Diesel power vs Petrol and maybe auto vs manual

[glojo]

C'mon guy's and girls let's resolve this issue once and for all.

Petrol heads

We can now buy a diesel powered ML off the shelf, no chipping, nothing just a bog standard diesel.

0 - 62.5mph in 6.8 seconds.

I've read that the diesel will not give that initial acceleration, a diesel won't make it on the race track blah de blah, but what took pole at Le Man and what won the overall race?

I love the sound of a petrol V8, but is that enough to warrant buying one?

I was once a very much dyed in the wool manual gearbox petrol head, now as a non driver the jury is out so please feel free to give vent and also let's discuss the manual gearbox vs automatic?

No religion, no politics and NO handbags

Game on

Regards
John

 

[MBManInKen]

let's resolve this issue once and for all.

There I was thinking you were very much a "each to their own" kind of man .

I love the sound of a petrol V8, but is that enough to warrant buying one?

The overall smoothness and the flexibility of the engine, as well as the V8 sound have hooked me since I got my first V8. Never again a 4-cyl and certainly no diesel for me .

let's discuss the manual gearbox vs automatic?

I was one of those ignorants who used to think autos are for boring elderly types . How wrong I was!

No religion, no politics and NO handbags

How about manbags??

I wonder how quickly this question will end up in a flame war ?

I'd say: let's all pick what we like and let's not try and preach(*) to other people what we think their car should be .

(*) Not that I think for a moment you would, John, but others here I'm not so sure .

 

[BonzoDog]

Likewise one time petrol head/manual purist but now diesel auto comfort purist.

 

[kveysey]

Likewise one time petrol head/manual purist but now diesel auto comfort purist.

Sorry to say I'm the same. Seeing 45mpg keeps me from being young & reckless:bannana: . Gears? Got to be joking!

 

[BTB 500]

Interesting to compare the ML420 diesel and ML500 petrol. 0-62 and top speed are almost identical, the diesel is only around 4 mpg better on the combined rating and £1000 or so more expensive.

When diesel cost more than unleaded there'd have been little point in the 420 unless you were doing mega miles, now diesel has dropped in price it probably makes more sense if you want that level of performance?

 

[MBManInKen]

Seeing 45mpg keeps me from being young & reckless

I'm neither young nor reckless, but I'm not too bothered about fuel costs. Yes, it's nice to see that I can achieve up to 34mpg with a V8 5L, but I won't lose any sleep over my fuel expenses .

I agree that for those who seek lowest driving cost and best economy, diesels make a lot more sense than a big petrol engine, but the point is that not all of us put that requirement high on our list.

 

[kveysey]

I'm neither young nor reckless, but I'm not too bothered about fuel costs. Yes, it's nice to see that I can achieve up to 34mpg with a V8 5L, but I won't lose any sleep over my fuel expenses .

I agree that for those who seek lowest driving cost and best economy, diesels make a lot more sense than a big petrol engine, but the point is that not all of us put that requirement high on our list.

You're lucky, I do about 50 000 miles a year on a pitiful fuel allowance.
I do miss sneaking up behind people in car parks with a big car though.

 

[fredfloggle]

Well I wouldn't buy a manual box with a merc diesel , it wouldn't be right . but I have driven plenty of manual diesels and liked them -

I wouldn't have any petrol car by choice , I like the strength and (tongue in cheek) reliability of an oil burner . A good diesel on song has a lovely sound too . Just been driving a rented 1600 twin port Astra and forgot just how gutless they are - I had an old 1.7 Astra diesel years ago that was far superior , probably not so powerful but a decent level of torque without driving it like a racing car .

So for me , a diesel engine and a nice autobox (wouldn't mind a 320CDi of some description) - horses for courses without doubt - a big bubbly V8 petrol is nice , but so is keeping my hard earned in my pocket .

 

[robert.saunders]

Having moved to a 6spd manual Mondeo 2.2 diesel it's a very different beast to the 5spd auto C220 diesel I had prior.

I really miss the auto for sheer driving ease and the reasonably powerful engine of the Mondeo leaves a very short 1st gear (2nd is pretty short too)but once up to 3rd it gets better - 4th is staggering for demonstration of the decent torque and 5th into 6th are strong gears for motorway work. The Mondeo is hard to drive smoothly in town, but generally the Mondeo is the better motorway car, on a strict comparison of the 2 motors. I haven't driven many V8 engines, the last one being a Range Rover which had me grinning for days afterwards The fast depleting fuel guage I didn't care for however

 

[Godot]

I am now driving the first diesel I have owned. It gives me better m.p.g., lower VEL band (last one was £168 for my old A160auto) now £115 for my A180CDI AUTO. Fuel is now cheaper(certainly abroad)

Conclusion YES!!!!!!

 

[grober]

DIESEL AUTO and 4MATIC please.

 

[timskemp]

I've always been a petrol manual person, then petrol became expensive, and congestion became silly, so I want diesel automatic.

Given unlimited budget I'd be back to a petrol car in a flash.

 

[DieselE]

C'mon guy's and girls let's resolve this issue once and for all.

I suspect John that the "issue" will be alive as long as this forum is.

Some people swear by diesels and some swear at them. It's the same with automatics.

It was a holiday in the lake district in the late 1980s that decided me that I'd had enough of manual gearboxes and I've never bought another one. My wife on the other hand much prefers manual gearboxes which is probably why we have two cars in the family.

