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PB -PC Challenger 2009 - 2014 Covering 2.5 HP diesel

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  #41  
Old 19-09-14
fester fester is offline
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Lucky I did ask. There appears to be merit in that thought. Didnt think that way as I never did the mechanical blank.
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  #42  
Old 19-09-14
greig greig is offline
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The increased EGT's sound like a good explanation, but I'd like to see real world figures to back that claim up..

Anyone with an EGT gauge installed ??
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  #43  
Old 19-09-14
Giddyup Giddyup is offline
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Quote:
Originally Posted by greig View Post
The increased EGT's sound like a good explanation, but I'd like to see real world figures to back that claim up..

Anyone with an EGT gauge installed ??
+1

I wouldn't have thought it would make any difference. The ECU knows how much oxygen it is getting by using the MAF and calculates fueling accordingly. This amount of oxygen doesn't change if you add exhaust gas to the mix as it is oxygen depleted. So blanking the egr will reduce the volume of gas in the cylinder, but not the ratio of fuel to oxygen.

I thought that was why you get a little more power with the resistor mod. The throttle valve is 100% open all of the time, so more oxygen enters the engine, the ECU realises this through the MAF, so adds fuel to compensate, hence more power than when the engine is sucking in oxygen depleted exhaust gas. The ratio of oxygen to fuel remains constant though.

Would like some hard evidence either way.
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  #44  
Old 19-09-14
CC2005 CC2005 is offline
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A slight deviation from the actual topic. In Thailand and in Indonesia they are all trying to find the best work around for the EGR gasses. We are not alone.

http://www.pajerosport-thailand.com/...action=search2

http://www.kaskus.co.id/thread/512f6...ort-dan-triton
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  #45  
Old 19-09-14
fester fester is offline
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Quote:
Originally Posted by Giddyup View Post
+1

I wouldn't have thought it would make any difference. The ECU knows how much oxygen it is getting by using the MAF and calculates fueling accordingly. This amount of oxygen doesn't change if you add exhaust gas to the mix as it is oxygen depleted. So blanking the egr will reduce the volume of gas in the cylinder, but not the ratio of fuel to oxygen.

I thought that was why you get a little more power with the resistor mod. The throttle valve is 100% open all of the time, so more oxygen enters the engine, the ECU realises this through the MAF, so adds fuel to compensate, hence more power than when the engine is sucking in oxygen depleted exhaust gas. The ratio of oxygen to fuel remains constant though.

Would like some hard evidence either way.
I thought the oxygen input was reduced as I thought the throttle valve was partially shut to reduce air inlet but the overall volume remained the same with the introduction of the EGR. That is how the temp is reduced as the burn is actually made less efficient.

The odd factor in all this theory is that the EGR is only introduced on light cruising throttle situations rather than high load situations. At lighter throttle openings and load exhaust temps are generally lower and normally only ram up with high load situations so the EGR is not reducing peak temps when needed most. Least that's my understanding.
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  #46  
Old 19-09-14
MatthewP MatthewP is offline
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Blanking the egr wont effect egt's by any noticable ammount because the egr is only activated during idle, cruise and decelleration conditions.

Egt's are only a concearn when you are giving it a bootfull and the engine is loaded up and fuel is pouring in.

Even if it did increase egts, which I dont think it does, all it would do is maybe help spool the turbo a little bit.

Edit.

Lol Fester beat me to it.

The exhaust gas is used to replace excess oxygen in the combustion chamber so it is not there to be turned in to oxides of nitrogen.

The exhaust gas absorbs heat from the combustion process which helps to reduce
peak combustion temps to a level below which oxides of nitrogen are formed.

The total heat from combustion stays the same, its just the peak temp reached that is slightly lower because of the extra density of the recirculated exhaust gas when compared to fresh air.

Oxides of nitrogen have always been formed during the diesel combustion cycle, it is only in low fuel situations, like idle and cruise conditions, that exhaust gas recirculation is able to lower peak combustion temps enough to make any difference to the levels of oxides of nitrogen produced.

Last edited by MatthewP; 19-09-14 at 07:52 PM.
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  #47  
Old 20-09-14
MatthewP MatthewP is offline
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A diesel engine does not run at a set air fuel ratio like petrol engines do.

