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Our new GPF equipped GTI+ seems consistently 10% thirstier in every situation than our pre WLTP Polo GTI+.

monkeyhanger wrote:Our new GPF equipped GTI+ seems consistently 10% thirstier in every situation than our pre WLTP Polo GTI+.

My 400 mile GTI+ is also a little thirstier than expected.
Hopefully just needs to be run in a little more. My second tank of fuel is expected to last about 50 miles more than the first, so I'm hoping it's still loosening up.

MattHGR wrote: Fri May 17, 2019 8:45 am

monkeyhanger wrote:Our new GPF equipped GTI+ seems consistently 10% thirstier in every situation than our pre WLTP Polo GTI+.

My 400 mile GTI+ is also a little thirstier than expected.
Hopefully just needs to be run in a little more. My second tank of fuel is expected to last about 50 miles more than the first, so I'm hoping it's still loosening up.

I am expecting loosening up gains, not sure whether to the tune of 10% though, or whether the GPF one will be thirstier. Only done 56 miles in the new one. The one we got in Aug is nearly at 7k miles.

Full tank yesterday was telling me 290 miles. Work commute has gone up to 35mpg (275 miles in).

Not the current model GTI, but the previous generation model, and l thought some of you (lucky) current model GTI / GTI+ owners might be interested in my real world mpg figures in my 1.8 192ps 6 speed manual GTI.

This was on one of my typical ‘A’ / ‘B’ road journeys between 4.00 and 5.00 pm yesterday afternoon, travelling at around 60 mph for most of the journey outside of 30/40 mph speed limit zones (basically just going with the flow of the traffic - no opportunities for overtaking and no benefit to be gained if I did overtake!). The last 10 minutes of the journey was stop start town driving in rush hour traffic. This was my mpg over a distance of 28 miles; On the return journey in the evening, with much less traffic on the route, a speed (outside the 30/40 mph limit zones) of around 65mph for most of the journey, with 70-75 mph on a short dual carriageway section and a stop start section at overnight roadworks and temporary traffic lights, the mpg dropped to just over 41. Stop start was switched off for both the outward and home journeys as I dislike it, so mpg would probably have been a bit better if I’d had it switched on.

My long term average mpg is currently showing 41.2. Car has covered nearly 20k miles so the engine is well and truly loosened up.

^ I think the new GTI could match that on a 28 mile journey if you were consistently doing 40-60mph for most of it. 6th gear is pretty tall on the DSG box, allowing me to get 45mpg for a 100 mile journey down to York whole doing 80mph most of the way.

I noticed a difference between my pre-WLTP GTI+ and the new one, which might affect mpg between the 2.

I generally drive with the performance monitor screen on the infotainment system, setting it to show oil temp, kW output and boost pressure.

On the pre WLTP GTI+ (no GPF), boost pressure drops to zero at idling or driving with little/no throttle input (engine deceleration). On the new one, it doesn't drop below 0.29bar, and every reading at any given throttle input seems correspondingly about 0.3 bar higher on the new one vs the old one - presumably higher back pressure required to overcome the restriction of the GPF. The new one does seem to pick up a little quicker from a standstill, presumably because the turbo is always partially spooled.

Wonder if the WLTP Polo GTI has a slightly bigger turbo if it needs to work harder?

monkeyhanger wrote: Fri May 17, 2019 10:47 am ^ I think the new GTI could match that on a 28 mile journey if you were consistently doing 40-60mph for most of it. 6th gear is pretty tall on the DSG box, allowing me to get 45mpg for a 100 mile journey down to York whole doing 80mph most of the way.

I noticed a difference between my pre-WLTP GTI+ and the new one, which might affect mpg between the 2.

I generally drive with the performance monitor screen on the infotainment system, setting it to show oil temp, kW output and boost pressure.

On the pre WLTP GTI+ (no GPF), boost pressure drops to zero at idling or driving with little/no throttle input (engine deceleration). On the new one, it doesn't drop below 0.29bar, and every reading at any given throttle input seems correspondingly about 0.3 bar higher on the new one vs the old one - presumably higher back pressure required to overcome the restriction of the GPF. The new one does seem to pick up a little quicker from a standstill, presumably because the turbo is always partially spooled.

Wonder if the WLTP Polo GTI has a slightly bigger turbo if it needs to work harder?

No throttle = no exhausts gases = nothing to drive the turbo, hence the zero boost in your old car.
That's what I'd expect, so how are they keeping the turbo spooled in the new one at times when there's no gases to drive it?
I've never heard of something like an electric motor keeping a turbo spooled, but I'm not a turbo expert (they've always been a disaster on motorbikes so I haven't had to learn about them much).
I did fit a 'vaned' seal to my Mini Cooper that made a difference to the responsiveness.
The vanes made the intake air swirl around as opposed to just a hole.

Andy Beats wrote: Fri May 17, 2019 10:56 am

monkeyhanger wrote: Fri May 17, 2019 10:47 am ^ I think the new GTI could match that on a 28 mile journey if you were consistently doing 40-60mph for most of it. 6th gear is pretty tall on the DSG box, allowing me to get 45mpg for a 100 mile journey down to York whole doing 80mph most of the way.

I noticed a difference between my pre-WLTP GTI+ and the new one, which might affect mpg between the 2.

I generally drive with the performance monitor screen on the infotainment system, setting it to show oil temp, kW output and boost pressure.

On the pre WLTP GTI+ (no GPF), boost pressure drops to zero at idling or driving with little/no throttle input (engine deceleration). On the new one, it doesn't drop below 0.29bar, and every reading at any given throttle input seems correspondingly about 0.3 bar higher on the new one vs the old one - presumably higher back pressure required to overcome the restriction of the GPF. The new one does seem to pick up a little quicker from a standstill, presumably because the turbo is always partially spooled.

