Performance VS Economy
Discussion
StottyZr said:
IMO a load of tosh. I can get the combined cycle figure on my commute, 22miles about 50% motorway in rush hour. I've been getting low-mid 40's recently but I'm crusing at above a leptop when possible...
If you can get the combined cycle figures on petrol and not diesel cars, I'd suggest your driving the diesels wrong (too high revs, not shifting up at the right time etc...)
You don't tend to do much shifting on long Motorway trips with the cruise control on so its pretty hard to drive it wrong. Generally speaking on a long Motorway drive in the petrol ones I got about smack on 'Extra Urban' and in the diesel ones over the same route I got about bang on 'Combined'.If you can get the combined cycle figures on petrol and not diesel cars, I'd suggest your driving the diesels wrong (too high revs, not shifting up at the right time etc...)
You also need to read what I said - I didn't say you cannot get the 'combined' figure, I said you cannot get the 'extra urban' figure.
I think that what has happened is that it's far easier to get the diesels to perform awesomely in the EU tests - which results in inflated figures. This is fairly obvious when you look at the figures for torque convertor autos these days - often quite a lot more economical. In reality this is of course not the case, what happens is that on the EU test an Auto is allowed to select its own gears (therefore it can have a particularly efficient programme..) whereas the manual has mandated gears..
Don't get me wrong - I didn't find say the 320d was not economical - it just wasn't quite what you are led to expect.
I agree that "real" figures are usually a lot lower for mpg than the factory numbers.
My old Astra 1.9CDTi 150 was meant to be 45mpg - I usually got high 30s
My 335d is meant to be high 30s - I get low 30s.
Our Defender was a surprise - 26mpg claimed, we got 27mpg!
The VW van isn't run in yet and the mpg is improving all the time but so far it's regularly low 20s...!!
But our driving is all rural roads which does hammer any engine a fair bit.
My old Astra 1.9CDTi 150 was meant to be 45mpg - I usually got high 30s
My 335d is meant to be high 30s - I get low 30s.
Our Defender was a surprise - 26mpg claimed, we got 27mpg!
The VW van isn't run in yet and the mpg is improving all the time but so far it's regularly low 20s...!!
But our driving is all rural roads which does hammer any engine a fair bit.
Fox- said:
StottyZr said:
IMO a load of tosh. I can get the combined cycle figure on my commute, 22miles about 50% motorway in rush hour. I've been getting low-mid 40's recently but I'm crusing at above a leptop when possible...
If you can get the combined cycle figures on petrol and not diesel cars, I'd suggest your driving the diesels wrong (too high revs, not shifting up at the right time etc...)
You don't tend to do much shifting on long Motorway trips with the cruise control on so its pretty hard to drive it wrong. Generally speaking on a long Motorway drive in the petrol ones I got about smack on 'Extra Urban' and in the diesel ones over the same route I got about bang on 'Combined'.If you can get the combined cycle figures on petrol and not diesel cars, I'd suggest your driving the diesels wrong (too high revs, not shifting up at the right time etc...)
You also need to read what I said - I didn't say you cannot get the 'combined' figure, I said you cannot get the 'extra urban' figure.
I've just looked up my cars extra urban and its exactly 65.7.... My post now sounds like a lie as its just too perfect but I assure you thats what the OBC read.
And yes I have checked the accuracy of my OBC over a full tank, it was about 1mpg off calculated.
Although as I've posted before, I had use of a courtesy car (like for like except auto) for a week that only had 7,000 miles on the clock and it was noticeably worse on fuel than my car.
StottyZr said:
Although as I've posted before, I had use of a courtesy car (like for like except auto) for a week that only had 7,000 miles on the clock and it was noticeably worse on fuel than my car.
Every single one of the diesels I'm talking about have been new or nearly new. I don't think any of them had more than about 7k on the clock so perhaps that it.BMW diesels are definitely the furthest from "combined" in my experience. I struggled to get more than 40mpg in my 123d (should be 54), and the 330d.
The same is not true for their N/A petrols - i get 26-27mpg out of the z4m (doing exactly the same commute, but going faster) and it only claims 23mpg.
The 135i was supposed to be 30, and that was about 23-24.
I have decided based on empirical evidence that
- forced induction = knock at least 20% off combined
- normal aspiration = add 20% to combined
The same is not true for their N/A petrols - i get 26-27mpg out of the z4m (doing exactly the same commute, but going faster) and it only claims 23mpg.
The 135i was supposed to be 30, and that was about 23-24.
I have decided based on empirical evidence that
- forced induction = knock at least 20% off combined
- normal aspiration = add 20% to combined
Fox- said:
Every single one of the diesels I'm talking about have been new or nearly new. I don't think any of them had more than about 7k on the clock so perhaps that it.
