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Planning on doing the LS6 intake on my 99 A4 with necessary EGR delete. Looking for experiences with passing emissions afterward assuming that codes are deleted and testing is primarily tailpipe. I am in CT so I do not believe that our testing involves a visual inspection though my DD are newer. Anyone with similar state testing situations have problems with passing or other hassles?
C5s don't have an EGR system. The LS6 will go right on once you figure out what you want to do with your coolant crossover system. Emissions wise your car will not know the difference.
C5s don't have an EGR system. The LS6 will go right on once you figure out what you want to do with your coolant crossover system. Emissions wise your car will not know the difference.
Thought what I will be removing and blocking on exhaust manifold was EGR which I believe was still used in 99. Will remove air pump and cap vacuumas well. Got the coolant lines figured with LS6 line upfront and simple crossover (not delete) in rear.
Thought what I will be removing and blocking on exhaust manifold was EGR which I believe was still used in 99. Will remove air pump and cap vacuumas well. Got the coolant lines figured with LS6 line upfront and simple crossover (not delete) in rear.
Removing the air system is totally separate from just installing an LS6 intake. Like I said there is no EGR system on a C5, The pipes to the exhaust manifolds are strictly from the air system. Removing the AIR system like I said has no bearing on installing your new intake. It should however be turned off in the PCM to avoid any future CEL turning on if you want to get rid of that system. Personally with stock manifolds if that's your case, I would just leave that system installed if it's operational. Installing long tubes in the future then by all mean ditch that system and get a full dyno tune.
Thought what I will be removing and blocking on exhaust manifold was EGR which I believe was still used in 99. Will remove air pump and cap vacuumas well. Got the coolant lines figured with LS6 line upfront and simple crossover (not delete) in rear.
i assure you, my ls6 has those same plates as your 99. There isn’t an egr on any c5, and you will not need to remove the air pump or block off those pipes off the manifold if you’re doing a simple ls6 intake
My understanding is that this “AIR” system ties into the back of the ls1 intake and that the ls6 does not have a tie in. Until the intake is off, I’m going by what I read in various posts and articles (where many refer to it as EGR). If if doesn’t need to come out and is functional, I wouldn’t remove it. If it will cause malfunctions and throw codes, I would remove it and clear the system out in the PCM. Lots of conflicting info on this one.
The secondary air system is completely separate from the intake manifold. The air system has two check valves, one of them is bolted to the drivers side rear head. If you are going to keep the air system, it wouldn't be a bad idea to replace this $24.00 check valve because you can only get at it with the intake off.
If the system is throwing codes and or you will be doing headers, then it will be a good time to remove it completely because that is accessible with the intake off.
I just did this a few months ago, I left the air system in and replaced both check valves.
I’ve had an ls1 or ls6 intake off at least 20 times in the past 2 years. Neither intake setup has anything to do with the air pump.
Theres not conflicting info I’ve ever seen on this, and anyone who calls the system an egr, needs to quit offering advice. The air pump literally pumps fresh air into the manifold to improve catalyst efficiency.
Here is a diagram of the entire system that I found on google, which connects in no way to the intake manifold:
If the OP didn’t get the point from the first time someone mentioned the AIR system was separate, he got it from the other 3
OP, the only components that have anything to do with the intake manifold beyond the throttle body is the MAP sensor (back of manifold), injector/fuel rail mounting points/through holes, and (to cover everything) the intake port gaskets. All of said items will swap right over to an LS6 intake manifold.
All other systems mentioned, (AIR, coolant crossover, etc) are annoyances to the swap, but shouldn’t interfere once removed or properly configured.
Last edited by wscott62893; Apr 3, 2019 at 06:03 AM.
If the OP didn’t get the point from the first time someone mentioned the AIR system was separate, he got it from the other 3
OP, the only components that have anything to do with the intake manifold beyond the throttle body is the MAP sensor (back of manifold), injector/fuel rail mounting points/through holes, and (to cover everything) the intake port gaskets. All of said items will swap right over to an LS6 intake manifold.
All other systems mentioned, (AIR, coolant crossover, etc) are annoyances to the swap, but shouldn’t interfere once removed or properly configured.
Thanks. Just trying to get my ducks in a row before I tear apart a perfectly running car. I’ve done an intake plenum on my Toyota but this is a little more involved. Seems some other LS based cars might have an “EGR” issue with this swap or others are misusing the term and are as confused as I was. Whatever. I’ll be an expert after Imndone and can exasperatedly correct others . Looking forward to it😜
Thanks. Just trying to get my ducks in a row before I tear apart a perfectly running car. I’ve done an intake plenum on my Toyota but this is a little more involved. Seems some other LS based cars might have an “EGR” issue with this swap or others are misusing the term and are as confused as I was. Whatever. I’ll be an expert after Imndone and can exasperatedly correct others . Looking forward to it😜
That's always a great plan. I believe early LS1s in Fbody Camaros and Firebirds had EGRs but to my knowledge nothing with an LS6 intake from the factory had it.
I think once you get into it you're going to find it quite easy to work on. Tricky parts IMO especially on an older car is getting the brake booster hose off, not damaging the vacuum line for the HVAC system and being careful not to hit or snag the oil pressure sensor.
Just so you know your coolant cross over pipe Will be in the way.. You can remove part of the LS6's bottom ribs to clear this...
Thanks. Got that covered with the upgraded GM crossover in front and simple crossover (ICT Billet) in the rear. Should have just cut it down cost-wise but hoping to T the front with the TB bypass. This whole job gets more expensive as I go. Hopefully the used ported BBK TB that I bought is functional. Upgrade creep!
Completed! Funny, there was no “EGR” port. Started and actually ran. Then the rear steam ports leaked from the crossover. ICT Billet crosser over did not go in like it did on the engine stand model used in the video. Now, just going to block off rear ports. Going to pull off intake and see how it leaked but this design increases possible leak points from 2 to 4 as braided line threads in on each side. I’m sure it works but too difficult to install with limited clearance. The flat washers that were under the orig steam tubes - are they necessary for replacements that come with o-rings? Installed over them this time but not sure if I was supposed to? For those who have blocked off, did you used these washers AND supplied rubber gaskets?
Does an 86 c4 have an EGR valve? What is the pipe that goes from the exhaust to the intake on the passenger's side? Do I need it? It keeps breaking off.
Last edited by smitty1460; Aug 14, 2021 at 10:56 PM.
Reason: Adding something
EGR delete and emissions
