Understanding DPF Regens

[Optimus prime]

Another trigger is the pre-turbo temps need to be above 700C to activate a regen 

Good luck doing that in 4th at 40mph as per the handbook 

Your forgetting that the car will double inject to raise the temp (hence the poor mpg) & most turbo's run above 500C normally so the extra temp will not be difficult to get to if you run the car in manual sport mode  & keep the rpm above 2K. 

[Rhyso]

Another trigger is the pre-turbo temps need to be above 700C to activate a regen 

Good luck doing that in 4th at 40mph as per the handbook 

Your forgetting that the car will double inject to raise the temp (hence the poor mpg) & most turbo's run above 500C normally so the extra temp will not be difficult to get to if you run the car in manual sport mode  & keep the rpm above 2K.

Hence why I said 'good luck doing it in 4th'. Sat at 40mph the car generally runs at 300C unless going up a hill

The car simply doesn't reach those temps at that speed; much better to run the car in 3rd gear at 50mph

I've done a few forced regens for people over the years.....

[Optimus prime]

Another trigger is the pre-turbo temps need to be above 700C to activate a regen 

Good luck doing that in 4th at 40mph as per the handbook 

Your forgetting that the car will double inject to raise the temp (hence the poor mpg) & most turbo's run above 500C normally so the extra temp will not be difficult to get to if you run the car in manual sport mode  & keep the rpm above 2K.

Hence why I said 'good luck doing it in 4th'. Sat at 40mph the car generally runs at 300C unless going up a hill

The car simply doesn't reach those temps at that speed; much better to run the car in 3rd gear at 50mph

I've done a few forced regens for people over the years.....

Yes me to and to be honest I would take 40mph as the min speed required.  I usually do it on a motorway @ a steady 60 mph for about 20 mins as I find this works best.  With my laptop plugged in you can monitor all that is required

[Sootchucker]

An interesting thread for sure.

Like McMaddy, my weekly routine is relatively small journeys (10 miles to work and 12 miles back - (different route on the way back before you ask)). My route home is usually Motorway for about 8 or 9 miles @ 65-75mph.

Whilst I've never had the DPF light come on the dash in nearly 2 years of ownership, I do experience quite a few regens (stop start turned off, engine revs raised), at least once every couple of weeks or so (so about  200-300 miles), so no where near the 800 miles McMaddy is getting between his regens ?

[Optimus prime]

An interesting thread for sure.

Like McMaddy, my weekly routine is relatively small journeys (10 miles to work and 12 miles back - (different route on the way back before you ask)). My route home is usually Motorway for about 8 or 9 miles @ 65-75mph.

Whilst I've never had the DPF light come on the dash in nearly 2 years of ownership, I do experience quite a few regens (stop start turned off, engine revs raised), at least once every couple of weeks or so (so about  200-300 miles), so no where near the 800 miles McMaddy is getting between his regens ?

Lets face it monitoring dpf regens with accurate figures is child's play if you have vcds.  Just select 507 measuring block and convert the figure that is in metre's into miles and deduct from your speedo.  This will give you almost the exact mileage when your last regen was completed.  Use this as a base point and recheck 507 after a few weeks easy.  I think Mcmaddy's figures maybe off slightly and without doing the above it is difficult to be accurate.  We have to remember that fuel quality plays a major part and I don't mean the cheapest.  My local indy VW tech swears by BP ultimate for our engines with regards to fewer regens due to less soot production so I am currently testing with a full tank just to see.  In theory with a cleaner burn you get less soot so this should work out but we will have to wait and see, if it does I am more than happy to spend an extra £5 per full tank fill up for the results especially as my trip to work is only 14 miles each way and as we no regens hurt your mpg.

[mcmaddy]

I only ever use esso or shell and occasionally give it done shell v power when the price is low. I also use millers diesel power plus every fill up so maybe that is helping with regens too.

[Optimus prime]

I only ever use esso or shell and occasionally give it done shell v power when the price is low. I also use millers diesel power plus every fill up so maybe that is helping with regens too.

Millers increase's the cetane by 4 which makes it the same as bp ultimate from a burn point but unsure if it increases the clean level to the same quality?  Used it in my 535d but never noticed any difference other than the smell of the stuff in the boot   Will see how the ultimate works out then perhaps try normal derv + millers.

@ Mcmaddy are you regens measured via vcds or just the feeling of the car with noted mileage?  With your driving distance I can't believe the regens are every 800 miles or is that when it happened?  As driving 3 miles each way 5 days a week you won't even meet the ECT criteria for the regen process let along a full regen.

Forgot to mention the Mk7 does not passive regen

[mcmaddy]

I can do short journeys for a fortnight and then go out for a good drive on a weekend. It just seems the fans are blaring away at approximately 800 miles ish, can be less miles but strange it always happens at the end of a decent drive out.

[itavaltalainen]

I think you may not notice all regens. 

Even I don't get 800 miles between them and on average my journeys are around 100 miles - one way.

[mcmaddy]

Possibly. Could just be coincidence that it looks like 800 miles between when in fact it's done some in between.