I'm on the verge of getting a Superb for taxi use but I'm worried about comments I've seen here on the forum about the effect of the DPF system if used for high urban mileage.

Someone said that if your mileage is high and urban you should favour the petrol engines because the DPF will cause a problem. Can someone explain what problem ? Practically speaking I ought only to be looking at diesel because of the extreme high mileage I'll do and the cost implications of it, plus the sheer longlevity of diesels which again is appropriate for it's intended usage.

If there actually is an issue with DPF involved in high urban mileage this is disappointing but I must know if there is one and understand it.

I need to know if it can be deselected and what will be the implications of not having it in use ?

I'm on the verge of getting a Superb for taxi use but I'm worried about comments I've seen here on the forum about the effect of the DPF system if used for high urban mileage.

Someone said that if your mileage is high and urban you should favour the petrol engines because the DPF will cause a problem. Can someone explain what problem ? Practically speaking I ought only to be looking at diesel because of the extreme high mileage I'll do and the cost implications of it, plus the sheer longlevity of diesels which again is appropriate for it's intended usage.

If there actually is an issue with DPF involved in high urban mileage this is disappointing but I must know if there is one and understand it.

I need to know if it can be deselected and what will be the implications of not having it in use ?

The DPF just catches soot in the exhaust - it can be removed (and the engine remapped to cope without it) by a specialist third-party, but not as a Skoda-approved option.

The issue with DPFs and urban driving is two-fold:

1) On short journeys, the engine never gets warm enough to heat the DPF up to the point where it can regenerate.

2) A cold engine generates more soot than a warm engine, filling the DPF further.

There is a third issue with the older PD engines (not fitted to current models), where the DPF was retrofitted to an existing design, and not put in the best place to keep it hot. The current CR engines don't have this flaw.

To get the DPF to regenerate, it needs hot air run through it steadily, which is easiest done by driving normally until the engine is fully warmed up (easy for a taxi), then driving at a steady high speed (50 mph or more) for several minutes. http://www.theaa.com/motoring_advice/fuels-and-environment/diesel-particulate-filters.html has detailed advice - the ideal is passive regeneration, but I've heard of taxi drivers coping fine on the odd active regeneration.

I think perhaps I'd be okay though, if as you say the issue is engine temperature due to how long it's on before shutdown. Although taxi work is mainly urban in nature, the car is nevertheless in use throughout the day. So I presume the engine will after all be continuously hot enough for the DPF to function as intended.

On the other hand, when waiting for a job I'd tend to switch off the engine to save diesel. I suppose the issue would then be how long I have to wait for the next job and therefore how much the engine will cool by while waiting.

It's a difficult thing to judge I suppose. Okay, so if I wanted to get it disabled I'd need to "re-map" the engine profile. Er ............ but , wouldn't that invalidate my warranty ? Shouldn't Skoda be offering this for taxi drivers if it is actually an issue ?

Shark Performance can remove the DPF, remap & modify ECU to cope with the new changes. It comes with a price of course. You could ask them how much.

Shark Performance can remove the DPF, remap & modify ECU to cope with the new changes. It comes with a price of course. You could ask them how much.

But future regulations, in 2012 I think, might mean it will fail an MOT (when Required) if the DPF has been removed.

I think perhaps I'd be okay though, if as you say the issue is engine temperature due to how long it's on before shutdown. Although taxi work is mainly urban in nature, the car is nevertheless in use throughout the day. So I presume the engine will after all be continuously hot enough for the DPF to function as intended.

On the other hand, when waiting for a job I'd tend to switch off the engine to save diesel. I suppose the issue would then be how long I have to wait for the next job and therefore how much the engine will cool by while waiting.

It's a difficult thing to judge I suppose. Okay, so if I wanted to get it disabled I'd need to "re-map" the engine profile. Er ............ but , wouldn't that invalidate my warranty ? Shouldn't Skoda be offering this for taxi drivers if it is actually an issue ?

The DPF is required to meet the emissions levels that Skoda have to conform to - AFAICT, every Euro 5 compliant diesel (not just Volkswagen Group vehicles) has a DPF (and at this point, I'm sure someone will find me a counter-example). They therefore can't remove it for you, as that would make the car not legal for them to sell.

It's not just engine temperature that matters - it's the exhaust gas that needs to get hot, while still containing enough oxygen to let the DPF burn the soot. On my DSG-equipped Superb, I sometimes notice it choosing to stay down a gear for a little bit longer than normal, to keep hot air flowing through the DPF (holding 5th at 40, instead of shifting up to 6th, for example); it appears to aim to keep the engine revs above 2,000 rpm when it wants to regenerate the DPF, while being happy (170 CR) at under 1,500 rpm most of the time.

Note, therefore, that if you're prone to a bit of "spirited" driving to get to the next job, you'll help regenerate the DPF anyway, as long as the engine is already hot - hot exhaust gases (from a high revving engine) will help the DPF regenerate passively, and the occasional stretch on a fast road will let it add fuel for an active regeneration.

