) : Fully Loaded F32 430D M Sport sDrive : Previously Full-Spec 335D E92 2006 : Capri MK1 full rebuild in progress

Appreciate 0
      10-16-2012, 05:19 PM   #13
The_Bear_Yid
BM Noob
The_Bear_Yid's Avatar
England
10
Rep
932
Posts

 
Drives: E92 325i
Join Date: Mar 2011
Location: Kent

iTrader: (1)

I cannot see the first post and 3/4 other posts in this thread on the app
Appreciate 0
      10-16-2012, 05:23 PM   #14
IanS100
Colonel
IanS100's Avatar
United Kingdom
32
Rep
2,641
Posts

 
Drives: 320d LCI M Sport Plus
Join Date: Nov 2011
Location: Southport UK

iTrader: (0)

Is there much difference in insurance costs between the various cars?
Appreciate 0
      10-16-2012, 05:58 PM   #15
omaragha
Lieutenant Colonel
United Kingdom
21
Rep
1,868
Posts

 
Drives: 335i DCT E93
Join Date: Mar 2009
Location: Windsor, UK

iTrader: (4)

Quote:
Originally Posted by rickyjones1209 View Post
Diesel is for company cars, tractors, trucks and boats. Not premium German cars, especially not e92 and e93.

I fear I may be shot down with that one ha ha
Allow me to aim - shoot and say bolox !!!!
__________________
Engine Mods: JB4 G5 ISO, Wedge Flash, BMS DCI, ETS FMIC, ER CP, AR Catless DP's, BMS OCC, BMS Cowel filters & Forge DV's.
Running Gear Mods: Graphite Atomic CSL's, Birds B3 Suspension, Stoptech Grooved Rotors & Yellow Stuff pads.
Cosmetic: Performance Grill and Diffuser, Carbon Badges, Carbon Interior
Appreciate 0
      10-17-2012, 03:23 AM   #16
E92Dan
Captain
E92Dan's Avatar
9
Rep
646
Posts

 
Drives: 330d
Join Date: Jul 2012
Location: northampton

iTrader: (0)

Quote:
Originally Posted by Kerr View Post
BMW claim to be "the ultimate driving machine".

I'm suprised how many people choose their car based on saving a relatively small amount of cash.
My ultimate driving machine saves me 1300 a year in fuel over my old golf gti, i would call that a relatively large amount of cash!
Appreciate 0
      10-17-2012, 03:25 AM   #17
xPETEZx
Lieutenant
United Kingdom
8
Rep
560
Posts

 
Drives: BMW 325i SE 6MT (E90 LCI)
Join Date: Oct 2012
Location: London

iTrader: (0)

Quote:
Originally Posted by IanS100 View Post
Is there much difference in insurance costs between the various cars?
For me, insurance was identical. Which did slightly surprise me.
I thought it being a 2.0L d or 3.0 i would affect the price.

I will say, the in-gear pickup of the 320d (and 120d I drove) was amazing!
Can get off the line nice and quick in the 325i, but if sitting at 50 and put my foot down, not a lot happens unless I drop 2 gears.

I can only imagine what a 330d would do!
I really would love to get a big BMW d for the drive style.

Part of my reason for putting these figures together again was in the hope that the 330d would make more sense in terms of cost.
Give me some kind of justification for saving another 4-5-6k together to try pickup a LCI 330d!
Appreciate 0
      10-17-2012, 03:39 AM   #18
Subzero2003
Captain
9
Rep
665
Posts

 
Drives: E92 335i
Join Date: Apr 2011
Location: UK

iTrader: (0)

Quote:
Originally Posted by acerboo View Post
run a 330i and a 335d even cpmparing to a 335i id go for diesel every time on driveability
"Driveability" - explain? I find my 335i and my previous 330i very "driveable" and far far more enjoyable than any diesel i have ever driven or been in.

Quote:
Originally Posted by takumichinoku View Post
You forgot about the all important sound test.
Ha, indeed. The diesel boyz still refuse to accept their diesels do sound like diesels though. The almost brand new 320d i had as a courtesy car sounded like a tractor. My colleagues 325d 6 pot diesel sounds like a diesel.

