LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Getting rid of EGR

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Old 02-17-2005, 01:53 AM
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Question Getting rid of EGR

with race headers and pcm tune would i run in to any problems pulling the EGR system? Also is there any benefit to getting rid of AIR?
Old 02-17-2005, 06:56 AM
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Removing EGR and AIR and the benefits has been a ongoing discussion on every board. From what I have read, you can remove AIR (on an OBDI car) as long as there is a fuse in the fuse block that is good. This will keep you from throwing a code. EGR has been blamed for contributing to the infamous LT1 intake leak. Both can be removed and it will clean up the engine bay alot.

I wouldn't know personally about either .
Old 02-17-2005, 08:58 AM
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most lt1's leak regardless of removing the egr. people say that if you remove the egr you pick up a few hp but as long as it is working correctly there isnt that much there. with the air, i dont think there have been any documented numbers on hp gains but i wouldnt think it would be much. i put pulleys on my car and couldnt tell any difference but maybe if the air was taken off and the pulley added you might feel something.
Old 02-17-2005, 09:11 AM
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The biggest thing I have notices on !AIR cars is that you can actually see the front of the engine. It has been claimed that the high heat temperatures added by the EGR valve on the rear of the intake aids the breakdown of the gasket on the intake. Like you said, it seems almost all LT1 intakes leak.... I know from experience .
Old 02-17-2005, 08:05 PM
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Can the AIR be removed when using shortys? If so, how?
Old 02-17-2005, 09:11 PM
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The 95-6 B-bodies GM will defeat the AIR for you, too many warranty claims so they jumped through the hoops needed to make it legal to defeat but not remove it. No power to be had there though. EGR is not active at WOT so no power gain to be had in defeating it either and with a stock cam you might get worse milage due to some knock retard, larger cams will self EGR like the stock LT4 cam does so they have no issues. The LT1 intake leak is overblown much like the dexcool and opti complaints, not a fraction as bad or common a problem as most would lead you to believe, but the EGR is a very likely contributor to the cases that do occur.
Old 02-18-2005, 07:01 AM
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AIR and EGR can be removed from any car, even with factory exhaust manifolds. All you have to do is block the various connections to the manifolds and intake and ****** it out. You may need to check to see how strict your state is on emissions before you do it......
Old 02-18-2005, 02:09 PM
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smog's no problem for me in MI (thank god) anyway, thanks for all your info
Old 02-18-2005, 02:39 PM
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Does Anyone Have A Step By Step Guide To Taking One These Off??? Andwill I Need A Shorter Belt If I Get Rid Of The Pump???
Old 02-18-2005, 03:55 PM
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The pump is electric. No belt change necessary.

GM makes the "LT4 blockoff plate" for the back of the intake manifold. It bolts to where the EGR valve is (the valve comes off). I don't have the part number handy...

Then you'll need a blockoff plate for the exhaust manifold. I built one out of a piece of 1/4" scrap aluminum and about 10 minutes with a jigsaw. Little Permatex Copper and nary a leak to be found. The other end of that tube (that goes to the intake) can be left open, if you use the LT4 blockoff plate.

As for AIR, you'll need some fittings (I forget, some sort of fittings for a manual transmission? drain plugs or something?) if you want to plug them directly. Otherwise, I'd bet that you could simply cap them with pipe fittings if you want. All the hoses can be pulled out, but don't forget to put a breather cap on the tube that ties to the air intake.

You may want to reprogram the PCM so that no codes get thrown... I think it's DTC29 for AIR and DTC32 for EGR...
Old 02-18-2005, 04:42 PM
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I have all the block-off plates and even the exhaust manifold "plugs" if you are interested. I'll make you a deal!! They have been laying around for a while. Drop me a PM if interested.
Old 02-18-2005, 05:14 PM
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I Have The Block Off Plates Already. I Just Dont Know What All To Take Off. Lol
Old 02-18-2005, 07:40 PM
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Maybe these will help, I searched for some of the sites which had detailed removal procedures but all of them had been moved.

http://shbox.com/ci/AIR.jpg

http://shbox.com/1/air_pump_recall.jpg

http://shbox.com/1/egr.jpg

If you look at the links (copied from Shoebox's website.... gotta give credit ), you should be able to figure what needs to be removed.
Old 02-19-2005, 03:21 PM
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Default block offs

Hey do you still have all of the block offs. If you do I would be interested in them.

Thanks
James



Originally Posted by curlyws6
I have all the block-off plates and even the exhaust manifold "plugs" if you are interested. I'll make you a deal!! They have been laying around for a while. Drop me a PM if interested.
Old 02-25-2005, 03:54 PM
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So I just ordered the block off plate from GM. That's the only one I'll need for the Intake Manifold If I'm completely removing EGR/AIR right? I'm putting on non emissions LT's the same time I'm doing this, so headers aren't the issue.
Old 02-27-2005, 01:41 AM
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This ISN'T all that hard now. Air is simple to elminate. Just start with the two check valves coming off the manifolds and follow the tubes/pipes take it off piece by piece. The pump is electric so just unbolt/unplug and remove! EGR, is a little more of a pain just due to the location but thats about it. Remove it and its tube connecting to the passenger side manifold, plug it up and your done. I'm no expert but, I'd say there's no HP gain period from the removal of these parts. Although, I've read in a haynes manual that the EGR supposedly lowers the combustion temperatures and so, removing it could do the opposite. As long as you have a functional cooling system, there should be no problems other than the codes you might throw. But then, a little PCM tuning/deleting/modifying is all you need.
Old 02-27-2005, 01:02 PM
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my question is..... when you remove the EGR how do you reroute the vaccum hoses and do you just unplug the EGR valve solenoid and leave it unplugged and remove it from the intake???? i have always wondered that.
Old 02-27-2005, 01:12 PM
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I think there is only 1 EGR vacuum hose and you can plug up the hose with a screw, or plug up the connections with a vacuum cap. You also need 2 block off plates for the intake.

The EGR only works at part throttle anyway, so removing it wont affect WOT performance. Maybe not having it will remove some turbulence in the exhaust from the open areas where it connects, but i cant see it being a benifit. To me, it just cleans up the engine bay, and makes installing the headers a little bit easier.
Old 02-27-2005, 07:00 PM
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http://shbox.com/1/4th_gen_tech1.html this site should help out alot of people
Old 03-01-2005, 06:59 PM
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Default hotcam?

would having EGR help or not help a lt4 hotcam passing emmisions.. I have one installed in a 94 lt1 and have been told repeatedly it was close to failing, the motor is mostly stock otherwise and I never heard the lt4 had it deleted before.. I'm surprised no one mentioned this as the testing was done at a chevy dealer... would it run any better either, I do notice some slight throttle hesistation now and again...?



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