Roel
Member Since: 16 Aug 2008
Location: home
Posts: 1215
  
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As there is good succes on removing the EGR on a diesel, can you do the same to aV8? I believe the petrol engines have a EGR system.
Will have an effect and will I get 30 mpg the too?  Roel
1997 Camel Trophy Disco ex-P101JWK (traded it for a Britains 42101)
1984 90 TD5
2005 G4 Disco 3 BN55WPT
Also member of club MTR
and Club Faultmate
Interested in my 4x4 history see my website: www.mudmachine.webklik.nl
Sorry it's in Dutch and with google translator it gets funny.
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 19th Dec 2008 5:26 pm |
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heine
Member Since: 07 Feb 2007
Location: Midrand
Posts: 4054
 
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I read somewhere that EGR is actually beneficial for a petrol engine. Can't remember where though . Do a search on EGR
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| 19th Dec 2008 5:32 pm |
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heine
Member Since: 07 Feb 2007
Location: Midrand
Posts: 4054
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Here we go
n a typical automotive spark-ignited (SI) engine, 5 to 15 percent of the exhaust gas is routed back to the intake as EGR. The maximum quantity is limited by the requirement of the mixture to sustain a contiguous flame front during the combustion event; excessive EGR in an SI engine can cause misfires and partial burns. Although EGR does measurably slow combustion, this can largely be compensated for by advancing spark timing. The impact of EGR on engine efficiency largely depends on the specific engine design, and sometimes leads to a compromise between efficiency and NOx emissions. A properly operating EGR can theoretically increase the efficiency of gasoline engines via several mechanisms:
* Reduced throttling losses. The addition of inert exhaust gas into the intake system means that for a given power output, the throttle plate must be opened further, resulting in increased inlet manifold pressure and reduced throttling losses.
* Reduced heat rejection. Lowered peak combustion temperatures not only reduces NOx formation, it also reduces the loss of thermal energy to combustion chamber surfaces, leaving more available for conversion to mechanical work during the expansion stroke.
* Reduced chemical dissociation. The lower peak temperatures result in more of the released energy remaining as sensible energy near TDC, rather than being bound up (early in the expansion stroke) in the dissociation of combustion products. This effect is relatively minor compared to the first two.
It also decreases the efficiency of gasoline engines via at least one more mechanism:
* Reduced specific heat ratio. A lean intake charge has a higher specific heat ratio than an EGR mixture. A reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.
EGR is typically not employed at high loads because it would reduce peak power output. This is because it reduces the intake charge density. EGR is also omitted at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle.
http://en.wikipedia.org/wiki/Egr
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| 19th Dec 2008 5:36 pm |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50967
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heine wrote:. Do a search on EGR
Yeah ...like that won't bring up many posts 
 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 19th Dec 2008 5:36 pm |
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Roel
Member Since: 16 Aug 2008
Location: home
Posts: 1215
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I did a search on EGR and get a long list off severall pages and can't find anything petrol based in the titel.
Heine: Good technical answer but will it be a good idea or not?
I think some points will be valid for diesels too. Roel
1997 Camel Trophy Disco ex-P101JWK (traded it for a Britains 42101)
1984 90 TD5
2005 G4 Disco 3 BN55WPT
Also member of club MTR
and Club Faultmate
Interested in my 4x4 history see my website: www.mudmachine.webklik.nl
Sorry it's in Dutch and with google translator it gets funny.
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| 19th Dec 2008 5:47 pm |
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heine
Member Since: 07 Feb 2007
Location: Midrand
Posts: 4054
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Roel the mere fact that no one seems to have done it yet - probably means that it doesn't really make a difference
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| 19th Dec 2008 6:06 pm |
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IKke
Member Since: 29 Apr 2008
Location: Brabant
Posts: 327
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Aren't you worried that the probally higher NOx may be to high to pass a APK (MOT) test?
EDIT: Or will the catalyst take care of that. If yes, then why install an EGR system?
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| 19th Dec 2008 8:01 pm |
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Roel
Member Since: 16 Aug 2008
Location: home
Posts: 1215
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That nobody has experience with it can mean 2 things:
1 In europe there are not that many V8's so maybe nobody with the guts or expertise to do it happened to drive a V8.
2. Or it doesn't effect the petrol engines the same way as it does diesels.
Am I afraid for failing the MOT/ APK? No not really. If it fails you just take the blanking plates out and everything is back to normal. At least that is what I try to find out.
If it saves me a few % on fuel it might be a good idea as I did more than 10000 km in my 3 months of ownership. Roel
1997 Camel Trophy Disco ex-P101JWK (traded it for a Britains 42101)
1984 90 TD5
2005 G4 Disco 3 BN55WPT
Also member of club MTR
and Club Faultmate
Interested in my 4x4 history see my website: www.mudmachine.webklik.nl
Sorry it's in Dutch and with google translator it gets funny.
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| 20th Dec 2008 5:51 pm |
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IKke
Member Since: 29 Apr 2008
Location: Brabant
Posts: 327
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I suppose that it doesn't do as much for petrol as it does for diesel because diesel has much more carbonstuff (the black smoke). But it will probally still make a difference.
I'd say go for it and if it doesn't work just return it to standard 
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| 22nd Dec 2008 1:33 pm |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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IKke wrote:I'd say go for it and if it doesn't work just return it to standard
I'd be a lot more cautious than that, mess with the air/fuel mixture on a diesel by altering/blanking the EGR and worst case is a slower car or more soot.
Worst case on a petrol is a lean mixture under load and holed piston(s). Cheers
Simon
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| 22nd Dec 2008 8:53 pm |
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Roel
Member Since: 16 Aug 2008
Location: home
Posts: 1215
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I thought that the egr wouldn't work on idle and under load only in the middle ranges were you normally would drive most of the time.
But this are the warnings and discussions I was waiting on.
Does make blanking the egr the mixture more lean? I thought the exhaust gases would just take up space and keep it more cool. Roel
1997 Camel Trophy Disco ex-P101JWK (traded it for a Britains 42101)
1984 90 TD5
2005 G4 Disco 3 BN55WPT
Also member of club MTR
and Club Faultmate
Interested in my 4x4 history see my website: www.mudmachine.webklik.nl
Sorry it's in Dutch and with google translator it gets funny.
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| 24th Dec 2008 1:55 pm |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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...but with no EGR to intake, the engine will breath in more air instead for the same throttle setting, and excess air makes it a leaner/weaker mixture...  Cheers
Simon
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| 24th Dec 2008 2:15 pm |
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raftrey
Member Since: 29 Oct 2006
Location: wigan
Posts: 59
 
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I think the ecu would detect the change through the lambdas and compensate for what must be a relatively small change.
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| 24th Dec 2008 8:28 pm |
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IKke
Member Since: 29 Apr 2008
Location: Brabant
Posts: 327
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isn't that what the airmass/flow meters are for  ?
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| 24th Dec 2008 10:23 pm |
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