I plugged in VCDS today and decided to change the EGR setting. It's adaption default value is 32768 which is about 270 mg/stroke. I first altered it to 33768 (370 mg/stroke) which is the maximum setting. I then finally decided on 33268 (320 mg/stroke) and took the car for a drive. It would seem the the drivability has slightly improved, and the small hesistation I get on acceleration is better. Also my fuel economy seems a bit better, up by about 5%. A 75 mile run today returned about 53mpg. Previously the same run would've achieved 50-51mpg.

Has anyone else experimented with this and what were the results?

I just blanked mine off and terminated the vacuum hose, and did not worry about doing any adaption stuff.

Just blank if off and do away with it, all it does is clog your engine up with crap anyway, nothing but trouble

I didn't particularly want zero EGR, which although would prevent intake manifold clogging it would also increase NOx and exhaust gas temperature. I don't know what kind of effect this might have on the turbo, and that's why I went for a reduction in EGR and not complete elimination. I guess it'll be a bit of trial and error, and with VCDS the default values can be reset if required.

I suspect that a catchcan or an elephant mod is the best way to keep the inlet manifold clean. Mine smokes well out of mine - even the MOT tester approved (while getting a faceful!).

I suspect that a catchcan or an elephant mod is the best way to keep the inlet manifold clean. Mine smokes well out of mine - even the MOT tester approved (while getting a faceful!).

doing the elephant mod stops the oily muck getting into the intake then it doesn't form the gunge with the soot from the EGR so I suspect that this is the easier way to stop things getting cacked up.

Mine always looks a bit odd with what looks like smoke coming out from the headlight in winter because I vent the CCV via a catch can.

doing the elephant mod stops the oily muck getting into the intake then it doesn't form the gunge with the soot from the EGR so I suspect that this is the easier way to stop things getting cacked up.

Mine always looks a bit odd with what looks like smoke coming out from the headlight in winter because I vent the CCV via a catch can.

:+1:

I figured the gasses/soot from the EGR would be much "drier" and thus were less likely to clog the inlet if the warm oily air from the crank case wasn't added to the equation.

I do wonder what the cars behind me in a traffic jam think in the winter months when this "smoke" is coming out from under my car and shows up well in the headlights

I do wonder what the cars behind me in a traffic jam think in the winter months when this "smoke" is coming out from under my car and shows up well in the headlights

The "smoke" on mine shows up in my own headlight!

Edited 20 June, 201115 yr by trundlenut

The "smoke" on mine shows up in my own headlight!

Mine does that, but only when I am going in reserve (like down the driveway and into the garage). I decided to vent mine closer towards the back of the car as I was getting an oily whiff into the car..

I plugged in VCDS today and decided to change the EGR setting. It's adaption default value is 32768 which is about 270 mg/stroke. I first altered it to 33768 (370 mg/stroke) which is the maximum setting. I then finally decided on 33268 (320 mg/stroke) and took the car for a drive. It would seem the the drivability has slightly improved, and the small hesistation I get on acceleration is better. Also my fuel economy seems a bit better, up by about 5%. A 75 mile run today returned about 53mpg. Previously the same run would've achieved 50-51mpg.

Has anyone else experimented with this and what were the results?

So, if I read this correctly, your car is running better with the EGR putting more stuff back into the inlet manifold than when you started, or am I misunderstanding the way these things work? :S

The figure relates to perceived air flow. The greater the air flow the the less recirculated exhaust.

It’s not a good idea to remove the EGR due to the fact that one of its main roles is to cool the exhaust side of the engine, it also lowers cylinder temperatures.

If you remove this you are raising internal temperature quite a bit and have no idea what it could be doing to the internals with the increase in temperature.

I know they don’t have them on many race applications but that’s fine when you’ve not got to worry about longevity of the engine!

The way to think of it it’s there for a reason VW wouldn’t spend thousands of pounds in development to fit a part that’s not really needed, they would only put it in if it was a real need!

I understand that things probably aren’t as good or as efficient as they could be but when something’s there to provide cooling or the like then leave it be!

You wouldn’t remove the radiator or cooling fans to make it run warmer or save weight! So why remove the EGR valve, asking for trouble.

That’s why it’s got a warning light to tell you it’s not working!!!

IMHO Leave it be!!!!

