It seems that passive regen does reduce Soot grams but not the soot trigger

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@Luxmoggy:

Interesting.
I’ve never had the %Soot drop by even one percentage point on a Passive Regen.
However, that could be because when I am looking at it, it’s always on the 20-odd mile return trip on the way back from an AR, the exhausts are still pretty hot and I’m doing 70mph, so I guess not much to improve, in fact the soot bottoms out at 7%, then by the time I get home again, its gone back up to 10% usually, even though I do see “1” (PR) in the display for a minute or two on the way back.

Tomorrow I’m off on a 300-mile round trip (mostly motorway), so it will be interesting to see what happens with PR and %Soot as we go, I’ll keep the “Kot Kit” plugged in, & report back on here

Must remember to take my Anorak with me

EDIT: UPDATE:-
Well, back from my 300-mile round trip Newcastle to Manchester and back with the kit plugged in all the way, a bit disappointing really:
Even at motorway speed most of the time (70ish) and several periods with regen status of “1” (PR) the soot level just climbed steadily from 30% on departure to 48% about halfway through the outbound trip to 48%, then I forgot to look for a short while and suddenly it was doing an active regen and dropped to 7% about 15 mins later. Finished the trip down at about 13%, and on the return trip, guess what? It’s back up to 46% and almost ready to do another active regen and burn another £20 worth of diesel

VERDICT: Passive Regen is totally ineffective. “If it ain’t broke, don’t fix it” -where’s the fun in that?

Last edited by Gremlin500 on 17th Dec 2023 10:23pm. Edited 1 time in total

Better monitoring the soot in grams rather than the % trigger pid.
Which reminds me to put an alarm on the grams lol just to increase the excitement
 2018 SE SDV8 4.4 Byron Blue

I have set the numbers to change to yellow and red.

But I don't know what values to set for soot grams. @kot what have you experienced?

DPF Regen: Yellow 1 passive and Red 2 Active. plus make a sound when active regen starts and ends.

Soot %: Yellow 95, Red 97
Distance Since Last: Yellow 730 KM and Red 740 KM

Exhaust Gas: Yellow at 500 and Red at 600 (these may need to be reduced - I will watch the next couple of regions)

I hope I have many red numbers to warn me that an active regen is ready to happen. SDV8 AB MY 2020
MINI Cooper S Cabrio
Kit: Jaguar XK140 (in progress - the website is link to build)

mine starts its AR just over the 20.5 gram mark and stops around 5.4 gram.

The amber light on the vehicle dash comes on at 24.5 grams and goes off at 22.5 gram, the amber light is when you really need to take action. As your AR should have kicked in by that point and it soon goes to Red and just before Red further AR are inhibited, then you are truly .

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So first Active Regen with soot grams…
I started with 15.7g and while driving it dropped to 15.0g with passive regen. While soot % went up 2%.

When soot was 100% and km was 752. The soot was 15.1g. The Active regen started. The soot g jumped to 24g.

When the regen finished the soot was value 3.3g.

But with road works my speed dropped before the soot % dropped.

Next active Regen will happen on Friday. I will also see what happens to the soot gram during a lot autobahn drive.

For me the best indicator is the km since followed by the soot %. Soot g I don’t have enough data, but today’s trigger point I wouldn’t have found with just grams.

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I thought I'd share some observations on how the DPF regen is working in my car a 2016 4.4 SDV8

On my display I have
DPF soot concentration [g/m3]
Distance since last regeneration
Exhaust gas temp Bank 1 sensor 3
Exhaust gas temp Bank 1 sensor 4

Making short journey's of less than 3 miles, the soot value climbs quite quickly, maybe 1 to 2 units each time
When it gets to about 22 which doesn't take long, I then see the exhaust gas start to climb from 2-300 usually to 490 to 520, it is then in rgen mode, I guess this is Active regen
It takes about 10 minutes after which the soot drops to between 5 and 6 and the Distance since last regen changes to 0.


On a motorway journey, using decent rpm, towing a trailer, the exhaust temps will be 400 or so and the soot will drop to between 3 and 4, so this must be passive regen.

