EGR delete?
Thread Starter
Burning Brakes
Joined: Mar 2012
Posts: 770
Likes: 22
From: California
FL Events Coordinator
St. Jude Donor'13
EGR delete?
So I just recently bought some new headers and an exhaust for my 1989 corvette and had a random question about the EGR system. The main thing is my new headers have no smog connections at all. I was wondering if it would hurt the car to leave the EGR system hooked up and it feed air from the engine Bay Area instead of the exhaust due to it not having the EGR hookup welded onto it. Is that a crazy/bad concept? I would like to have the hookup cut off the old manifold and welded onto the new one but due to my crazy schedule I won’t have time to have it welded for a quite a while but eventually want to have it done.
On the other hand, I have also contemplated have the EGR system completely removed and was wondering what kind of pros and cons there are to it.
I did some reading on the topics above and found no information for my first question, maybe I was looking in the wrong place, and didn’t seem to find many cons to removing the system other than it will throw a code that I would have to get tuned out.
Thanks for any and all help.
On the other hand, I have also contemplated have the EGR system completely removed and was wondering what kind of pros and cons there are to it.
I did some reading on the topics above and found no information for my first question, maybe I was looking in the wrong place, and didn’t seem to find many cons to removing the system other than it will throw a code that I would have to get tuned out.
Thanks for any and all help.
Safety Car
Joined: May 2001
Posts: 4,761
Likes: 1,648
From: Fairfax Virginia
You really don't want to get rid of the EGR system. It actually helps your car in several ways. Without an EGR your mileage will probably suffer and potentially lose performance.
I took the following out of the book: How to Understand, Service and Modify FUEL INJECTION CORVETTE& Electronic Engine Management, Author: Charles D. Probst published by Bentley Publishers
"Disabling the EGR valve is a No-No. Even if you don't care about emissions, the engine calibrations depend on EGR flow to reduce Knock and fuel flow."
"The engine control already shuts off EGR under high-performance conditions, at idle and during cold operation."
"The rate of Fuel Injection, and the spark advance are calculated for EGR under part throttle conditions. If you block off the EGR, you stand a good chance of experiencing knock and wasting fuel. You might even lose power output and you are dirtying the air"
I have the EGR working on my 1988 C4 and still pass emissions with flying colors. Since you live in California you are pretty much stuck aren't you? If the EGR is not working the NOX in your exhaust will go really high and fail any emissions test. Here in Virginia I am not required to have the 1988 tested anymore but I still do as I like to know that everything is working like GM designed it to.
Good Luck and Enjoy Your Corvette out on the roads of that beautiful state!
Chris
I took the following out of the book: How to Understand, Service and Modify FUEL INJECTION CORVETTE& Electronic Engine Management, Author: Charles D. Probst published by Bentley Publishers
"Disabling the EGR valve is a No-No. Even if you don't care about emissions, the engine calibrations depend on EGR flow to reduce Knock and fuel flow."
"The engine control already shuts off EGR under high-performance conditions, at idle and during cold operation."
"The rate of Fuel Injection, and the spark advance are calculated for EGR under part throttle conditions. If you block off the EGR, you stand a good chance of experiencing knock and wasting fuel. You might even lose power output and you are dirtying the air"
I have the EGR working on my 1988 C4 and still pass emissions with flying colors. Since you live in California you are pretty much stuck aren't you? If the EGR is not working the NOX in your exhaust will go really high and fail any emissions test. Here in Virginia I am not required to have the 1988 tested anymore but I still do as I like to know that everything is working like GM designed it to.
Good Luck and Enjoy Your Corvette out on the roads of that beautiful state!
Chris
Thread Starter
Burning Brakes
Joined: Mar 2012
Posts: 770
Likes: 22
From: California
FL Events Coordinator
St. Jude Donor'13
To all i am going to keep the EGR system in place and just wait until my welder and I are both available to do the work. Thankfully my car is also registered in Florida do emissions is not much of an issue which is why I am getting rid of the ugly air system. Thanks for all the comments about the topic. You guy are great.
Last edited by Red89'-L98; Jul 10, 2019 at 08:16 PM.
Team Owner
Joined: Sep 2001
Posts: 62,178
Likes: 1,740
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
No you don't want engine bay O2 feeding it, delete it entirely, or weld it on. You can activate or deactivate its function in the chip tune if you like. Not having it will not hurt the car, just hurt your ability to pass CA emissions.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
The pipes going to the headers have nothing to do with the egr system. They are part of the AIR circuit. The smog pump dumps air to the headers during warmup to decrease emissions. The egr takes exhaust gasses from one of the heads and dilutes the intake mixture in the intake manifold. Also, you will have to swap out your headers every 2 years in California.
