VRS TDI CR low mpg - Problem?

[Jim1556]

Hi all,

I've had my VRS TDI CR hatch from brand new (6 miles) since January, now gone just over 9200 miles and I'm not entirely happy with the mpg.

I've still got all my diesel receipts and log the miles on fill ups, most of my journeys are a weekly commute 80% motorway at 80mph with cruise control on, 20% A roads. The rest is a little local stuff but no short journeys.

I used to have a 2001 Octy 1.9 TDI estate which doing the same driving (took longer to get up to speed) got me 53-55mpg.

I expected a slight drop but my new commuter (brilliant at everything else) is only managing about 45-47mpg (c8%), I would have thought after bedding in a little this would have improved but has remained fairly static.

I only ever use Shell Fuelsave, it had an oil change at 4500miles to remove any running in debris, tyres are Contis around 35psi IAW manual.

Anyone else doing similar commutes getting any different?

[Guest Tim31]

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Edited 18 May, 2012 by Tim31

[Jim1556]

I know what you mean, my E36 328i does between 12-30 depending on how much fun I'm having.

But, 9244 miles in less than 4 months = circa 30,000 miles a year! Low mpg can mean there's an underlying problem, I'm just curious, that's all...

[xreyuk]

I had problems with my 1.6CR in my Leon, and am in the middle of testing, but I've been sidelined due to a hip operation. Problems in teh 1.6TDI seem well documented.

The first thing to check is maybe your driving style, the CR has to be driven differently to the PD engine, and likes to be driven at higher revs.

[jrw]

Its the short journies that kill it but that sounds about right for the mileage. I'm coming up to 30k now and doing 65-70mph on my 20mile commute each way to work i can see 55-60mpg. My average for the last couple of tanks is 50mpg (using fuelly). I do 40miles each day to work then just pottering about on a weekend. This really sees the mpg dive as unless you are doing more than 10miles, the engine on these just doesn't get warm.

Cruise control also tends to use more fuel as it can't anticipate the road ahead. Try driving without the cc on and try 5mph slower and see how you get on.

I too came from a 1.9pd 130 and you have to drive it differently and took me a while to get used to. When accelerating you have to let the revs go higher (I have a DSG though) to get the best out of it.

Edited 9 May, 2012 by jrw

[Kiwibacon]

For a lot of 80mph I'd think 45-47mpg is about right. Try driving slower and see if the numbers improve.

[Jim1556]

Hmmm, I like to bang up through the gears and into 6th as quick as possible (worked in my old Skud), I'll try not to for my next few tanks...

[xreyuk]

Hmmm, I like to bang up through the gears and into 6th as quick as possible (worked in my old Skud), I'll try not to for my next few tanks...

Yeah, it won't like that. Especially the DPF.

I usually try to drive around 1500-1700RPM (because that's where my engine is most effficient), or 2,000 revs if the next gear up is no good, but I am in a Seat Leon Ecomotive remember. I CANNOT use 5th gear until 60mph. I won't usually switch gear until about 2,400RPM. The only time I"ll switch earlier is if the cruise RPM is above 2,000.

Part of your problem may have been forcing your DPF into regens, because they do not like too light a throttle position.

Edited 9 May, 2012 by xreyuk

[vRS Bob]

My vRS CR has now clocked up 56k and the consumption throughout that has been pretty much consistent at around 45mpg, mostly motorway driving. Much of the higher fuel consumption is down to the wider lower profile tyres on the vRS. When I put 16" wheels on with narrower higher profile winter tyres I was immediately getting 54 mpg average. Took them off this Spring, back down to mid 40s.

[LeeHarrison]

Pretty much ditto to jrw. My vRS is only a couple of weeks old and I'm getting low 40's at the moment. I know this will go up a bit once the engine has loosened up but I'm not too bothered as the Octy is a cracking car. Daily commute in to work is about 40 miles pretty much crawling all the way but the drive back is mainly motorway. I have found though that if you hover just above 70 the consumption does seem to improve.

As also mentioned, with the CR you do need to hold out on the gear changes, although I have got the joys of the lazy mans gearbox!

Give it another 5k with a slightly different driving style and see how it gets on, but most importantly, enjoy the car

[Kiwibacon]

My vRS CR has now clocked up 56k and the consumption throughout that has been pretty much consistent at around 45mpg, mostly motorway driving. Much of the higher fuel consumption is down to the wider lower profile tyres on the vRS. When I put 16" wheels on with narrower higher profile winter tyres I was immediately getting 54 mpg average. Took them off this Spring, back down to mid 40s.

For the great unwashed, can you share which size each of those tyres are?

[jrw]

For the great unwashed, can you share which size each of those tyres are?

