legal headers
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
sanderson, mc jacks
the search option is your friend
https://www.google.com/url?sa=t&rct=...aCvrVO3mQJw2zg
the search option is your friend
https://www.google.com/url?sa=t&rct=...aCvrVO3mQJw2zg
Last edited by oldalaskaman; Dec 25, 2012 at 11:57 PM.
Racer
Joined: Aug 2005
Posts: 355
Likes: 17
From: Corona Ca
redvetteman
I did get your email regarding smog, and thought I'd reply here if OK with you.
As far as headers, if your car has air injection, I would imagine that installing headers that have the AIR fitting install points at each exhaust port would fit the bill. However, I don't know of a header that has the flapper in it for the exhaust crossover preheat system. Decades ago in 1987, I was looking for smog legal headers for my 71 Monte. This was during the initial heavy crackdown on Smog Check, where every old car, and young hot rodder, was suspect as to what was under the hood - I lived in Orange County at the time and hated smog time, it was really difficult.
The only headers I could find that had a smog buyoff or exemption back then were made by Doug Thorley. And back then they had headers with smog tube ports for Corvettes. Now, many companies have smog leagl headers; I would call Summit and/or some of the bigger names in header manufacturing.
Your question about smogging my ZZ3 motors is a little hard for me to help you with, as my motors are installed in exempt vehicles. But I will share what I have learned and know as a hobby mechanic.
California Air Resources Board wants the car to have ALL factory installed smog comtrols and sytems installed completely, correctly, and in working order. Anything that the car had from the factory must still be there and be operating correctly. Now, where can one go from there?
Interpretation of the rules doesn't rulle out dual exhaust, or headers, or <some> performance intakes, as long as the factory smog system isn't diabled or bypassed. You still need the AIR, the flapper valve, the cat converter (with the AIR tube if equipped), the EGR and vacuum sensors. If your headers accommodate the AIR system and flapper, and you have dual cats on your now dual exhaust (with dual AIR tubes if needed), that portion should be covered. No limits on exhaust tubing size or mufflers. If your perf intake supports the EGR and all vacuum sensors, you should be good there as well.
Now, on a ZZ3, the aluminum heads do not have an exhaust crossover, so no preheat to the carb and the EGR will not work. I imagine the ZZ4 is the same. Vortec headed engines are the same, without a crossover. If you need to have a working crossover for carb preaheat and EGR function for smog, you're out of luck. However, for using Vortec heads on TBI motor equipped trucks there was a kit for adding a tube that connects the EGR point on the intake manifold to an exhaust manifold to get the exhaust gasses up to the EGR. Something like this may work on a ZZ4. The ZZ style aluminum heads were used on C4 Corvettes with a similar tube bypass system to get exhaust gasses to the EGR for the TPI system. May be worth a look.
I am sure there are many here who have cars that have better performance than what the factory supplied and have working smog legal emission control systems, and I hope they will chime in. Look at what is available from the aftermarket that is smog exempt or has an Exemption Order (EO) number and build a system from there.
Good luck,
Tom
I did get your email regarding smog, and thought I'd reply here if OK with you.
As far as headers, if your car has air injection, I would imagine that installing headers that have the AIR fitting install points at each exhaust port would fit the bill. However, I don't know of a header that has the flapper in it for the exhaust crossover preheat system. Decades ago in 1987, I was looking for smog legal headers for my 71 Monte. This was during the initial heavy crackdown on Smog Check, where every old car, and young hot rodder, was suspect as to what was under the hood - I lived in Orange County at the time and hated smog time, it was really difficult.
The only headers I could find that had a smog buyoff or exemption back then were made by Doug Thorley. And back then they had headers with smog tube ports for Corvettes. Now, many companies have smog leagl headers; I would call Summit and/or some of the bigger names in header manufacturing.
Your question about smogging my ZZ3 motors is a little hard for me to help you with, as my motors are installed in exempt vehicles. But I will share what I have learned and know as a hobby mechanic.
