Anyone had forced GPF regens yet?

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monkeyhanger
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Anyone had forced GPF regens yet?

Post by monkeyhanger »

400 miles in on the new GTI+ and not a hint of the GPF wanting a regen or seeing the usual signs of a DPF needing one (high idling speed, poor mpg, low availability of stop-start)- assuming the signs are the same for a GPF and DPF.

Has anyone with a WLTP compliant Polo seen signs of the GPF in regenning operation.
Last edited by monkeyhanger on Sun May 26, 2019 10:16 am, edited 1 time in total.
JMiddo94
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Re: Anyone had forced GPF regens yet?

Post by JMiddo94 »

I've not checked the manual so I don't know if the GPF needs a regen or not but 3000 miles in I haven't had a single one yet.
SRGTD
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Re: Anyone had forced GPF regens yet?

Post by SRGTD »

monkeyhanger wrote: Sun May 26, 2019 10:09 am Looking out of the bedroom window this morning yo survey the grim weather, I looked down at our 2 GTI+ and noticed a external difference - the old (Aug 18) one has a black sill trim running between front and back wheel arches and the new one (May 19) does not. A sneaky elimination by VW for MY19.

https://imgshare.io/image/poAzj
If you mean the black plastic sill extension with the ‘grained’ finish, then I’m pretty certain I can see it on your white car in the photo st the link you’ve posted. It’s also present on other owners Polo GTI+‘s in the photo gallery thread where they’ve taken delivery of their cars very recently (so very likely to have been built around the same time as yours).

I know the configurator on VW’s website isn’t always accurate, but it’s shown on the images in the configurator too.

If your white GTI+ doesn’t have these fitted, then I’d say it’s a production / build error.
monkeyhanger
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Re: Anyone had forced GPF regens yet?

Post by monkeyhanger »

SRGTD wrote: Sun May 26, 2019 10:20 am
monkeyhanger wrote: Sun May 26, 2019 10:09 am Looking out of the bedroom window this morning yo survey the grim weather, I looked down at our 2 GTI+ and noticed a external difference - the old (Aug 18) one has a black sill trim running between front and back wheel arches and the new one (May 19) does not. A sneaky elimination by VW for MY19.

https://imgshare.io/image/poAzj
If you mean the black plastic sill extension with the ‘grained’ finish, then I’m pretty certain I can see it on your white car in the photo st the link you’ve posted. It’s also present on other owners Polo GTI+‘s in the photo gallery thread where they’ve taken delivery of their cars very recently (so very likely to have been built around the same time as yours).

I know the configurator on VW’s website isn’t always accurate, but it’s shown on the images in the configurator too.

If your white GTI+ doesn’t have these fitted, then I’d say it’s a production / build error.
Yep I deleted it from my post when I got downstairs and realised I had them. From upstairs I could not - they must have blended into the tarmac of the road from my almost birds eye view.

Damn your promptness! :lol:

I deleted that about a minute after posting! False alarm everyone!
monkeyhanger
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Re: Anyone had forced GPF regens yet?

Post by monkeyhanger »

My wife achieved an abysmal 20mpg on her 8 mile commute to work yesterday and 19mpg home. Worst ever by a long margin.

She normally gets 30mpg, and works 7am to 2:30pm, missing all the traffic.

We went out in it last night and stop-start wasn't available (it is more frequently available on her 2019 GTI+ than my 2018GTI+ - I attribute that to mine having the dashcams installed and bringing the battery charge level lower between uses)

There were no dash lights or messages to indicate desperation by the system to force you to drive in a certain way to induce a forced regen.

This morning, I took her car to work (13 miles) and got 35mpg, and stop-start was available once the car warmed up.

I'm assuming her particulate filter was pretty full yesterday and it's now cleared. If so, regen isn't as obvious with the PPF as it is with DPF - no burning smell, no increased idling speed or more eager like you'd get with a VW TDI.

I was amazed how big the mpg dip was though.

