Calling All Diesel Drivers!

So what would be the most economical diesel car out there at the moment? Trying to work out would it be cheaper to drive to Galway (from Carrick on Shannon) Monday to Friday for a full time college course or would I be better renting in Galway (don't really want to do this as have a mortgage to pay and if I rented out my property I would have to make up the difference between rent earned and mortgage owed). But I guess it all depends on overall figures!
 
Have a Citroen 1.4 Grand Picasso. careful driving gets me 1000 Km on a tank of 60 L
 
Pique318 said:
And there, boys and girls, is the perfect example of why you should'nt buy a big car with a small engine ! It has to work harder to do the same job and ends up costing more !

And Peugeots are well experienced in making diesels too...
Click to expand...

Could not agree more, before I had the 1.4 d4d , the company van was the corolla 2.0 d4d and was getting the same MPG but driving it was so much easier and better!
 
1.9 tdi Audi. Costs €85 to fill and get 700 miles out of it. Never really drive it over 100 k/h, as when I do it eats the diesel
 
1.9TDi €85 to fill. Computer says 950Km per tank.

Summer MPG higher than winter on account of using the Air Con more.

I drive mostly rural roads also. Motorway driver might be better results.

2006 Audi A4
 
Hi petrolhead.
All due respect but i do know how the figures work. Yes 65mpg is good but i wondered if anybody could better that. I did one evening in a kia cee'd sw 1.6crdi. From the N2 junction to coolock i got 188mpg. The display only went to 99mpg so i switched over to l/100k and it showed something like 1.5l/100k. Average. Hasn't been repeated again though. I wish!
It will only do that kind of thing after a hard drive and everything is heated up; engine, gearbox etc. Then i drive handy and it goes into the 3 figures in mpg. Not for long (10 mins) as the engine cools off and it just goes back to its normal 5l/100k. So how do i get the heat into a diesel engine without having to drive it like i stole it?

ollie
ps; thanks for the link to the conversion site. I'll be bookmarking that one
 
You won't get anything like 188mpg on a realistic drive. In the real world you start from cold, and stop and start in traffic and overtake.

65mpg would be excellent.
 
Like i said, it was after a fast drive and all was hot in the engine bay. The road works on the M50 had things slowed to 60kph posted speed limit (which i stick to after a 100mph court appearance a few years ago!) I averaged that mpg for 10 to 15 minutes. From cold, over a 50km drive in the 1.6 diesel i have done about 80 mpg. Hard work though.....

ollie
 
With all due respect, you did not get 188mpg...ever !

Yes the display may have said you were, but what the OBC says and what actually happened are 2 different things.

If I jump really high, for a nanosecond, I am floating/weightless. I can not however claim to be able to float.
 
I understand why you would disbelieve my claim but i have no reason to lie here about this matter. I have filled my car many times with fuel and logged the distance travelled when i re-filled. If anything, the computer is under reading by a small amount. Under gentle acceleration up to 60kph the instant consumption display was jumping around between 40 and 60mpg. As the road went up and down along the M50 northbound, the instant reading went from 80 to 200mpg. In the end i got 188mpg over 10 to 15 minutes. I got 150 mpg on the same run the next day. A workmate was with me in the car when i did both runs and he can back up my claim if needs be. I have my tyres aired up to 45psi (sidewall max 51psi) and have the lower grille blocked, apart from the intercooler opening. Now, if somebody has scientific data re: tyre pressure vs braking distance that would be great. I've been looking for two years and have had very little luck, apart from this:
And here:[broken link removed]
Have a look at the section marked:"Table III-7" and "Table III-8"
Anyway, i had to air up the tyres as they were wearing on the sidewalls when i cornered. Now they're not.
Finally, please bear in mind that i don't get this kind of mileage all the time. Definitely not if i zero the mpg display at the start of the journey. The warm up time takes a big toll on the mpg for sure. If i were to hold the speed steady at 80kph over, say, 200km then i'd get around 60 mpg; still short of the official mpg stated by kia. And before anyone chimes in with the "nobody gets the figures quoted by the manufacturer" line, i say this: My 16 year old civic is quoted as being able to do 50mpg. I routinely get better than that. My last fill got me 61.6mpg in fact.
Sorry if i'm coming across as being smart. I mean well and am here to learn. It's just that i've done the research on mpg related subjects and have slowed down my driving. My mpg has improved dramatically as a result. Not to mention not getting speeding tickets in over 8 years....Wahoo!!
 
This is my point....if you drive and get 188mpg, you are basically coasting. If I drive a 3L petrol down a hill without touching the accelerator, I'll probably get 100mpg too....it doesn't mean it's practical or realistic.
If you drive like Mother Teresa on valium, you'll get great mileage....what I don't understand is how you can scrub the sidewalls of your tyres with that kind of driving !? Does your wife absolutely cane the car when you're not looking ?