California Air Resources Board wants the car to have ALL factory installed smog comtrols and sytems installed completely, correctly, and in working order. Anything that the car had from the factory must still be there and be operating correctly. Now, where can one go from there?
Interpretation of the rules doesn't rulle out dual exhaust, or headers, or <some> performance intakes, as long as the factory smog system isn't diabled or bypassed. You still need the AIR, the flapper valve, the cat converter (with the AIR tube if equipped), the EGR and vacuum sensors. If your headers accommodate the AIR system and flapper, and you have dual cats on your now dual exhaust (with dual AIR tubes if needed), that portion should be covered. No limits on exhaust tubing size or mufflers. If your perf intake supports the EGR and all vacuum sensors, you should be good there as well.
Now, on a ZZ3, the aluminum heads do not have an exhaust crossover, so no preheat to the carb and the EGR will not work. I imagine the ZZ4 is the same. Vortec headed engines are the same, without a crossover. If you need to have a working crossover for carb preaheat and EGR function for smog, you're out of luck. However, for using Vortec heads on TBI motor equipped trucks there was a kit for adding a tube that connects the EGR point on the intake manifold to an exhaust manifold to get the exhaust gasses up to the EGR. Something like this may work on a ZZ4. The ZZ style aluminum heads were used on C4 Corvettes with a similar tube bypass system to get exhaust gasses to the EGR for the TPI system. May be worth a look.
I am sure there are many here who have cars that have better performance than what the factory supplied and have working smog legal emission control systems, and I hope they will chime in. Look at what is available from the aftermarket that is smog exempt or has an Exemption Order (EO) number and build a system from there.
Good luck,
Tom
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
I could be creative and cut one tube and flair it for the flapper.....
,...gotta do what you gotta do. Tell me more about the egr attachment. Im going to run in to that problem at check time. ( no ex cross over in the aluminum head, intake is good).............ramair.
,...gotta do what you gotta do. Tell me more about the egr attachment. Im going to run in to that problem at check time. ( no ex cross over in the aluminum head, intake is good).............ramair.
Racer
Joined: Aug 2005
Posts: 355
Likes: 17
From: Corona Ca
here is a link to the Vortec-heads-on-TBI-engine kit. the special manifold and tube is at the top of the pic.
http://paceperformance.com/i-5146532...onversion.html
here is the GMPP link, input this number, 12496821, for the TBI conversion manifold and there are more part numbers for the tube and exhaust mani:
http://store.chevroletperformance.com/store/Welcome.do
Doing something similar would entail a manifold/header with an outlet point to get the exhaust gases from, the tube from the manifold to the EGR mounting point, and an appliance to get the gases to the EGR mount, maybe some sort of riser that will allow the tube to be screwed to it and supply the exhaust gases to the EGR and then into the intake air stream.
I have only seen the system used on TPI Corvettes with Aluminum heads and this one for TBI/Vortec converted truck motors. Maybe a kit has been developed by someone in the aftermarket, seems to be something that can be done with a little thought and work.
If it works as intended, should be smog legal in spirit. Of course som smog guys will just give visual fails on things that they don't understand instead of seeing if it really works and complies with the smog requirements.
Tom
http://paceperformance.com/i-5146532...onversion.html
here is the GMPP link, input this number, 12496821, for the TBI conversion manifold and there are more part numbers for the tube and exhaust mani:
http://store.chevroletperformance.com/store/Welcome.do
Doing something similar would entail a manifold/header with an outlet point to get the exhaust gases from, the tube from the manifold to the EGR mounting point, and an appliance to get the gases to the EGR mount, maybe some sort of riser that will allow the tube to be screwed to it and supply the exhaust gases to the EGR and then into the intake air stream.
I have only seen the system used on TPI Corvettes with Aluminum heads and this one for TBI/Vortec converted truck motors. Maybe a kit has been developed by someone in the aftermarket, seems to be something that can be done with a little thought and work.
If it works as intended, should be smog legal in spirit. Of course som smog guys will just give visual fails on things that they don't understand instead of seeing if it really works and complies with the smog requirements.
Tom