I'd hope so.I get quite defensive on this subject
I did lots of research before buying my car and from lots of forum information I expected to average low 40's.As you can see my own experiance is quite different!
ref the A5 i have never driven one but came across a few on local roads when they first came about (also sure i saw V6 badge on them somewhere?)
anyway one was on the way to luton airport from aylesbury (back roads) with lots of corners etc and all under 60mph it seemed to be in its element and even if mine was an M3 i would of had to have been sat in the powerband after leaving every corner. where he probably was in 3rd gear i had to be in 2nd (plus side of powerful tdi engines)
one the long straights the advantage was in my hands and my car was slightly faster, this was confirmed on a new,long bypass by me when another same model A5 booted it where the bypass starts (30ish mph) up to about 80ish mine slowly walked away.
fast cars for a tdi yes, but hitting 60 in under 6 seconds im dont think so ( i would cause a storm on here if i claimed the 330ci did 60 in under 6 seconds
)
anyway one was on the way to luton airport from aylesbury (back roads) with lots of corners etc and all under 60mph it seemed to be in its element and even if mine was an M3 i would of had to have been sat in the powerband after leaving every corner. where he probably was in 3rd gear i had to be in 2nd (plus side of powerful tdi engines)
one the long straights the advantage was in my hands and my car was slightly faster, this was confirmed on a new,long bypass by me when another same model A5 booted it where the bypass starts (30ish mph) up to about 80ish mine slowly walked away.
fast cars for a tdi yes, but hitting 60 in under 6 seconds im dont think so ( i would cause a storm on here if i claimed the 330ci did 60 in under 6 seconds
)bigsillyV10 said:
Is it possible to have a car that delivers the best of these 2 worlds?
A bit like the old, cook in the kitchen/w
e in the bedroom quote from Jerry Hall.
I had a 525d touring that was great had a nice punch but good fuel as well.
In these days of stupid fuel costs surely its prudent to look at something that offers more smiles per miles (sorry soo bad)
Something like the BMW 123d Coupe gets a great review, 50-60mpg and twin turbo motor.
Needs to be able to fit 4 adults, return 40+ combined and go like stink when you want it to.
Suggestions?
Thing is, you've moved the goal posts a bit in your op compared to your thread title.A bit like the old, cook in the kitchen/w
e in the bedroom quote from Jerry Hall. I had a 525d touring that was great had a nice punch but good fuel as well.
In these days of stupid fuel costs surely its prudent to look at something that offers more smiles per miles (sorry soo bad)
Something like the BMW 123d Coupe gets a great review, 50-60mpg and twin turbo motor.
Needs to be able to fit 4 adults, return 40+ combined and go like stink when you want it to.
Suggestions?
Economy is largely going to come down to weight, although engine type/design will have a huge affect too.
Performance is going to come down to power to weight ratio. Evidently this will be easier with a lighter car.
But the thing is, you've said 4 adults. Ok, so how often and for how far?
But importantly what other factors are important to you? e.g.
-cost
-age
-gadgets
-comfort
-nvh
-image
-spec
-luxury
-boot space
-drive type
-custom or modified vehicle vs standard production
In short to get performance AND economy you need lightweight with a fuel efficient engine giving good power to weight.
Trouble is, most modern cars are heavy, so you might need to look at older cars with engine swaps. Also modern luxuries, comfort items and safety features all add weight. So to attain lightweight you'll have to forgo most of them too.
e.g.
A Rover 100 with a 175hp modified VVC 1.8 engine.
700-800kg
will seat 4
power to weight ratio of around 220-250bhp/tonne
VED £210/year
MPG 40-50mpg on 95 RON
Or
Rover P6 with a 2.7 TDCi 260hp Jag diesel V6 in.
50-60mpg I'd have though
Fairly rapid
Good residuals
4 seats
VED £210/year
rich85uk said:
ref the A5 i have never driven one but came across a few on local roads when they first came about (also sure i saw V6 badge on them somewhere?)
anyway one was on the way to luton airport from aylesbury (back roads) with lots of corners etc and all under 60mph it seemed to be in its element and even if mine was an M3 i would of had to have been sat in the powerband after leaving every corner. where he probably was in 3rd gear i had to be in 2nd (plus side of powerful tdi engines)
one the long straights the advantage was in my hands and my car was slightly faster, this was confirmed on a new,long bypass by me when another same model A5 booted it where the bypass starts (30ish mph) up to about 80ish mine slowly walked away.
fast cars for a tdi yes, but hitting 60 in under 6 seconds im dont think so ( i would cause a storm on here if i claimed the 330ci did 60 in under 6 seconds)
Those A5 tdi quattros weigh 1.8 tonnes according to the Autocar test weight - that's going to blunt the performance.anyway one was on the way to luton airport from aylesbury (back roads) with lots of corners etc and all under 60mph it seemed to be in its element and even if mine was an M3 i would of had to have been sat in the powerband after leaving every corner. where he probably was in 3rd gear i had to be in 2nd (plus side of powerful tdi engines)
one the long straights the advantage was in my hands and my car was slightly faster, this was confirmed on a new,long bypass by me when another same model A5 booted it where the bypass starts (30ish mph) up to about 80ish mine slowly walked away.
