EGR valve removal.

[tbaerg]

Ahoy dudes,
I having a bugger of a time getting the EGR tube removed from my bro's 95 240sx. One of my buddies told me to just hack saw the tube and just pinch it off; claiming that its only used for emissions certification. Can anyone verify or disqualify this for me? THanks guys. Tom

[NewSpeedSteed]

Well I have a friend with a first gen TSi and his egr valve is screwing up on him (its getting alot of carbon buildup) and its causing the car to idle poorly and stall sometimes. So in my opinion it has to have more of a purpose that purely emissions. But hey I don't know for sure, maybe someone else can give you a better answer.

[tbaerg]

I suppose it might have helped it I would have mentioned that the reason for trying to remove the valve is because he's replacing the exhaust header

[Drifte]

egr valve is emissions only. the guy with the dsm should replace it with a block off plate/gasket. the 240 guy should look into it more for his options but it is not necessary on most cars...very very slight power gains are supposed to be made by not having the exhaust gas recirculated. like .25hp maybe.

in the 240 case sounds like you just need a vacume line cap and a block of gasket as well. or try twisting the rubber hose on the egr valve with pliers (not squeezing too hard) that usually breaks them looses

[s13kid]

Pretty sure you dont need it. Not 100% but from what i've read about the EGR valve I would think it wouldnt matter.

[tbaerg]

I hacked it off and sealed it off with a cap and soldered it shut. Someone told me to think about drilling a small hole in it so that the engine isn't sucking vaccum from that line. Just a tiny hole to let a little air back in. Any thoughts??

[s13kid]

Im a bit confused by that last statement? are you saying you cut the EGR line. Caped it and now you are going to drill a hole?

I probably would leave it sealed, if you drilled a hole it would be pulling in fresh air. may through off the idle a bit.

[tylers88]

i think egrs are just basically for warming up an engine thats why my pickup idles @ 1250 when its cold but about 600-650 when its warmed up but its coming off in the summers now anyway.

[s13kid]

EGR route the exhaust gas into the combustion chamber and somthing to do with the tempature and the already combusted gases, it kind of dilutes the exhaust fumes or somthing to help with emissions, I read up on it a few months ago but never fully understood it.

[tbaerg]

it's settled then. I have it completely sealed and it will stay that way unless a compelling argument is presented. Thank you very much everyone that helped out on this.

[DragonUSMC]

Wow I’m actually surprised that Justin or Kristen didn’t say anything yet.

Yeah block it off if you like, they make a block off plate if you want it to look pretty otherwise just weld it up. As for the vacuum lines, remove em all and block em off with the little rubber plugs. NOT ALL the vacuum lines, just the ones for EGR stuff. =)

[krustindumm]

EGR valve allows small amounts of exhaust gas to be recirculated through the engine to introduce non-burnable gasses, like CO2 to the combustion chamber. This lowers peak combustion temps, preventing formation of NOx gasses.

On the DSM, it is effecting the idle because egr is not supposed to be open at idle, it's basically a vacuum leak. His valve is sticking open because of carbon buildup.

Some car's also use EGR to prevent preignition. The CO2 works the same way the N does in N2O. It dampens combustion. Some Camaro owners have experienced preignition/detonation after disabling the EGR systems.

[DragonUSMC]

and now i'm confused... =D

[tbaerg]

yeah, me too.

[krustindumm]

oh god...

exhaust is burned, therefore it won't burn again. dump it into the intake and it displaces some air, and dilutes the oxygen content. Less oxygen means you need less fuel. Less fuel & oxygen means it will burn cooler.

NOx's (x meaning a number, NO2, NO3, etc..) occur at lean air fuel mixtures and hot combustion temperatures. Running rich causes HC emissions, so the best way to prevent NOx's from forming is to reduce the temperature.

EGR does not function at idle, when the engine is cold, and most of the time does not function during acceleration.

Removing EGR will not increase power, because it usually does not function at WOT. It will increase NOx emissions, which will cause your car to fail a sniffer test.

[Drifte]

^duh...

[tbaerg]

as long as I can disable it without seriously affecting the drivability then that's a great weight off my mind.