But future regulations, in 2012 I think, might mean it will fail an MOT (when Required) if the DPF has been removed.

It's pure myth, removing the DPF will not cause an Mot failure, including new regs for 1st Jan 2012

Cheers

Steve

I'm beginning to think I'm probably going to okay since the engine will be in use a lot albeit stopped between jobs, therefore it might be kept hot enough to work, and yes there is some "spirited driving" involved at certain points of the work.

But if the dpf does clog up through lack of continual use, just how much does it cost to be rectified ? And just how regularly need it be done ?

I must say I find this whole thing quite bizarre and I'm left wondering what the position is for things like delivery vans and the purpose built wheelchair capable taxi conversions that are derived from then ( Cab Direct E7 and M8 , Voyager NX8 , etc ), and the TX4 ( London black cab ) also.

I'm beginning to think I'm probably going to okay since the engine will be in use a lot albeit stopped between jobs, therefore it might be kept hot enough to work, and yes there is some "spirited driving" involved at certain points of the work.

But if the dpf does clog up through lack of continual use, just how much does it cost to be rectified ? And just how regularly need it be done ?

I must say I find this whole thing quite bizarre and I'm left wondering what the position is for things like delivery vans and the purpose built wheelchair capable taxi conversions that are derived from then ( Cab Direct E7 and M8 , Voyager NX8 , etc ), and the TX4 ( London black cab ) also.

The worst case is that the orange DPF warning light comes on - you ignore it, and don't take the car for a decent stretch at high speed (both 2,000 rpm or more and 40 mph or more) until it turns off. You also don't immediately take it to a garage for a forced regeneration (where they tell the ECU that it can do an active regeneration while stopped, as the car won't be turned off). You then get a ~£1,000 bill for replacing it. In my generation of Superb Combi, page 30 of the manual talks about how you should react to the DPF warning light - it doesn't mention that the engine needs to be up to temperature to start the regeneration, though.

AFAICT, all Euro 5 diesel engines have a DPF, even delivery vans and the TX4 - big trucks have had them for much longer than cars. The horror stories come from two places:

1) The old VW PD engines, which had a DPF retrofitted in a bad place. These were prone to DPF problems even if looked after by someone who read the appropriate bit of manual and tried to give the engine a chance to regenerate the filter.

2) People who ignore warning lights on the dashboard, then get surprised when the car gives them trouble. On the Superb, you get one warning light to tell you that you need to drive in a way that lets it do an active regeneration, and a second to tell you to take it to the dealer for a forced regeneration; you must ignore both of those before it fails.

Given your expected use, here's a thought - does your current vehicle get fully warmed up by about half-way through a shift? If you reach normal engine temperature most of the time, you will probably be able to cope with a DPF.

Well of course it ( the rented purpose built diesel taxi ) gets warmed up long before half way, as indeed any vehicle would I think. I should think a Superb would be so too.

It gets turned off a lot between jobs but of course the engine doesn't get cold as such.

Also, there are longer runs involved in the day's work, on through roads and even country roads occasionally.

Between the above and the earlier advice about heeding warning lights, I reckon now I'll be okay. That doesn't mean the situation is any less silly, but at least I think in my case I'm going to be alright.

Have Greenline 1.9 TDI PD Manual

40 000 Milles done no probs with DPF (no lights or else)

I know when PDF regenerating and just helping the car to do this (driving more constant speed and about 2500 rpm)

How do I know when DPF on, because I do not have smart "Colour one " MDF display

My MDF standard one not upgraded so when DPF kick on the gears show change to higer

If Im driving lower that 2000 rpm the gear indicator show UP so than I know that DPF regeneration starts.

No speeding “aggressive” driving when DPF regenerating this is the main role.

As some say the CR rail engine do not have probs with DPF no not all but when DPF kick in and someone driving aggressive not for long when something will go wrong .

On old engine 2.0 PD DPF my friend car failed and valves blow up causing all other failure – basically new engine needs . He saw maybe ten time that DPF lights come on and latter gone he done how book tells .

The main thing he is “speeding” heavy foot driver and the results need new engine - because DPF do not like breaking and later accelerating when the process start

and if you will have taxi car with DPF you will know when DPF kick on

1 For me 250 - 300 Milles interval always the same (as Im driving same road each day )

2 The engine sound and power delivery changes when DPF working I do not know for CR but for PD you can feel that something going on

My point that you will know when DPF will be regenerating so you will help the car to do the job

I do not know how often this will happen to you but say one time per week IS IT HARD TO DRIVE 10 -15 MIN CONSTANT SPEED AND TO KEEP 2500 RPM

The answer will no it is takes just 10 min to regenerate for me it is one time per week So

No to remove DPF 500 – 1000 Pounds Need new bypass pipe needs ECU program + how is MOT ?

The MOT it is not biggest problem

1 Do not forget your TAX band with DPF are lower so if you remove DPF it is not legal

2 If you want to sell the car put back DPF or sell without DPF ? so another cost to put back DPF and program ECU

Do you see the point :

Cost 1000 Pound and TAX probs or MOT change low and that put back or be legal 10 min of driving properly once a week to help DPF

and if yo

1 Do not forget your TAX band with DPF are lower so if you remove DPF it is not legal

I'm sorry but this statement is wrong.

