I've driven quite a few of both over the last 10 years.

I like diesels, I like the load of torque you get when accelerating and I don't mind the short power band. I like the fuel economy and the fact you can drive hard without incurring much of a penalty in fuel. I don't like the high initial cost.

I don't actually like the driving characteristics of low capacity petrol engines. The lack of torque irritates me. I only considered the petrol vRS because it did have a good wallop of torque and pulled in a diesel like way but for longer.

I worked out on paper that both cars would cost the same to run over 3 years so I picked the petrol to get the extra 30bhp and the extra thrill of revving a powerful petrol engine.

When I feel like I'm filling up a lot it does niggle in the back of my mind that I should have got a diesel but I have to remember that that extra £50 on fuel would have just been and extra £50 on loan payments for the diesel.

And I've found the economy on the TFSI to be a little better than expected, I regularly get 35-37.

But I'll probably go back to diesel next since I could have kids etc by then and will probably need to buy a 5 year old Galaxy :(

I disagree that a diesel has a narrow power band - it's petrol engines which tend to have narrow power bands right up near the redline. The diesel's rev range is small, but power (once the turbo kicks in around 2k) tends to be fairly even across the rest of the rev range.

Typically...

2-4.5 = 2.5k range (diesel)

3-7 = 4k range (petrol)

QED diesel has a narrow power band.

And that's comparing forced-induction diesel against NA petrol...shall we compare NA diesel and NA petrol?

Rob.

No, let's not eh? That would be bad.

I take your point, although they're quite similar as a percentage 55-57%.

One ace that the diesel has up its sleeve - they are very difficult to stall. You can do hill starts with no throttle at all.

It's not much of an ace admittedly, but it can make driving in traffic a little easier.

i was a total petrol head before driving a vRS 170bhp.

no im very happy with my fabia 1.9tdi. its quick off the mark, easy to drive what ever might be the conditions, and it dosnt matter how hard i try i cant get the average mpg to fall below what i could get out of a petrol car driving carefully!

BUT i do still own 2 petrol cars. 2ltr and 3.0 v6. although i really like the sound of the fab engine, the v6 is a awesome soundtrack! and when i let the 2ltr 4 pot scream its way upto the rev limiter its grand fun!

theres always going to be a petrol/diesel split. but i think most people would have a diesel to get to work and sit in traffic and a petrol car to hoon about on the weekends

and as for racing, what about the diesel le man cars???

and as for racing, what about the diesel le man cars???

Exactly. Some people put the advantage down to the length of time they can go without refuelling, but if that were the case it would be like a 'tortoise and hare' type race. As it is the Audi and Pug diesels are also setting fastest laps.

The only explanation I can think of is that Le Man cars are horsepower limited - but for a petrol and diesel putting out the same bhp the diesel is going to have loads more torque, so is it a bit unfair? (IIRC the Audi R10 had 1000 torques!)

so is it a bit unfair? (IIRC the Audi R10 had 1000 torques!)

nah not unfair, the smoke screen they put out while on full chat might have been though

F1 diesel anyone? lol

Typically...

2-4.5 = 2.5k range (diesel)

3-7 = 4k range (petrol)

QED diesel has a narrow power band.

And that's comparing forced-induction diesel against NA petrol...shall we compare NA diesel and NA petrol?

Rob.

Typically -

69% diesel

48% petrol

Expressing usable powerband as a percentage of total rev range, and using your figures. With the last NA petrol I drove that would rev to 7000, it would be more like 5 - 7 = 2k = 32%.

Still think diesels have narrow powerbands, rather than just punishing you if you're incompetent enough to drop out of them?

Expressing usable powerband as a percentage of total rev range, and using your figures.

But why would you express it as a percentage, it's meaningless!

The point is, because in absolute terms because you have a wider power band in a petrol engine, you don't have to keep changing gear so much.

Rob.

The Le Mans Pug and Audi run in a class that allows continual development, dont forget that Audi does not run in the same class as the Astons/ Porche / ferrari etc.

The figures quoted above for the ' power' bands are not correct, the diesels power is not very high complared to torque, whilst petrol is the reverse situation, so direct power / torque comparisons are pointless.

But why would you express it as a percentage, it's meaningless!

The point is, because in absolute terms because you have a wider power band in a petrol engine, you don't have to keep changing gear so much.

Rob.

But that is just wrong - at least in terms of the actual experience of driving a diesel. The only time you 'change gear so much' is when doing a 0-xxx drag, in almost all other situations you are in a high gear and have the torque available to accelerate (say 30-40, 40-60 etc) without dropping a cog. On motorways being able to go from 60-80 in 6th with no more than a gentle squeeze of the right foot is invaluable.

POWER AND TORQUE ARE THE SAME THING!!!

I think we're talking about butt dyno here - the part of the rev range where you feel you are actually accelerating at a useful rate - such as you might use in an overtaking manoeuvre. Petrol wins that argument hands down. My Octy will comfortably accelerate in 3rd from 30mph to 100mph. A comparable diesel would require 2 gearchanges to achieve the same thing, methinks.

But that is just wrong - at least in terms of the actual experience of driving a diesel. The only time you 'change gear so much' is when doing a 0-xxx drag,

Or, if you're driving along a piece of road which dictates using a relatively wide range of speed. For example, on a twisty B-road, I can use 3rd gear and then don't have to change to go from anywhere between 30mph and 70mph - this allows for more time to spent with the clutch engaged and both hands on the steering wheel.