The figure relates to perceived air flow. The greater the air flow the the less recirculated exhaust.

Now I see

Dannyboy759. I haven't removed it, nor have I blocked it off. It's still in place and still working. All I've done is made a reduction in the amount of exhaust gas that's recirculated by around half. Whilst you are quite right about the purpose of the EGR valve it's also worth remembering that too much recirculation will cause other problems such as poor idle, poor acceleration and excessive smoke.

How does a egr cool the exhaust when it is pumping hot exhaust gas back into the inlet, surly it will increase combustion temp thus increasing exhaust temps

It’s not a good idea to remove the EGR due to the fact that one of its main roles is to cool the exhaust side of the engine, it also lowers cylinder temperatures.

If you remove this you are raising internal temperature quite a bit and have no idea what it could be doing to the internals with the increase in temperature.

I know they don’t have them on many race applications but that’s fine when you’ve not got to worry about longevity of the engine!

The way to think of it it’s there for a reason VW wouldn’t spend thousands of pounds in development to fit a part that’s not really needed, they would only put it in if it was a real need!

I understand that things probably aren’t as good or as efficient as they could be but when something’s there to provide cooling or the like then leave it be!

You wouldn’t remove the radiator or cooling fans to make it run warmer or save weight! So why remove the EGR valve, asking for trouble.

That’s why it’s got a warning light to tell you it’s not working!!!

IMHO Leave it be!!!!

Utter Nonsense.

EGR reduces the excess oxygen and combustion temp in order to reduce NOx by upto 40% without retarding the timing. This is the only reason.

This does not mean that the engine will suffer any damage without it. It makes no difference to the longevity of the engine.

Diesels perform most efficiently at high temperatures. The EGR duty cycle is controlled by the ECU to ensure there is still always an excess of air. It is almost off at WOT.

Given that the sum of gases entering the engine is EGR+MAF, you should adjust the EGR duty cycle to off with VCDS to match a blanked off EGR. The ECU now knows that only MAF gases are entering the engine.

Utter Nonsense.

EGR reduces the excess oxygen and combustion temp in order to reduce NOx by upto 40% without retarding the timing. This is the only reason.

This does not mean that the engine will suffer any damage without it. It makes no difference to the longevity of the engine.

Diesels perform most efficiently at high temperatures. The EGR duty cycle is controlled by the ECU to ensure there is still always an excess of air. It is almost off at WOT.

Given that the sum of gases entering the engine is EGR+MAF, you should adjust the EGR duty cycle to off with VCDS to match a blanked off EGR. The ECU now knows that only MAF gases are entering the engine.

Agreed but im still not convinced of its removal!

Agreed but im still not convinced of its removal!

well mine has been ok for the last 100K with it blanked off and thats with towing heavy cars on trailers and lots of thrashing too.

I didn't particularly want zero EGR, which although would prevent intake manifold clogging it would also increase NOx and exhaust gas temperature. I don't know what kind of effect this might have on the turbo, and that's why I went for a reduction in EGR and not complete elimination. I guess it'll be a bit of trial and error, and with VCDS the default values can be reset if required.

Did you adjust the EGR values using the instruction from the Ross Tech website?

http://www.ross-tech.com/vag-com/cars/tdi.html

(About 3/4 of the way down).

Did you adjust the EGR values using the instruction from the Ross Tech website?

http://www.ross-tech.com/vag-com/cars/tdi.html

(About 3/4 of the way down).

Yes, exactly that. Go into the Engine module and click on Login. Enter the login code of 12233 and go to channel 3 for EGR. The default value is 32768 which equates to 270 mg/stroke of intake air. As I stated earlier in this thread I changed the value to 33268 which is halfway between the default value and the maximum value permitted. I discovered that the intake air is now 320 mg/stroke because less exhaust gas is being recirculated, and as a result the engine runs smoother for it. Give it a try. You can always go back to the default value if you don't like it, or try a different value. One tip though, when you do it make sure all electrical loads including climate control are switched off, otherwise the extra load on the engine will increase air flow and your readings will be confusing.

Edited 22 June, 201115 yr by Railroad

Changed to the 33268 value at lunch time and it does seem to run more smoothly. The fuel consumption on the computer seemed better on the run home too, but I'll see on the next couple of fill ups. Thanks for the tip