She drove mine to work (no PPF) and got her usual 30mpg.
vc-10
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Re: Anyone had forced GPF regens yet?

Post by vc-10 »

I've done over 9k in my 1.0 115PS TSI now, and I've not noticed a regen. I have noticed that sometimes on my commute I get 50mpg and sometimes it's more like 45, so maybe those times it's been doing a regen? But maybe it's just the weather, as my commute is 35 miles on the motorway each way, so I'm not sure that I would ever actually need to regen.
monkeyhanger
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Re: Anyone had forced GPF regens yet?

Post by monkeyhanger »

vc-10 wrote: Fri Nov 29, 2019 10:57 am I've done over 9k in my 1.0 115PS TSI now, and I've not noticed a regen. I have noticed that sometimes on my commute I get 50mpg and sometimes it's more like 45, so maybe those times it's been doing a regen? But maybe it's just the weather, as my commute is 35 miles on the motorway each way, so I'm not sure that I would ever actually need to regen.
35 miles each way on the motorway? All your regenning will be passive and your filter shouldn't contain any meaningful quantities of soot ever.

What surprised me most was the drastic drop in mpg and no other signs it was happening. When I had my MK7 Golf GTD, idling speed went up from 850rpm to 1200rpm during a regen, there was a strong smell like burning paint and mpg was down maybe 15% while it was doing one.

A 33% drop in fuel economy for a petrol based PPF/OPF seems drastic, more so as even one short run PPFs are expected to clear quickly due to a much higher exhaust temp than diesel engined cars. 33% drop in fuel economy yet seemingly driving normally - not sluggish or lumpy in delivery. How much worse could the fuel economy be for a user prompted forced regen?
TurboTrev
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Re: Anyone had forced GPF regens yet?

Post by TurboTrev »

I think our GTI+ went through this earlier in the week (approx 3,000 miles). The car suddenly became a bit "rougher" to drive. The exhaust note seemed to deepen, with a bit of vibration and when the car's engine was turned off the the fan was going balistic compared to normal. Also, there was sort of a burning smell in the air being driven out by the fan. After using the car a couple of more times over the rest of the day, it suddenly went back to "normal". No roughness, no vibration, no mad fan and no smell. Been perfect since. Anyone had anything similar?
monkeyhanger
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Re: Anyone had forced GPF regens yet?

Post by monkeyhanger »

TurboTrev wrote: Fri Nov 29, 2019 2:51 pm I think our GTI+ went through this earlier in the week (approx 3,000 miles). The car suddenly became a bit "rougher" to drive. The exhaust note seemed to deepen, with a bit of vibration and when the car's engine was turned off the the fan was going balistic compared to normal. Also, there was sort of a burning smell in the air being driven out by the fan. After using the car a couple of more times over the rest of the day, it suddenly went back to "normal". No roughness, no vibration, no mad fan and no smell. Been perfect since. Anyone had anything similar?
According to the wife, the fans weren't blaring when stationary, nor was there a burning smell (I had asked the wife at the time because these are all things you'd expect as per a TDI's DPF doing a regen.

She did think the engine was noisier, but couldn't be sure as she had the radio turned right down due to a headache. Didn't drive any differently for me last night but perhaps it was all over by then.

Was your mpg shocking that day?
TurboTrev
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Re: Anyone had forced GPF regens yet?

Post by TurboTrev »

monkeyhanger wrote: Fri Nov 29, 2019 3:01 pm
TurboTrev wrote: Fri Nov 29, 2019 2:51 pm I think our GTI+ went through this earlier in the week (approx 3,000 miles). The car suddenly became a bit "rougher" to drive. The exhaust note seemed to deepen, with a bit of vibration and when the car's engine was turned off the the fan was going balistic compared to normal. Also, there was sort of a burning smell in the air being driven out by the fan. After using the car a couple of more times over the rest of the day, it suddenly went back to "normal". No roughness, no vibration, no mad fan and no smell. Been perfect since. Anyone had anything similar?
According to the wife, the fans weren't blaring when stationary, nor was there a burning smell (I had asked the wife at the time because these are all things you'd expect as per a TDI's DPF doing a regen.

