Engine: D5: Removed my DPF

[Bill_56]

Originally Posted by foggyjames

The pressure sensor looks interesting...not what I expected. Since it's a differential device (one hose each side of the DPF?), couldn't you leave the take-off points where they are and simply insert a restrictor, varying the size of the orifice until the read-out reported by VIDA matches that on a car with a DPF still fitted?

I'm willing to bet (like the Jeep example S60D5-185 mentioned) that not all markets had a DPF. The engine management was changed to a more advanced system when the Eu3 to Eu4 transition happened, but I bet there is a "No DPF" mode. There might even be a piece of Volvo software which does the job for you if you know what to look for...

I've never studied gas flows but, intuitively, I'd have guessed that a restriction in a pipe would only give rise to a pressure differential if there were a continuous flow, such as occurs with the DPF in the exhaust flow. In this case there would be no flow past the sensor, so I suspect a restriction in the pipework would have no effect on pressure.

It would be interesting no know whether the Eu4 engine software has a 'no DPF' mode. If it does, I would speculate that other components such as the throttle body would also need to be removed. Not impossible, but getting more complex, and hard to find out exactly what else would be affected.

Originally Posted by hobbyhorse

I might seem a bit thick here but 2 questions come to mind :

1. Is it possible to remove & clean the DPF ?

2. How about: remove the DPF & drill a bypass hole ( say, 20mm) straight through the matrix, then refit.

I believe there would be some advantage in removing and cleaning the DPF as, over their lifetimes, they are said to accumulate ash deposits that are not removed by regeneration. Whether it is feasible or not, I do not know.

A partial bypass is an interesting idea that might reduce the unwanted effects of the DPF. But might that lead, during regeneration, to unburnt fuel reaching further into the exhaust? I know that with petrol engines unburnt is supposed to damage the catalytic convertors, don't know if the same risk applies with diesels.

[S60D5-185]

Originally Posted by Bill_56

I believe there would be some advantage in removing and cleaning the DPF as, over their lifetimes, they are said to accumulate ash deposits that are not removed by regeneration. Whether it is feasible or not, I do not know..

Strangely enough the ASH aspect was a major issue with the DPF's on the Jeep fitted with Mercedes 3.0 Diesel. As such one of the main oils that was highly recommended was Mobil 1 ESP formula which has very low ash content and as such was designed primarily for vehicles fitted with the dreaded DPF.

Unfortunately it only comes in a 5W-30 grade so strictly speaking should not be used in the later D5 where a 0W-30 is specified.

Seeing as i had 10 litres of the stuff in the garage when i bought the Volvo i took a calculated decision to use it and so far 20k miles and 2 oil changes later all has been well, economy superb and no DPF problems whatsoever.

Darryl

[Bill_56]

I'm actually not convinced that the simple idea of a pot' to emulate the sensor, is necessarily dead in the water. There seemed to be a leap in reasoning that, because it all stopped working when out on the road, the pressure sensor needed to be load-specific. We should be open minded that there may be other reasons it didn't work.

In the other thread, Morsing stated that the pot 'should' be 70k, but he didn't say why. That seems awfully high to me. The higher the pot' resistance, the higher will be the effective source impedance of the signal presented to the ECM. A high impedance signal is less well controlled, as it may drop (or rise) more than a low impedance signal, depending upon the loading imposed upon it by the ECM's internal circuitry.

The danger of using a low value pot' is that it may overload the 5V supply. The Kavlico device I referenced earlier is specified as drawing a supply current of <5mA, which would suggest that even a 1k pot might be safe enough, and it would provide a much more stable control voltage.

I repeat yet again I am just interested in the theoretical concept, absolutely not suggesting that anybody else try it, it is almost certain to end in complete disaster owing to other factors, such as mileage-based regeneration!

[foggyjames]

If there is a mileage back-up, that would have to be removed in software. I still think that's the better way to proceed.

