As am I rebuilding the engine I want to know what to do. Remove/Block the EGR or replace it.

 

if you dont have to do any emisions test i would get rid of it.

 

It'll hurt your MPG to remove it. I would replace it. I did when I installed my LT headers. Only way to really remove it without throwing a code is to reprogram teh ECU.

 

Keep it. No reason not to, it helps your mileage and general performance/reliability (not much, but it does)
-Mike

 

I always thought removing it would help fuel economy.
Guess thats why I asked.

 

what motor do you have? you could do an egr restrictor plate mod.

 

egr's are not at all helpful for reliability or engine longevity. egr cycles to engines are like cigarettes to lungs.

you only need to retain it because the computer is programmed to run with it, and is the primary reason why performance/mileage is worse when its not functioning properly (the computer reads that its not functioning and does all sorts of wacky things with fueling). this doesnt mean you cant block it off, its very cheap and very easy. you block off the egr tube @ the manifold (either exhaust or intake depending on which motor you have) and at the egr valve base. ive always used pennies on these motors and just sandwiched them where the tube ends used to be. this allows you to leave the valve plugged in, the computer thinks its there, and you get rid of the cycle.

 

^ truth.com

 

So if I block it, I would get the same mpgs? Its a 302. Im rebuilding it for fuel efficiency/torque monster.

 

You might be surprised what happens thermodynamically. It does some interesting things, when you can see them. They end up mostly neutral as far as reliability goes, assuming you have a mostly functional engine. However on the MPG front they do have a positive effect besides the fact that computer fuel curves are engineered for them. Blocking it should (will) lower MPG's.
-Mike

 

you might as well remove all the smog equipment and convert it to a carb but seriously, i would just leave everything alone if its all there. it can always be removed in the future if you really want

 

X2 on the statement in bold. The factory computer is programmed to add timing when under light load/cruise conditions as it adds EGR. The recycled exhaust gases lower combustion temperature therefore the engine can withstand more timing without pinging.

If you are going for a custom tune, then you can program the PCM accordingly.

You stated you were building a "torque monster". In order to do that and realize the full potential of the parts you plan on using, a custom tune is in your future. Yes, depending on the parts selected you may be able to get by with a factory tune but that will hamper the "torque monster" goal.

 

egr's decrease reliability of any motor. its not too often a vehicle will survive its entire life without an egr related problem. i.e. a broken tube that needs to be replaced, broken/malfunctioning sensors/valves that need to be replaced and often dont-causing the performance to suffer, etc.

in a longevity standpoint, the egr is cancerous. over 100k miles an egr equipped motor is far more caked with soot and carbon deposits than a motor in comparable conditions without an egr. egr's cake intake manifolds, valve seats (preventing them from sealing completely, and wearing faster), combustion chambers (causing a less efficient burn), valve stems (increasing friction and wear of the valve guides), and cause excessive wear on the cylinder walls and rings. its not that egr's ruin motors in an instant. but, just like cigs for lungs, cause all sorts of respiratory issues after prolonged use.

everything in the above paragraph also hurts performance.

i noticed no change in mileage by blocking mine or tuning it out on any of my vehicles or any vehicle ive ever worked on/tuned. im not saying that a loss of mileage would never be seen, but in my experience there is no change one way or the other.

 

Everyone has their own opinion on the effects of EGR. For me, I have never had any issues attributed to negative effects of EGR. But then again I also repair any issues in a timely manner.

My opinion is to keep a functioning EGR on a street driven vehicle. You have your own opinion to the opposite. I am simply stating my opinion and some tidbits of info I have picked up along the way.

For me, as I stated before, I suggest to keep the EGR if you plan on running a factory tune.

 

I thought this for years, then last fall I saw some tong term test data from my University's combustion/engine lab. Turned out not to be the case. (test used 2 4 cyl and 2 8 cyl engines, same hours with mixed city/highway simulations) What I've personally noticed is people who block off EGR's (or even think to) also take better care of there engines than those who don't.
Oh, and .
-Mike