77 GP 400ci EGR delete or replace valve
 

I'm trying to decide if it's easier to just delete the EGR or replace it? My egr back pressure valve is damaged and I'm not sure about the condition of the EGR valve itself. If I just install blocking plates will it cause any other performance issues?

i blocked the EGR on my 78 400, no noticeable issue in performance or how it idles & runs. did it on an 81 turbo as well. some say it can actually increase performance by eliminating the hot exhaust gas in the combustion.

on my 78 i used a block off plate but kept the EGR in place to hold the block off plate & it still looks stock.

I used to have a customer that owned a 77 S/E T/A 6.6 4 speed car, even when it was new, the EGR system was having problems, and wasn't operating properly. One attempt to get it repaired under warranty, and it still didn't get squared around, so per the customers request we deleted it. I believe it was the back pressure valve that the dealer replaced.

I remember that the parts were hard to get at that time, and as I remember, expensive. One of the brazed joints cracked at under 10,000 miles, just not a very reliable system.

It ended up with an 068 cam in it, headers, H tube balance pipe, recurved distributor, re-jetted Q Jet, and true dual exhaust with dual cats, and a Holley Street Dominator intake manifold, it ran very well with the modifications to a smog era engine.....;)

I borrowed the car from him once to race in the local SCCA chapter autocross, and won my class with it. If memory serves, I gave him the trophy that I won.

:focus:

Ok thanks for the info!

I left everything visibly intact on my '77 T/A with the W72 400. All that was done to disable the EGR is to place a bee bee in the vacuum hose to the valve. That way it appears hooked up and functioning, but no exhaust gas to enter the intake mixture.

http://forums.maxperformanceinc.com/...1&d=1490314458

https://forums.maxperformanceinc.com...7&d=1214967448

That's a good idea to plug the vacuum hose.

Do they even make the backpressure assembly anymore?

No they don't make it anymore! It's ebay, repair or delete it!

If you want to get rid of the operation but keep the look do like we used to do when they were new. Put a ball bearing in the vacuum hose and reinstall the hose. The only problem you might have on a completely stock engine is is a ping at low speed and a heavy load. Use better gas. As for getting more power that's bull. The valve is NOT open at wide open throttle. There is no vacuum to open it.

I was actually thinking of just leaving it the way it is! I don't believe there is a vacuum leak. The pipe on the back pressure valve has come off so I'm thinking it won't open the EGR valve possibly leaving it stuck closed? I have to drive the car and see if I have any issues!

I would leave it all there and make it nonfunctional. I wish I had all of the original emissions stuff for my 1976 Firebird. I am going to make my engine look as stock as possible while still having headers, Edelbrock heads and intake. I like a more sleeper appearance car. If I remember correctly, when we used to remove EGR, back in the day, we had to adjust the timing and richen the carburetor.

Yeah sounds like a good plan!

Maybe bull in the regards of WOT power, but certainly more power at part throttle and tip in.