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[Webby the Bear]

Evening fellas,

Read lots of posts on this subject and I have one question that doesn't seem to have cropped up......

Is blocking the EGR off not just the same as having a stuck closed EGR? Thus by doing this are you not going to increase the temperature in the cylinders and cause a pinking / knocking condition?

[Broomies Mate]

EGR valve gets dirty, so doesnt work properly.  Clean the EGR and it works.

Blank off the EGR port and leave the valve plugged in, the ECU thinks the valve is working correctly and all is honky dory.

By not allowing the shite to block the valve, you are eradicating a reoccurring problem.

[Webby the Bear]

Thanks BM,

If its stuck closed that's essentially the same as blanking it off isn't it (both things mean that no exhaust gas getting back in to inlet).

So, wouldn't both scenarios mean the cylinders are going to be too hot and cause pinking or perhaps warpage?

[Broomies Mate]

The recirculation will allow hot air back into the combustion sequence.

Without EGR, the engine will be fuelled purely by fresh air, meaning cool air.

The EGR system is a waste of time and money in the UK as NOx (the gas it is intended to reduce) is not tested in the MOT.*****

*****Edited to add:  When the engine is cold! 

[Webby the Bear]

The recirculation will allow hot air back into the combustion sequence.

Without EGR, the engine will be fuelled purely by fresh air, meaning cool air.

The EGR system is a waste of time and money in the UK as NOx (the gas it is intended to reduce) is not tested in the MOT.

I thought because the exhaust gas is inert means that it doesn't combust so therefore that's where the temperature is kept down (and power  )?

[Broomies Mate]

The recirculation will allow hot air back into the combustion sequence.

Without EGR, the engine will be fuelled purely by fresh air, meaning cool air.

The EGR system is a waste of time and money in the UK as NOx (the gas it is intended to reduce) is not tested in the MOT.

I thought because the exhaust gas is inert means that it doesn't combust so therefore that's where the temperature is kept down (and power  )?

OK - I assume you have read a textbook on this recently, because it is true that lean intake charge has a higher specific heat ratio than an EGR mixture. To answer the power issue, a reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.

Theory is theory, practice is practice.  Modern engines don't run lean or rich (unless they are wanked).  They run as best as they can for the environment they are in.  If it's hot outside, you wear a T-Shirt.  If it's cold, you wear a jumper.  The ECU does the same thing, and supplies the correct air to fuel mixture.

[Webby the Bear]

The recirculation will allow hot air back into the combustion sequence.

Without EGR, the engine will be fuelled purely by fresh air, meaning cool air.

The EGR system is a waste of time and money in the UK as NOx (the gas it is intended to reduce) is not tested in the MOT.

I thought because the exhaust gas is inert means that it doesn't combust so therefore that's where the temperature is kept down (and power  )?

OK - I assume you have read a textbook on this recently, because it is true that lean intake charge has a higher specific heat ratio than an EGR mixture. To answer the power issue, a reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.

Theory is theory, practice is practice.  Modern engines don't run lean or rich (unless they are wanked).  They run as best as they can for the environment they are in.  If it's hot outside, you wear a T-Shirt.  If it's cold, you wear a jumper.  The ECU does the same thing, and supplies the correct air to fuel mixture.

Sorry BM, didn't mean to come across as all knowing (cos most on here know I'm not hence all the questions  )

I just didn't want to block it off and find I'm over heating the block and end up causing damage for the sake of a bit of extra pull.

 

[Broomies Mate]

The recirculation will allow hot air back into the combustion sequence.

Without EGR, the engine will be fuelled purely by fresh air, meaning cool air.

The EGR system is a waste of time and money in the UK as NOx (the gas it is intended to reduce) is not tested in the MOT.

I thought because the exhaust gas is inert means that it doesn't combust so therefore that's where the temperature is kept down (and power  )?

OK - I assume you have read a textbook on this recently, because it is true that lean intake charge has a higher specific heat ratio than an EGR mixture. To answer the power issue, a reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.

Theory is theory, practice is practice.  Modern engines don't run lean or rich (unless they are wanked).  They run as best as they can for the environment they are in.  If it's hot outside, you wear a T-Shirt.  If it's cold, you wear a jumper.  The ECU does the same thing, and supplies the correct air to fuel mixture.