fast cars for a tdi yes, but hitting 60 in under 6 seconds im dont think so ( i would cause a storm on here if i claimed the 330ci did 60 in under 6 seconds
)As for the 330ci, if you believe the Racelogic V-box timings, EVO achieved under 6 with their early red E46 model
kambites said:
pilchardthecat said:
- normal aspiration = add 20% to combined
I agree with the general comment, but do you really manage to average 20% over the combined figure on a modern N/A car? I take it you do almost exclusively long journeys? If i'm just commuting and don't take any detours i usually average 27-28. This is a mixture of A roads being stuck in long lines of 50mph traffic, red-line overtaking in 2nd, 3rd. Entering dual carriageways and flooring it. Commute is about 30 miles each way.
Weekly average drops to about 25 if i go out and do sport after work (this involves a 25 mile return trip late at night down a twisty b road and i probably get 19-20 on that trip).
As i said i did the exact same commute/etc in both a 330d and a 123d and got nowhere near the M, despite going much slower in the diesels. Maybe my style of driving is at fault?
Not again.
The official fuel consumption figures are there for comparisons, not for indication as to how much fuel you will use in the real world.
The real world has hills, poor roads, cats jumping across the road, satnavs to distract, lanes to change, spare crap in the boot and so on and so on.
The official fuel consumption figures are there for comparisons, not for indication as to how much fuel you will use in the real world.
The real world has hills, poor roads, cats jumping across the road, satnavs to distract, lanes to change, spare crap in the boot and so on and so on.
pilchardthecat said:
Over 22,000 miles in the z4m, averaged 25.9.
If i'm just commuting and don't take any detours i usually average 27-28. This is a mixture of A roads being stuck in long lines of 50mph traffic, red-line overtaking in 2nd, 3rd. Entering dual carriageways and flooring it. Commute is about 30 miles each way.
Weekly average drops to about 25 if i go out and do sport after work (this involves a 25 mile return trip late at night down a twisty b road and i probably get 19-20 on that trip).
Ah OK, that explains the high figures then. Your driving is essentially 100% "extra-urban". If i'm just commuting and don't take any detours i usually average 27-28. This is a mixture of A roads being stuck in long lines of 50mph traffic, red-line overtaking in 2nd, 3rd. Entering dual carriageways and flooring it. Commute is about 30 miles each way.
Weekly average drops to about 25 if i go out and do sport after work (this involves a 25 mile return trip late at night down a twisty b road and i probably get 19-20 on that trip).
pilchardthecat said:
kambites said:
Ah OK, that explains the high figures then. Your driving is essentially 100% "extra-urban".
How come i got 40mpg in the 123d then? if it's "extra urban" i should be getting 64mpg!For my typical driving (which is much shorter trips than yours) I tend to find I average about 20% below the official combined figure for turbocharged engines and maybe 5% below it for N/A ones.
Edited by kambites on Thursday 15th March 13:42
calibrax said:
Simple. Look for a performance car you like, and then LPG it.
^^^ This.Just bought a Mazda6 Sport for my wife (might not sound that sporty but compared to her X Type diesel, it's a ferrari) it is newer, has done half the miles, much better spec and including the LPG conversion cost the same amount.
It will also be cheaper to run.
A site visit this morning meant a trip over Woodhead to Sheffield, result of which has to be one of my favourite drives yet! Clear run on the way over and an even clearer run on the way back including taking a detour off Woodhead down a lesser known, tight country lane which brings you out back in Glossop. Anyway back to the car, a RenaultSport Megane 175DCi, 99% of the time it is a stupid peice of French toss that I could quite happily set fire to (read, rattle galore!) anyway this morning that all went out of the window and it was just "right"!
However having said that what was the main thing missing from that drive.......noise! No matter how good a drive it was if I had had a supercharger whine coming from under the bonnet or a V8 etc etc then it would have made it THE best drive ever but no matter how good any modern day diesel is at handling, performance or economy the petrol head in me always wants some kind of noise!
When I set out this morning the MPG was around 44, it's only dropped to 42 when I got back to the office, and its taken a hell of a good thrashing over approx 50 miles today!
However having said that what was the main thing missing from that drive.......noise! No matter how good a drive it was if I had had a supercharger whine coming from under the bonnet or a V8 etc etc then it would have made it THE best drive ever but no matter how good any modern day diesel is at handling, performance or economy the petrol head in me always wants some kind of noise!
When I set out this morning the MPG was around 44, it's only dropped to 42 when I got back to the office, and its taken a hell of a good thrashing over approx 50 miles today!
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