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Diesel vs Petrol

Posted: Wed Apr 02, 2008 8:08 am
by wanda
Personally I would not go back to petrol as the torque is treating me very well. Good with over taking and excellent with fuel consumption but here is a little theorem I devised let me know what you think.

Compare megane cc 1.6 and megane cc 1.5dci


Lets asume 12000miles a year

Here is the theory.

12 000 miles uses roughly 214 gallons with a 1.5dci engine (assume 56mpg)
which is roughly 857 litres (say one litre is £1.10) thats roughly £943 a year.

12 000 miles with the most economical petrol engine uses roughly 300 gallons with a 1.6 petrol engine (assume 40mpg) thats roughly 1200 litres (say one litre is £1.05) thats roughly £1260 a year.

Thats £317 less a year.

The diesel is £110 a year on road tax, the petrol is £150 a year

Thats £40 less a year.

The diesel is in insurance group 6 and the petrol is in group 7.

Thats roughly £100 less.

The diesel should be more to service but longer intervals (no 100% sure on that) so lets say it works out to be the same.

The diesel costs £1010 more to buy but is worth 50% after 3 years while the petrol is worth 46%. This means in three years the diesel is worth £9665 and the petrol is £8436.

This means in three years the diesel is worth £1229 more than the petrol which more than covers the cost of buying a diesel.

So in three years the diesel should be 3 x £450 = £1350 better off than the petrol.

There is my research please give me my masters.
:pc

Re: Diesel vs Petrol

Posted: Wed Apr 02, 2008 8:33 am
by Stranger
Do you work for or provide information to the government Wanda?

The reason that I ask is that if you do I think that you're heading the right way for not only a masters but aso to be knighted, if you don't you are merely using common sense and won't even be given a second glance ;)

Re: Diesel vs Petrol

Posted: Wed Apr 02, 2008 8:41 am
by wanda
Why, thank you my good lad :D

Next I will prove to you mathematically that pigs can fly. :lol:

Re: Diesel vs Petrol

Posted: Wed Apr 02, 2008 12:39 pm
by Gav
I doubt that 1 insurance group is £100 a year difference. It might be if you're young and have no NCB, but to those of us with some experience, it's definitely under £50, probably closer to £25.

Service intervals are the same or shorter for Diesels too, so servicing does cost more. If you only cover 12k a year, then both cars should be serviced annually.

For your 12000 miles a year, the Diesel is cheaper overall, and the gap only gets wider the more miles you do. For my 1.5dCi it's cost me on average 8.215p per mile in Diesel over 13k miles in ~10 months. The Petrol 307 I used to run was 10p a mile (over 22k in ~19 months) when fuel was cheaper (averaging 90p/l), thus costing 11.7p a mile with todays fuel price of 104.9p/l. That's not a a 3.5p/mile saving as diesel has gone up in price, so more like 2.9p/mile. 12000 * 2.9 = £348 a year less for me - but then I get better mpg than suggested - which is more than a normal service. So even without depreciation, insurance & tax, diesel is cheaper.

Re: Diesel vs Petrol

Posted: Mon Apr 07, 2008 4:46 pm
by snowy
but then really in three years time it will be worth 10p...fact.just cause its a renault. :banghead

Re: Diesel vs Petrol

Posted: Tue Apr 08, 2008 10:56 am
by wanda
No snowy, the manual will be worth 10p :D

Re: Diesel vs Petrol

Posted: Sat Aug 02, 2008 1:45 pm
by pjsmoothie
Hi, i'm new to the site, and do not own a Megane (YET!).
I am thinking of buying a 1.9 DCI or the 1.6 VVT Petrol.
I read your comparison with the 1.6 and the 1.5DCI, but would you recommend the 1.9DCI over the 1.6 petrol.
Fuel prices here are going up every month and Diesel is quite high now, looking at the stats the 1.6 petrol is only 10 miles to the gallon less then the 1.9, and there doesn't seems to be much between them in performance.
Has anyone drove both, still in two minds which one to go for , any suggestions are welcome.

Re: Diesel vs Petrol

Posted: Tue Aug 05, 2008 8:59 pm
by 72uoba
What about the initial purchase price of the diesel which can be up to £1000 more.