By comparison, in a diesel every time I went between the 30-40 and 40-60 ranges I'd have to change gear.

Rob.

Just how old are you, Chris

Same age as you Val

POWER AND TORQUE ARE THE SAME THING!!!

I think we're talking about butt dyno here - the part of the rev range where you feel you are actually accelerating at a useful rate - such as you might use in an overtaking manoeuvre. Petrol wins that argument hands down. My Octy will comfortably accelerate in 3rd from 30mph to 100mph. A comparable diesel would require 2 gearchanges to achieve the same thing, methinks.

1 gear change.

My point being that you're talking about the advantage of petrol when driving fast (i.e. 70mph in 3rd) - I'm talking about everyday cruising. Apples and oranges.

And I know the Power and Torque thing wasn't aimed at me, was it?

But surely when cruising, petrol and diesel are the same as you're holding them at fixed revs and doing a constant speed? Except the petrol is generally quieter and more refined and diesel is more economical.....

Chris

Thing is, the majority of people driving diesels who think they are saving money, actually aren't.

You need to be doing serious mileage to re-coup the extra costs of both the purchase price/servicing costs and fuel price.

Personally, I do over 40k a year and even then, I'm only just making diesel worthwhile financially.

If I didn't have to do such mileage I'd never chose to drive a diesel, no genuine petrol head ever would!

kaiser have you ever driven a 1.8T? it doesn't sound like you have.

on a standard 150bhp 1.8T you have full torque from something like 1750-5200rpm and in my octavia with a 1.8T i can do hill starts in a multistorey car park9so quite steeep no problems at all using nothing but the brake pedal and the clutch pedal. hell i could easily pull away with no accelerator when towing my mates capri with 2 passengers in each car so pulling around 3.5ton with no accelerator!

my 1.8T with a bigger turbo on it pulls hard from about 3k onwards and doesn't stop till about 7k so thats quite a wide power band

But surely when cruising, petrol and diesel are the same as you're holding them at fixed revs and doing a constant speed? Except the petrol is generally quieter and more refined and diesel is more economical.....

Chris

No, I meant cruising as opposed to 'booting it' or 'pressing on' as is sometimes referred to. Plus, a diesel is at its most refined when doing motorway speeds, it's only when idling that the old 'tractor' jibes are accurate (and who gives a stuff what it sounds like at idle? My cousin had a TVR Cerbera V8 and that sounded like a bag of spanners at tickover ).

Thing is, the majority of people driving diesels who think they are saving money, actually aren't.

You need to be doing serious mileage to re-coup the extra costs of both the purchase price/servicing costs and fuel price.

Personally, I do over 40k a year and even then, I'm only just making diesel worthwhile financially.

If I didn't have to do such mileage I'd never chose to drive a diesel, no genuine petrol head ever would!

I've had the same arguement with friends before, they were on about part-x'ing their car for a diesel to save money, when you point out that exchange would cost them 2k, the fuel costs more, the servicing costs more and the fact that they would have to be doing 40k+ a year for 4 years or more simply to break even makes them think twice.

I must be the odd one out on this forum. I can make much better progress, AND have more fun in a tuned Fabia vRS than in a Tuned Octavia vRS, excluding the ring, where I slashed 40 seconds off my Fabia time in the Octy........or was that just the benefit of more track knowledge?

Bang for buck, and sheer grin factor, I havent driven anything that comes close for less than 35k.

My mate has a VXR 500 Monaro....... I'd swap for that all day long, but other than that, there are no new petrol cars that I have driven that put the same smile on my face - and at the end of the day, thats all driving is to me, fun.

yeah, a bag of platinum plated gold spanners in a pure silk bag being rattled by a foxy young lady

But why would you express it as a percentage, it's meaningless!

The point is, because in absolute terms because you have a wider power band in a petrol engine, you don't have to keep changing gear so much.

Rob.

And so is expressing width of powerband as engine revs. What controls your road speed is revs * overall gearing, and the diesel frequently matches or even betters (due to using the torque) the petrol in terms of when you can put your foot down and actually get acceleration.

POWER AND TORQUE ARE THE SAME THING!!!

I think we're talking about butt dyno here - the part of the rev range where you feel you are actually accelerating at a useful rate - such as you might use in an overtaking manoeuvre. Petrol wins that argument hands down. My Octy will comfortably accelerate in 3rd from 30mph to 100mph. A comparable diesel would require 2 gearchanges to achieve the same thing, methinks.

I can accelerate, albeit slowly at first, from 30 mph - 140+, in 6th

kaiser have you ever driven a 1.8T? it doesn't sound like you have.

on a standard 150bhp 1.8T you have full torque from something like 1750-5200rpm and in my octavia with a 1.8T i can do hill starts in a multistorey car park9so quite steeep no problems at all using nothing but the brake pedal and the clutch pedal. hell i could easily pull away with no accelerator when towing my mates capri with 2 passengers in each car so pulling around 3.5ton with no accelerator!

my 1.8T with a bigger turbo on it pulls hard from about 3k onwards and doesn't stop till about 7k so thats quite a wide power band

Nope. Would quite like to. And if petrol was cheaper I probably would be :P

The hillstart thing is from my extensive previous experience of Mini's, Astra's, Primera's, Carina's and Avensis's... None of those have/had turbos :(