Pros and Cons of DPF Delete

Cons? None other than regulations. Make sure to get EGR done as well (and adblue if it has it), and then get all 3 mapped out properly. Don't just cut out the DPF and not map it out as this may be damaging.

Also make sure to leave a gutted dpf in place not a straight pipe, for NCT checks.

You can get an economy remap as well. No extra power just better fuel consumption.

Talk of this in our house with new (2016 A6). Son is on about EGR removal and a box in place instead, gutting DPF and putting in a straight pipe, remap but not a power map.

Can someone explain the EGR removal part please, specifically, is it just a map so valve stays open or does not open and what welded box is he possibility on about. The DPF straight pipe inside body of gutted DPF I understand plus mapping out adblue and EGR function. What would be a typical cost of this ?

I have that engine in my Mondeo, DPF gutted EGR deleted and a power map, 160k miles on mine and the car shudders going past 2k revs at wide open throttle so if you're due a flywheel it'll bring that on sooner, can even see the spike in power and the rolling road printout at 2k revs. easy drive around it though, if I'm flooring it I'll wait until 2.5k revs and all is well. Been a couple years now and no issues with it since.

Power map yields increased economy due to not needing to press the accelerator as much to get the car going. Youll drive the car harder through excitement at first, then the novelty wears off and youll gain mpg from not flooring it every chance you get.

To the best of my knowledge an Economy map still has some bhp and torque increases, it's just not the main priority.

The mechanics and DPF cleaning companies who don’t offer a removal service have been peddling that information for about 10 years now. There is already a visual inspection of the DPF and theres no obvious plans to make any changes to this.

Most cars being sold now don’t even have a DPF. Its all EV, hybrid, or petrol these days so I can’t see any NCT changes being brought in personally.

On a mondeo, they take the exhaust off, cut dpf open in the top side (facing underbody), hollow it out and weld it back together. Then refitted and you cannot see the welds at all. Passed NCT about 4 times since. Depending on where you are, maybe talk to coby autos at red cow…. Also do remaps and the mondeo is still going strong 4 years later.

It's advisable to get an oil change after a forced regen.

Also a forced regen should be absolute last port of call, it's a lot of added stress on an engine.

Option number 1 would be find and sort whatever issue is causing the DPF to not regen.

Fuel vaporiser attached to exhaust can give trouble, has your mechanic checked the DPF pressure sensor readings on a scan tool to see if DPF is blocked or if there's an issue with the pressure sensor itself? Glow plugs could need doing, ambient air temp sensor being bad can cause DPF issues.

Getting the DPF cleaned using high air pressure and a proper cleaning agent fed through a high pressure gun is more effective than letting it do a forced regen.

DPFs very rarely actually need to be replaced, but if you do a forced regen and the DPF is in fact blocked, it will get too hot and will probably crack the DPF. certain things need to be checked before just going ahead and running a forced regen.

Won't repeat what been said before.

But I've noticed the fumes of some diesels is really bad, like gives you a bad headache bad. I assume it's from a dpf delete.

Kinda crazy the NCT doesn't check for it.

Pressure drop across a functioning DPF is minimal.

Plenty of people (including myself) driving around in diesel cars that never had a DPF.

The cars sold by Renault during the scrappage scheme mostly had no DPF and these cars have proven to be very reliable, economical and hassle free.

I don't have strong views either way on the ethical/moral implications of removing a DPF from a car that originally had one but because I'm goody two shoes, I probably wouldn't do this.

If a DPF was expected to last 200k kms and could be replaced for say, 1000 euro with a high expectation that the new one would last a further 200k then not so bad. We know that this isn't the case. Other factors can affect the DPF and many mechanics don't know how to diagnose and fix diesels. They also contribute to problems by using the wrong oil because they don't understand the implications and/or don't give a sh*te.

I'm currently looking at used diesels from about 2015-2018 from dealers and haven't yet found one that I'm confident is running correctly. Could well be DPF related. Idle lumpier than it should be, random small hesitations and fuel economy clearly not what it should be. Most buyers wouldn't spot these things.