GTD vs GTI vs R urban MPG (from cold)

[Sootchucker]

So it would seem from this admittedly very small poll, that a GTD from a cold start is typically getting high thirties / low fourties, and a GTI low to mid thirties. Not a lot in it is there. Just goes to show you what we all knew, that the diesel advantage only really comes to fore when a) the car is completely warmed up (mine can achieve easily 45mpg under the same conditions when warmed first) and b) or when doing lots of motorway / a-road cruising.

Oh and hats off to Watts for going above and beyond for this little test (even if he did get his kippers  )

I certainly think the days of diesels are numbered. My wife's Polo Blue GT with 150ps and the innovative cylinder deactivation tech matches mine in the urban cycle and is only 4-5 mpg down on mine on a good run.

I can imagine the days of a car with GTI performance, with similar cylinder deactivation tech along with some sort of light weight hybrid technology aren't far away and we'll then probably be able to have our cake and eat it - 150+mph, sub 6.5 sec 0-62 and 50-60mpg seems doable in the next few years ?

[rwleigh]

11 mile commute of town for 2 miles then 50/60 most of the way then the last 2 miles through a village and onto an industrial estate. My Clubsport has only just done 900 miles and it gets about 32/33 mpg on that run from a cold frosty start.

[Exonian]

I've always kept an eye on the MPG readouts but generally go more by the miles per tank as it's easier over the longer term.

Bearing in mind my driving has hardly changed in years with much the same routes until fairly recently when my likely mileage was going to quadruple or more with a change of job role which I've so far neatly ducked and have stayed office based (and seen my actual mileage go down to such a degree I really barely even need a car of my own).

Going by my old and fairly steady averages which didn't change much for years my mk7 GTI PP did between 320 worst and 370 best for a tankful and my R did 260 worst and 320 best. Bear in mind the R has, I think, a bigger tank and runs on dearer fuel.
No big deal for me doing sub 5k PA but painful if you were doing above average miles I'd think.

That's not driving like Lewis Hamilton either, my commute is around 5 miles with little traffic in general all in 30mph limits, 6 roundabouts I think and 11 sets of traffic lights. Aside from that the bulk of the mileage will be once a year to an airport and a couple times a year longer distance on a 'touring' type holiday visiting family. Weekly standard mileage will have been generally one trip of around 20 miles in mostly 40mph semi rural roads that would bump the fuel consumption up to a reasonable figure and a weekly blast in the early hours on some very winding and hilly dual carriageway, again with speeds kept in check thanks to the proliferation of nocturnal wildlife that likes to wander across the road in front of you. The fox and badger near misses are scary enough but the deer are much worse and the gypsy horse that had wandered into the road in the pitch black plus added atmosphehric mist one night really turned my hair instantly grey. If it hadn't been for me really keeping my speed down due to the mist i'd possibly be sat on a cloud now playing a harp.

I can't comment on a GTD but the family hack Cooper D has a 35 litre tank and seems to do around 350 miles to a tank so it's reasonably easy to work that one out. That one does 90% town driving in reasonably heavy traffic too. Weather conditions don't seem to affect it massively.

All cars were run with air-con left on to preserve the seals in the system as ordered by the instruction manual.
All manual transmissions.

And for reference going back even further which had an even shorter commute as I used to live 2 miles from work:

Golf mk6 GTIs x2 did between 290 and 350 miles to a tank worst to best. Touring mileage with added remap improved the mpg significantly due to the extra torque and lower revs needed to make progress.

mk5 GTI was broadly similar to the mk7 R funnily enough.

Oh, and I've never eaten a kipper. Am I missing much?
I don't really do seafood, I think it stems from when I was a kid I'd always be the one with a bit of bone in my fish. I'd be merrily chomping away then the next second I'd be doing Homer Simpson like gagging noises whilst trying to remove a fragment of fish bone from the back of my mouth. Fair play I guess, you can't blame the fish for trying to get its own back on the person that had it murdered...

[Watts]

Oh and hats off to Watts for going above and beyond for this little test (even if he did get his kippers  )

More than welcome, any excuse to go for a drive

Oh, and I've never eaten a kipper. Am I missing much?

Kippers are lovely and juicy, mmmmmmmmmm. A bit boney but they go down fine. Very tasty, extremely nutritious (apparently the rise in cardio vascular disease was inversely proportional to the drop in kipper consumption) and the smell lingers in the house from lunchtime past when my OH gets home from work which she hates. So, win win

[corgi]

My test for my GTD this weekend was the boys road trip to the Alps to watch the Andros Trophy... 1520 miles at an average of 44.66 mpg temperatures below freezing pretty much all the time in France (-16C both nights in the Alps). Car fully loaded.

At UK speed limit average > 50 mpg (more like 52-53) at French limit more like 42-43 (especially when my mate forgets it has 6 gears... "Its so quiet!" he says 

The mpg for the first 10 miles or so at those temperatures in the mountains was mid to high 30s but that was all D roads...

