EGR Valve operation

wammers · Jul 27, 2012

Saint.V8 said:
I am not gonna enter the argument (this has been through the ringer a number of times previous) - I just want to check something.....

You said the Recirc. air goes through the intercooler.....I thought the charged air goes through the intercooler first, then picks up the recirc air from the EGR then into the manifold...???

Or am I wrong and the charge air goes throught the EGR first then into the intercooler before being inducted through the manifold..!!??

That was not what i was saying. The air goes through the EGR valve after it has been through the intercooler. What i was saying is that the airflow restriction of a blocked off EGR valve makes little or no difference to the amount of air entering the engine. So buying a £50.00 bypass unit is a waste of money.

Saint.V8 · Jul 27, 2012

Not you Tony - it was a response to Paul D, he said (subsequently he corrected himself) that the charge air is fed to the EGR before the intercooler.....I was questioning that statement, not yours..!!

wammers · Jul 27, 2012

Saint.V8 said:
Not you Tony - it was a response to Paul D, he said (subsequently he corrected himself) that the charge air is fed to the EGR before the intercooler.....I was questioning that statement, not yours..!!

Ok Ant i was replying to the post before mine. About removing restriction. The restriction left after blocking an EGR valve is neither here nor there on a turbo charged engine. The manifold will always be pressured the main restriction to air flow is then the inlet tract and the inlet valve itself. The EGR valve internals unless clogged with **** pose no real airflow restriction. Not one that will cause any performance increase by removing it. So those who pay silly money for an EGR block and bypass unit do so for naught. They read (and believe) to many adverts basically.

Diesel Do · Jul 27, 2012

wammers said:
The restriction value of the EGR valve is much over stated unless it is clogged solid. The only time removal of restriction would have much effect is at low RPM when turbo pressure is low. At all other times air is being blown into the engine and providing the intercooler is clear the engine will never lack air.

Not totally true! Traditional tuning techniques still apply to turbo charged engines ie. gas flowing heads and manifolds, free flowing exhausts etc. so removing any restriction is likely to improve air flow, even pressurised. To increase cylinder charge.

Diesel Do · Jul 27, 2012

Admittedly removing a restrictive EGR valve won't turn it into the millennium falcon

wammers · Jul 27, 2012

Diesel Do said:
Admittedly removing a restrictive EGR valve won't turn it into the millennium falcon

It won't do anything. Removing the hot exhaust gas input is what does the trick.

Diesel Do · Jul 27, 2012

wammers said:
It won't do anything. Removing the hot exhaust gas input is what does the trick.

But it should only put that in when you're not requesting power if it's working properly, so flat out EGR inop no gas going thru engine!

Diesel Do · Jul 27, 2012

When I blanked my 300tdi it made bugger all difference! When I did my td5 the turbo seemed to spin up a smidge quicker but it was very minimal! It also seemed a bit more willing to rev at the top end, again minimal. Over all benefit not a lot but I'd say more than on a 300tdi on which there is no restriction.

Diesel Do · Jul 27, 2012

I'm gonna ask about fitting a dump valve in a minute

wammers · Jul 27, 2012

Diesel Do said:
Not totally true! Traditional tuning techniques still apply to turbo charged engines ie. gas flowing heads and manifolds, free flowing exhausts etc. so removing any restriction is likely to improve air flow, even pressurised. To increase cylinder charge.

We are not talking race tuning here, we are talking a road going diesel engine. Removing whats left of the EGR valve will do diddly squat for the engine performance.

wammers · Jul 27, 2012

Diesel Do said:
When I blanked my 300tdi it made bugger all difference! When I did my td5 the turbo seemed to spin up a smidge quicker but it was very minimal! It also seemed a bit more willing to rev at the top end, again minimal. Over all benefit not a lot but I'd say more than on a 300tdi on which there is no restriction.

The turbo will spin up quicker because removing the EGR gas allows more Oxygenated air in, bigger bang, more exhaust gas to spin turbo. The idea of an EGR valve is to reduce the oxygen content of the charge therefore reducing the burn temperature and cutting down the production of NOX.

wammers · Jul 27, 2012

Diesel Do said:
I'm gonna ask about fitting a dump valve in a minute

You can't, don't go there again for Christ sake.

Saint.V8 · Jul 27, 2012

wammers · Jul 27, 2012

Don't you bloody start with your bloody daft pop corn packet.

Paul D · Jul 27, 2012

.. and I'll get the route wrong and ask for a map ..

Saint.V8 · Jul 27, 2012

wammers said:
don't you bloody start with your bloody daft pop corn packet.

:bounce:

2.0_hippo · Jul 27, 2012

Wammers loves a good old EGR valve

Diesel Do · Jul 27, 2012

wammers said:
The turbo will spin up quicker because removing the EGR gas allows more Oxygenated air in, bigger bang, more exhaust gas to spin turbo. The idea of an EGR valve is to reduce the oxygen content of the charge therefore reducing the burn temperature and cutting down the production of NOX.

Possibly when cruising at a constant throttle then accelerating but at most other times the egr should be closed!

Diesel Do · Jul 27, 2012

2.0_hippo said:
Wammers loves a good old EGR valve

Not as much as a diesel dump valve

wammers · Jul 27, 2012

Diesel Do said:
Possibly when cruising at a constant throttle then accelerating but at most other times the egr should be closed!

It will spin quicker at all times when the EGR valve would normally be open. With the EGR open less exhaust gas is produced.

EGR Valve operation

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