EGR should we all be more concerned

[wai]

Just a query,

On vehicles with a DPF, is the take-off point for EGR before or after the DPF?

Thanks.

[5pot]

My car rarely spends time just sitting in traffic. My morning commute is half an hour and I might spend 10 mins in traffic (<60kph just stopping at lights) but the next 20 mins is on the freeway. Mind you, the previous owner probably did have a lot of time in traffic...

oh well...

[Greg Roles]

Just a query,

On vehicles with a DPF, is the take-off point for EGR before or after the DPF?

Thanks.

Before, the EGR is piped directly out ot the log manifold before the turbo, so you get full soot introduction!

In the newer MK6 they have an EGR filter as well intheir even more expansive EGR system, so they are trying to combat the buildup.

Niel, all high speed country driving will do is produce less soot overall as you arenlt in start stop traffic, accelerating, blowing max soot. It's still going to build up eventually. Seems to be a lot of factors, but driving style is definately part of it. Lots of acceleration from zero, produces a lot of soot till it's on boost. Oil quality and overall engine condition will no doubt be a player, but oddly enough EGR addition and lowering combustion temps actually CREATES more soot, so go figure. You add EGR to drop NOX, but in turn increase soot, and block your DPF even quicker.

My idea is to drop combustion temps by other means, for both NOX and turbo safety, and to ditch EGR which becomes quite redundant. It DOES help your car warm up faster though, my TDI is taking a long time to reach temps in winter up here in QLD, be a real problem down south.

[wai]

Before, the EGR is piped directly out of the log manifold before the turbo, so you get full soot introduction!

In the newer MK6 they have an EGR filter as well in their even more expansive EGR system, so they are trying to combat the build up.

Thanks for that. I collect my new Caddy Maxi Life tomorrow. Maybe it will have the filter, but then the filter would need replacing. Hopefully it is not an expensive replacement.

EGR is not a good solution, and never really has been. I used to work for the DMT in NSW too many years ago, and then we were looking at LPG vehicles for the departmental fleet. I went out to the EPA labs at Rookwood to have two test vehicles go through the drive cycle. In discussions there, the EGR systems (just coming out) and the air injection where air was pumped into the exhaust (remember them) were really only designed to take maximum advantage of the test methodology (i.e. to artificially dilute the exhaust stream) and not really to reduce emissions.

Even take E10 (which is the only standard ULP you can get in Sydney). Unless the vehicle is specifically re-tuned for E10, while you get a reduction in unburnt HC and CO, the NOx can be double that of standard ULP because of leaning as a result of the oxygen released when ethanol burns. If the engine is specifically tuned for E10, then as soon as you travel outside metropolitan Sydney, you can only get standard ULP and now the engine will run rich.

On my Torana, I purchased an EGR blanking plate from Holden as the automatic versions were the only models fitted with EGR. Unfortunately with the amount of computer control involved in modern engines, such things are not really possible.

[Greg Roles]

Unfortunately with the amount of computer control involved in modern engines, such things are not really possible.

I beg to differ, Sir!

Zero EGR or flap in my MKV, stock ECU. FAR better driveability. I'd wait till warranty is up though, you'd freak out those dealer techs!

[wai]

I beg to differ, Sir!

Zero EGR or flap in my MKV, stock ECU. FAR better driveability. I'd wait till warranty is up though, you'd freak out those dealer techs!

Ok, they are

It can be a convoluted path (somewhat) though.

I suppose it is a bit like turbochargers and diesels. If you dared put one on a diesel that did not come like that from the factory in the early days, motor registries and insurers would have kittens. Now they are common place both as original equipment and after market.

[DkN]

Been lurking around these forums for some time, I own an 08 GT and I've been particularly interested in some of the EGR and Provent talk around here. Out of curiosity though, I haven't seen anyone mention this, but is anyone aware of a dynamic EGR tune for the TDI? Malone tuning in the US do them, and I assume they are available through the usual Alientech units that store their ECU tunes. Link here:

Dynamic EGR Control for TDIs - TDIClub Forums

Basically it allows the EGR to operate during warm up as it is beneficial to the car but once it is warmed up the EGR is turned down as far as it is allowed - seems like the best compromise short of removing the EGR and dealing with the many complications that you would have to face.

I apologise if this has been discussed, I just haven't seen this mentioned in my time of trawling through this forum.

edit: Malone Tuning's website lists only 1.9 PD TDI but I emailed them a while ago when I was still looking for a new tune from ChippedUK, they do tune 2.0 TDI as well, although I'm uncertain about the dynamic EGR for 2.0 TDI - I would assume they do though, Mark @ Malone Tuning develops all these tunes himself so he would definitely have the knowledge.

[Greg Roles]

Yeah I was of the impression it was 1.9 only, and the 2.0 MK6 is in development as we speak. i know a TDI club member who has a EGR tune from Malone, but I thought it was rather experimental.

I've found removing the EGR only means a dash cel light, whereas removing the EGR flap prevents DPF regen and throws more serious engine fault codes. If you can live with a light ( like me for now ), just blank off the EGR and get an O2 sensor spacer to aid the situation - oh and be warned your EGT temps can now skyrocket if you flog it senseless, but I have as yet to confirm that, in daily driving my EGT's are still quite normal.

Thanks for the input all the same, let's hope Malone find a good solution, as driving around with bits hanging in the breeze like me is less than ideal!

[DkN]

I thought that the dynamic EGR tune was past experimental stage at least for the 1.9 TDI, it's been listed on Malone's website for a while, and the post in the link I posted says that it has been in use for years with no issues. There isn't any concrete proof of just how much it helps with the gunk buildup though, but it certainly sounds tempting. I might look into it and see if there's any chance it will be available for the mk5 2.0 TDI. It does make me wonder, how difficult is it to make a dynamic EGR tune? Would there be any chance any other custom tuners would offer something like this?

I'm hoping to get my EGR/manifold looked at and cleaned at my next service to see just how concerned I should be since different people seem to be reporting different levels of gunk. I'd do it myself but under the hood I'm still a mechanical noob and installing an APR intake is about as adventurous as I've been.

As for the DPF, for me that's long gone from the car. Maybe you and I should meet up some time Greg, I can have a look at all the tinkering you've done with your car and you can get a feel of what a DPF deleted GT with a Custom Code tune feels like

[Greg Roles]

Sorry I meant the 2.0, in MK6 guise, as the USA never got the 125kw MKV at all.
You can virtually turn off the 1.9 with Vag Com for free, there's instructions up on TDI club about that, but there is no such option for the 2.0 that I have been able to find in Vag Com myself, though I am no Vag Com expert that's for sure. The EGR is controlled by a pretty complex 3D map, Parso Rex started looking into it for me, and may still need him to write out the bits I have hanging in the breeze, but hoping Gav comes through there in the Stage 3 Custom Code tune I want.