Interestingly, on Sunday morning very reluctant to start... but did so on the third go... I'll ask them to check at the service which is due in the next 800 miles...

[monkeyhanger]

My R is averaging 33mpg (always in Race) and i'm getting about 350 miles to the tank (Momentum 99) right now. On a hot summer's day, the average goes up to 34mpg. Ambient temp differences and whether the engine is hot or cold doesn't have a huge bearing on petrol mpg, and that's down to the way petrol is combusted by the engine.

Petrol is only 8% less calorific than diesel, yet is 30-40% down on mpg like-for-like (cylinder deactivation engines excepted). Petrols are far more wasteful than diesels - the exhaust gases are much hotter on the petrols as they convert less chemical energy into kinetic energy - with the fuel expanding less under combustion.

The petrol combusts almost as well in a cold engine as a warm one - but cold oil will be a little thicker.

It is the middle part of my 20 mile each way commute that is thirstiest. Coming to work I have 3 miles at 30mph (average speed camera controlled road works), another 3 at 60-80mph, 2 miles at 40mph (at which point the oil temp is at 90C even in the middle of winter and i'm up to about 31mpg), then 8 miles on the motorway (mpg drops to 29mpg), and the last 4 miles is maintaining 60mph after a few short bursts, by which time the mpg has crept to 33-35 mpg, depending on whether i've had to overtake a few slow moving lorries hard on my last stretch.

Coming home, i'm up to about 33mpg at my first 4 miles, motorway sees it drop to 29mpg and the last stretch (first stretch coming) is far busier going home , so the mpg is 33mpg if the going is good, but there are far less chances to put your foot down coming home.

One thing I have noticed consistently is that when ambient temps approach zero, my R will struggle to get oil temp above 98C (no matter how long the journey, but tops out at 102C with ambient temps above 10C.

The one thing that amazes me about the R is how well it maintains its momentum on the flat without any gas, i'd have expected the speed to drop quite quickly considering the frictional losses you'd expect with running a 4WD Haldex system vs FWD.

Running warm is critical to good mpg from a GTD, with mpg much worse cold than warmed up, and even when warm, mpg drops 10% in the winter (lack of moisture content in cold winter air significantly affects gas expansion in diesel combustion.

My GTD had a high of 59mpg on a long summer journey, to lows of 17mpg (when a 6 mile journey took 140 mins during flash floods), averaging 44mpg in the winter and 49mpg in the summer for my (then) 12 mile commute.

The R copes with slow moving city traffic much better than the GTD - it is happier doing 15mph in 3rd, 30mph in 5th and 40mph in 6th than the GTD is doing 15 in 2nd, 30 in 4th or 40 in 5th, with no real drop in mpg over 60mph+ driving, same cannot be said for the GTD.

[mcmaddy]

6 miles to work at -1° this morning doing the usual 30 and 40 speed limit and just about broke 30mpg. Same journey in 4 motion Tiguan before Christmas and was just about getting 33mpg so not much difference for me.

[Bullfinch]

In my GTi PP the morning commute is 15 miles which takes around 30-40 mins.  MPG varies from around 32mpg to 36 mpg.  On long distance drives (M-way and 50 miles plus) it generally gets close to 40mpg.  Interested to see that R's aren't too much behind.  Back in the late 90's I owned a Mk4 GTi 1.8T and mpg on that was around 30-35 mpg so not much advance in economy albeit I now have 80 bhp more.

[monkeyhanger]

In my GTi PP the morning commute is 15 miles which takes around 30-40 mins.  MPG varies from around 32mpg to 36 mpg.  On long distance drives (M-way and 50 miles plus) it generally gets close to 40mpg.  Interested to see that R's aren't too much behind.  Back in the late 90's I owned a Mk4 GTi 1.8T and mpg on that was around 30-35 mpg so not much advance in economy albeit I now have 80 bhp more.

The Manual R isn't far behind a DSG GTI in mpg - DSG is 10% thirstier than manual (real life driving - I wonder how the 7 speed stacks up against manual), I bet there's not too much between a DSG GTD and a manual GTI - in the winter at least.

[I wanted a GTi]

Obviously proves that Carbon Grey is the best colour and the most efficient 

Ignoring the colour quote as obviously red is best in every way

In the spirit of assisting a fellow forumite, I undertook an unnecessary detour on my way to Tesco today (other supermarkets are available though not round here ). Started from cold, no ice scraping required just a wipe over to remove that that had already defrosted. 2C on leaving, 6C on arrival at destination. Didn't need the rear screen demister but put it on for a while anyway. 15 miles, some stop/start, mostly 40 mph roads and a brief peak at 80. No motorways. Average was exactly 35mpg. Had it not been for some traffic in the last half a mile then 36-37 would likely been the result. Real bonus though was that finally they had my undyed kippers back in stock

He might have a point. I covered 360 miles in the loner GTD(red) that I got last week from the dealer and it cost £40 in fuel. I know it is not that scientific but that is what it took to get the fuel gauge to the same place after putting the £40 of diesel in it.