Notices
C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

EGR delete?

 
Old 07-05-2019, 05:41 PM
  #1  
Red89'-L98
CF Senior Member
Thread Starter
 
Red89'-L98's Avatar
 
Member Since: Mar 2012
Location: Sacramento California
Posts: 647
Likes: 0
Received 4 Likes on 4 Posts
FL Events Coordinator
St. Jude Donor'13
Default 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 wonít 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 didnít 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.
Red89'-L98 is offline  
Old 07-05-2019, 07:42 PM
  #2  
RWDsmoke
CF Senior Member
 
Member Since: Jan 2005
Location: San Antonio Tx
Posts: 708
Received 52 Likes on 48 Posts
Default

Air from the engine bay has oxygen in it and would make your fuel mixture lean, just like a vacuum leak. Better to just cap it off.
RWDsmoke is offline  
Old 07-05-2019, 08:27 PM
  #3  
65Z01
CF Senior Member
 
65Z01's Avatar
 
Member Since: Dec 2000
Location: SE NY
Posts: 83,237
Likes: 0
Received 154 Likes on 146 Posts
Cruise-In II Veteran
Default

Since you live in CA, might be better to have the EGR interface welded into the new headers.
65Z01 is offline  
Old 07-06-2019, 10:38 AM
  #4  
ctmccloskey
CF Senior Member
Support Corvetteforum!
 
Member Since: May 2001
Location: Fairfax Virginia
Posts: 891
Received 207 Likes on 175 Posts
Default

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
ctmccloskey is offline  
Old 07-10-2019, 08:14 PM
  #5  
Red89'-L98
CF Senior Member
Thread Starter
 
Red89'-L98's Avatar
 
Member Since: Mar 2012
Location: Sacramento California
Posts: 647
Likes: 0
Received 4 Likes on 4 Posts
FL Events Coordinator
St. Jude Donor'13
Default

Originally Posted by RWDsmoke View Post
Air from the engine bay has oxygen in it and would make your fuel mixture lean, just like a vacuum leak. Better to just cap it off.
Ok, good. That is what I figured would happen and exactly why I asked first. I just wasnít sure if the car could compensate for it or not but better safe than sorry.

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; 07-10-2019 at 08:16 PM.
Red89'-L98 is offline  
Old 07-12-2019, 10:42 AM
  #6  
vader86
CF Senior Member
 
vader86's Avatar
 
Member Since: Sep 2001
Location: Athens AL
Posts: 51,142
Received 338 Likes on 283 Posts
Default

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.
vader86 is offline  
Old 07-12-2019, 06:32 PM
  #7  
383vett
CF Senior Member
 
383vett's Avatar
 
Member Since: Apr 2003
Location: moraga ca
Posts: 16,056
Received 742 Likes on 550 Posts
Default

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.
383vett is offline  
 


Thread Tools
Search this Thread
Quick Reply: EGR delete?


Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: