A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D3 > D3 - Engine Bay

D3 - Engine Bay Everything under the bonnet

Reply
 
Thread Tools Display Modes
  #1  
Old 29th July 2018, 12:14 PM
jonnypym123's Avatar
jonnypym123 jonnypym123 is offline
Member
 
Join Date: Oct 2017
Location: Northumberland
Posts: 79
Default egr restrictor plate

Being a curious man I purchased one of these and fitted it yesterday to my 3.0tdi, it restricts the flow of EGR gases, I know if it had been a plane blanking EML would have likely come on and that would be an MOT fail but with the restrictor all is good, Initial response is it seems to have a better pick up, I will test the economy of it tomorrow, amazing the lengths they go to for emissions at the sacrifice of your engine

https://www.ebay.co.uk/itm/EGR-valve....c100005.m1851
__________________
Jonny P
Audi A8 D3 2006 3.0TDI Quattro Sport
Added: Bluespark CR 1, two new front tyres, 20mm hubcentric spacers on the rear, rear audi number plate surround with new plates, new Bosch Aero wipers, Standardigital TV, Bose sound system, heated seats, sports suspension, 20x9 9 spoke RS4 style rims, audi aluminium valve caps, bumper resprayed, mirrors sprayed, a wash every few weeks

Future mods: Turbo uprgade possibly and sort out those downturned exhausts only a mother could love 😂
Reply With Quote
  #2  
Old 29th July 2018, 09:53 PM
Johnmed Johnmed is offline
Senior Member
 
Join Date: Dec 2014
Location: Cheshire
Posts: 1,414
Default

Iím relatively new to TDi powerplants, what if any is the advantage of these?
__________________


CURRENT CAR: Quartz gray 2008 A8 3.0 TDi. My installs: (2009) AMI and ViseeO Tune2Air WMA3000A, generic RVC, Westfalia OEM towbar, D4 19s and S8 MFSW with paddles.

LAST CAR: Black 2001 A2 1.4 TDi, winter pack, leather/alcantara sports seats, DIS and BrokenSky
Reply With Quote
  #3  
Old 30th July 2018, 06:49 AM
jonnypym123's Avatar
jonnypym123 jonnypym123 is offline
Member
 
Join Date: Oct 2017
Location: Northumberland
Posts: 79
Default

It'll reduce exhaust gases being fed from the exhaust into the engine, the engine is fed its own waste to reduce emissions in normal egr operation, worth having a read around this madness. I didn't want a full egr blank as eml light would come on and thats an mot fail, will see what its like on ecomony today
__________________
Jonny P
Audi A8 D3 2006 3.0TDI Quattro Sport
Added: Bluespark CR 1, two new front tyres, 20mm hubcentric spacers on the rear, rear audi number plate surround with new plates, new Bosch Aero wipers, Standardigital TV, Bose sound system, heated seats, sports suspension, 20x9 9 spoke RS4 style rims, audi aluminium valve caps, bumper resprayed, mirrors sprayed, a wash every few weeks

Future mods: Turbo uprgade possibly and sort out those downturned exhausts only a mother could love 😂
Reply With Quote
  #4  
Old 30th July 2018, 07:11 AM
Johnmed Johnmed is offline
Senior Member
 
Join Date: Dec 2014
Location: Cheshire
Posts: 1,414
Default

Cheers Johnny. I was aware of the very basics of its function, but unsure of its effects on fuel economy. Iíll be interested too in what differences you see.
__________________


CURRENT CAR: Quartz gray 2008 A8 3.0 TDi. My installs: (2009) AMI and ViseeO Tune2Air WMA3000A, generic RVC, Westfalia OEM towbar, D4 19s and S8 MFSW with paddles.

LAST CAR: Black 2001 A2 1.4 TDi, winter pack, leather/alcantara sports seats, DIS and BrokenSky
Reply With Quote
  #5  
Old 30th July 2018, 10:29 AM
jonnypym123's Avatar
jonnypym123 jonnypym123 is offline
Member
 
Join Date: Oct 2017
Location: Northumberland
Posts: 79
Default

Hey John, I drove to work today 26 mile It looks like it has no effect on economy which I was surprised, 40.5mpg for that trip which is the usual I normally get, I'm sure it must be better for the engine though less inhaling all that muck from the exhaust
__________________
Jonny P
Audi A8 D3 2006 3.0TDI Quattro Sport
Added: Bluespark CR 1, two new front tyres, 20mm hubcentric spacers on the rear, rear audi number plate surround with new plates, new Bosch Aero wipers, Standardigital TV, Bose sound system, heated seats, sports suspension, 20x9 9 spoke RS4 style rims, audi aluminium valve caps, bumper resprayed, mirrors sprayed, a wash every few weeks

Future mods: Turbo uprgade possibly and sort out those downturned exhausts only a mother could love 😂
Reply With Quote
  #6  
Old 30th July 2018, 10:33 AM
snapdragon's Avatar
snapdragon snapdragon is offline
Senior Member
 
Join Date: Nov 2011
Location: Registered Homeless
Posts: 1,428
Default

TBH, if less EGR gas is entering the intake than is specified (demanded) by the ECU, you will get an 001025 - EGR System P0401 - 002 - Insufficient Flow code. It is measured by the drop in the the airflow meter reading that happens when the EGR allows unmetered exhaust gas into the intake and corroborated by the O2 sensor in the pre-catalyst on 06-on models which looks for a small enrichment.
This is continually monitored by the ECU and the EGR valve position modulated to keep it within tolerance. I suspect the restriction is not adequate to reduce it enough to trigger.