A mag recently suggested that you now need to do an annual mileage of 20,000 for a diesel to pay for itself.


Maybe a 1.5 dci versus 1.4 petrol would be a fairer comparision?

Re: Diesel vs Petrol

Posted: Wed Aug 06, 2008 11:36 am
by andywills
several garages are starting to discourage people from buying a diesel if you are doing less than 20k a year now aswell

Re: Diesel vs Petrol

Posted: Thu Aug 07, 2008 12:13 pm
by Gav
pjsmoothie wrote:Hi, i'm new to the site, and do not own a Megane (YET!).
I am thinking of buying a 1.9 DCI or the 1.6 VVT Petrol.
I read your comparison with the 1.6 and the 1.5DCI, but would you recommend the 1.9DCI over the 1.6 petrol.
Fuel prices here are going up every month and Diesel is quite high now, looking at the stats the 1.6 petrol is only 10 miles to the gallon less then the 1.9, and there doesn't seems to be much between them in performance.
Has anyone drove both, still in two minds which one to go for , any suggestions are welcome.


In the stats the 1.9dCi is quite a bit quicker than the 1.6 petrol, as it has an extra 20bhp and almost double the torque.

The 1.4 petrol is no better on fuel than the 1.6 on the combined cycle (which I know is not what everyone achieves, but I get close, so I use that figure). Therefore matching the 1.6 petrol against the diesels makes sense:
1.5dCi 106 is down 5bhp, but up 88Nm in torque compared to the 1.6 petrol. It's 0.2s slower to 62mph and can only do 117mph rather than 119! So in the real world is as quick.
The difference in economy is significant, and should work out at today's prices at 10p/mile for diesel and 13p for petrol. Purchase price difference close to £800 means around 26,000 miles before the diesel is cheaper (excluding servicing, maintainance etc).

Therefore if you do only 5,000 miles a year, get the 1.6 petrol! The higher the mileage you'll put on the car, the more a diesel starts to make sense. If you need to save money when filling up, (a £70 spend isn't so bad when you've done over 700 miles), the 1.5dCi 106 is hard to beat. If you need performance with reasonable economy, 1.9dCi is good (and they're supposedly most efficient cruising on the motorway).

Re: Diesel vs Petrol

Posted: Sat Sep 06, 2008 8:25 pm
by gavnaysh
i dont do major miles but the 1.9 dci is averagin 40mpg just over and the torque makes it so easy to drive and overtake i wouldn't have a petrol again apart from a big petrol lol then the economy wouldn't be as good in my bmw i would use 30-35£ where i will use 20£ in meggy so its cheaper still on short journeys (i travel 11 miles each way to work in about 15-20 mins every mornin) and its 210 pound cheaper insurance!!

Re: Diesel vs Petrol

Posted: Sat Sep 06, 2008 9:09 pm
by Deano16v
I'm saving 150 a month with the meg. i dont enjoy driving it, and it isnt a good car but you cant argue with 50+ mpg

Re: Diesel vs Petrol

Posted: Wed Sep 24, 2008 12:10 pm
by MeganeChick
petrol all the way!

i had looked into a diesel for economy - looked at the renaultsport dci 175 (with cup pack ;)) knowing i could get it mapped to 200bhp and would still be a great beast to drive - however, after jumping into the 225 - the petrol stole my heart!
yes the fuel use is noticeably different - but worth every penny! :D

Re: Diesel vs Petrol

Posted: Thu Sep 25, 2008 11:45 am
by wanda
MeganeChick wrote:petrol all the way!

i had looked into a diesel for economy - looked at the renaultsport dci 175 (with cup pack ;)) knowing i could get it mapped to 200bhp and would still be a great beast to drive - however, after jumping into the 225 - the petrol stole my heart!
yes the fuel use is noticeably different - but worth every penny! :D


What about those times when you need the extra torque like when that idiot is behind you on the motorway and tries to force you out of their way..... what if its a 225 trying to bully a 175 on the motorway?

Re: Diesel vs Petrol

Posted: Thu Sep 25, 2008 2:38 pm
by MeganeChick
:eek as if a 225 would try and bully a 175 on the motorway lol! where is the renaultsport love?? lol

yeah more torque from the 175 - not yet had that experience so not sure what would happen? lol