EGR Do I need it offroad

[Bluegoose]

I'm running a 3100 SFI in my sandrail and wondering if I really need the EGR.

Thanks,
Ronnie

[bszopi]

There are several people on here not running them on the street, so you definately don't need it in a sandrail.

[ForcedFirebird]

Don't know about the SFI, but it throws codes on my MPFI. However it does not affect performance or driveability.

[sil]

Don't know about the SFI, but it throws codes on my MPFI. However it does not affect performance or driveability.

its best to disable it in the pcm

[ForcedFirebird]

its best to disable it in the pcm

Mine will be as soon as the Mega Squirt install is finished .

[MMGT1]

Set the pcm to "no light". Dissabling it completely can cause funny things with your timing. These cars refrence a crap load of tables in cruise mode(not in PE). Removing one can hurt more that help.

[SappySE107]

Must be an OBD2 thing. It doesn't hurt anything in OBD1. What kind of computer are you using for the 3100?

[motorbreath]

Out of curiosity if all these people are deleting thier EGR valve what are they doing to keep their combustion temps down?

[ForcedFirebird]

Out of curiosity if all these people are deleting thier EGR valve what are they doing to keep their combustion temps down?

Now that makes no sense to me. The EGR valve is supposed to INCREASE intake temps to help increase the completion of combustion as to help lower emmisions (emmisions come from INCOMPLETE combustion or known as carbon monoxide).

[StudlyCamaro]

Out of curiosity if all these people are deleting thier EGR valve what are they doing to keep their combustion temps down?

nothing (well i didn't anyway (i removed my EGR system at least 3 years ago (and i've passed illinois emissions 2 times since then)))

Now that makes no sense to me. The EGR valve is supposed to INCREASE intake temps to help increase the completion of combustion as to help lower emmisions (emmisions come from INCOMPLETE combustion or known as carbon monoxide).

the EGR system is not designed to counteract CO emissions

by adding the exhaust gases back into the combustion chambers the combustion temps will become lower. The reason for lowering the temp of the combustion process is NOx gasses are formed at higher temps.

[ForcedFirebird]

Still doesn't make sense to me?! Incomplete combustion = more emmisions.I guess I've been spoiled too long since emmision enforcement was done away with in the early 90's here in FL. ;p.

[IsaacHayes]

Man I gotta move to Florida. No emissions, no income tax, warm weather!!!! argh!!!

[ForcedFirebird]

Remember, though it's a right to work state
Translation : Right to be broke state!

[motorbreath]

Still doesn't make sense to me?! Incomplete combustion = more emmisions.I guess I've been spoiled too long since emmision enforcement was done away with in the early 90's here in FL. ;p.

It didn't make sense to me either at first but heres how it works. Don't think of EGR gasses as being hot and adding heat to the intake charge because it just came from the exhaust. Think of it as 'dead air' i.e. it has no oxygen in it because its already been burned. The more oxygen you add to a fire the hotter it gets. the hotter it gets the more Oxides of Nitrogen (iirc) you create therefore creating higher emissions and also iirc hotter combustion increases the probability of detonation. So by adding the 'dead air' from the exhaust you are decreasing the combustion temperature reducing nox and emissions. I do beleive you can overcome this problem by using higher octane gas but I wasn't sure which is why I asked what everyone else was doing.
Remember also that the EGR valve is only open when the engine is under load and also varies with engine load, less load means less EGR, more load means more EGR.

[torq455]

you mean load under light to part throttle. EGR is closed at WOT. like the vac controlled ones we used to have in the old days--only works when the vac is high enough to open the diaphragm that allows the gases in. From what a GM mechanic told me...EGR recirculates the unburnt gases from combustion as well as cooling the combustion temps down. then i have to ask: what about the newer cars that have the variable cams? they don't need an EGR and they run fine. so i ask, other than emissions, what is the benefit of the EGR? yeah, i might be contradicting myself here, but i tend to see things from both sides, and i still have questions about both.