I think diesel owners often like to kid themselves about:

A: How many MPGs they get
B: How their cars are faster than petrols
C: How their cars sound pretty much the same as petrols.
Appreciate 0
      10-17-2012, 04:00 AM   #19
E92Dan
Captain
E92Dan's Avatar
9
Rep
646
Posts

 
Drives: 330d
Join Date: Jul 2012
Location: northampton

iTrader: (0)

Quote:
Originally Posted by Subzero2003 View Post
"Driveability" - explain? I find my 335i and my previous 330i very "driveable" and far far more enjoyable than any diesel i have ever driven or been in.



Ha, indeed. The diesel boyz still refuse to accept their diesels do sound like diesels though. The almost brand new 320d i had as a courtesy car sounded like a tractor. My colleagues 325d 6 pot diesel sounds like a diesel.

I think diesel owners often like to kid themselves about:

A: How many MPGs they get
B: How their cars are faster than petrols
C: How their cars sound pretty much the same as petrols.
A: my car gets a far higher mpg figure than my old golf gti and z4 3.0
B: my car is faster than a golf gti, but slower than a z4 3.0
C. my car doesnt sound as nice as the z4 3.0 but does sound nicer than a golf gti especially at tick over!

Its important to remember that both petrol and diesel cars have strong points and weak points.
It comes down to what you need from a car.
Appreciate 0
      10-17-2012, 04:14 AM   #20
Subzero2003
Captain
9
Rep
665
Posts

 
Drives: E92 335i
Join Date: Apr 2011
Location: UK

iTrader: (0)

Quote:
Originally Posted by E92Dan View Post
Its important to remember that both petrol and diesel cars have strong points and weak points.
It comes down to what you need from a car.
Oh no doubt, i wasn't saying anything different. I was making the point that many diesel owners feel the need to exaggerate the qualities of their cars, i'm guessing on some level, to try and justify their purchase.*

For instance, i've found petrol owners far more realistic about the MPG figures they get, than diesel owners.


*Awaits every diesel owner on E90Post saying "I DON'T GIVE A STUFF ABOUT WHAT ANYONE ELSE THINKS ABOUT MY PURCHASE!11!!!1"
Appreciate 0
      10-17-2012, 04:46 AM   #21
CarAbuser
Captain
CarAbuser's Avatar
United Kingdom
11
Rep
794
Posts

 
Drives: E89 Z4 35i
Join Date: Jul 2010
Location: Worcestershire

iTrader: (0)

The 330d would be a sensible choice if you're after low running costs.

Not quite as good on fuel as the 320d but offers more power to compensate, will have even better residuals than a 320d and from what I've gathered is a lot more reliable.

The petrols are cheaper to buy but will hold considerably less value, have quite a poor reliability record and drink a fair amount of fuel. They do sound nice so if that's your number one priority then I would buy a 335i.

From an insurance point I did notice the 330d is the same cost to insure as the 335i which seems strange considering the petrol is more powerful and more likely to be ragged around by boy racers.

I get the impression you're buying on the numbers so make sure you consider depreciation as that will be the biggest loss.
Appreciate 0
      10-17-2012, 04:47 AM   #22
Hotcoupe
Major General
Hotcoupe's Avatar
United Kingdom
70
Rep
6,105
Posts

 
Drives: Don't know yet!
Join Date: Jul 2007
Location: UK

iTrader: (2)

Garage List
Quote:
Originally Posted by Subzero2003 View Post


*Awaits every diesel owner on E90Post saying "I DON'T GIVE A STUFF ABOUT WHAT ANYONE ELSE THINKS ABOUT MY PURCHASE!11!!!

1"
I don't,both petrol & diesel cars have their merits,as they do their weaknesses.

This argument has been done to death,and is arguably more dull than the seasonal winter tyre threads.
__________________
=================================


Never argue with an idiot on the internet. He will drag you down to his level and beat you with experience.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 11:22 PM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST