Diesels About To Get Expensive????
Discussion
daemon said:
neil1jnr said:
Pan Pan said:
I think it depends on how many miles you do, if you do high mileage especially on motorways, a diesel might be the better option, if you do average mileage, then a petrol engined car would be more suited.
I do between 37000 and 42000 miles a year, so fuel type can make a useful difference in costs.
I can get around 1000 miles per fill up with a Passat Bluemotion, and the convenience of being able to drive past fuel station, after fuel station, whilst travelling at the NSL in near silence, with the engine barely turning above idle RPM is worth considering. (Particularly useful when travelling abroad)
1000 miles between fill ups? Sorry I don't believe this. Unless the tank is a fair bit bigger than most cars?I do between 37000 and 42000 miles a year, so fuel type can make a useful difference in costs.
I can get around 1000 miles per fill up with a Passat Bluemotion, and the convenience of being able to drive past fuel station, after fuel station, whilst travelling at the NSL in near silence, with the engine barely turning above idle RPM is worth considering. (Particularly useful when travelling abroad)
http://green.autoblog.com/2010/10/04/passat-bluemo...
That said, I would always take MPG claims on PH with a pinch of salt as would say many people (probably most) do not know how to calculate MPG properly, (or quote their trip computer MPG at its best and multiply that by the tank size and quote that as how many miles they get to a tank
)Maybe there should be a rule that all MPG claims are supported by how they were calculated, formula used etc.
Dracoro said:
Maybe there should be a rule that all MPG claims are supported by how they were calculated, formula used etc.
I've got no problem doing that 
.Having said that, as a rough guideline, 10 miles to a litre of fuel is 45 mpg give or take. That extrapolates quite nicely, so 200 miles on 20 litres, 450 on 45 litres etc is all the same.
You then know straight away from a tank fill whether or not you're in the right ball park, so if you've done say 650 miles to 50 litres, you're in the mid to high 50's to the gallon without resorting to a calculator. That's an off-the-top-of-my-head-after-only-one-coffee-this-morning figure, not calculated, before anyone re-quotes me to 2 decimal places
.Super Slo Mo said:
Dracoro said:
Maybe there should be a rule that all MPG claims are supported by how they were calculated, formula used etc.
I've got no problem doing that .Having said that, as a rough guideline, 10 miles to a litre of fuel is 45 mpg give or take. That extrapolates quite nicely, so 200 miles on 20 litres, 450 on 45 litres etc is all the same.
You then know straight away from a tank fill whether or not you're in the right ball park, so if you've done say 650 miles to 50 litres, you're in the mid to high 50's to the gallon without resorting to a calculator. That's an off-the-top-of-my-head-after-only-one-coffee-this-morning figure, not calculated, before anyone re-quotes me to 2 decimal places
.Even with a 70 litre tank, it is possible to get quite a bit more fuel into the car in the filler pipe etc. but as noted above my figures are based on actual fuel in, compared to actual miles travelled between each visit to a fuel station.
Dracoro said:
So 65mpg * 15.5 gallons = c1000 miles, not totally unbelievable.
That said, I would always take MPG claims on PH with a pinch of salt as would say many people (probably most) do not know how to calculate MPG properly, (or quote their trip computer MPG at its best and multiply that by the tank size and quote that as how many miles they get to a tank)
Maybe there should be a rule that all MPG claims are supported by how they were calculated, formula used etc.
Its only as accurate as the speedo though!That said, I would always take MPG claims on PH with a pinch of salt as would say many people (probably most) do not know how to calculate MPG properly, (or quote their trip computer MPG at its best and multiply that by the tank size and quote that as how many miles they get to a tank
)Maybe there should be a rule that all MPG claims are supported by how they were calculated, formula used etc.
Pan Pan said:
I always fill brim to brim to make the number of visits I have to make to a fuel station as low as possible. I find the on board fuel consumption monitors to be over optimistic, so my figures are based on fuel actually put in, compared to miles actually covered between fill ups.
Even with a 70 litre tank, it is possible to get quite a bit more fuel into the car in the filler pipe etc. but as noted above my figures are based on actual fuel in, compared to actual miles travelled between each visit to a fuel station.
I do largely the same, I prefer, where possible, to not have to refuel when I'm out on the road, partly because I live in an area with one of the lowest fuel prices in the country, and the psychological effect of saving 50 pence on a tank of fuel is important Even with a 70 litre tank, it is possible to get quite a bit more fuel into the car in the filler pipe etc. but as noted above my figures are based on actual fuel in, compared to actual miles travelled between each visit to a fuel station.
.Dracoro said:
daemon said:
neil1jnr said:
Pan Pan said:
I think it depends on how many miles you do, if you do high mileage especially on motorways, a diesel might be the better option, if you do average mileage, then a petrol engined car would be more suited.
