Another mpg thread.

[t70spm]

Hi,
I think that anything over 50mpg when you are sitting at 70 mph is pretty good. Keep in mind, that the faster you are driving the greater wind resistance, thus more drag and increased fuel consumption.

I'm not sure what SEAT quote for your fuel consumption, but generally there will be 3 figures quoted, an urban cycle for around town, Optimal, which is +/- 56mph and a figure for 70mph. The combined figure they quote is for an industry standard mix of driving conditions and depending on where you drive most will depend on what you see.

I would keep a record of what mpg you get and mention this when you get the first service. The oil change at your first service should see you another few mpg.

Good luck.

 

[skiddusmarkus]

Had a search on how they come to the claimed mpg's and found this:

Europe
Irish fuel economy label.In the European Union, passenger vehicles are commonly tested using two drive cycles, and corresponding fuel economies are reported as 'urban' and 'extra-urban', in litres per 100 km and (in the UK) in miles per imperial gallon.

The urban economy is measured using the test cycle known as ECE-15, introduced by the EEC Directive 90/C81/01 in 1999. It simulates a 4,052 m (2.518 mile) urban trip at an average speed of 18.7 km/h (11.6 mph) and at a maximum speed of 50 km/h (31 mph). The extra-urban cycle or EUDC lasts 400 seconds (6 minutes 40 seconds) at an average speed 62.6 km/h (39 mph) and a top speed of 120 km/h (74.6 mph).[24] EU fuel consumption numbers tend to be considerably lower than corresponding US EPA test results for the same vehicle. For example, the 2011 Honda CR-Z with a six-speed manual transmission is rated 6.1/4.4 l/100 km in Europe and 7.6/6.4 l/100 km in the United States[citation needed].

So don't feel too bad if you cannot match their figures for extra urban, they don't seem very lifelike to me.
I'm not sure if this is tested on a track or rolling road.I'd assume a RR as then you can accurately control the enviroment.I wonder if they also simulate the wind resistance associated with the speeds the cars are doing, as this will have a pretty bi impact, especially at higher speeds.

 

[avendit]

I've come to think of 'extra urban' as busy A road driving. That is 60mph limit, but busy so doing 40-60 varied, with gentle speed changes. Motorway speeds are too fast for this and your mpg will be lower. The Leon is not an aero-dynamic shape I'm afraid.

I'm driving a chipped petrol FR (so probably have no business here!) but I still like to do as best as I can. If nothing it keeps you awake on the commute. On my 4 mile commute through Edinburgh I can hit 33mpg, bettering the official number by 5mpg! On the motorway tho I refuse to do less than the speed limit on a clear road, but do use the cruise control to keep the MPG up, and the points down. At just over 70mph I tend to be around 35-36mpg, which is way off the official 'extra urban' 49mpg.

Sometime I'll try cruising at 55-60mph, just so see if I could really get near that mpg, but I think my patience would run out first Government says going at 80* rather than 70 will use 10% more fuel. but... you will get somewhere 14% quicker! So, it depends on how you value your time (and how loud the baby is likely to scream if you aren't somewhere by his lunch time).

Just my take on these things. Sorry for the lack of advice re the ecomotive...

Avendit
* just the first set of figures I came across on google, was really looking for the 70 vs 55 comparison I had previously seen, same calc works tho!

 

[Deleted member 74601]

Cheers mate.

Yeah well on works time, when it doesn't really matter, I do 60mph. I'm getting in the high 60s average for that at the moment, so not too bad. From other people using this engine, I expect that to get a touch higher though, they've been having the in the 70s quite easily at 60mph. One guy even got 92mpg average over one journey in his octavia (he was averaging going downhill though )

I think part of the problem came that I was driving it like a traditional diesel, at low revs. I was informed by a diesel engine engineer that the common rail engines are more like petrols, and that you need to drive them halfway between the petrol and the diesel. He said especially at low revs in the city, the DPF becomes angry very quickly, and well actively regen on the motorway. If you drive at little higher revs, the regen won't do that, and then you just make sure you give it a 10 minute blast at 70mph or so once a week to clear the DPF passively. It's more to do with throttle position than speeds, so this stuff you see about driving over 40mph doesn't make any difference unless you do it at over 2000 revs.

The problem comes at 65mph, as soon as you go over that it plummets, at 70mph, it's late 40s, which for any diesel, isn't good, seeing as I could get about 43mpg at 80mph in my 1.2L PETROL Corsa.

I'm just going to get them to check it anyway, the car is under warranty and is going in for some other things (whistling noise which I think might be something to do with Turbo, a strange sound coming from front right wheel after going over bumps, and there is a lot of wind noise around the front doors, suggesting something isn't sealed/soundproofed right). So I'll probably get them to check for ECU updates, and if there is nothing, or an update doesn't improve it, I might ask them to try resetting the ECU so it can learn my proper motorway driving, as opposed to the urban crap the dealer had it doing.

Considering it's only got nearly 5000 miles on it (I've done 1,500 miles in 2 weeks!) it's not going good if you look at the above! Problem might come because it was a demo car and only did 3,500 miles in the first 2 years of it's life (so it's been sat there too). It's quite common in my job that when you buy a car that's used to city mileage, we start putting them on the motorways and they start falling apart. You get everything fixed under warranty, and it's fine till over 100,000 miles then. That's why we always buy cars with warranty left on them! So I did kinda expect to have a few problems

 

[Deleted member 74601]

Just an update for some guys who may have the 1.6CR TDI engine like me.

