Blanking the EGR Valve....?

[busta]

StoatInACoat said:

cirian75 said:

StoatInACoat said:

Indeed. Ours did and it's unplugged but no pesky ECU to throw up a fault code.

I pretty sure that gen of pug with that motor could withstand a nukes EMP and still keep working.

They are indestructible and I love the little empty plastic box that PSA left in the bay where the ECU lives on a "normal" 306. Only thing that'll kill it is eating some water as the airbox lives very low in the bay but our last one went on until 250k when dead axle syndrome killed it off.

My 306 ate water twice the other day. Took the glow plugs out, cranked her over, re-assemble and within 30 mins she's running again. (twice because I forgot to drain the water out of the turbo the first time...)

[GroundEffect]

Centurion07 said:

GroundEffect said:

There are no benefits from blanking your EGR.

EGR is a good thing.

No of course there aren't. Do you even know what an EGR valve does?

http://www.fordwiki.co.uk/index.php/EGR_Valve_and_...

Take a a look at those pictures & tell me how having something that deliberately clogs your inlet manifold & ports with that amount of black st is a good thing and that removing it has no benefit whatsoever.

Just to add, I personally blanked mine off in a MK3 mondeo that had 80K on the clock, and not only should you notice a gain in MPG but you will also notice an improvement in performance.

As others have mentioned, it may cause your EML to come on but it won't affect anything else.

I'd like to think I do.

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

[C.A.R.]

GroundEffect said:

I'd like to think I do.

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

What about on a diesel though, which is the topic of this discussion?

[GroundEffect]

C.A.R. said:

GroundEffect said:

I'd like to think I do.

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

What about on a diesel though, which is the topic of this discussion?

Same situation.

[McSam]

GroundEffect said:

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

I wasn't under the impression it was ever intended to improve BSFC, and I can't see how increasing the average inlet temperature and decreasing the combustion temperature could do that - in fact that sounds like just what I'd do if I was trying to reduce thermal efficiency.

Perhaps I'm missing something?

[Centurion07]

GroundEffect said:

Centurion07 said:

GroundEffect said:

There are no benefits from blanking your EGR.

EGR is a good thing.

No of course there aren't. Do you even know what an EGR valve does?

http://www.fordwiki.co.uk/index.php/EGR_Valve_and_...

Take a a look at those pictures & tell me how having something that deliberately clogs your inlet manifold & ports with that amount of black st is a good thing and that removing it has no benefit whatsoever.

Just to add, I personally blanked mine off in a MK3 mondeo that had 80K on the clock, and not only should you notice a gain in MPG but you will also notice an improvement in performance.

As others have mentioned, it may cause your EML to come on but it won't affect anything else.

I'd like to think I do.

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

That's as maybe, but I guarantee an engine will run better when it is fed clean, cold air rather than hot, dirty air that has already been through the combustion process.

What you lose in BSFC through increased cylinder temps is more than compensated for by the engine being fed clean, colder air. IME.

When combined with a decat pipe & cleaning the inlet manifold & ports, the difference is huge.

[Captain Muppet]

Centurion07 said:

GroundEffect said:

Centurion07 said:

GroundEffect said:

There are no benefits from blanking your EGR.

EGR is a good thing.

No of course there aren't. Do you even know what an EGR valve does?

http://www.fordwiki.co.uk/index.php/EGR_Valve_and_...

Take a a look at those pictures & tell me how having something that deliberately clogs your inlet manifold & ports with that amount of black st is a good thing and that removing it has no benefit whatsoever.

Just to add, I personally blanked mine off in a MK3 mondeo that had 80K on the clock, and not only should you notice a gain in MPG but you will also notice an improvement in performance.

As others have mentioned, it may cause your EML to come on but it won't affect anything else.

I'd like to think I do.

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

That's as maybe, but I guarantee an engine will run better when it is fed clean, cold air rather than hot, dirty air that has already been through the combustion process.

What you lose in BSFC through increased cylinder temps is more than compensated for by the engine being fed clean, colder air. IME.

When combined with a decat pipe & cleaning the inlet manifold & ports, the difference is huge.

I'd be tempted to trust the chap who designs engines for Ford on this one.

