EGR system question

[holden_calais_VT_1999]

hay all just a quick question my EGR system. the metal pipe coming from the back of my EGR system looks like it had been cut and a stopper put one one end (a nut and bolt) but on my extractors it has been welded shut.

now if that made no sense i am sorry not mech minded lol nbut heres a pic

[azzfox]

No pic? And did VT's have EGR? Thought that ended in the VK era? Might be wrong but you could be thinking about the oxygen sensor bung

[MR_VX]

i believe they even have them in the vx mate, a pipe that runs from the plenum (i think) back to the exhaust headers/extractors. some people make a thin plate up to block it off so the hot air doesnt get into the intake. a cheap mod i believe and was thinking of doing the same to mine!

[holden_calais_VT_1999]

ive got the pic added but not sure whats going on but u can see the pics here on my other thread Need help asap

[acarmody]

JUst get another EGR pipe, attach it and go. I don't know why the pipe that blew had a stopper in it, as it makes the car illegal to drive.

I would also get that weld in the extractors drilled out.

[holden_calais_VT_1999]

ok cool can anyone think of any reason why it would be not connected

[acarmody]

Retard mechanic?

Did you get the extractors fitted or did you buy the car like that? If you got it fitted, then I'd talk to the fitter.

[holden_calais_VT_1999]

yer got them fitted at a1 exhaust in gympie

[billy bob]

leave it welded shut and just put a new pipe on to make it look legal.
you're better off without all those hot exhaust gasses in your plenum

[moose man]

You guys do actually realise that exhaust gas is only recirculated at light throttle cruise, don't you?

EGR makes 0% difference to power output at anything above a low throttle opening. The ECU commands it to shut at anything higher.
Fools that think they are getting more power are only removing the one defence your engine has of lowering combustion temperature and spraying your shitty exhaust everywhere.

[Tsunamix]

EGR valve being steel is a source of heat transfer to the intake plenum. Removed (sealed off) reduces intake plenum temperatures slightly, more apparent over long drives.

I broke mine when refitting theplenum and blanked it off. Have had a reduction in fuel economy at light throttle settings.

Undoubtedly I'm experiencing an increase in NOx emissions.

[MR_VX]

so is it worth blocking off?

[acarmody]

I would say not worth it.

MR_VX i'm assuming you have a raptor charger judging by your title. Do you really think that the small amount of hot air is going to make a substancial difference in air temperature, when you already have 9psi of cool air going in.

[billy bob]

If your going to unblock it and put it back to standard do some before and after fuel economy tests.
I swear you'll use more fuel with it connected.
You think about it. Your putting air back into your motor which has allready been thru your motor.
This air will have had the oxygen burnt out of it. No oxygen means your car will run richer and therefore use more fuel.

[acarmody]

The few extra mL you use would hardly make any difference at all. The system was put there for a reason so hook it up and leave it alone.

[billy bob]

It was put there to reduce emissions NOT fuel economy

[acarmody]

Where did I post that it was there to improve fuel economy?

Yes the EGR valve is there to reduce emissions. BUT it will not noticably reduce fuel economy by having it.

[moose man]

It was put there to reduce emissions NOT fuel economy

bzzzzt. Wrong, sorry.

Fuel economy and low emissions go hand-in-hand. You rarely get one without the other. Think about it, the only reasons your engine would create poor emissions is if there is too much fuel compared to air, or if the combustion temperature is too high.

Now, I'll explain a little bit about how an EGR programmed engine management system works for those that don't believe me.

Your engine has a mass air flow sensor, right?
It measures the amount of air travelling through the intake at any time. Let's say it measures 50g/second of air with EGR closed.
When the ECU opens the EGR to allow a calculated 5g/second of burned gasses in, what do you think happens to the MAF sensor reading? How do you think it knows that it's only letting in 5g/sec of exhaust?
It's because it the MAF measurement lowers to 45g/sec. Consequently, the ECU lowers the amount of fuel entering the engine to match that 45g/sec of air.
You use less fuel for the same running conditions, with less emissions.

Still don't believe me? Go and speak to your local ECU programming engineer.

[acarmody]

You mean the fact that its illegal isn't a downside?

[billy bob]

The VS never had EGR. Some updates aren't a step forward

[Cheap6]

Rather than repeat what is already easily available, try these:

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Think of EGR as steam (H2O) and CO2 injection.

My guess is that the EGR is not connected because of one of the following:

The pipe twisted and broke when the extractors were being installed.

The mechanic installing them was under the misguided opinion that disabling the EGR would increase performance or economy.

All VT V6 will have EGR.

[holden_calais_VT_1999]

ok well it loks like i am going to get it hooked back up there has been alot of different apouins when my car goes in for a service i will get them to fix it then thanks heaps everbody for ur help
cheers matty