The new aluminum heads have no exhaust crossover port in the middle. The 3860 intake manifold has one for the EGR. What does one do with this setup? Does the EGR get relocated to the Corvette position at the back near the distributor hole?

 

Only if you need to have it and can install the corvette lower intake to make it work.

 

The 3860 lower intake will accept it. My issue is how to get exhaust gas to it. I think the Corvette had a port on the #4 exhaust tube that had a pipe over top the valve cover over to the manifold.

 

The flex tube is discontinued. SDPC made a kit for welding a flange to a header tube and using the Vette tube. However once the Vette tube was discontinued so was the exhaust flange tube setup. I had one on my G20 van with Vortec heads when it still had to pass emissions. That being said EGR was only on for smog tests. Might be able to use a Junkyard LT1 or LS tube. There was zero fuel economy benifit to running it, it sooted up the whole TPI intake and cost power by adding more heat to the TPI.

 

I thought the whole point of EGR was to lower temps to control N20. I personally don't care. I'll delete the thing if I can make it run right. I have a moates programmer so I can turn it off. There seems to be a lot of debate on the subject of deleting the EGR.

 

How I did it for the t-ram. Vet and aftermarket will be pretty much the same

 

Did you just get a bung welded to the header?

 

Yup, a tube with a flange. Not hard to do at all.

 

EGR reduces NOx gasses. Reroutes unusable air back into the intake system to make the combustion less effective to reduce exhaust Temps that cause NOx gas. The bulk of the NOx gasses is produced from the catalytic converter. So for the most part EGR is an attempt to fix harmful gas that's a byproduct created by fixing harmful gasses the catalytic converter was trying to fix.
EGR will only come on at a steady part throttle

 

Personally I would remove it. Not for the "it's robbing my power" reason but the fact that if it sticks open your car won't idle, so to me it's something that if it's there it can cause driveability problems and if it's not there it doesn't affect driveability at all.

 

In these cars it comes on alot more than steady part throttle. Its on almost all the time except for WOT. The newer EGR systems with electronic valves are on all the time, even at WOT with the exception being idle. My L31 had very little EGR% commanded at cruise, but it was wide open when the engine was under load, accelerating or at WOT. My buddy has a L29 454 in his dually. That EGR valve was open 100% just off-idle.

 

It's not hard to see on vacuum controlled egr, just put a vacuum guage on the vacuum line to the egr valve. Common sense would show you can't have something turn on with vacuum at WOT because of the lack of vacuum at WOT. But trying to stay on topic you don't need EGR for anything beyond being compliant with your state inspection. Here in Texas we quit doing emissions testing on cars 25 years and older but we still have to verify all of the emissions devices are still there. They don't have to work they just need to be there and look like they might work.

 

I'm just going to use mine as a block off basically and disable it with the moates.

 

The induction system does still make vacuum even at WOT. Carb engines alao used ported vacuum for EGR. It only takes a little bit of vacuum to unseat that valve.

In Texas a 25 year old vehicle does not even need an inspection and can get a registration for 5 years for $75.

 

you're partially right on both accounts.
some makes do use ported vacuum to control egr even on fuel injection. The tpi is that way. I'm not sure about the tbi.
and in Texas you have to register your car as an antique in order to get away from yearly safety inspections. If you don't the it's 7 dollars a year for safety only. I'm a state inspector.

 

On a vehicle that does not get daily driven it is a good option though. You can still operate them as required to keep them operable even as an antique. The state understands that the mechanicals need to be exercised, battery needs to charge, tires need to roll, etc. My 97 gets driven 2-3 times a month and has antique registration. I have not been hassled over it either, even though it looks almost identical to a 2022 model from the back. The vehicle and block are 25+ years old. I have driven it 400 miles from home for some different cruises and events as well, even got pulled over by a DPS Trooper for speeding 300 miles from home. I was 7 mph over on I35 and still getting passed like I was standing still at times. Got a warning and zero questions about what I was doing there.

I have also been a state inspector and have ASE certs in both repair and parts. Flaunting it like some kind of badge, LMAO! I almost never bring any of that up to anyone. It is just funny that you threw that out there to me.

FWIW TBI is also ported vacuum. Pulls from about the same point above the closed position of the throttle plate as the purge canister. The solenoid is only there to prevent EGR with a cold engine and in some cases one that is overheating.

 

Since you have been to school recently on this. Is window tint checked on 1988 and down now? My problem is when I did inspections, 88 down was exempt. My 83 G20 does not have any additional front tint. It is literally what GM tinted the factory front side glass. I have had hell the last few years because these younger inspectors simply do not believe that the factory tinted glass is darker than what is now the legal limit. A few years ago I even had to go to the exemption building and show them the RPO label that it had factory deep tint RPO code, it had factory glass, and show them it had no additional tint. It is getting downright annoying. It was built that way and always has been and suddenly it will not pass safety inspection because the factory glass is too dark. Yet every DPS or Police Tahoe is even darker.

 

I'm not flaunting that I'm a state inspector im just saying it because I've had to deal with these things. I'm not trying to be a ******** like you seem to naturally be. I also am L2 certified, it doesn't mean **** beyond you know how to take a test that the answers are given to you, and you get to put a patch on your jacket. Now if you're done trying to think you're better than me and failing at it we can move on.

 

https://www.dps.texas.gov/section/ve...ting-standards
The inspection laws are always changing. Recently they added you can have windshield tint if you have a doctor note to allow it. I can't see your front window glass being tinted darker than 25% from the factory. Yes window tint is checked with the safety inspection but like my sidekick brought up, if you register your car as an antique you can get around the safety inspection.

 

They are right around 20% depending on the meter and they are factory OEM from 1983. The only glass on the vehicle that is not tinted is the windshield.

 

Never said that I was. Merely pointing out how that response seemed from you. I have had to repair EGR on these GM vehicles for years. I know how they work and what is in the ECM side of things as well. I may also even still have the factory GM TPI/MPFI Drivability manual from 1984 that came out and went to the dealerships so that they could diagnose the TPI systems when they were new. The EGR solenoid is commanded on with a warm engine, anywhere above idle, the vacuum port at the throttle is ported for an additional step to prevent it from operating at idle and the actual valve opening or metering rather is controlled by exhaust backpressure.

I rarely deal with these in stock form now. The last TPI I even touched we swapped from the early mass air system to a LS DBC P59 PCM, vortec crank sensor and Vortec 350 distributor. LS3 cartridge MAF on a 4" air inlet. Ran great in the off-road buggy it was in.

 

Most of the egr systems i worked with had temp sensors to verify operation. How does the computer know that egr is working on this system?

 

It's funny that most car makers stopped using egr valves because they are getting egr effect through variable valve timing but then diesels got egr valves added to their list of emissions devices.

 

The MAF cars used the temp switch. The MAP cars and trucks use MAP rise when the valve is cycled for testing purposes. Ford used the worst systems ever. An actual EGR valve position sensor oth the top of the vacuum EGR then transfered to an orifice in the EGR tube with a DPFE to measure pressure on both sides of said orifice.

 

yea I replaced a bunch of dpfe sensors back in the day.
so bypassing it won't cause a driveability concern but will more than likely set a engine light.