She did think the engine was noisier, but couldn't be sure as she had the radio turned right down due to a headache. Didn't drive any differently for me last night but perhaps it was all over by then.

Was your mpg shocking that day?
I'm not sure about the mpg, it's not something we ever check!
monkeyhanger
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Re: Anyone had forced GPF regens yet?

Post by monkeyhanger »

Normal mpg restored for the wife's GTI+ - Very close to the mpg I would expect for my 2018 model with no PPF. on a 35 mile tun each way to Teesside (40mpg) and to the Metrocentre (35mpg) over the weekend.

One thing I have noticed in driving the wife's car is that it runs a lot cooler than mine. My car's oil gets to 98C and stays there. My wife's gets to 91C and only a short bout of driving a bit harder (Uphill, dual carriageway) will get it up to 94C but is very eager to get back down to 91C when on 40mph roads.

My wife had my car yesterday - started it up and had a red warning for low coolant level. Turned it off and back on, and the warning went. I have looked at the level tonight and it is a little lower than the min mark, but still within the confines of the expansion tank. So I potentially have a coolant leak. Will have to keep an eye on it.

Coolant leak isn't an uncommon issue for VW Golfs.
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Re: Anyone had forced GPF regens yet?

Post by phillos »

I believe my GTI went through this last monday at about 5000kms on the clock.

The symptoms are:
  • Higher fuel comsumption
  • Increased resonance in the exhaust. It becomes very 'boomy'
  • Sluggish/hesitant performance
  • Funny smell from outside the car
The fix according to workshop:
  • At least 20 mins drive
  • Keep rpms above 2000 if possible
At first I was quite scared/surprised at the behaviour, but quickly remembered reading about this elsewhere on another forum.
To alleviate/get the regen properly done, I drove about 40km highway with lots of rpms (above 2000rpm) and a good few pulls, 80-120ish (km/h :P ). When I returned home, the car had returned to normal.
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Re: Anyone had forced GPF regens yet?

Post by OomStu_ZA »

I'm curious since I have approx 18000KM's on the clock and havent seen this regen thing pop up and fuel economy is more or less a constant now.

Does it depend how one drives that determines if a regen is required or not?
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Re: Anyone had forced GPF regens yet?

Post by phillos »

OomStu_ZA wrote: Thu Dec 05, 2019 11:48 am I'm curious since I have approx 18000KM's on the clock and havent seen this regen thing pop up and fuel economy is more or less a constant now.

Does it depend how one drives that determines if a regen is required or not?
I would strongly believe so. My commute contains primarily city driving with lots and lots of bumper-to-bumper traffic. While there are lots of people claiming that the hot exhaust gasses of a gasoline engine will regenerate the OPF at pretty much idle, I can't help but believe that the filter somehow clogs up anyhow if it isn't exposed to prolonged driving that thoroughly heats it up. Otherwise I can't explain the phenomenon I experienced that monday.

If you're on the highway for extended periods at regular highway speeds im sure the OPF filter will regenerate on its own, without you noticing.
monkeyhanger
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Re: Anyone had forced GPF regens yet?

Post by monkeyhanger »

If you do 15+ miles each way on your commute, you'll probably have all your regeneration being done passively, under the hear of the exhaust gases, and won't even be aware.

When you're doing short journeys, the PPF doesn't get hot enough for long enough to burn off the soot being collected faster than it's being collected. At a certain loading point (usually 65% capacity with a diesel DPF, don't know if PPF is exactly the same), the car creates a situation to heat up the PPF quickly, by burning fuel in the exhaust system - the cause of the exhaust note change and poor fuel economy. This is a forced regen.

I was amazed just how poor the wife's mpg was during the forced regen - I did not expect a 33% reduction in fuel economy for 16 miles (there and back from her place of work).
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