[GroundEffect]

McSam said:

GroundEffect said:

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

I wasn't under the impression it was ever intended to improve BSFC, and I can't see how increasing the average inlet temperature and decreasing the combustion temperature could do that - in fact that sounds like just what I'd do if I was trying to reduce thermal efficiency.

Perhaps I'm missing something?

EGR helps BSFC by 3 ways:

1) Since it works only at part-load, it reduces pumping losses
2) Reduced conduction/convection/radiation to cylinder walls
3) reduction of dissociation in burned gasses, using more chemical energy efficiency

There is a plot in the book that shows a clear relationship between % EGR to decrease in BSFC.

[andymk3]

EGR is a devil. I recently did some work on a 1.6hdi (DV6) engine, and the entire inlet was so thick with black soot it's amazing it ran at all really. I couldn't even fit my little finger into the inlet ports, it was shocking.

[Centurion07]

Captain Muppet said:

I'd be tempted to trust the chap who designs engines for Ford on this one.

Thing is, engines are designed to be at their peak when nice & new-ish and all shiny and clean. After a few thousand miles this is no longer the case. So although having the egr valve functioning as it should reduces nasty emissions, it also gradually clogs up your inlet manifold & inlet ports with a sticky black mess similar to tar.

When I removed my valve & manifold to clean them, their capacity was reduced, no exaggeration, by about a third, which you can see in those pictures in my link. I think that's where the improvement comes from.

So yes, running an EGR valve improves BSFC, but if in doing so you reduce your engine's breathing capacity by a third, that's not very conducive to efficency is it?

Edited by Centurion07 on Thursday 14th March 13:34

[Limpet]

As a general point, you need to research engine type carefully before you consider doing this. Renault 1.9 dCi engines, as an example, have a habit of melting their turbos if the EGR valve isn't functioning exactly as intended.

[C.A.R.]

GroundEffect said:

C.A.R. said:

GroundEffect said:

I'd like to think I do.

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

What about on a diesel though, which is the topic of this discussion?

Same situation.

Is it though? As lots of online sources suggest that whilst EGR systems do inherently reduce Nox they can have a detrimental effect on fuel efficiency and engine power. Modern diesel engines have an EGR valve with cooling system as I understand it, so your engine is effectively putting out hot exhaust gasses which then have to be cooled down and then re-cycled through the engine. This seems largely wasteful just for the reduction of NOx. It's also proven that the EGR system will increase soot production which is why modern diesels have these new 'hateful' DPFs or particulate filters, another over-complicated system which renders second-hand cars a much more expensive ownership proposition due to their need for maintenance requirements.

It all seems a little mad on a diesel engine.

I have a 'simple' 2.0 8v diesel engine with no fancy turbo, no fancy dual-mass flywheel, no variable-vane-turbo, no DPF and a blanked-off (with the help of eBay!) EGR system. It gets very good fuel consumption and it hasn't yet poisoned me or anyone else (to my knowledge).

Just keen to find out why you think it would be a good idea to keep such an inefficient system?

[Stinkfoot]

Been thinking about doing this to my 06 Ford Duratorq powered TX2 taxi. In fact anything help the frankly shocking mpg of that is truely welcome !

[Centurion07]

Stinkfoot said:

Been thinking about doing this to my 06 Ford Duratorq powered TX2 taxi. In fact anything help the frankly shocking mpg of that is truely welcome !

Follow the instructions in the link I posted and be amazed at the improvement. Especially when fitted in conjunction with a decat pipe.

[AJB]

GroundEffect said:

McSam said:

GroundEffect said:

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

I wasn't under the impression it was ever intended to improve BSFC, and I can't see how increasing the average inlet temperature and decreasing the combustion temperature could do that - in fact that sounds like just what I'd do if I was trying to reduce thermal efficiency.

Perhaps I'm missing something?

EGR helps BSFC by 3 ways:

1) Since it works only at part-load, it reduces pumping losses
2) Reduced conduction/convection/radiation to cylinder walls
3) reduction of dissociation in burned gasses, using more chemical energy efficiency

There is a plot in the book that shows a clear relationship between % EGR to decrease in BSFC.

On a petrol, I can see that introducing "inert" exhaust gasses, will reduce pumping losses as you're reducing the vacuum that the induction stroke is pulling against whilst getting in the same (correct) amount of oxygen. And I can see that this could increase efficiency.