You should get better economy if anything and cleaner intake, but it may be noisier coming off the overrun as the EGR's richer mixture makes for a quieter combustion.
__________________
A8L 3.0TDi SE Quattro 2006
Reply With Quote
  #7  
Old 30th July 2018, 10:35 AM
Johnmed Johnmed is offline
Senior Member
 
Join Date: Dec 2014
Location: Cheshire
Posts: 1,414
Default

Thanks for the update John.

How do people get these MPG figures? I’m a former hypermiler, in my A2 I got 60mpg around town and at 60mph 70mpg. Similarly in the wife’s 2015 Honda I get the same mpg as I did in the 3 cyl TDi.

My A8 used to get around 35mpg on a run to SW France, now it gets 33mpg, I put this down to wider tyres and bigger and heavier wheels. To get in the 40s I have to drive on the motorway at 56mph.
__________________


CURRENT CAR: Quartz gray 2008 A8 3.0 TDi. My installs: (2009) AMI and ViseeO Tune2Air WMA3000A, generic RVC, Westfalia OEM towbar, D4 19s and S8 MFSW with paddles.

LAST CAR: Black 2001 A2 1.4 TDi, winter pack, leather/alcantara sports seats, DIS and BrokenSky
Reply With Quote
  #8  
Old 30th July 2018, 11:13 AM
jonnypym123's Avatar
jonnypym123 jonnypym123 is offline
Member
 
Join Date: Oct 2017
Location: Northumberland
Posts: 79
Default

Haha that's exactly it really, I do 60 instead of 70 on the way to work, do put my foot down now and again. I'm using a tuning box plus mufflers are off and straight pipes fitted mpg went up by 3mpg when I had the exhaust done, prior it was 37/38, Its 52 miles a day so saving money helps
__________________
Jonny P
Audi A8 D3 2006 3.0TDI Quattro Sport
Added: Bluespark CR 1, two new front tyres, 20mm hubcentric spacers on the rear, rear audi number plate surround with new plates, new Bosch Aero wipers, Standardigital TV, Bose sound system, heated seats, sports suspension, 20x9 9 spoke RS4 style rims, audi aluminium valve caps, bumper resprayed, mirrors sprayed, a wash every few weeks

Future mods: Turbo uprgade possibly and sort out those downturned exhausts only a mother could love 😂
Reply With Quote
  #9  
Old 30th July 2018, 12:39 PM
ainarssems ainarssems is offline
Senior Member
 
Join Date: Aug 2010
Location: Rushden, Northants
Posts: 3,082
Default

I am not sure these restrictor plates do much or anything at all on modern engines which determine how much EGR is open based on measured airflow. If something is blocking EGR flow and metered airflow is too high ECU will just open EGR valve more, if the air flow or EGR duty cycle is out of tolerance sit will throw error code. Have a look at measuring blocks in VCDS for specified and actual airflow and EGR duty cycle. If the specified and actual airflow ar close together you have not made much difference on amount of EGR entering engine, if the EGR duty cycle % is high it means ECU is opening EGR valve more to meet the specifications. It would have been great for comparison if you had a log before and after fitting plate.

Restrictor plates were working for older cars like 1.9TDI where EGR was only mapped in ECU as duty cycle and not as specified airflow on newer cars. Basically on old cars ECU just looked at the map and choose EGR duty cycle depending on rpm and injected fuel quantity and did not care about airflow, on newer cars it looks up required airflow depending on rpm and injected quantity and then adjusts EGR valve duty cycle to meet specified airflow value.

You can turn off or reduce EGR by remapping ECU and on some ECUs you can adjust it through adaptation with VCDS as well.
__________________

1997 S8 was Cat B write-off in 2007 but still going strong
Reply With Quote
  #10  
Old 30th July 2018, 03:08 PM
snapdragon's Avatar
snapdragon snapdragon is offline
Senior Member
 
Join Date: Nov 2011
Location: Registered Homeless
Posts: 1,428
Default

The ECU on our cars will also partially close the throttle behind the nearside headlight to cause a vacuum if it is not getting enough exhaust gas - in order to 'suck' more through the EGR. The best thing to do is completely disable it by pulling the vacuum pipe off and plugging it with a bit of artist paintbrush handle or ball bearing. You will get an EML after a while but at least you can compare and contrast, and if you want, you can just unplug and pop the pipe back on and normal service will resume, you don't need to clear the code, but the light will stay on for a few journeys.
__________________
A8L 3.0TDi SE Quattro 2006

Last edited by snapdragon; 30th July 2018 at 03:11 PM.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 05:45 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.