I'm considering having my Octavia remapped, it's a '61 plate CR140 which hasn't had the 'fix' applied. Ideally, I'd like to keep the DPF/EGR for legal/MOT reasons but I'm not sure what effect a remap will have on their longevity.

 

It's had a pretty easy life, I bought it at three years old with 48k miles on the clock suggesting mostly long distance use. I've put another 100k (fast A-roads) taking it to 148k at just under 7 years old. I know that DPF/EGR/DMF/clutch can all be cause for concern on older cars when remapping. Looking on VCDS, the oil ash level is lower than younger cars and based from that, my latest prediction is the DPF may last until 240k+ miles. The DMF/clutch should also be in pretty good condition given it's mostly cruising.

 

Obviously , a remap will increase boost and fuelling to get more power/torque and probably produce more soot at full throttle. Does anyone know how they work at part throttle cruising? Given the remap is unlikely to have been emission tested, I'm not sure if it will have been optimised to reduce NOx, PM or neither. Ideally, I'd like to retain or drop PM at part throttle which should also reduce EGR use and therefore match or even increase DPF/EGR lifespan.

 

I'd much rather than a proper remap rather than a tuning box, Shark, Revo and ARP seem to frequently mentioned here and offer similar estimates.

 

Any input from a resident expert would be great, even if it's just to say I'm completely misunderstood DPF/EGR operation or what a remap does

I see u live in east anglia so would visit Clive atthowe as they are agents for Oscarli 

Given that Shark looks to have gone under, I'd probably drop Clive an email at some point, looks like they are Revo agent too.

 

Thanks!

EGR doesn't reduce PM, it reduces NOx formation. So a map that creates less PM doesn't imply that EGR flow can/will be then be reduced "cos there's less PM to deal with".  It's more like the converse; to produce less PM, reduce EGR flow (at the expense of increased NOx).

@Wino

So are you saying that a 'clean' map is detrimental to the egr and that a good map will just create more soot, that you then have to deal with via dpf?

Depends on what criteria define your idea of 'clean' and 'good'.

If the car is always at full throttle, more soot will probably get produced as it's using more fuel.

 

At least on my normal commute, only a small percentage is at full throttle. I'm more interested in PM production at a steady 60 or 70mph. Surely the engine will need to create the same about of power/torque to keep the car at a steady speed so the PM production and fuelling should be pretty similar? Or at least a sensible map could be optimised to give a similar amount of PM?

If you want to produce less PM, get the fuelling just right (not excessive) and map a low EGR flow rate. This will produce more NOx emissions than a higher rate of EGR flow would, but only your conscience will probably ever know/care.

Just now, Wino said:

If you want to produce less PM, get the fuelling just right (not excessive) and map a low EGR flow rate. This will produce more NOx emissions than a higher rate of EGR flow would, but only your conscience will probably ever know/care.

 

I was curious if a standard stage 1 map would create a similar amount of PM on a steady drive. It's not so much about wanting to producing more or less PM/NOx, given I've probably got another 2/3 years with the car and it's DPF is on course to last the distance, I don't really want to remap it if it's going to half or third the remaining DPF lifespan.

 

I was hoping someone would know if the popular tuning companies normally tried to keep PM to stock levels when used normally or if they favoured NOx or PM production. As mentioned, they aren't emissions tested so I'm not sure if changing the bias would give any advantage to power. For instance, plenty of people blank the EGR for performance, is a remap likely to reduce EGR usage for similar reasons?

2 minutes ago, langers2k said:

For instance, plenty of people blank the EGR for performance, is a remap likely to reduce EGR usage for similar reasons?

In a word, yes.

2 minutes ago, Wino said:

In a word, yes.

 

Cool, so generally speaking, a remap will probably create:

- more NOx and less PM under part throttle due to less EGR usage

- more NOx and more PM at full throttle due to more fuel and no EGR

 

Therefore, under a normal usage with a bias towards steady high speed cruising, it's unlikely to significantly reduce either EGR or DPF lifespan.

 

That's exactly the answer I was looking for, thanks!

 What has always put me off remapping a DPF car is that you can't see what is coming out of the back. All you have to go on is if the regen frequency increases and how reputable the person doing the map is.

 

1 hour ago, langers2k said:

 

- more NOx and more PM at full throttle due to more fuel and no EGR

 

 

I might be wrong here but I thought at WOT on a standard map the EGR closes anyway, not that I'm saying that statement is wrong btw

Edited 23 August, 20187 yr by SuperbTWM

8 hours ago, SuperbTWM said:

I might be wrong here but I thought at WOT on a standard map the EGR closes anyway, not that I'm saying that statement is wrong btw

 

That's my understanding too

I'm pretty sure some clever fella pointed out that NOx going through the DPF helps to burn off soot within it; so a bit more NOx is not all bad.

6 hours ago, Wino said:

I'm pretty sure some clever fella pointed out that NOx going through the DPF helps to burn off soot within it; so a bit more NOx is not all bad.

 

Yes, coupled with the fact that during an active regen the car produces a hell of a lot more NOx it goes hand in hand really

 

 

So are we saying that well thought out map (not just chucking more fuel and boost in) will do little to harm the long term use of a dpf?  Assuming you only use the extra go when needed rather than "I've got it so I'll use it".

Disagree and anyway the sensors will pick up readings outside ecu parameters and probably throw up a warning light.

Sorry @john2017 I don't understand your post. If it's a map then parameters will be different to stock and expecting different values so I wouldn't expect any warning lights. Never did over 50k miles in my mk11.

11 hours ago, MarkyG82 said:

Sorry @john2017 I don't understand your post. If it's a map then parameters will be different to stock and expecting different values so I wouldn't expect any warning lights. Never did over 50k miles in my mk11.

As long as the tables/ array values are changed for sensors I think pre and post dpf

On ‎12‎/‎09‎/‎2018 at 12:51, MarkyG82 said:

So are we saying that well thought out map (not just chucking more fuel and boost in) will do little to harm the long term use of a dpf?  Assuming you only use the extra go when needed rather than "I've got it so I'll use it".

 

So anyone care to shed some light?  still like to get a map but with the worry of a dpf blocking up it could get expensive.