I do between 37000 and 42000 miles a year, so fuel type can make a useful difference in costs.
I can get around 1000 miles per fill up with a Passat Bluemotion, and the convenience of being able to drive past fuel station, after fuel station, whilst travelling at the NSL in near silence, with the engine barely turning above idle RPM is worth considering. (Particularly useful when travelling abroad)
1000 miles between fill ups? Sorry I don't believe this. Unless the tank is a fair bit bigger than most cars?I do between 37000 and 42000 miles a year, so fuel type can make a useful difference in costs.
I can get around 1000 miles per fill up with a Passat Bluemotion, and the convenience of being able to drive past fuel station, after fuel station, whilst travelling at the NSL in near silence, with the engine barely turning above idle RPM is worth considering. (Particularly useful when travelling abroad)
http://green.autoblog.com/2010/10/04/passat-bluemo...
That said, I would always take MPG claims on PH with a pinch of salt as would say many people (probably most) do not know how to calculate MPG properly, (or quote their trip computer MPG at its best and multiply that by the tank size and quote that as how many miles they get to a tank
)Maybe there should be a rule that all MPG claims are supported by how they were calculated, formula used etc.
I used to have a Passat Bluemotion and it was an amazing car for economy, given its size, and i would have done my calcs brim to brim and was getting around 1,000 miles per tank from it.
The golf i have now is a 1.6TDI non bluemotion, but is capable of very high MPG too, because its predominantly very long runs i do in it and relatively static 55mph sort of speeds.
daemon said:
Dracoro said:
daemon said:
neil1jnr said:
Pan Pan said:
I think it depends on how many miles you do, if you do high mileage especially on motorways, a diesel might be the better option, if you do average mileage, then a petrol engined car would be more suited.
I do between 37000 and 42000 miles a year, so fuel type can make a useful difference in costs.
I can get around 1000 miles per fill up with a Passat Bluemotion, and the convenience of being able to drive past fuel station, after fuel station, whilst travelling at the NSL in near silence, with the engine barely turning above idle RPM is worth considering. (Particularly useful when travelling abroad)
1000 miles between fill ups? Sorry I don't believe this. Unless the tank is a fair bit bigger than most cars?I do between 37000 and 42000 miles a year, so fuel type can make a useful difference in costs.
I can get around 1000 miles per fill up with a Passat Bluemotion, and the convenience of being able to drive past fuel station, after fuel station, whilst travelling at the NSL in near silence, with the engine barely turning above idle RPM is worth considering. (Particularly useful when travelling abroad)
http://green.autoblog.com/2010/10/04/passat-bluemo...
That said, I would always take MPG claims on PH with a pinch of salt as would say many people (probably most) do not know how to calculate MPG properly, (or quote their trip computer MPG at its best and multiply that by the tank size and quote that as how many miles they get to a tank
)Maybe there should be a rule that all MPG claims are supported by how they were calculated, formula used etc.
I used to have a Passat Bluemotion and it was an amazing car for economy, given its size, and i would have done my calcs brim to brim and was getting around 1,000 miles per tank from it.
The golf i have now is a 1.6TDI non bluemotion, but is capable of very high MPG too, because its predominantly very long runs i do in it and relatively static 55mph sort of speeds.
On fairly level roads the car will travel at 40mph in top with the engine at idling speed, without even touching the throttle, and at circa 35ish in 5th at idling speed. consequently the engine is virtually silent at these, and at the motorway speed limit.
Pan Pan said:
The Passat is doing around 1475 and 1500 rpm for 70mph. barely above idling speed for the engine.
On fairly level roads the car will travel at 40mph in top with the engine at idling speed, without even touching the throttle, and at circa 35ish in 5th at idling speed.
That is true, but (now referring to the second sentence) remember a diesel engine doesn't have a throttle - torque output is determined by the amount of fuel injected, so even if the engine is turning at near idle speed, the ECU will be injecting the appropriate amount fuel to maintain the required power to overcome friction and wind resistance.On fairly level roads the car will travel at 40mph in top with the engine at idling speed, without even touching the throttle, and at circa 35ish in 5th at idling speed.
The power required to maintain e.g. 40mph will be nearly identical for petrol and diesel versions of the same car (I'd guess there's more friction along the drivetrain of a petrol car if the engine is spinning faster, and gearbox bits depending on the ratio comparisons).
Using the (very) old figures for thermal efficiency of 25% for petrol and 40% for diesel, and my vague recollection that 27hp is required to maintain 70mph, the petrol car would still require the equivalent 108hp-worth of potential energy in the fuel and the diesel would need 67.5hp-worth of fuel.