On a diesel, though, there's no throttle and so I don't see how EGR would reduce pumping losses. So I wonder if it gives an improvement in efficiency on a petrol but not a diesel?

If I was keeping a car for ages, I'd always be slightly wary of changing things away from the manufacturers tested design. For example, if EGR reduces combustion temperature whilst cruising, might the exhaust valves start running hotter if EGR is blanked off. Have they been tested for 100,000 miles at that higher temperature?

Also, EGR's primary purpose is to reduce NOx, and a bit of me would feel slightly bad about increasing my emissions above what's legal for a new car to be sold, even though there's no MOT test for it and it won't fail anything.

[A.J.M]

Popular mod for LR owners of pre 07 models, they gunge up. Fail and throw up running issues, loss of power, mpg etc.
Blanked my old freeby td4 and it ran much better, had nicer power delivery and gained a few mpg.

Current car has them already blanked. Saves me the job of doing it.

[McSam]

GroundEffect said:

EGR helps BSFC by 3 ways:

1) Since it works only at part-load, it reduces pumping losses
2) Reduced conduction/convection/radiation to cylinder walls
3) reduction of dissociation in burned gasses, using more chemical energy efficiency

There is a plot in the book that shows a clear relationship between % EGR to decrease in BSFC.

Thanks. I had forgotten that it doesn't usually operate at full load, which would render the peak power argument irrelevant. I would tend to think that the greatly reduced difference between inlet and peak combustion temperatures would still cause you to lose efficiency, despite the other advantages, but if you've seen solid test data from real engines then clearly my ideas of how heavily each factor is weighted are a bit out. Maybe you can reduce heat loss from the cylinder far more than I thought?

It seems extremely counter-intuitive, though. I imagined it would help when fully off load, when no fuel is injected, but not all the rest of the time.

[GroundEffect]

C.A.R. said:

GroundEffect said:

C.A.R. said:

GroundEffect said:

I'd like to think I do.

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

What about on a diesel though, which is the topic of this discussion?

Same situation.

Is it though? As lots of online sources suggest that whilst EGR systems do inherently reduce Nox they can have a detrimental effect on fuel efficiency and engine power. Modern diesel engines have an EGR valve with cooling system as I understand it, so your engine is effectively putting out hot exhaust gasses which then have to be cooled down and then re-cycled through the engine. This seems largely wasteful just for the reduction of NOx. It's also proven that the EGR system will increase soot production which is why modern diesels have these new 'hateful' DPFs or particulate filters, another over-complicated system which renders second-hand cars a much more expensive ownership proposition due to their need for maintenance requirements.

It all seems a little mad on a diesel engine.

I have a 'simple' 2.0 8v diesel engine with no fancy turbo, no fancy dual-mass flywheel, no variable-vane-turbo, no DPF and a blanked-off (with the help of eBay!) EGR system. It gets very good fuel consumption and it hasn't yet poisoned me or anyone else (to my knowledge).

Just keen to find out why you think it would be a good idea to keep such an inefficient system?

Compare the NOx and CO outputs of your engine compared to a modern one...and the amount of soot it chucks out.

Anyway, I had a look at some graphs online and they are conflicting with what Haywood states. To be honest, I would be hesitant not trusting his book to be honest as it's very widely regarded as the go-to for this sort of stuff.

None of the engines I work on have EGRs - yet - so I wont bother for now

[Le TVR]

GroundEffect said:

C.A.R. said:

GroundEffect said:

I'd like to think I do.

EGR decreases NOx production and improves BSFC by way of reducing heat transfer in the cylinder.

My reference? Internal Combustion Engine Fundamentals by Haywood - THE reference text for engines.

What about on a diesel though, which is the topic of this discussion?

Same situation.

I would be concerned about the rise of contaminants in the oil that increase engine wear when an EGR system is employed.

[McSam]

GroundEffect said:

Anyway, I had a look at some graphs online and they are conflicting with what Haywood states. To be honest, I would be hesitant not trusting his book to be honest as it's very widely regarded as the go-to for this sort of stuff.

None of the engines I work on have EGRs - yet - so I wont bother for now

Phew. I'm glad I wasn't that far off the mark after all, then