Wonder if the WLTP Polo GTI has a slightly bigger turbo if it needs to work harder?

No throttle = no exhausts gases = nothing to drive the turbo, hence the zero boost in your old car.
That's what I'd expect, so how are they keeping the turbo spooled in the new one at times when there's no gases to drive it?
I've never heard of something like an electric motor keeping a turbo spooled, but I'm not a turbo expert (they've always been a disaster on motorbikes so I haven't had to learn about them much).
I did fit a 'vaned' seal to my Mini Cooper that made a difference to the responsiveness.
The vanes made the intake air swirl around as opposed to just a hole.

Not sure what's happening - old one 0 bar when at rest, new one at a minimum 0.29 bar and correspondingly higher by 0.3 bar for similar throttle given vs old one.

Maybe it has one of those new electric driven rather than blown turbos?

monkeyhanger wrote: Fri May 17, 2019 2:16 pm Maybe it has one of those new electric driven rather than blown turbos?

I wasn't even aware such a thing existed, but indeed they do.
Either fully electric driven or hybrid.
Would have liked one of these on my Alpina, the turbo lag on that was terrible.....
EDIT and a wee bit more investigation reveals it is indeed a hybrid turbo.

Been down to the South Coast recently in my 95ps and checked the real consumption. Light traffic driven steadily but not slow got me 56.4mpg worked out properly. M1/M40/A34/M3/M27/A31 was the route taken so mostly 70mph. Still under 2,000 miles too.

Coming back I "made progress" plus had some more traffic. Still around 50/52mpg at a guess but the average will come down with my commute next week before I need to fill up again.

In my previous Mii Sport on exactly the same route in similar traffic it returned 52mpg so I'm really pleased given the elevation in comfort/space/refinement.

CJ-77 wrote: Fri May 17, 2019 2:35 pm Been down to the South Coast recently in my 95ps and checked the real consumption. Light traffic driven steadily but not slow got me 56.4mpg worked out properly. M1/M40/A34/M3/M27/A31 was the route taken so mostly 70mph. Still under 2,000 miles too.

Coming back I "made progress" plus had some more traffic. Still around 50/52mpg at a guess but the average will come down with my commute next week before I need to fill up again.

In my previous Mii Sport on exactly the same route in similar traffic it returned 52mpg so I'm really pleased given the elevation in comfort/space/refinement.

Literally no idea how you're achieving this.
I can only get mid to low 40s cruising at 70mph.
My tyre pressures are spot on, my boot is completely empty etc.

If it does turn out that the GPF causes a decrease in fuel efficiency of 10% then doesn't the point of having one be completely pointless? Ok, it reduces the noxious gases just that tiny bit more but at the cost of burning more fuel increasing the carbon footprint. Not taking into account the cost of manufacturing these GPF's along with the materials they use to make them. Am I missing the point?

Andy Beats wrote: Fri May 17, 2019 2:38 pm

CJ-77 wrote: Fri May 17, 2019 2:35 pm Been down to the South Coast recently in my 95ps and checked the real consumption. Light traffic driven steadily but not slow got me 56.4mpg worked out properly. M1/M40/A34/M3/M27/A31 was the route taken so mostly 70mph. Still under 2,000 miles too.

Coming back I "made progress" plus had some more traffic. Still around 50/52mpg at a guess but the average will come down with my commute next week before I need to fill up again.

In my previous Mii Sport on exactly the same route in similar traffic it returned 52mpg so I'm really pleased given the elevation in comfort/space/refinement.

Literally no idea how you're achieving this.
I can only get mid to low 40s cruising at 70mph.
My tyre pressures are spot on, my boot is completely empty etc.

I honestly can't answer, Andy. All I can say is I drive it like every vehicle I use. I filled the car up and drove 216 miles and then put in 17.4 litres (second click) to fill it back up. A few weeks ago I did a 500 mile trip in a works Golf 1.5TSI 130ps and got 53.x mpg from that with just under a quarter of a tank left. In another example I did over 900 miles (to a very windy Peterhead!) in a BMW 116d and that gave me 54mpg over 2 tanks (didn't like the car at all). The van I use a lot always gives me 42mpg or 700 miles on a tank.

Do you know anyone else locally with the same car/engine to compare with? Maybe your car has a problem?

CJ-77 wrote: Fri May 17, 2019 3:47 pm Do you know anyone else locally with the same car/engine to compare with? Maybe your car has a problem?

Nah, I'm happy enough with mid 40MPG at 70mph.
Just weird when people get a lot more.
Cruising at 70 is the same no matter who's driving.
I suppose it's feasible changing the fronts to Michelin Cross Climate could account for some difference compareds with low rolling resistance standard Falkens.
Didn't have them on long enough to tell (changed at 76 miles).

Andy Beats wrote: Fri May 17, 2019 4:07 pm

CJ-77 wrote: Fri May 17, 2019 3:47 pm Do you know anyone else locally with the same car/engine to compare with? Maybe your car has a problem?

Nah, I'm happy enough with mid 40MPG at 70mph.
Just weird when people get a lot more.
Cruising at 70 is the same no matter who's driving.
I suppose it's feasible changing the fronts to Michelin Cross Climate could account for some difference compareds with low rolling resistance standard Falkens.
Didn't have them on long enough to tell (changed at 76 miles).

If you are happy then that's the main thing. Low 40's at a 70mph cruise still seems wrong to me, though. No way would the tyres cause such a big difference in mpg. I will check it in the weeks ahead but I think I'm getting at least 40mpg on my short 3.5 mile each way city commute....