Popular articles

Tuning Diesels
Remapping the ECU
Dashboard Styling
Induction Kits
Chip tuning
Modified car insurance
Insuring Track days
Remapping Diesels
MPG calculator

Engine Tuning

High performance engine tuning mods that improve performance.
Read more...

Induction Kits

Best cold air intake induction kits and performance impact
Read more...

Stretched Tyres

Are stretched tyres legal and safe
Read more...

De Locking

Delocking a car how to delock a car
Read more...

France Driving

Requirements for driving in France: speed limits and highway code.
Read more...

Hitech Tailored Car Mats

Hitech tailored car mats
Read more...

MPG Calculator

MPG calculator UK miles per Gallon – calculate MPG
Read more...

Member Benefits

Join our forum today and benefit from over 230,000 posts on tuning styling and friendly car banter.

You will also have full access to the modifed car gallery, project updates and the exclusive member only areas.

(All car owners of all ages and from all countries are welcome).
Sign up now!!!

Forum Hot topics

  • Forced induction. Should I supercharge or add a turbo to my ...
    Sign up now
  • Looking for tuners in Guernsey...
    Sign up now
  • How much power do you think I will get from a ...
    Sign up now
  • Problem adding headlight conversion ...
    Sign up now
  • I'm in Texas and want the best ...
    Sign up now
  • What is the best launch method on a drag race ...
    Sign up now

 

 

Share this link on a forum or bookmark it:-

Particulate filters and their impact on performance

"Getting particular about your filter!"

If you've read our diesel tuning article then you probably want to know more about particulate filters. The particulate filter is a stand alone unit. It is located upstream of the cat in the exhaust system and its purpose is to remove soot particles from the gas stream.

The cat the proceeds to do its usual job of converting CO to CO2 and is in no way dependent or relied upon by the particulate filter.

In diesels the cats are two way devices and run in unregulated mode (ie. no O2 sensor like a petrol car). Petrol cats are 3 way closed loop controlled devices, although the principle is much the same.

Diesels are much more efficient that their petrol counterparts and release less CO2 however diesel exhaust fumes are black and sooty which is what the particulate filter attempts to address.

What does a particulate filter do and does it affect performance?

Most particle filter systems require some kind of fuel catalyst to be mixed in with the fuel. This is done automatically each time the filler cap comes off; the car registers the amount of fuel added and then administers the appropriate does of additive to the fuel tank directly.

This additive is stored in a vessel adjacent to the fuel tank and needs periodic refilling, typically every 50,000 miles. PSA vehicles use an additive made by Rhodia Inc (formerly Rhone-Poulenc); its brand name is Eolys. The additive lowers the burning temperature of carbon so that the soot can be cleaned out of the particle filter periodically. This process is known as regeneration.

Regeneration is triggered automatically when pressure sensors either side of the FAP (particle filter) register a pressure differential due to partial blocking (by the soot). During this process a number of things happen:

1. Intercooler is bypassed

2. Glow plugs turn on

3. Extra fuel is injected into the combustion chamber during the expansion phase.

This creates lots and lots of heat. So much in fact the the accumulated soot is literally burnt away. To my mind it's the equivalent of a horizontal chimney fire and probably as dangerous as one.

The process can be induced manually by a technician who has access to the appropriate diagnostic tools. This is called forced regeneration and can occur with the vehicle stationary in the workshop. In this situation, in addition to the intercooler/plugs/post injection the engine revs itself up to about 4500rpm for up to 40 minutes to burn off the soot. There's a rumor flying about that this creates so much exhaust heat that it's been known to burn the workshop's painted floor.

I'm told that some systems operate without the fuel additive but the principle is much the same.
So, no, a particle filter is not a cat. No, you can't get a sports one - its job is to primarily filter out larger airborne particles from your exhaust fumes.

Technically you can remove it but you'd have to re-program the ECU to ignore the pressure sensors otherwise the system is likely to go into limp home mode with fault lights all over the place.

My car is fitted with a FAP, and to my mind it's technology taken too far. What's the point of getting rid of a bit of smoke and replacing it with very very carcinogenic cerium compounds?

As far as particulate filters and performance go they're OK - the Peugeot LE Mans car used them. I am told though that if I removed it from my remapped 406 (192 bhp currently) it would go to nearly 200! So to summarise they are a necessary evil. They're not ideal for performance. But I wonder how much crap mine would belch out without it? I at least have that warm fuzzy feeling that I am not contributing to the suffering of Asthmatics around the country. Article submitted by HDI-fun a TorqueCars forum member and our resident Diesel head.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile. Car Cleaning tips Tips for cheap motoring Power gain calculator Guide to induction kits

Feedback

Please use our forums if you wish to ask a tuning question, and please note we do not sell parts or services, we are just an online magazine.

Help us improve, leave a suggestion or tip

Your Constructive comments on this article



3 Responses to “Particulate filters and FAP Performance gains.”

  1. SMV says:

    I don’t think there is much back presure from these particulate filters and without them deisels would have been banned decades ago.

  2. Marko Tomic says:

    Ok, so you wanted to know what is the downside having FAP on your car? Well, let say that you can have your car burnt out, literally! My car (C4 1.6hdi) caught fire because regeneration started while I was in low gear almost still on the road. It generated so much heat that plastic cover under the engine started to burn and melt. My mechanic told me he had C5 in his shop doing the same thing, but with so much damage, it’s exhaust system got so hot it glowed red and malted everything under the car, even rear bumper! I use my car for urban driving mostly, so that could be the part of the problem, there are no high revs and speeds, I was told that could be the reason.

  3. gn0rfa says:

    I have removed mine on a 320D and it does almost as much as remap to remove the filter also. There are additives you can poor into your tank that burns the soot at low temps directly in the cylinders if you want to feel good about removing it. Dpf is a evil as it states in the article. I use the additive. Google and you will find it.

Web search.