I'm sorry but this statement is wrong.

From the skoda superb brosure 2009 - 2010

Engine Specifications

1.9 TDI PD 105bhp(no DPF) CO2 emissions g/km* 149

1.9 TDI PD 105bhp DPF CO2 emissions g/km* 129

Can you see diference ?

http://www.direct.gov.uk/en/Motoring/OwningAVehicle/HowToTaxYourVehicle/DG_10012524

First year rates - cars registered on or after 1 April 2010 (based on fuel type and CO2 emissions)

The rates in the table below are only payable for a vehicle’s first tax disc taken out at first registration. All other tax discs will be charged according to the standard rate tables shown above.

Petrol car (TC48) and diesel car (TC49)

A Up to 100 £0.00 Not available

B 101-110 £0.00 Not available

C 111-120 £0.00 Not available

D 121-130 £0.00 Not available "with DPF"

E 131-140 £115.00 £63.25

F 141-150 £130.00 £71.50 "none DPF"

G 151-165 £165.00 £90.75

H 166-175 £265.00 Not available

I 176-185 £315.00 Not available

J 186-200 £445.00 Not available

K 201-225 £580.00 Not available

L 226-255 £790.00 Not available

M Over 255 £1,000.00 Not available

Hi

Sorry I thought I was clear. Your statement was wrong. It is not illegal if you remove the DPF. As long as the vehicle passes emissions test at MOT time it is perfectly legal to do so.

VED is calculated based on manufacturers figures at time of manufacture. There is no retrospective testing or calculation of VED.

Cheers

Steve

It will be fine with the cr and your mileage

Just FYI, your car will not fail MOT, if you remove the DPF and get a proper chip tuning. Emissions will be ~ same.

Diesels aren't measured on emissions they are measured on smoke.

Then you have even less to worry about.

Then you have even less to worry about.

except the controls for smoke will be tighter from next year and a car MOT'd that should have a DPF is going to emit too much smoke.

except the controls for smoke will be tighter from next year and a car MOT'd that should have a DPF is going to emit too much smoke.

This is simply not true! Try doing some research before posting such bull****!

The majority of post euro II diesel without DPF should have no problem getting a current fast pass, which is the new max for 2008 and on vehicles in the 2012 MOT reqs

This is simply not true! Try doing some research before posting such bull****!

The majority of post euro II diesel without DPF should have no problem getting a current fast pass, which is the new max for 2008 and on vehicles in the 2012 MOT reqs

Share your research then instead of just slating other peoples posts.

Share your research then instead of just slating other peoples posts.

I'm not slating other people's posts, I'm merely correcting ones that are wrong, especially when they make statements like it's illegal when it's not, or like yours that states that vehicles with the DPF removed will emit too much smoke and will not pass an MOT.

They are wrong and if not corrected are misleading. Personally, it amazes me why people like you will happily makes these sweeping statements and mislead readers of this forum, when clearly you haven't looked into it.

If you want facts, the new diesel smoke test pass level coming in to force on Jan 1 2012 is for 2008 and on vehicles only. It is the same level as the current fast pass level. It's impossible to say all, but the majority of post 2008 cars will easily pass this level without a Cat or DPF fitted.

Removing a DPF is not illegal, it doesn't affect VED and is highly unlikely to affect a smoke test pass at an MOT test. Is that ok? Also if you did a search you'll see that this has already been discussed on this forum.

Thanks stevehg.. :-)

I'm not slating other people's posts, I'm merely correcting ones that are wrong, especially when they make statements like it's illegal when it's not, or like yours that states that vehicles with the DPF removed will emit too much smoke and will not pass an MOT.

They are wrong and if not corrected are misleading. Personally, it amazes me why people like you will happily makes these sweeping statements and mislead readers of this forum, when clearly you haven't looked into it.

If you want facts, the new diesel smoke test pass level coming in to force on Jan 1 2012 is for 2008 and on vehicles only. It is the same level as the current fast pass level. It's impossible to say all, but the majority of post 2008 cars will easily pass this level without a Cat or DPF fitted.

Removing a DPF is not illegal, it doesn't affect VED and is highly unlikely to affect a smoke test pass at an MOT test. Is that ok? Also if you did a search you'll see that this has already been discussed on this forum.

I asked for proof as how do i know that you are just posting a sweeping statement. I never said that removing a DPF is illegal but it will cause the car to emit smoke (which with a DPF it doesn't do). If it is the case that post 2008 cars are stopping on the same fast pass level then why do manufacturers bother to fit these expensive, pointless, unreliable items to their cars?

You can't say for sure that a DPF deleted car will pass an MOT test at all but what i can safely say is that a DPF equipped car will pass a smoke test unless there is a serious fault with the DPF.

Personally i can't stand the things, not from my point of view but from what i have read on here and elsewhere they seem to be more trouble than they are worth but they must be there for some reason. :wonder: