DPF....Bypass? | Motoring discussion | Back Room Forum

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Fri 29 Aug 2008 22:04

DPF....Bypass? - gordonbennet

The morals police don't need to get upset, this is theoretical.

We are aware that many owners of performance petrol cars buy themselves aftermarket freer flowing exhausts, often with a straight thru piece of pipe where there should be a cat, and only fitting the cat for MOT tests.
I don't condone this, but it does go on, and i can understand why its being done.

Now in my ignorance i am assuming that the large cat like bulge in the downpipe of the exhaust system of a modern DPF equipped diesel car is in fact the DPF.
If its not tell me i'm a berk, everyone else does...;)

If thats not the case, and its a diesel cat, where is the dpf situated?

Whats to stop someone doing the same with their diesel exhaust and fitting a by pass pipe eliminating the DPF?
Would it in fact be beneficial to the overall running of the car.
I'm asking as posters constantly refer to modern diesels needing to be regularly driven long distances to keep the dashed thing clear, is this really the case?

Are there any other more reasonable preventative measures we can take to help prolong the life of these emission systems?

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Fri 29 Aug 2008 22:07

DPF....Bypass? - Alby Back

Um... buy a petrol car.....

;-)

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Fri 29 Aug 2008 22:46

DPF....Bypass? - qxman {p}

I imagine most recent vehicles (petrol or diesel) incorporate some sort of sensing and diagnostic system so that the efficiency of the cat/DPF can be monitored and will flag a fault if its messed about with. I don't think you can bypass the cat on a modern petrol car (not without a fault code showing). I suppose you could spoof the sensor signal, but sounds like a lot of hassle.

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Fri 29 Aug 2008 22:51

DPF....Bypass? - smokescreen

Talking to the guy who remapped my car.

Basically said Euro4 Diesel cars are a nightmare overall to remap because of DPF issues. The remap either causes the DPF warnings to come on sooner because of the extra boost pressure going past the DPF sensor's threshold, or in the worst case, set on fire!

The only ones that remapped well without issues with the DPF are the 1.9CDTi's found in Vauxhall/Alfa/SAAB etc.

So as qxman rightly said, gotta bypass the DPF sensor first.

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Fri 29 Aug 2008 22:55

DPF....Bypass? - rtj70

I'd have thought there has to be a sensor on the DPF for the ECU to decide when to regenerate.... so no DPF = a confused ECU.

I still am surprised so many Euro IV diesels need a DPF when my last car (first of the Euro IV Mondeo Mk IIIs) did not need a DPF to achieve this. Maybe they are experimenting with us before they are really neeed for Euro V?

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Fri 29 Aug 2008 23:58

DPF....Bypass? - Screwloose

Removing the DPF would certainly avoid all the nightmares that they're causing - they aren't proving viable, so an alternative must be found.

The only practicable solution to de-DPFing is a re-map of the ECU to eliminate all DPF-related software. Trying to fool the ECU would require a very sophisticated interface to substitute for the differential pressure sensor.

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Sat 30 Aug 2008 01:05

DPF....Bypass? - Hamsafar

Most delete kits contain a control unit which you plug in to trick the ECU. I think these will become more and more common and cheaper.

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Sat 30 Aug 2008 18:03

DPF....Bypass? - gordonbennet

Thanks for the replies chaps, was hoping for some secret formula's for keeping things together for a long trouble free life.

From the sounds of it, removing the things altogether could become quite popular in time to come, when the aftermarket tuning lads find better ways to fool the ECU.

Edited by Dynamic Dave on 30/08/2008 at 21:28

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Sat 30 Aug 2008 18:14

DPF....Bypass? - Screwloose

when the aftermarket tuning lads find better ways to fool the ECU.

It would be a piece of cake for the VMs to add the differential pressure sensor to the security CAN network. [Yes; I know that's a tautology...]

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