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How important is the EGR valve on a 305 small block...?

LT1 Kayker
01-18-2005, 07:20 AM
Ok I wont lie, this post is about my truck. I only posted here because of the supreme intellegence that just oozes from you guys compared to the C/K forums. :iceslolan

Anyways, my questions pretty simple. Im just wondering how much of an influence the EGR valve is for my 305. Its got 305,000ish miles on it and a while ago I was just doing some daily maintainance and found my EGR diaphram to be shot. I was thinking of just blocking off the entire system with like, putting a plate on the intake manifold then just ripping out the rest of the system and then block of the intake on the throttle body. I almost did this but take into mind that im seriously getting 4MPG now, so anything that saves a bit of gas is needed.

To the point though, I know what the EGR is and all that im just wondering if it would be worth it to buy a new valve, or just block the whole system off completely? Do you think running it with a busted EGR valve could be causing some or maybe even most of its problems, like its vampiric lust for gas, or is it no big deal and just chuck the whole thing? Thanks a ton for any help guys. :)

01-18-2005, 09:42 AM
That question kinda goes by who you ask and were they got there info from plus every system is a little different so remving on different engine will yield different results, however I removed mine on my LT1 and put block off plates in its place and despite what you hear I didn't have any temperature issue's my gas mileage didn't suffer and there was no smoking issue. Even though it is said to raise combustion temps it is send hot gases into the intake so I don't see how that possible and articles from professionals have asked the same question about this theory but it will raise emission levels do to having more unburned gas present in your exhaust stream and if you need your vehicle to pass emissions I would just buy a used unit off ebay or from ( . I mean removing doesn't really provide any performance gain(maybe 1-2 horses) and the block off plates cost almost as much as a replacement unit.

01-19-2005, 02:32 AM
I have a 96 Chevy Tahoe I might stop by the C/K forums and teach them a lesson or 2 lol,

Iam guessing your not living in California and you dont have to Smog anyway do you have the orignal engine in your truck? if you block the EGR valve/emission system block it as far as you can at least before the Smog pump over time the benifit of blocking the system is you stop alot of carbon bulidup and you engine will last longer, man whats buggin me is that low 4MPG its 2wheel drive and you have a weight savings as a pick up you cut the cat out so that gets rid of alot of backpressuer, for Fuel econ can you get the Computer retuned/programed to run a tad leaner as Chevy runs all there engines abit rich.

LT1 Kayker
01-19-2005, 07:15 AM
Yeah it's the origional engine, but she is quite the Frankenstien. The heads and probably half of everything else is from a different truck. I cut the cat off about half a year ago because it was just a pile of cloth. I live in Minnesota and we don't have emissions, all I want is better mileage. Im not too worried about the engine getting grimey and making it last longer since its already over 300K. No need to fix a broken leg if the guy is 300 years old and has a stroke every other day. :rolleyes: :biggrin:

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