Passed CA Emissions

[zr1don]

First I would like to give a shoutout to JR at TeamZR1 in Oregon. He runs a shop there that does custom tunes for anyone that wants to pay for the service. He came up with a number of sugestions that led to my passing emissions. I have contracted with him for a performance tune for my ZR1.
Thanks to all members who have posted info regarding their emissions testing, it took me a while to process the info and I believe I have a descent understanding of what effects emmisions testing and what to do to pass. I began the current testing process last August and failled. In 2010 CA reduced the measured emissions gases allowable from the previous standards. I last tested in 2008 and passed. My numbers in August would have passed with the old standards (what happened to the EPA rule that standards cannot be changed to become more restrictive?) Sorry, thats a little frustration coming through. My tests failled to meet the required NOX standards. My factory cats failed in 2009 and I replaced them with SSW headers and their bullet cats. I removed the AIR inj tubes from my stock manifolds and installed them on the SSW headers. My first attempt at passing in August was w/the aftermarket cats and headers. After failing I found the exterior cat temps were in the neighbor hood of 250 d F, not hot enough to significantly reduce emissions gases. An inquiry to SSW tech support brought the response "our cats are not certified to meet CA standards". Time to look for another set of cats. GM does not sell the cat/manifold for 90 LT5's so thats not an option. I have personal experience using after market magnaflow cats on a 96 Chevy 454 p/u, so I talked to their tech reps about it and found they have a CA approved cat for the 90 LT5. I was concerned about how to get the cat to heat up enough to work efficiently, and came up with a possible solution - thermo wrap. Several companies make the stuff, I chose Thermotec from NAPA. I wrapped both headers and both cats (see attached pics) Additionally I installed an oil catch can between the pcv valves and the intake manifold (as a result of finding oil in the intake manifold during a plenum pull to check all vacume lines. Of course you need to go through all the normal stuff if you are trying to pass an emissions test - fresh gas, fresh oil, plugs, pcv valves, all vacume lines, properly functioning O2 sensors, I Seafoamed the engine to assure no carbon buildups, and stock chip programming. My cats are now heating to 450d + and I passed. Anyone who isn't bored to death can ask whatever questions you might have, don't know if I have an answer but someone here will.
Just to summerize: Trying to pass CA smog w/aftermarket cats and headers:
1. Do all the normal stuff: fresh Chevron premium gas, fresh oil, fresh plugs, pcv valves, all vacume lines, properly functioning O2 sensors, Seafoam the engine to assure no carbon buildups, and stock chip programming.
2. Thermo wrap headers and cats (I did ask Magnaflow if this was OK, they said no problem)

[mike100]

It seems the NOx (and the other limits too) are based on county. Some people are held to higher limits. What year is your car? mine had a limit of 750 on high speed NOx the last time it tested- it's a 91 model year.

The NOx is mainly ign timing and engine load dependent- (combustion temps to be exact). So they let you by with headers?

Also, once the cat gets hot, did you feel that it wasn't staying hot? Usually HC and CO is easy to pass if the valve seal and compression are healthy-then it's just finding lambda on the fuel mix. Mostly NOx issues worry me because the 3-way part of the catalysts that deal with that do not have a lot of capacity and deactivates kind of easy compared to HC scrubbing ability.

I have a collection of LS3 catalysts that I'd love to graft onto some manifolds like that.

[mike100]

Let me also say that I thought that maybe the EPA levels were always low and the state is now just converging on those levels in an attempt to retire older cars sooner. They never had an underground regulation if the law allowed them to go lower the whole time.

[tccrab]

Congratulations on passing the CA SMOG Nazis!!
This is valuable information for any of our brothers having problems with their respective SMOG Nazis.
I suspect that our cycloptic Moderator will be very interested in your cure, as he's been trying to pass AZ SMOG since last year.
How much trouble was it with the referee in getting your headers waived?
My '90 still has her original manifolds/cats but I wouldn't mind switching over to headers in the off hand possibility that my original cats should fail *wink*wink*.

TomC
'Crabs

[zr1don]

I've had past experience with the referee system, I put a 96 454 engine and trans (w/all wiring) in a 95 Chevy p/u. That was a change from obd1 to obd2 and required a referee inspection and approval. It really isn't that difficult, DMV has a list of referee's you can use, call them explain what you are doing and if it within their purview, they will schedule an appointment to bring your vehicle for the inspection. If you pass their inspection you take it to a smog test station for testing, bring your successfully completed inspection back to them and they issue you an approval w/your changes.

I believe the key to passing w/aftermarket headers and cats is getting the cats to a high enough temperature to allow them to convert. Of course that assumes all the stuff on your engine functions as its supposed to. The aftermarket cat system will not cover other systems not functioning properly like the factory cat will.

[mike100]

The remaining question is if that company listed a cat for the LT5, was it intended to be grafted onto the original manifold? Did the ref even realize the headers were not oem?

considering our options, or lack thereof, I like your idea of air-injecting aftermarket pipes.

[zr1don]

I don't know the intent of Magnaflow, the cat manufacturer, but the cat comes w/inlet and outlet pipe, looks like it was intended to be installed in line in the exhaust, not attached directly to the stock exhaust manifold. They recommend you have them installed at a "professional installation shop". The shops are required to make the installation as close to original oem as possible? The referee approves or disapproves the exhaust manifold, which GM no longer makes. You have to show proof to the referee that the part is no longer available.

[tf95ZR1]

Wrapping the CATs- great idea!

[FU]

Remember one thing , that is while your car is on the rollers testing emissions. That one of the big advantages of the stock chip is the 1-4 skip shift. Take a second to think about that .

[tomtom72]

Thank you Don as you added some info for me to think about on my car. NYS is also somewhat strict. I was thinking that I would send my CATs out with the headers and get them coated as well.

Thanks for the tip on the magnaflow cats too!


Tom