Now I need to know the energy densities of petrol and diesel, but I can't be arsed.
Fastdruid said:
That is perfect DMF ruining treatment though.
Plus I don't know how you put up with the lack of any go between tickover and ~1500-1700rpm (depends on which derv). It's my biggest hate of driving a diesel car, I've not driven one yet that doesn't have it.
I can only speak for myself, but I change gear.Plus I don't know how you put up with the lack of any go between tickover and ~1500-1700rpm (depends on which derv). It's my biggest hate of driving a diesel car, I've not driven one yet that doesn't have it.
xRIEx said:
Fastdruid said:
That is perfect DMF ruining treatment though.
Plus I don't know how you put up with the lack of any go between tickover and ~1500-1700rpm (depends on which derv). It's my biggest hate of driving a diesel car, I've not driven one yet that doesn't have it.
I can only speak for myself, but I change gear.Plus I don't know how you put up with the lack of any go between tickover and ~1500-1700rpm (depends on which derv). It's my biggest hate of driving a diesel car, I've not driven one yet that doesn't have it.
(and annoying to have to change much more often than in a petrol car).Fastdruid said:
xRIEx said:
Fastdruid said:
That is perfect DMF ruining treatment though.
Plus I don't know how you put up with the lack of any go between tickover and ~1500-1700rpm (depends on which derv). It's my biggest hate of driving a diesel car, I've not driven one yet that doesn't have it.
I can only speak for myself, but I change gear.Plus I don't know how you put up with the lack of any go between tickover and ~1500-1700rpm (depends on which derv). It's my biggest hate of driving a diesel car, I've not driven one yet that doesn't have it.
(and annoying to have to change much more often than in a petrol car).Fastdruid said:
Er yes. Not much help when you're already in 1st though. (and annoying to have to change much more often than in a petrol car).
I'm not getting what you're seeing as a major problem. (and annoying to have to change much more often than in a petrol car).If tickover is say 850rpm, my turbo starts to kick in around 1300/1400 rpm, so i've 550 rpm there to move off with which is quite negligable - i certainly dont notice it anyway.
I think part of the problem is that people who drive a petrol jump into a diesel and they're driving it "wrong" for the first several days.
Also, not getting the "gear changing" thing - i've you're going from a standard start to say motorway speeds, you're going to end up in fifth gear in your petrol car, i'm going to end up in fifth gear in my diesel car, so wheres the extra changes?
Likewise, if anything i would have to change gear less often in a diesel as i'm more likely to be on the power without having to drop down.
daemon said:
Fastdruid said:
Er yes. Not much help when you're already in 1st though. (and annoying to have to change much more often than in a petrol car).
I'm not getting what you're seeing as a major problem. (and annoying to have to change much more often than in a petrol car).If tickover is say 850rpm, my turbo starts to kick in around 1300/1400 rpm, so i've 550 rpm there to move off with which is quite negligable - i certainly dont notice it anyway.
I think part of the problem is that people who drive a petrol jump into a diesel and they're driving it "wrong" for the first several days.
Also, not getting the "gear changing" thing - i've you're going from a standard start to say motorway speeds, you're going to end up in fifth gear in your petrol car, i'm going to end up in fifth gear in my diesel car, so wheres the extra changes?
Likewise, if anything i would have to change gear less often in a diesel as i'm more likely to be on the power without having to drop down.
This is really really annoying when you say pull out and for example misjudge the point at which to stop slipping the clutch and especially bad if you've had the temerity to attempt to nip into a gap. At which point the car behind then wonders wtf you pulled out like it's a GP start and then all but stopped.
Or another example so you're coming up to a roundabout, change down to 2nd or 3rd and just as you're coming up to stop it's clear, enter and "bluuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuugh....scalded cat".
But as ever having to change much more often and disliking it is "driving it wrong".
Edited by Fastdruid on Thursday 21st August 13:21
Any chance you can edit that last post so it fits on the page?
Also, my diesel isn't really like that, it pulls adequately in the lower gears from 1000 rpm, adequately enough that I'm never waiting for it to reach a certain RPM, although there are points on the rev band where it pulls harder than others. I don't know if it's something that's largely consigned to the past in older diesels but the newer stuff seems to pick up fairly well at just over tick over.
Also, my diesel isn't really like that, it pulls adequately in the lower gears from 1000 rpm, adequately enough that I'm never waiting for it to reach a certain RPM, although there are points on the rev band where it pulls harder than others. I don't know if it's something that's largely consigned to the past in older diesels but the newer stuff seems to pick up fairly well at just over tick over.