Sorry BM, didn't mean to come across as all knowing (cos most on here know I'm not hence all the questions  )

I just didn't want to block it off and find I'm over heating the block and end up causing damage for the sake of a bit of extra pull.

 

No No no - You didn't come across as that at all, and I apologise if I made you feel that way!  Difficult to express things via text I guess.

Think about it.

Block the EGR valve and what is feeding the engine?

Clean combustible air and fuel.




That's how the internal combustion engine has operated since it's birth.

[Webby the Bear]

The recirculation will allow hot air back into the combustion sequence.

Without EGR, the engine will be fuelled purely by fresh air, meaning cool air.

The EGR system is a waste of time and money in the UK as NOx (the gas it is intended to reduce) is not tested in the MOT.

I thought because the exhaust gas is inert means that it doesn't combust so therefore that's where the temperature is kept down (and power  )?

OK - I assume you have read a textbook on this recently, because it is true that lean intake charge has a higher specific heat ratio than an EGR mixture. To answer the power issue, a reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.

Theory is theory, practice is practice.  Modern engines don't run lean or rich (unless they are wanked).  They run as best as they can for the environment they are in.  If it's hot outside, you wear a T-Shirt.  If it's cold, you wear a jumper.  The ECU does the same thing, and supplies the correct air to fuel mixture.

Sorry BM, didn't mean to come across as all knowing (cos most on here know I'm not hence all the questions  )

I just didn't want to block it off and find I'm over heating the block and end up causing damage for the sake of a bit of extra pull.

 

No No no - You didn't come across as that at all, and I apologise if I made you feel that way!  Difficult to express things via text I guess.

Think about it.

Block the EGR valve and what is feeding the engine?

Clean combustible air and fuel.




That's how the internal combustion engine has operated since it's birth.

No worries mate. and thanks for your help - ill block the sodding thing off! 

do I recall a chap on here selling egr blanks he'd made at work? I don't have those nifty tin snips so id prob make a bad job of it 

[Broomies Mate]

In my opinion, (and I'm full of them) if you can cut it with tin snips, it 'aint thick enough. 

[Webby the Bear]

In my opinion, (and I'm full of them) if you can cut it with tin snips, it 'aint thick enough. 

  good point mate.

the only other thing I have is a hacksaw  and that'd take foooooooooooorever!

think the guy on here was making them with 3mm steel. will that be good?

[Broomies Mate]

In my opinion, (and I'm full of them) if you can cut it with tin snips, it 'aint thick enough. 

  good point mate.

the only other thing I have is a hacksaw  and that'd take foooooooooooorever!

think the guy on here was making them with 3mm steel. will that be good?

That's what I usually use. 

[Webby the Bear]

In my opinion, (and I'm full of them) if you can cut it with tin snips, it 'aint thick enough. 

  good point mate.

the only other thing I have is a hacksaw  and that'd take foooooooooooorever!

think the guy on here was making them with 3mm steel. will that be good?

That's what I usually use. 

Cheers mate! 

[Andy H]

The recirculation will allow hot air back into the combustion sequence.

Without EGR, the engine will be fuelled purely by fresh air, meaning cool air.

The EGR system is a waste of time and money in the UK as NOx (the gas it is intended to reduce) is not tested in the MOT.

I thought because the exhaust gas is inert means that it doesn't combust so therefore that's where the temperature is kept down (and power  )?

Exactly.
When the engine is cruising exhaust gases are recirculated back into the intake to reduce NOx. It doesn't help at idle or at full throttle so the valve must shut then presumably. It doesn't reduce maximum power (assuming the valve is working) and it should improve MPG at part throttle openings by increasing the pressure in the combustion chambers and dropping the temperature.

[Webby the Bear]

The recirculation will allow hot air back into the combustion sequence.

Without EGR, the engine will be fuelled purely by fresh air, meaning cool air.

The EGR system is a waste of time and money in the UK as NOx (the gas it is intended to reduce) is not tested in the MOT.

I thought because the exhaust gas is inert means that it doesn't combust so therefore that's where the temperature is kept down (and power  )?

Exactly.
When the engine is cruising exhaust gases are recirculated back into the intake to reduce NOx. It doesn't help at idle or at full throttle so the valve must shut then presumably. It doesn't reduce maximum power (assuming the valve is working) and it should improve MPG at part throttle openings by increasing the pressure in the combustion chambers and dropping the temperature.

So you are for the EGR, Andy?