Whether or not the differential pressure sensor is affected by the absence of the DPF depend on how it works. I'm assuming it consists of two pressure sensors, rather than a through-flow design. If it's a through-flow design, I agree that you're more likely to run into problems. I think software remains the better way of doing it.

cheers

James

[hobbyhorse]

Originally Posted by Bill_56

I'm actually not convinced that the simple idea of a pot' to emulate the sensor, is necessarily dead in the water. There seemed to be a leap in reasoning that, because it all stopped working when out on the road, the pressure sensor needed to be load-specific. We should be open minded that there may be other reasons it didn't work.

In the other thread, Morsing stated that the pot 'should' be 70k, but he didn't say why. That seems awfully high to me. The higher the pot' resistance, the higher will be the effective source impedance of the signal presented to the ECM. A high impedance signal is less well controlled, as it may drop (or rise) more than a low impedance signal, depending upon the loading imposed upon it by the ECM's internal circuitry.

The danger of using a low value pot' is that it may overload the 5V supply. The Kavlico device I referenced earlier is specified as drawing a supply current of <5mA, which would suggest that even a 1k pot might be safe enough, and it would provide a much more stable control voltage.

I repeat yet again I am just interested in the theoretical concept, absolutely not suggesting that anybody else try it, it is almost certain to end in complete disaster owing to other factors, such as mileage-based regeneration!

The sensor is a curious thing - perhaps is somebody hooks up a dvm on lead leads & goes for a drive we'll be able establish the voltage offsets.

[Jim314]

If a 5W-30 oil met all the important specs, then I don't see how it could be a problem in the UK. I would not think that the winter temperatures in the UK were low enough for the difference between 0W-30 and 5W-30 to matter. Of course, I suppose that during every cold start even in moderate weather, the 0W starts flowing better than the 5W.

Concerning removal of the DPF, this is not good citizenship to disable a system which catches harmful particles. I can understand doing it if in a given car, if the DPF were causing serious trouble which was unresolved after multiple attempts by a Volvo dealer or other capable professional. But to remove it when it is not causing any trouble, is unconscionable in my opinion.

[TiredGeek]

Originally Posted by Jim314

a Volvo dealer or other capable professional.

Surely you're not saying Volvo dealers are capable? I must have miss-read that bit

[S60D5-185]

Originally Posted by Jim314

If a 5W-30 oil met all the important specs, then I don't see how it could be a problem in the UK. I would not think that the winter temperatures in the UK were low enough for the difference between 0W-30 and 5W-30 to matter. Of course, I suppose that during every cold start even in moderate weather, the 0W starts flowing better than the 5W.

These are prices and specs for Mobil 1 ESP that i have been using.

I can normally get it considerably cheaper than this .

http://www.opieoils.co.uk/p-6362-mob...ngine-oil.aspx

[Jim314]

I use Mobil1 Extended Performance 5W-30 in both of our cars, which the Mobil oil selector function gives. My local climate is very hot summer and relatively mild winter.

The owner's manual of the XC90 3.2 gives a variety of choices depending on expected ambient temperature range, but gives 0W-40 as the overall best viscosity type. Mobil do sell a 0W-40 which they label something like European Car Formula, but 0W-40 doesn't come in an extended performance version. I follow Mobil's advice for highest protection from their product line which is Mobil1 0W-30 Ext Perf.

Volvo's recommendation for a 40 as the upper number mistifies me.

I used to change oil myself, but don't anymore. I want to minimise the number of changes both for my convenience and to reduce the risk of mishaps.

[Jim314]

Originally Posted by Jim314

I use Mobil1 Extended Performance 5W-30 in both of our cars, which [is what] the Mobil oil selector function gives. My local climate is very hot summer and relatively mild winter.

The owner's manual of the XC90 3.2 gives a variety of choices depending on expected ambient temperature range, but gives 0W-40 as the overall best viscosity type.

Mobil sell a 0W-40 which they label something like European Car Formula, but 0W-40 doesn't come in an extended performance version. I follow Mobil's advice for highest protection from their product line which is Mobil1 [5]W-30 Ext Perf.

Volvo's recommendation for a 40 as the upper number mistifies me.

Correction of typo. Should be 5W-30.

Anybody know why Volvo would recommend 0W-40 for the 3.2L I6?