Hi Guys,

Im in the process of detailing my engine bay and doing a few little other bits and pieces and have just removed the TB and Intake Plenum and came accross something I have NO idea what it is...

It is a pipe that connects to the rear bank of exhaust headers and to the back of the intake plenum. It its rigged up to a vaccum operated valve which appears to allow exhuast into the intake manifold.

What the hell is it for???? lol I've never heard or read about it before.

Here is another pic, seriously, what the hell does this do lol

Probably part of the EGR gear.

I could be wrong but its just a guess.
It might open when your car is cold and the car isnt burning at a effiecient rate so the car would bring back some of those exhaust gasses back into the the engine to help heat up the car quicker or to further reduce emissions by making the exhaust gasses go through the engine more then once.

This might have something to do with the emissions of the car but dont quote me on that.
Im guessing its something like that oil catch line that goes back into the engine that, you would have the oil catch can take the oil from now on, from what i remember u bought one.

Tom

The oil catch can goes between the PCV valve and the intake and doesn't have anything to do with exhaust gasses. I've just never seen this before... How odd. Any mechanics around here? lol

cooling?

Egr pipe from exhaust, runs along the manifold and the egr valves opens and closes to let in into the manifold etc.,

i just meant with the oil catch can its a similar thing as it brings back the dirty crap back into the engine not that they have anything to do with each other.

Tom

Ah Gotchya,

So when and why does it let exhuast gasses in?

i would guess it lets gasses in when the engine is cold, if it lets em in when hot it would be kinda stupid.

It could run on the same basis as the T/B getting the coolant running through it to heat it up, so it could get the enigne hotter as it would have some fairly hot exhausts through it.

Tom

NO, gases would only be let into the engine once it is hot, when cruising etc., and on deceleration.

Yeah it would be part of the Exhaust Gas Recirclation System (EGR)
It's used to reduce the combustion chamber temperatures, and control emmissions of Nitrogen Oxide or Nox.

Because the exhaust gases are the products of combustion consiting of mainly CO2, they are considered to be inert, and thats why the exhaust gas is used to cool rather than just sending in more O2.

Interesting... Im assuming its obviously best to leave it hooked up if it brings cylinder temperatures down.

Just thought for a second that by sealing it off with a specially fabricated plate I would be able to increase the o2 content being sucked in by the engine...

Yeah, I don't know that it cools the engine that much, but it's enough to stop, or atleast reduce to an acceptable level the amount of NoX that is emitted in the exhaust.
From what i've read about it, if the EGR valve is blocked, or malifunction's it can cause detenation.

If you get a chance, have a quick read through this http://www.autoshop101.com/forms/h61.pdf

The 3.0's don't have this hardware :badgrin:

*hugs his 3.0l*

Very interesting article cjohnno, thanks for that :thumbsup:

I notice the article says that at WOT, EGR gas flow should be zero. If this is the case then I can't see the need remove it as it wouldn't be robbing power when you need it (when your at WOT - Wide Open Throttle)

I was thinking of putting a blanking plate between the EGR Pipe and plenum to stop the exhaust gasses from entering the plenum.

Nah it doesnt rob power at WOT, but it does fill your engine with carbon, given time egr will gum your intake up, because when you mix it with oil vapour from your breather it makes vegemite :P so best to get rid of it, tossing the legalities aside.

But blake your oil catch can should fix the vegemite problem ;)

Matthius

I hope so, when i took my plenum off I was pretty shocked to see how much crap was inside the plenum champer and down the intake runners.

I will do a little more research before blocking it off, as the last thing i need is for my motor to detonate and shatter pistons next time a try to attempt a 14.8 quarter mile lol

Hi Guys,

Im in the process of detailing my engine bay and doing a few little other bits and pieces and have just removed the TB and Intake Plenum and came accross something I have NO idea what it is...

It is a pipe that connects to the rear bank of exhaust headers and to the back of the intake plenum. It its rigged up to a vaccum operated valve which appears to allow exhuast into the intake manifold.

What the hell is it for???? lol I've never heard or read about it before.

I'd be more worried that someone stole your intake plenum :P

I agree with AussieMagna, I found alot of grime inside the intake.One thing else is the design of the EGR, it push's against the hole to the exhaust side, something I think that is stupid as high manifold vacuum could cause some leakage into the intake.Blake, think Coke can gasket.Does the job.

Coke can gasket? That would have to be the most ingenious idea ever lol Would it be strong enough though? I would probobly put it between two new gaskets to make sure its sealing.

definately a good idea to block it off. it is contaminating youre engine with recycled exhaust gas and soot, and a good analagy is vegemite. block her off and route youre crank case breathers into a catch can as these vapours upset air/fuel ratio mixture with oil vapour ultimately assisting the engine to detonate. remeber this simple theory...if its not fresh fuel and fresh air it doesnt need it.

cheers mon