225 40 18 and 205 55 16

[Chrispy]

That MPG sounds pretty normal to me. Mapped / unmapped, made no real difference to me. I'm getting mid to late 40's depending on how I drive and 500 miles from a tank is normal. I have found that tyre pressures and good servicing are key, and I mean changing air filters etc here. A lube change (mine's on fixed so ever 10k) didn't make that much difference but I've just had all the other filters done in my 40k service (i asked for it) and that made a big difference. Went from 130 miles to the first quarter of a tank to about 160/ 170 with the same driving style and conditions.

The 170 CR is not that economical to be honest, compared to the likes of BMW's 2.0d, which are just a little bit more clattery. Regens don't help either - that GOBBLES fuel when it does that on mine. :(

[Jim1556]

Some good tips/observations so far... Thanks!

How do you know when it's doing a regen? I've noticed the fans come on when I've driven to the petrol station before continuing the journey - I assumed that was it, but I don't get any dash indications...?

[jrw]

Some good tips/observations so far... Thanks!

How do you know when it's doing a regen? I've noticed the fans come on when I've driven to the petrol station before continuing the journey - I assumed that was it, but I don't get any dash indications...?

Yeah thats pretty much it. You only get a light if it fails the 'passive' regen a number of times as you describe above.

I have never had a light on mine and only had the fans on a couple of times. You may also notice a slightly higher and lumpy idle whilst this is going on.

[silver1011]

Part of your problem may have been forcing your DPF into regens, because they do not like too light a throttle position.

I don't think the throttle position has anything to with with it?

A steady and prolonged cruise can be acheived with a light throttle. A heavy right foot will just produce more soot.

As long as you meet the minimum speed, rpm and time criteria then everything will be in place for the DPF to regen.

[dubbers]

I've had my VRS TDI CR hatch from brand new (6 miles) since January, now gone just over 9200 miles and I'm not entirely happy with the mpg.

I got my vRS exactly same time and condition as you. As you can see from my fuelly tag Im getting an accurate 46mpg from my daily commute and longer regular trips to see family. Fuel wise I have been using Tesco, Sainsbury's and currently using Esso which seems better but could be that the ambient temp has risen.

I've played with tyre pressures and now +0.2bar on front and rear which made a very small difference. - I dont think the Continental SC2 are particularly good for economy or handling (I'll switch to Michelin Pilot Sports as soon as the fronts

have expired)

My own opinion is that the car is geared exactly for the european market, ie travel at 110kph and 130 kph seems provide balance between economy and progress. I've not yet found the torque sweet spot which was very apparent on the PD130 MkIV Golf I ran some years ago.

[ChrisRs]

Im not anal on MPG just enjoy your car. Or get a push bike no fuel then

...and the point of this post was?

If youre not interested in helping...Just dont bother posting :think:

[xreyuk]

I don't think the throttle position has anything to with with it?

A steady and prolonged cruise can be acheived with a light throttle. A heavy right foot will just produce more soot.

As long as you meet the minimum speed, rpm and time criteria then everything will be in place for the DPF to regen.

EstateMan explains it better in the big thread in the Fabia II forums.

[Kiwibacon]

High engine load can heat the DPF enough to regenerate itself. But it has to be under high load for long enough.

[Davidsr20]

My pd Vrs does 825km to a tank so whatever that is in miles. And that's combined driving.

[Jim1556]

Hmmm, at 80mph it's in 6th doing about 2.4k rpm - enough to not need a regen? I've only heard it a couple of times.

500miles = 800km (ish) so around 515miles to a tank - I'm getting between 500 + 580 (not necessarily empty)...

[gsp]

Getting 48-50 on mine currently. Now at around 14k doing a 35mile each way commute, 90% motorway, 70-80mph. My fuelly is showing a little higher at the moment as I only took the winter wheels off a month ago, 16" wheels gains me 3+ mpg, probably mainly due to the lighter weight (you notice the difference in weight when you swap them over, quite noticeable when trying to lift them!) However, I do notice a sharp drop off if I start doing more local driving, the more powerful diesels aren't as efficient as they could be for non-motorway stuff.

So maybe 45-47 is about right for 80/20% mway/A roads.

[Kiwibacon]

Are the VRS lower geared than other octavias?

[FUBAR]

All of the advice above seems to cover everything I would do to help MPG when I am in that mood. I would think the changing gears may well indeed be a little early regardless of which gear you are in the bigger idea is not the rpm but how far in you have to press the accelerator to maintain the speed or rate of acceleration, having to push pedal in most of the way in 6th having changed up too early will use more fuel than if you left it in 4th or 5th and used the feather light touch on the pedal. If I sit at that sort of speed on cruise control in mine I get the same MPG as you but if I turn it off and drop 5-10mph I can get it 58mpg+ average had mine from 6 miles too and now on 6500miles.Unfortunately as well having come from a 1.9TDI PD it took a bit of playing to work out how to drive it for its best mpg but its not as easy as it was in the 1.9 for my anyway :( I miss 65mpg on demand. So if you fancy playing with the driving style a little if I were you I would kill 5mph better again 10mph and loose cruise control and then focus on using as little pressure on the pedal as possible to maintain the speed you are doing.