By the way...45psi is far too much....yes the tyre says max 51psi, but at 45psi in a light car like the Ceed, your tyres are useless as only the middle third of the tyre is in contact with the ground, so you're effectively running on 1.3 tyres, rather than 4...not good when it comes to grip under braking or in the wet (although if you do drive like Mother Teresa, it's probably not that important to you, but still, let some air out, down to 35psi max).

Oh, and one final thought

Michelin New Energy Saver Tyres Win Economy Drive Honours in 2007 MPG Marathon
Click to expand...
[broken link removed]

Now if a bunch of experienced MPG Marathon drivers can only get a max of 72mpg, beating the Ceed in the process, please stop trying to tell us that you can get 188mpg over a short stretch of motorway in non-standard conditions (no braking, accelerating of any note, tyres with less surface contact than a Tour de France rider etc)
 
Hi pique,
Thanks for the link about the michelin energy saver tyres. Seriously.
Now, re: your point about only being on the centre of the tread. The centre bulging out bit is a hangover from when tyres were cross ply and bulged like a good thing. Modern tyres dont do this. My tyres are certainly not standing on the centre of the tread. My civic has been on tyres at 44 psi for 3 years now and 100,000km and they are wearing perfectly. There is about 3 to 4 mm tread left on them, right across the tread. And with great grip too. If you're concerned about grip then by all means find me some test data similar to what i posted above.
The kia was at 50psi and the tread was NOT bulging as such in the middle but i experienced a LITTLE more wear on the middle than the edges so i dropped them to 44 and the wear is slowly evening out. Had i left them at 32 they would have worn out by now or ripped the sidewalls on something sharp.
Any time i go to a tyre shop i always have a look at the old tyres piled up to check the treadwear. Virtually all of them are worn bald at the edge. Now, if you go by the rules you will be told that edge/shoulder wear is indicative of UNDERINFLATION, centre wear is from OVERINFLATION. In my case with the kia, yes, 50psi was overinflation as shown by the extra wear in the centre. But 32psi was without a doubt, underinflation as the tyres were even wearing the sidewalls when cornering.
You asked me if my wife was rallying the car when i wasn't looking. Well, i often wonder that too but the tyres did that sidewall wear thing when i cornered at very reasonable speeds. In fact it felt like the tyres were going to pull off sometimes. I talked to a tyre guy about this and he said the tyres on my car have soft sidewalls for a more comfortable drive and that scrubbing the sidewalls was indeed dangerous. I said i had to bump the pressure up to 44psi before it stopped and he just nodded in approval and said that was fine once the sidewalls weren't contacting the road.
Re: my extreme mileage.
Look, it was not from a cold start. It was not a complete journey like those mpg marathon drivers. It was a part of a drive, virtually all of which was at 60kph with quiet traffic. It was 21:30 on a weekday. My foot was barely on the throttle and i was watching the instant consumption display like a hawk and coming off the throttle when the fuel consumption went up and vise versa but more or less holding 60kph. And yes i was coasting when the opportunity arose. Like the final few hundred metres to the lights at the end of the M50. They were green and i just held my speed (if you could call it that...) all the way through onto the M1 towards the tunnel. I know i got lucky and all i could do the next night was 150mpg on the same stretch of road. Again, all this was done with a hot engine that had been driven for about 40km at high revs to get this heat into the engine. If i did it cold i'd be lucky to clear 60mpg.
By the way, is there any way i could post pictures here? I'll take some pics of the tyres standing at 44 psi and you'll see that they are not on their tippy toes.
I appreciate your concern Pique but i'd hate for all this to get ugly and i hope we can keep this civil.

ollie
 

Recommended tyre pressures are just that. When cornering weight pushes to the outside of the tyre and wear will happen on the edges of the thread. That's how it's designed.

Overinflating tyres will limit the "contact area" of the tyre and road surface and can compromise handling, braking and also ride comfort. It's not a good idea.

The fuel computer reading on an old Civic is likely be erroneous. Substantially so. The guys who do these economy runs are experienced in that form of competition, and you simply cannot beat their superior skills and cars.
 
Hi RS2K,

Apologies, there is no mpg display in the civic (just about everything else though! Go on the japs!!).I included a reference to the civics tyres to back up my tyre wear claim. It is the kia that has the mpg display.
I hear what you're saying about the wear on the edges of the tread. All my tyres wear across all the tread available. Its where the wear goes up along the sidewall is the problem. There is no tread there, just writing and relatively thin rubber. That surely isn't good, for the tyre, for safety, or for mpg??

As a side note, i read somewhere that a fully loaded cee'd sw ALMOST rolled over during testing recently. I believe it was attributed to the pressure not being sufficient for being fully loaded and the placards on the pillar were updated with higher pressures for when fully loaded. I think its fair to assume they got the un-loaded pressure wrong too. Here's a link to the kia forum, which has a link to the test facility in Finland. Which is unfortunately in Finnish.....


ollie
By the way, i'm a member at www.cleanmpg.com and have learned a lot there about economical driving.
I forgot to mention that some car manuals say that the pressure on the placard is the MINIMUM recommended pressure. Also, they say to up the pressure by a few psi if going on long journeys. How many people do that? Not many, i'd say.
 
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