Egr Performance Upgrade?

[Jmaac]

I was wondering if anyone's ever removed the EGR valve and blocked its exhaust/intake ports to stop exhaust gasses entering the intake and improving things like fuel vaporisation and burn efficiency? Apparently upto 4% of exhaust gasses can pass through at any one time... (dyno results anyone???) Im assuming charge temperatures would also go up?

I have heard of people blocking the vaccum (i.e. ballbearing) to the EGR to stop it from working but apparently exhaust gasses can still circulate if the spring gate is left open. It also gives the appearance that its not working correctly for those RWCs/pink slips etc.

A small welsch plug would fit the round exhaust port nicely in the intake manifold and with the EGR valve put back on it would look like its operating normally but wouldnt be 'hampering' the engines performance?

Thoughts?

Edited December 6, 2007 by Jmaac

[mattymagoo22]

no need to do this not only is it bad for the environment( not that I'm a greeny) but it is an emissions system and is highly illegal.

The egr will open under cruise conditions unless its blocked open, so at idle and under full throttle it won't let exhuast in. It can bring cylinder temps down as the exhaust gas is cooler than the combustion taking place in the cylinder.

Once the engines warmed up the fuel being sprayed onto the back of the intake valve is plenty of heat to get the fuel vapourised.

the approx 5% of gas thats allowed to enter the cylinder would do little to hamper the engines performance especially when you're not after outright power under cruise conditions.

Just my thoughts on the matter.

cheers

[Cjmartz2k]

I have seen a motor crack the head due to excessive crank case pressure cuased by somebody just blocking off the EGR valve. Think about it, the gases have to go somewhere. They can build up for a little while, but after a while of constantly flogging it, it's something's going to give.

[GeeTR]

I have seen a motor crack the head due to excessive crank case pressure cuased by somebody just blocking off the EGR valve. Think about it, the gases have to go somewhere. They can build up for a little while, but after a while of constantly flogging it, it's something's going to give.

You could quiet possibly be mixing up, EGR gear and crankcase ventilation (I.E. PCV circulation)

... I would think the dipstick would pop out, before crankcase pressure cracked a head

Edited December 6, 2007 by GeeTR

[mattymagoo22]

yeah i think you're thinking of something else man. and the only thing you need to block would be the vacuum line to the diaphragm that controls the EGR or to unplug it if its electrically controlled. I really doubt that exhaust gas will crack a head.

[Jmaac]

Hmm Matty thats what I was wondering, so if i did block it off it would fill the cylinder better i.e. exhaust gas that wont burn will not occupy unnecessary cylinder volume, and thus improve potential charge mixtures/burn efficiencies/thermal expansion? and slightly faster spool times because of increased heat/exh. gas flow???

So it could potentially improve cruise economy/power? I assume this is the energy robbed by the engine by the pollution gear people talk about?

[mattymagoo22]

Give it a try, it may suprise us. If you look at it at its only 5% in each cylinder thats filled with exhaust that won't help the Fuel burn, so therfore the mixture effectively becomes richer and rich mixtures burn quicker which again helps to keep your exhaust valves where they're supposed to be and not melting or lodging themselves in the top of the piston.

There's another thing that makes me wonder. How many people out there when they get there cars dynoed get an exhaust reading before the Catalytic converter. The AFRs measured at the exhaust tip can be out (.3 - .4) when a measure is taken before the converter as the converter uses the oxygen left in the exhaust to carry out its function.

Just something I'd like put out there to get some feed back on.

Cheers

Matt.

[Jmaac]

So detonation may become a problem in some instances which would make sense- i like the sound of increasing cylinder capacity by upto 5% but

Good question, im interested in this one too

[courier33]

For starters im 99.99 sure skylines done have an egr valve (exhaust gas recirculation). If you are talking about the PCV valve, then its only sucking crankcase pressure under vaccum circumstances.

Think about it, its connected to the intake manifold, so when driving around in vaccum (75% of the time for most of us) the valve lets the engine suck all of the gasses out of the engine block and head area, stopping oil leaks through gaskets, and sucking up and burning all of the gases that get past the rings.

Ok, so may not be so good burning up already burnt gasses.

When you go into boost, the valve in the PCV closes, stopping the turbo from pumping up the crankcase to the same pressure as the boost your running. So as soon as you go into boost, the valve closes and none of those gasses get in to the manifold and burnt, thus having no effect on outright power at all.

[RB30-POWER]

yeah wtf, rb engines don't have an egr valve, what engine are you refering too?

[discopotato03]

Exhaust gas recirculation is a cheap nasty way of reducing combustion temperatures that are high enough to create NOx emissions . In certain circumstances it can also help prevent detonation but its probably the worst way to go about it .

80's era EFI systems sometimes resorted to these methods possibly because ULP and Cat converters were not as good as they are today . Also the sophistication of engine management systems with true wide band 02 probes and nock sensors means they have much tighter control over what happens in the combustion chambers .

I also suspect some of the late truly variable VCT systems are programmed to do their own internal EGR thing .

Cheers A .

[Jmaac]

Thanks, wasn't any particular motor, was just wondering if the increased cylinder fill/inc. temps made much (if any) difference to boosted performance...

Thanks for the help guys

Edited December 8, 2007 by Jmaac

[RB30-POWER]

well on idle its closed, under heavy load its closed, so for people to say it affects performance is probably wrong, the only time it will do that us if the valve is faulty and leaking etc, which can be reasonbly common on older vacuum operated systems, but with the new electronic operated valves with feedback, if you have a problem the engine light will come on to let you know.

i've always wondered if the egr system helps fuel economy or makes it worse during cruise.

you would naturally say worse because of the contaminated/reduced clean air charge, but because you may need to use more throttle opening for the same power/torque output as the same engine without an egr system, wouldn't this actually help reduce pumping losses a little and actually aid economy?

[T.D]

Sorry to bring a thread from the dead, but better than startinga enw thread haha

But does a RB25det from a S2 R33 have an EGR and if so, where is it?

[Beer Baron]

no it doesn't. it has a crankcase ventilation system it also has a charcoal canister (fuel system ventilation) but that's it. no EGR. this thread is a waste of reading.