It is definitely worth having the dashboard as both times recently I would have turned off the engine part way through an active regen but instead I ended up driving around for 10 minutes using up fuel and spitting burnt carbon out of the exhaust ! So much for saving the planet.


With regard to miles to next service indicator, i am convinced, this is just an algorithm that calculates the time to the next scheduled service, i.e in May and the miles I am doing and it just reduces it so by the time it gets to May it will say a service is due!

I have done 85 miles, over the last couple of weeks, and it has gone down from 6700 to now due in 5932 miles even though the DPF regen cycles have been completed successfully.

I have only actually done about 2800 miles in total since the last service and yes I know I should use it more but even so it should last longer between services. 2016 AB SDV8 Barolo black
2019 AB SDV8 Santorini black

Ok I haven't had soot grams before when I drive in the uk.

I think that there are two different triggers. Which are km since and soot grams. When either km since reaches the average km value and depending on the soot value the active regen triggers. Or the soot grams reach the values from the table in @kot post.

I am guessing here.

When I am in Germsny it is mainly the km since and soot values over 15g. In the uk when the journeys are shorter and slower it will be the soot grams which trigger the active regen well before the Km since.

I will look at this more next time I drive in the uk. Which would explain if I correctly get each active regen to trigger on my km since 751km. I can get 16,000 - 24,000km between oil changes.

If people can post their km/miles since, soot % and soot grams when the an active regen happens, we can hopefully get a clearer picture. SDV8 AB MY 2020
MINI Cooper S Cabrio
Kit: Jaguar XK140 (in progress - the website is link to build)

LM
Good guess
From page 5

The DPF software incorporates a mileage trigger which is used as back-up for active regeneration. If active regeneration has not been initiated by a back pressure signal from the differential pressure sensor, regeneration is requested based on distance travelled.

https://www.fullfatrr.com/gallery/albums/u...ration.pdf 2018 SE SDV8 4.4 Byron Blue

But I am thinking there is a 3rd trigger and its soot grams! maybe need to look at past graphs etc 2018 SE SDV8 4.4 Byron Blue

Now I have Re-invented the wheel. 🤣🤣
I will read the manual. SDV8 AB MY 2020
MINI Cooper S Cabrio
Kit: Jaguar XK140 (in progress - the website is link to build)

Great thread and thanks to this i am no longer Blind! Many thanks to Kot for thinking of this solution even i have managed to replicate with my limited knowledge when it comes to tech I have also experienced plummeting mileage till next service. So today soot reached about 21 grams just as i was about to pull up and park on my drive. Exhaust temp started to rise so i drove an extra 10 mins and regen done soot down to under 4 grams. I am still very much a novice but getting there thanks to the people on this forum i know a lot more about my FF than i did when i bought it in march. Great work by everyone else on this thread who contributed.

So yesterday's journey on the Autobahn.
Soot grams started at 8g. 600km later it was 3.5g. Then an active regen started and when it finished 4.7g - it wasn't the best active regen. It started as I entered the Mountain Roads.

The next active regen will be the return journey. But it seems the SDV8 engine enjoys long 90mph drives. Not much soot. SDV8 AB MY 2020
MINI Cooper S Cabrio
Kit: Jaguar XK140 (in progress - the website is link to build)

Does the software you are using give any indication of the canbus / PID code that its pulling the data from ? ( It’d likely be a 3 digit hex code value )

Reason for asking is for a wee project I’m looking at to create an LED indicator to signal regen. V8 or else ...

Last edited by fisha on 5th Jan 2024 10:15pm. Edited 1 time in total

Whilst not strictly in the interest of the thread, where everyone is quoting stats / figures on their DPF regen etc, but should this be something I should be concerned about when looking at choosing between the SDV8 and the 5.0S/C. I only to about 10-12k miles per year and this seems an awful lot of hassle, or incredibly regular servicing requirements.

Sorry for derailing a little bit here, but looking for some advice from clearly the experienced and knowledgeable owners that you all are.


Thanks in advance.