As I've posted before, when I bought my E320CDI it had the same posted performance as the petrol version but was £1,000 cheaper and more economic. I couldn't afford to run a petrol engined car with an engine big enough to match the mid-range acceleration of the E320CDI.

Having said that, nothing beats the sound of a petrol V8 or V12.

 

[kveysey]

Having said that, nothing beats the sound of a petrol V8 or V12.

My 220cdi ticking over must come close

 

[glojo]

C'mon guy's and girls let's resolve this issue once and for all.

That was very much my sense of humour taking charge of the keyboard

I find it amazing that we can compare the performance of a diesel against an equivalent petrol, but the fuel figures of the V8 petrol ML are still quite impressive and then we have to realise the smaller diesel engine is more expensive?

In 2004 the petrol 320 E-class was £1000 more expensive than the 320CDI equivalent, go figure?

I keep talking about the BMW duel between Jenson Button and Tiffany Dell, when Button drove the 3ltr petrol BMW and Tiff was in the 3ltr diesel. No way could Button get away and I wonder how the new twin turbo 3ltr diesel would compare?

Might have been different if they had used a more competitive F1 driver

John the cheeky

 

[kveysey]

I keep talking about the BMW duel between Jenson Button and Tiffany Dell, when Button drove the 3ltr petrol BMW and Tiff was in the 3ltr diesel. No way could Button get away and I wonder how the new twin turbo 3ltr diesel would compare?

Might have been different if they had used a more competitive F1 driver

John the cheeky

5th gear did something similar with the vauxhall astra vxr. Couldn't really pick a winner from the petrol or diesel in terms of speed.

 

[recycled]

I have said it before and i will say it again.
Normal aspirated Diesel does not stand a chance.
If you stick a turbo in as most diesels have ,then please stick one in the petrol as well , and if you do, no comparison again.
These are figures form VW non turbo diesel
output diesel 1.947 kW (64 hp) / 50 kW (68 hp) @ 4000 rpm, 125 N·m (92 lbf·ft) @ 1600-2800 rpm / 133 N·m (98 lbf·ft) @ 1800 rpm
Absolute rubbish

petrol 1.8
output 66 kW (90 hp) at 5500 rpm, 145 N·m (108 ft·lbf) at 2500 rpm in 76 kW (103 hp) at 5400 rpm, 155 N·m This is why diesels compete by fitting in turbos and then compare them with non turbo petrol cars.
so let us compare equivalent engines with turbos or with normal aspirations.
Diesels are very good and have come a long way now, but i feel the comparisons are not equivalent.
I do not want to go technical into calorific values and so on as i have already done that before.

As for lemans ,they are racing under completely different rules and that is why porsche is threatening to walk away.
Personally i think all racing cars in a particular class should all race with exactly the same rules.
Diesel cars in Lemans have smaller fuel tanks and bigger capacity engines with turbos
Petrol cars have bigger fuel tanks no turbos, or smaller capacity with turbo.
Just not a clear plain field for me.

And if you check the record books ,i do not think there are diesel cars faster than similar petrol engine cars of the same size and capacity fitted with the same no of turbos.
If there is ,please let me know and i will stand corrected.

e.g Rs6 4.2L V8 twin turbo

331 kW (450 bhp) between 5700 and 6400 rpm, 560 N·m between 1950 and 5600 rpm

4.2Lv8 tdi

240 kW (326 hp) @ 3750 rpm , 650 N·m @ 1600-3500 rpm aftermarket 272 kW (370 hp) @ 4000 rpm, 750 N·m @ 1600 rpm
I know dieselman will disagree and talk about torque figures but then i am a horsepower figure man.

As for autos or manuals, if i have a toyota i might consider an auto but i have had two merc autos and they were both unreliable,
From this forum as well, most problem gearboxes are autos so personally give me a manual.
They are cheaper, less hassle and less likely to need ECU,resetting, code fault,e.t.c
And for all those talking about resale values. why do we not all go out and buy an AMG as its resale value will be better than a normal merc.

I finish by saying every man to his taste so please do not crucify me.

 

[Dieselman]

I know dieselman will disagree and talk about torque figures but then i am a horsepower figure man.

Wasn't going to waste my time other than this comment.
An engine produces torque so it is the only relevant figure as Hp is only a theoretical figure depending on the revs at which an engine can rev to.

You have fallen into the old chestnut argument about turbo Vs n/a engines and different cubic capacity.
This is irrelevent as the energy isn't created by the cubic capacity of the engine but by the amount of fuel burned.
One simply cannot ignore the physics of thermo efficiency, how ever hard one tries.

You also say petrol engines are faster. Generally true for top speed due to revving higher whilst running lower gear ratios to act as a TORQUE multiplier, but for a given power output they always accellerate more slowly due to lack of TORQUE.

 

[recycled]

You have fallen into the old chestnut argument about turbo Vs n/a engines and different cubic capacity.
This is irrelevent as the energy isn't created by the cubic capacity of the engine but by the amount of fuel burned.

True but the amount of fuel burned is affected by the amount of air you can force into the combustion chamber i.e forced induction.
the more air you force in the bigger the explosion the more the fuel needed to create the explosion.

 

[Dieselman]

And Hey, Ho...even with all that extra cramming the diesel still burns less fuel due to....thermal efficiency...

See you just cannot escape it..