Diesil Vs Petrol

[Gazza1]

Hi All,

My 2.2DTI Vectra has got to go, too many faults to list. But I am struggling to decide on its replacement, bye bye Vauxhall though. Looking at second hand Mondeo's (especially the price tag) and also really like the Avensis (bit pricey though)around 05/06.

I have towed with both Diesel and Petrol and I must admit it seems you dont have to thrash a diesel as much as you do a petrol when towing (1298KG van)? Is it really worth paying the extra money buying a diesel over its petrol equivalent, especially since I am only doing around 10K a year?

Your advice on both the fuels and the cars would be very much appreciated.

Thanks

Gazza

 

[rob_jax]

Hi Gazza,

About 10,000 miles a year - and Diesel or Petrol?

A diesel engined car is at least 25% and up to 33% more efficient than an equivalent petrol unit:

So taking a generic mid-sized saloon (Mondeo equivalent), the petrol engine will use a bit over 1300 litres of petrol whilst the diesel will use a bit under 900 litres - depending on how you drive, etc., - so expect to save over

 

[JeremyClarksson]

Hi Gazza,

About 10,000 miles a year - and Diesel or Petrol?

A diesel engined car is at least 25% and up to 33% more efficient than an equivalent petrol unit:

So taking a generic mid-sized saloon (Mondeo equivalent), the petrol engine will use a bit over 1300 litres of petrol whilst the diesel will use a bit under 900 litres - depending on how you drive, etc., - so expect to save over

 

[mcghee]

Whilst what you say is true Rob, peak torque is not the whole story.Peak torque at 2000rpm is not a lot of use if the torque curve drops right off at 2100rpm.

Many petrol engines, while producing peak torque at 4000rpm, produce over 90% of that from 1500-6000rpm.

Similarly, turbos are fantastic but can be all or nothing, and can heat up alarmingly in high air temperatures.

I don't belive there is a definitive answer to the diesel v petrol argument. To be fair, if the choice was Mondeo petrol or diesel I'd take the diesel as I don't really rate the petrol Mondeo, but that's only one example.

 

[Lutz]

I think it is out of the question, however, that diesels generally have a flatter torque curve than petrol engines.

 

[Icemaker]

personally i would never buy another petrol again even if i give up towing, diesels are so much more relaxed and better to drive.

Depending on the car the difference in fuel can be huge, if you take my car as an example the petrol alhambra returns about 23 mpg my diesel returns 47 mpg round town and up to 55 mpg recorded on a run towing it does about 35 mpg with the coachman vip 530 on the back at 1500 kgs, i recon the petrol would do about 14 mpg with the van.

The mondeo diesel makes a very good tow car but im not too sure of the avensis, i have read some quite negative comments on the car regarding its towing ability. maybee some body on here has one and can comment further.

 

[Gazza1]

Thanks for your input guys.

Lutz, I guess a flatter torque curve is a good thing, more torque available at lower revs?!?!

Think its gunna be another Diesel and the Mondeo does seem to get the thumbs up in all the write ups and in this forum.

Thanks again

Gazza

 

[Sterlingstuff]

Hi

I tow a 2006 Sterling Eccles Emerald (1400kg) with a 2006 Honda Accord 2.4 litre Petrol and its great 2700 miles to Italy and back average 25mpg Towing 34mpg Solo without trying and then i unhitch I haven't got a vehicle that drives like a lorry to put up with. Over taken many a diesel up a hill then the turbo runs out of puff

 

[martin_5099952]

I drive an Avensis daily as a company car, although as a company car i am not allowed to tow with it, driving under normal conditions with just myself in the car is ok but load it up with a few colleagues and the car really struggles and becomes quite gutless with lacklustre takeoff and a nightmare on hills. I would not consider towing with the one i have for work but maybe there are different diesel engines i know they do a few variants in the mondeo ranging up to 130bhp.

This has probably been no help at all lol, but just my experience with a toyota.

Good hunting, Martin.

