I know I know, if I cared so much about gas mileage why did I buy a V8, lol. I did a search and the consensus seems to be mixed on this issue. Well I'm doing heads/cam and was debating whether or not to do these while I'm in there. I know it can clean up the engine bay a good deal. Just wanted to know if there are any detrimental effects on fuel economy. I know the newer LS1's don't even have an EGR. One last other thing, is it bad for the cats to !AIR, since from what I understand that is what it is pertinant to?
Thanks
Brian

 

I added SLP Mid lengths/tr55's /msd 8.5's and !air !egr no cats..

I get 30+miles to a tank then I did stock at 70k

 

I'll give you the bottom line from my experience.

EGR: Exhaust Gas Recirculation. This is a most effective device (when the EGR valve is clean), in cooling combustion temperatures. Would I remove it on a stock car? No! Its NOT a performance modification and increases emissions. It also would not be the second line protection against knock and ping.

The only time you can safely give up EGR, is when you're running a cam with significant overlap in the cam. Overlaps of atleast 114 and lift marginally higher than stock, give an intake "reversion", which basically acts like the EGR, by overlapping the intake and exhaust valves. Take for instance the LT4 engine. It has no EGR, due to the overlap in the cam. So if you have a cam equal or greater than the hotcam, I'd say you're safe removing it.

Second, take the LS1, I believe it was 2000 when they removed the EGR. Same reason, the cam had more overlap and reversion happening. I for example, have a mild cam in my 94 LT1. 222/222, .471/.471 114 LSA. I get EGR codes all the time under cruising conditions, as the computer simply isn't seeing the change in MAP that the EGR would provide. Thus setting a code.

Would I remove it? Yes. It is obvious I am outside the PCM's programming logic in EGR operation, and am running at a safe margin of reversion/lift.

AIR: Simple... it warms up your cats on a cold/cool start. Thats all. I cannot say from direct experience HOW long it would take to kill a cat without the air system. Will it clean up the engine bay? Most definately. I have done it because I have no cat.

I am by no means HIGHLY technical or experienced. The above is my understanding from limited experience. There are others on this board with a far broader knowledge base.

Hope this helps!

 

I check my gas mileage at each fill-up and I did not notice any change in my MPGs when I pulled the EGR and air pump. Granted, I'm only getting about 13-15 MPG as it is (all city driving), but I still didn't see any noticable changes.

 

I will be running a 230/242 544/576 113 LSA (I think), how would this impact the EGR decision? Thanks for your help guys.
Brian

 

Simple.

You don't need it.

Thats more than enough lift and overlap to be able to remove the EGR.

Enjoy that huge, bad *** cam, dude!

 

I stand corrected, its a 114 LSA, is that a big deal?
Brian

 

My cam is on a 114, and has MUCH less lift and duration than yours. It all affects how much reversion is going to happen.

No EGR foh you!