Edited by Super Slo Mo on Thursday 21st August 13:08
Fastdruid said:
Ok, so in every single petrol car I've driven if you are rolling along in 1st on tickover and put the throttle down it will accelerate. Every diesel I've driven it doesn't. Slowly oh so slowly it will lumber up to ~1500rpm and then take off like a scalded cat.
You dont have access to all the power from tickover, but you dont in a petrol car anyway?Fastdruid said:
This is really really annoying when you say pull out and for example misjudge the point at which to stop slipping the clutch and especially bad if you've had the temerity to attempt to nip into a gap. At which point the car behind then wonders wtf you pulled out like it's a GP start and then all but stopped.
Genuinely - never had that. Fastdruid said:
Or another example so you're coming up to a roundabout, change down to 2nd or 3rd and just as you're coming up to stop it's clear, enter and "bluuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuugh....scalded cat".
Then you've let the car get off its power band, by selecting the wrong gear? Same with a petrol car.Fastdruid said:
But as ever having to change much more often and disliking it is "driving wrong".
I didnt say "driving wrong", i said "driving it wrong". Clearly you believe the way you drive is the "only" way to drive, therefore if a car does not respond to that, then its s
te. Perhaps if you were to adjust your driving style to suit the car, you would get more out of it? Surely a good driver can maximise the performance of the car, not criticise the power delivery because it doesnt respond the way they're used to?
daemon said:
Its a thread about diesels and economy and how its likely to get more expensive to fuel a car.
Who mentioned speed? And why is so important if you're stuck in a 55mph drudge every day to work and back?
I've done the big engined big motors as commuting tools and frankly the novelty of pissing £500+ a month up the wall in fuel wears off quite quickly. Once went through a fill (£134.00) of fuel in four days commuting and it gets boring very quickly.
Would personally much rather have that £350 extra a month to spend on things i want to do.
Pistonheads - where not fking realising that other people have other interests matters.
I'd agree with you...provided you are in the position to own something more exciting/fast for the times when you are NOT commuting to work.Who mentioned speed? And why is so important if you're stuck in a 55mph drudge every day to work and back?
I've done the big engined big motors as commuting tools and frankly the novelty of pissing £500+ a month up the wall in fuel wears off quite quickly. Once went through a fill (£134.00) of fuel in four days commuting and it gets boring very quickly.
Would personally much rather have that £350 extra a month to spend on things i want to do.
Pistonheads - where not f
king realising that other people have other interests matters.I recently was forced into replacing my E36 328i saloon due to rust and age. I considered several alternatives, including a diesel or two, but decided to stick with BMW (cos I like RWD, I like BMWs for their general reliability and low running costs and cos I have more knowledge of them than most other vehicles) and I chose to stick with petrol (I bought an E46 330i touring)...I didn't want to add a 3rd car to my fleet (at present) due to the increased overall cost (insurance, tax, upkeep, etc) and the better fuel economy of a diesel (even an older one such as an E46 320d/330d or Jag x-type) is offset by the increased other costs.
I know my car is not very economical over the 20 miles each way to and from work, but it does everything well...it carries 5 in comfort (including one child in a child seat) along with a weekends' camping gear, it is cheap to run (other than the fuel) and easy to fix and source parts for.
I am lucky in that I have my E30 M3 fro when I want some excitement (on a racetrack), but if the whol;e family wants to come we can't fit all 5 of us in the strictly 4-seat M3.
It does get a bit tiresome spending maybe £40 per week extra on fuel compared to a more frugal car, but I remind myself that it is worth it for the other attributes it brings...
daemon said:
Fastdruid said:
Ok, so in every single petrol car I've driven if you are rolling along in 1st on tickover and put the throttle down it will accelerate. Every diesel I've driven it doesn't. Slowly oh so slowly it will lumber up to ~1500rpm and then take off like a scalded cat.
You dont have access to all the power from tickover, but you dont in a petrol car anyway?Not driven a VAG but the BMW, Ford and Nissan have all been exactly the same.
daemon said:
Fastdruid said:
Or another example so you're coming up to a roundabout, change down to 2nd or 3rd and just as you're coming up to stop it's clear, enter and "bluuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuugh....scalded cat".
Then you've let the car get off its power band, by selecting the wrong gear? Same with a petrol car.daemon said:
Fastdruid said:
But as ever having to change much more often and disliking it is "driving wrong".
I didnt say "driving wrong", i said "driving it wrong". Clearly you believe the way you drive is the "only" way to drive, therefore if a car does not respond to that, then its s
te. Perhaps if you were to adjust your driving style to suit the car, you would get more out of it? Surely a good driver can maximise the performance of the car, not criticise the power delivery because it doesnt respond the way they're used to?
So as I'm not a good driver I'm not allowed to dislike having to rev the tits off it to not pull away at a crawl and change umpteen times more often?
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