Advice about remapping and dpf removal

Sgt Tackleberry · 6 Feb 2017 at 18:07

Hi guys,

Need some advice about getting my car remapped, dpf removed and the egr value removed. I've found a local company near me who can do the whole lot for a very good price.

My car is VW passat 2011 2lt TDI with just over 125k miles, I do a lot of milage a month about 5k as I'm a taxi driver so I do a lot of town mileage with some motorway. My car is fine and I have no problems with it at all, I get it serviced every 6weeks by a vw specialist.

So is it safe to have this work done or not?. As I've spoked to a few people and read up on and it seems to be 50/50

Many thanks

Diddums x · 6 Feb 2017 at 18:12

Depends how much of a toss you give about other people.

I wouldn't bother, the car is getting on a bit and I'm sure it cycles fairly well given the use it gets.

Dav4 · 6 Feb 2017 at 18:16

Why would u want to remap it if it's used for your job? Why would u need more power? And people don't realise remapping adding extra power puts extra stress on already worn items.
Why would u also remove the dpf? Is that not illegal? And mot failure?

Nasher · 6 Feb 2017 at 18:17

It's an MOT fail, it's one of the things they check for specifically now

Diddums x · 6 Feb 2017 at 18:19

Nasher said:
It's an MOT fail, it's one of the things they check for specifically now

Good. The sooner we move on from our reliance on these stupidly over-polluting diesels the better. Seems even the gov has slowly started backtracking, hoping nobody would notice their balls-up.

Flack88 · 6 Feb 2017 at 18:22

It is safe if it done by someone who knows what they are doing with air/fuel ratios (this can melt pistons) and doesn't go overboard with the boost so you bend or throw a conrod, you may also need an up-rated clutch as the stock one can slip with the torque increase. A friend of mine had is VW Bora done and it used to slip the clutch in 5th and 6th.

No idea why you would want it done on a work car, as it's going to kill your MPG. Also if you cant get a 'friendly' MOT then you will have to put it all back to standard for the MOT.

Nasher · 6 Feb 2017 at 18:38

Personally I wouldn't mess with most turbo diesel engines. The amount of TDI engines that have gone bang is pretty high.

geekman · 6 Feb 2017 at 18:52

Currently the DPF removal will only fail your MOT if it's been obviously removed - the tester only does a visual check. Most places just gut them which gives the same result but passes an MOT.

A lot of remaps will actually improve economy, it depends if you ask for a map geared to economy or performance.

Frozennova · 6 Feb 2017 at 19:01

Flack88 said:
It is safe if it done by someone who knows what they are doing with air/fuel ratios (this can melt pistons) and doesn't go overboard with the boost so you bend or throw a conrod, you may also need an up-rated clutch as the stock one can slip with the torque increase. A friend of mine had is VW Bora done and it used to slip the clutch in 5th and 6th.

No idea why you would want it done on a work car, as it's going to kill your MPG. Also if you cant get a 'friendly' MOT then you will have to put it all back to standard for the MOT.

The only valid point you really make is clutch slip

Any tuner with any sort of reputation is going to know enough to leave you with a car that's knocking

I highly doubt any run of the mill diesel engine is fitted with a turbo anywhere near big enough to make enough boost to bend or throw a rod.

And tuned cars tend to either return the same or better MPG.

GeForce · 6 Feb 2017 at 19:03

Diddums said:
Good. The sooner we move on from our reliance on these stupidly over-polluting diesels the better. Seems even the gov has slowly started backtracking, hoping nobody would notice their balls-up.

Modern diesels with their antipollution systems working correctly are extremely clean.

Whether that technology works for the lifetime of the vehicle is a different argument though.

Sgt Tackleberry · 6 Feb 2017 at 19:04

Sorry I wasn't clear in my first post.

With the remap it would be for better fuel consumption not performance.
With the dpf and egr value being removed, I've known a lot of taxi drivers who have problems with these and car going into limp mode and getting them repaired or replaced it cost loads.. so having it done should save money in the long run. Dpf being removed so you won't see it not unless you take it off as the they go through the top and weld it back.

Swifty55 · 6 Feb 2017 at 19:11

Do it.

I had my old Zafira 1.9 CDTi remapped with an EGR and DPF delete.

They have to remap the ECU anyway to disable the EGR and DPF. So may as well give it a boost. 150bhp to about 180bhp iirc.

Cost me around £300 all in.

Swifty55 · 6 Feb 2017 at 19:13

Also. They cut on top of the DPF, gut it and then wield it back together. MOT is just a visual check so you will be fine. Also always good to know a tester.

OpenToSuggestions · 6 Feb 2017 at 19:18

It is obvious when I car has had the DPF removed.

A friendly (aka dishonest) MOT tester would pass it, but any mechanic with any level of job pride wouldn't.

Kamerad · 6 Feb 2017 at 19:28

No point remapping that car, just going to decrease it's reliability for pointless gains.

EddScott · 6 Feb 2017 at 20:30

My A4 TDI had the DPF, EGR and EGR cooler removed about 5 years ago. The mapping that was carried out only removed the DPF from map. Boost wasn't increased so it's never been an issue.

Dr Who · 7 Feb 2017 at 01:40

GeForce said:
Modern diesels with their antipollution systems working correctly are extremely clean.

Whether that technology works for the lifetime of the vehicle is a different argument though.

They are not extremely clean, they are better than petrol on some measures and worse on others.

The only extremely clean vehicles are EV's charged by solar, and then you have to factor in the environmental costs of manufacture.

Entai · 7 Feb 2017 at 09:29

DPF removal will be a thing of the past within six months.
The Department for Transport has commissioned research on how existing or new technology can be used to detect DPF removal by measuring exhaust fumes.
One possibility is adapting the use of the equipment that performs the current MOT smoke test to make it more sensitive.
The findings will be implemented as part of changes to the Roadworthiness Directive, which sets the framework for MOT testing, and is scheduled to be introduced in the UK in mid 2017.

sovietspybob · 7 Feb 2017 at 09:46

Entai said:
DPF removal will be a thing of the past within six months.
The Department for Transport has commissioned research on how existing or new technology can be used to detect DPF removal by measuring exhaust fumes.
One possibility is adapting the use of the equipment that performs the current MOT smoke test to make it more sensitive.
The findings will be implemented as part of changes to the Roadworthiness Directive, which sets the framework for MOT testing, and is scheduled to be introduced in the UK in mid 2017.

Good, i have to run catalytic converters on all my petrol cars so why should diesel owners get a free ride flaunting the emission laws.

GeForce · 7 Feb 2017 at 09:52

Entai said:
One possibility is adapting the use of the equipment that performs the current MOT smoke test to make it more sensitive.

The interesting thing will be how this is implemented.

Will the test be (like gasoline) that the car conforms to the specification for which it was type approved? I.e. a Euro 3 diesel emit particulate matter under 0.05g/km, but a Euro 5 diesel must be under 0.005g/km etc.

This must be so, it would be unfair to hold a Euro 3 vehicle to today's Euro 6 standards.

And if that is the case, that implies that a vehicle which has had its DPF removed, but still meets the emission limits, will pass the MOT.