No old diesels had throttle butterfly valves in the intake.
They sucked in the same ammount of air per stroke whether it was idling or reving flat out.
That is for NA motors anyway, motors with turbos on them obviously get more air flowing as boost pressure increases.

A diesel cant lean out, like a petrol engine.
Diesel burns the same no matter what the air fuel ratio is, up untill the point when there is that much fuel added that there is not enough oxygen left in the combustion chamber for all the diesel to completely combust.

It is this overfueling for the available oxygen that causes incomplete combustion and can lead to increased egts.

Egts are going to increase when there is more fuel added anyway because more fuel equals more bang and therefore more heat, but with enough fresh air its controlable.


When the ecu opens the egr valve it also partially shuts the intake throttle valve.
This restricts the intake of fresh air and allows the exhaust gasses to mix with the air that does get past the intake throttle valve, and the mix gets sucked into the engine.

In this mix of fresh air and exhaust gas there is enough oxygen for the diesel to combust.

With a blanking plate, there is no exhaust gasses to enter the intake manifold, but the intake throttle valve still partially closes.

This means that the only place that anything can come from is past the intake throttle valve.
Because of the restriction of the plate the pressure on the intake manifold side of the intake throttle valve lowers as the engine sucks in air.

This lower pressure means the engine is sucking harder at, and getting more of, the fresh air coming past the partially closed intake throttle valve.

If there was enough air for the complete combustion of the diesel added before the egr was blanked, then there will be more fresh available after the egr is blanked, even though the pressure in the intake manifold is lower then when the egr was working.

So blanking the Egr has no negative effect on the fueling when the throttle plate is partially closed.

On my NP Pajero an egr blanking plate does not cause any error codes because the egr flow is not monitored.


The only problem with a blanking plate on the Challenger is, that on new mitsubishi diesel engines, the map sensor is in the intake manifold after intake throttle valve, the map sensor will sense that the pressure in the intake manifold is lower than the ecu expects to see.

A fix for this has been to either remove or drill a hole in the intake throttle valve plate.
This allows enough extra air past so the pressure in the intake doesnt decrease.

Another option may be to move the map sensor to the intercooler side of the intake throttle valve.

There may be more info in the new triton thread linked in the first post of this thread, but I wouldnt know because it requires you to make an account before you can view any posts, and I cant be bothered.

As for an electronic fix to the egr problem, the best fix, but definately not the cheapest, is to get a performance ecu retune that removes the egr function.

The resistor in the wire going from the intake air temp sensor in the maf to the ecu, is a simple and effictive fix.
You may want to bypass the intake air temp sensor in the maf completely, and just have a resistor wired in, so there would be a constant voltage that the ecu would see, and not one that fluctuates with the temp,because of the sensor is still in the circuit.

The fixed resistor would have to be wired in between the wires going from the ecu to the intake air temp sensor in the maf and the wire coming back from the intake air temp sensor in the maf to the ecu.

I think that using a resistor to give a low intake air temp is the most effective electronic way, other than a retune, to stop the egr.
Unless someone can actually show that the new lower false temp that the intake air temp reads effects something else negatively, then I see no reason to make a more complicated circuit.

I would still recomend puting in a blanking plate, even with the resistor disabling the egr, because i like the idea of the metal plate completely blocking egr flow, instead of relying on how firmly the egr valve holds itself shut to stop the egr flow.

But im just paranoid with things like that.

* Edits for spelling and clarification.

Last edited by MatthewP; 21-09-14 at 02:58 PM.
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  #48  
Old 25-09-14
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Newton1! Newton1! is offline
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I just had my car serviced and my manifold was very kindly cleaned by my local MM guy.

Now I have an EGR plate from my triton which I can fit to my 3.2 Pajero, I assume they are all the same yes?

My question is there is some talk of sealant in this thread. I never used sealant in my Triton and was wondering what it is you use for sealant and is it essential or something you can miss?

J
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  #49  
Old 12-02-19
pajeromack pajeromack is offline
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Hey I know this is an old thread but was there a verdict on the blanking plates? I'm about to put one in and was wondering if I need to drill a hole.
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  #50  
Old 12-02-19
BMN BMN is offline
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Quote:
Originally Posted by pajeromack View Post
Hey I know this is an old thread but was there a verdict on the blanking plates? I'm about to put one in and was wondering if I need to drill a hole.
No hole on mine. Been fitted for at least 180k with no issues.
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