No issues for emmisions when done.
Attached is a test that was done last week , This was a chipped and NON egred disco .
This was from a customer of mine who has just had hid car for the mot

Regarding egr on a p38 to be honest ive not looked
 

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mmaddock said:
I'd also be concerned about the inherent higher combustion temperature causing problems, not to mention emissions.

The combustion temperature should be reduced due to lower inlet charge temperature.
 
No issues for emmisions when done.
I am surprised, maybe the MOT test doesn't test very well under condtions where the EGR is most effective??

Regarding egr on a p38 to be honest ive not looked
The reason I ask is that now I think about it, my P38 has a bit of a problem under certain conditions that could be down to a faulty EGR. Will have a look!

The combustion temperature should be reduced due to lower inlet charge temperature.
Now you've lost me there! Are you saying that by not introducing hot exhaust gas into the inlet that the inlet temperature is reduced?

Matt.
 
mmaddock said:
Now you've lost me there! Are you saying that by not introducing hot exhaust gas into the inlet that the inlet temperature is reduced?

Yes.:confused:

Exactly as you state, virtually un-cooled exhaust emissions, direct from exhaust manifold, fed back into inlet charge via the egr valve are bound to increase the inlet charge temperature.
'Fresh' air thru air filter, warmed by passing thru turbo by hot exhaust manifold is then cooled by passing thru the intercooler, egr gas isn't.
 
Thought I'd add a little to this discussion. Bought a 2003 TD5 GS last August and had a PSI Powerchip, uprated Intercooler and K+N air filter fitted after getting a little fed up with it's pulling power, or lack of it!
The difference is phenominal, I can now accelerate and overtake up a long steep hill down here in North Cornwall, whereas before, I was struggling to maintain 60 mph.
Sure, the fuel consumption suffers if you use the power, but on my monthly run to Oxford, a round trip of some 500 miles, I'm averaging 35 ish mpg, at an average 70 - 75 mph.
It's just sailed through it's first MOT with no emission issues.
Now, lets see, where's that EGR valve?
 
Exactly as you state, virtually un-cooled exhaust emissions, direct from exhaust manifold, fed back into inlet charge via the egr valve are bound to increase the inlet charge temperature.
'Fresh' air thru air filter, warmed by passing thru turbo by hot exhaust manifold is then cooled by passing thru the intercooler, egr gas isn't.

But AIUI - and counterintuitively, introducing exhaust gas (despite it being hot) reduces combustion temperature because of the chemistry involved. i.e. exhaust gas is pretty much inert and therefore does not re-burn, therefore reducing the combustion temperature (and consequently reducing emissions becaue NOx is produced at higher combustion temperatures)

I wonder in reality how much difference it makes? It must do something! Car manufactures do not just stick things on for the sake of it - it costs them too much.

Matt
 
Ah now see, umm err,

Combustion temperature will reduce, but we were talking about inlet charge temperature.

The less-combustible exhaust gas (would be non-combustable if the engine were 100% efficient) increases inlet charge temperature which reduces engine efficiency coupled with less combustable fuel / air mix further reducing efficiency, reduces engine emmissions.

Fit a Turbo Interheater, reduce fuel input accordingly and you will have a vehicle with very low emmissions.......and bugger all power!
 

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