 

[Icemaker]

Why would a diesel engine make the car drive like a lorry ?. the vehicles are generally exactely the same as thiere petrol equivelants appart from the engine.

Do you not think that the cars you have "overtaken" may not have been in such a hurry or may not have been screwing the arse of the vehicle just to prove a point after all the honda v-tec although a good engine is known to have to be reved very hard to get max performance out of it which is not ideal for towing or fuel economy.

It really is ridiculous to comment that a car would drive like a lorry becouse of its engine and just shows that the writer has views at least ten years out of date and probably will spend the rest of his / hers life cutting off there nose to spite there face.

Sorry to others for my rant but it really annoys me when people post comments with such silly remarks and about topics they so obviousley no little about.

 

[Meister]

I have to agree with Icemaker.

I have a Seat Toledo 2.0Tdi DSG and believe me it drives NOTHING like a lorry.

Steve

 

[Angus1]

I agree entirely Icemaker.

Living on the Pennines I regularly use the M62, and when baulked by a slower vehicle on an incline (usually J21 - J22) the ability to accelerate from 50mph to over 100mph (in theory, of course!) up the hill to the highest motorway summit in England in 6th whilst the petrol cars are still dropping a cog or two to regain momentum makes driving so much easier.

I have driven Honda Accord petrols, and they are stunningly smooth engines, but also gutless unless you cane them. Which is why it`s pretty universally accepted the best Accord is the diesel.

 

[Val & Frank]

Hi Gary,

I use a diesel Toyota and like Angus it will go at 100 +. I have never run out of revs on any incline, and that's with towing a 1850kg van. OK at a 100mph you know you have the van on the back back because the revs get up to the 4000 mark, but it's still not like a lorry.

Val & Frank

 

[JeremyClarksson]

Many moons ago I remember astonishing a friend in an XR3i by pulling past him at a rate of knots once we got to an incline (M5N from Avonmouth) holding above 100mph while he was losing speed fast.

(I know - but I was young then!).

Even though he could easily out accelerate and go faster than my car once you hit a hill the diesel torque would win out easily .

My car at the time - a bog standard non-turbo Citroen BX19RD and there is no question that, in the time since, advances in diesel technology have outpaced those in the petrol engine.

Anyone who has not tried towing with a modern diesel really should give it a go.

If I remember right on Top Gear a while back one of the german barges (BMW 535 or similar?) was actually far quicker in acceleration and speed in diesel form than in petrol.

 

[JeremyClarksson]

Found it -

http://www.youtube.com/watch?v=NH3FWW2-jLs

 

[rob_jax]

In response to mcghee's comments about peak torque - that's not a term I would use to describe a modern diesel engine - but certainly is a term to describe a petrol engined car.

For instance - the torque profile of my car is totally flat from 1400 rpm to 3000 rpm - whereas the petrol equivalent has a definite peak between 3500 and 4000 rpm - and the petrol peak is half the height of the diesel plateau.

Which one is better to drive solo? The diesel.

Which one is better to tow with? Definitely the diesel.

In response to points raised by others - there is a known issue with the Toyota Avensis having an overall too-high gearing and making them appear slow - the Sport versions have a more normal gearing and performance.

Robert

 

[David_374301039]

Frank has got to be joking when he say's he tows at 100mph!!!!

As regards to a Mondeo for towing, I have had one, a 2 litre TDCi and it was great. Thoroughly reccomended.

David

 

[Garfield]

Modern turbo diesels are almost as quiet as petrols when solo but they are quieter when towing as the petrol will be screaming away to produce the necessary power. At 2000 rpm a 2.0 turbo diesel is producing over 80% more power than a 2.0 petrol, @4000rpm the diesel is still 32% ahead of the petrol, some turbo deisels do die after 2000 rpm but the 140hp 2.0 tdci engine is still producing 75% of it's peak torque at 4000 rpm, petrols do have a flatter torque curve but FLAT is the operative term!