I've been speaking to a guy over at Briskoda, who used to be an engine tech.

He said that the CR engines really like to be run at higher revs compared to a conventional diesel, so much so he's been telling me switching gears at 2,400rpm might still be too low (usually drops me at 1,500rpm in the next gear). He had a couple of guys in the same position as me and told them to drive the car more spirited at first, and then when the engine has a few more miles on it, they can start doing economical journeys.

I've also been told to obviously have a good blast every now and then to keep the DPF clear. I asked over there on the forums for a good rpm figure, and was told more like 3.5k to 4k rpm for 10-15 minutes, once a week, just to make sure the DPF stays clear and stops regens.

Seems a bit bad to me having to be spirited with the engine for a few thousand, especially in my job where fuel economy is everything. It seems that driving them too gently to begin with is bad for the engines and barely loosens them up.

So I'm just going to take the plunge and drive a bit heavy for a few thousand miles and see how it goes.

 

[skiddusmarkus]

Well you might want to have a read on this thread, certainly throws in a different pov.Its how I ran my engine in which has used zero oil in the 1st 2500 miles since being built and has higher compresion than normal as a result.

http://www.mototuneusa.com/break_in_secrets.htm

 

[Deleted member 74601]

So you drove yours quite high on the revs for the first few thousand? And concentrated on breaking it in that way?

It seems a bit counter productive for me, in the search for better mpg for work, to drive it quite hard, but in the long run if it's better I'll try it.

I've been constantly asking people when it's best to change gear (i.e what revs), I have the ecomotive so have longer gear ranges, and have been changing around 2,500 revs, and that drops me at 1,500 revs in the new gear, I've been advised that this is still too low, and is causing DPF regens.

Does that sound right to you? as I've always been told to drive a diesel at lower revs.

 

[DerbyForget]

i dont mean to sound rude when i say this but maybe your getting a bit too caught up in all the figures??? it seems like you are forever chasing these magic numbers which will save you a couple of quid here and there at the pumps.

If you want my advice turn that display off and just enjoy driving the car will be a lot less stressful and much more rewarding... i like you find myself constantly looking at the average mpg reading etc and find that it just takes away from the driving experience. in my last car it had non of this modern technology so i didnt even consider it, i just enjoyed the sound of the engine and having the occasional blast... just some food for thought

 

[Deleted member 74601]

Yeah I understand what you're saying, but because I get private mileage from work, I can make quite a bit of money, and looking to move out etc, being 21, money is everything.

It is getting to the point where I'm getting fed up though, the way I have been driving it is economical, but it seems to be causing a lot of DPF regens, but yeah, I am just getting fed up.

Oh well, hopefully I can find it anwyay, after all it is my first diesel.

 

[coggie]

I know that if i drive casually then I get about 100 miles less per tank than driving economically....

 

[Deleted member 74601]

Aye, well I've been chatting to this engine tech guy, and looking on TDI club.

It seems as though that when the engine is young, running it at 60mph (around 1600rpm) often is not a great idea, and this, coupled with me doing the same amount of revs in the city, is probably the reason for my sometimes poor mpg. Even though it gives great MPG, cause the engine is still tight, it causes the DPF to soot up a lot quicker.

I'm going to drive it a bit harder, aiming to cruise around 2000rpm until I get the first 10k on it, just to help run the engine in, after that I'll settle down and drive it more economically, and it should be better.

I've been told that once it's run in, sitting at 1600rpm won't be anywhere near as bad for it, as the load will be significantly reduced on the engine, helping to keep the DPF clear) so I can start running more often around those figures, and just giving it a good blast once a week on the motorway will help keep the DPF clear.

So basically I'm gonna have some fun with it until about 11k miles on it, then start aiming to drive a bit more economically. Even driving in a more fun style, I'll have better MPG than a diesel.

 

[skiddusmarkus]

So you drove yours quite high on the revs for the first few thousand? And concentrated on breaking it in that way?

It seems a bit counter productive for me, in the search for better mpg for work, to drive it quite hard, but in the long run if it's better I'll try it.

I've been constantly asking people when it's best to change gear (i.e what revs), I have the ecomotive so have longer gear ranges, and have been changing around 2,500 revs, and that drops me at 1,500 revs in the new gear, I've been advised that this is still too low, and is causing DPF regens.

Does that sound right to you? as I've always been told to drive a diesel at lower revs.

Well that guide is more for brand new engines that are being started for the 1st time.Its to do with getting the car boosting and forcing the rings to bed into the cylinders well.Most people would say to granny it for the 1st few thousand miles.This says do the opposite.

 

[Deleted member 74601]

Well that guide is more for brand new engines that are being started for the 1st time.Its to do with getting the car boosting and forcing the rings to bed into the cylinders well.Most people would say to granny it for the 1st few thousand miles.This says do the opposite.

Yeah from what I've been reading, I'm just going to drive it in my 'normal' style for the first 10k, because apparently babying the engine all the time is no good for it, and I've already had it force a couple of DPF regens.

Then once I've got 10k on the clock, I can afford to drive more economically, just giving it a good blast once a week to clear the DPF.

 

[C_ED_99]

I'm surprised no one mentioned presenting the ecu- if its an ex-demo it won't have been driven with economy in mind. At least it gives you a clean sheet to work from. Though now you have been through quite a few tanks it shouldn't matter so much...

 

[Deleted member 74601]

Yeah, Well I'll have to see. Getting the ECU looked at would be last resort sort of thing. They're probably going to look for updates when it goes in next week fro another issue.