Passing CA Smog 968 write up

[JivenJim]

My write up, To Pass Tough smog Tests, such as California. Porsche (specifically 968’s, but also applies to all):

Original post for 924S with 968 Swap, Smog Legal swap in California: Smog legal 968 Engine Swap

In my attempt to pass on the lessons learned for keeping the front engine Porsche’s on the Road, I would like to pass on the Information that I’ve gathered.

As of January 2009 CA passed new ruling to “toughen”, the worlds most stringent smog regulations. New Release: 2009-11-24b California releases preliminary rules for cap-and trade-program
Good luck finding the real meat in there.

I personally believe it is to promote the sell of New cars and new Taxes, but that’s just me. Many other states are slowly adapting “The Land of Fruits and Nuts” laws, as the auto Industry/state taxes, typically benefit. So here’s what’s afoot and what I did.

What’s Changed 2009, as best as I can summarize.
New Cat’s must be warrantee for 5 yrs +. Could be a great thing, but in the short run most sellers will not ship to CA or have 6X prices! Yes that means the most aftermarket Cats being built, do not have as much precious metals/don’t work as well, and don’t last nearly as long as the OEM stuff. They call them high flow cause they are ½ as long.

You cannot put in a non-compliant new Cat to replace old.. (but it’s nearly impossible to tell ;+) Did I mention New Cat’s for CA are 6X prices.

You cannot put in more than one cat in line, and any replacement is suppose to be within 1 In of original position.

So what brought this on. By-annual Smog Inspection by the CA government DMV.

I failed first a smog check by about 15% on HC’s: I had an Completely Fresh, dead stock 968 Engine that you could and mostly likely would like to, eat on.

Parts: 4 year old Cat from Lindsey Racing.
Racer X chip. (didn’t think it would hurt since it not suppose to kick in till higher RPM’s)
Oil: Royal Purple XRP 20/50 with about 600 street miles and about 600 Racing miles.
Used and open air Box. (no filter)
Oil Filter, OEM and same as oil.
Plugs: NGK about 2-3 years old and good condition and freshly cleaned.

I Failed on 15 MPH test on HC’s. 92 Max. I got 108!

See photo copies for total numbers.



A week later what I did barely squeak by with Changes:

Parts: same 4 year old Cat from Lindsey Racing.
*Stock 968 Chip.
*Oil: New Royal Purple 20/50 (50$ worth)
Used and open air Box. (no filter)
*Oil Filter, New OEM
*Plugs: New NGK
*I drove the car at 4000-5000 RMP’s for 30 mins to get the CAT HOT and left engine running until the guy pulled the car on the test rack. (last time only 20 min at 3-4 K)

I wish I could break down what each of these factors changed the numbers. At least I did not have to pay $300+ to pass with New CAT nor bribe some underling.

So I passed the second time with 92 HC out of 92. My NO’s actually went up about 5%.



As a back up to failing the third time, I was going to use denatured Alcohol at about 1:3 with gas ratio to pass. There’s a lot out there about how this will trick the computers. (but is really bad for rubber seals)

Last straw would be to replace 4 year old Cat.

This car is mostly used for race and only gets about 3K miles a year. It also puts out about 1/10 the pollution of my truck, that managed to pass CA Smog.

I really Like all the products I have said I used. Just stating what happened in my example. This is not to blame any vendors on my post, Please…

I would welcome your comments from rookies’ and pro’s alike, to passing such tests and using the above or other methods.

Jim

[944Spec_bound]

Last time I did my CA smog on the 944, I had1/2 of the HC emissions, 1/3 of the CO, and 1/2 of the NO than the test I had to take 8 mos before. Only thing I had done was replace the factory muffler with a cylinder type. Makes no sense to me.

My daughter's VW Cabrio cat was rattling like a mother so I priced a compliant CAT....$800 from the dealer! I could get an aftermarket one for around $400. I had her do the smog test anyway, and the dam thing passed with a broken 14 year old cat! So I took it off and broke the loose chunk into pieces, put it back on...I'll deal with it again in 2 years when smog is due again.

[ScoobySteve]

The CA smog test / laws are a total joke. My roommate just completed a smog test on his modified Subaru. His car originally shipped 3 catalytic converters: one in the up-pipe (immediately before the turbo), one in the downpipe (immediately after the turbo) and a large one farther down the exhaust.

He has removed all cats except the final one. Technically, he would fail on the visual inspection alone. However, since most shops have no idea what things actually look like on these cars, they put on the sniffer. It passes, with just one cat once it's warmed up.

[JivenJim]

Subie's Rock,

Am Very surprised he passed with only one Cat. Just like RX7's and such, they require several in line to pass per factory spec.

They are however not tested on the CA Dino smog test, as per standard. 4 Wheel drive car vs 2 wheel rollers. So all time 4WD are exempt from the "loaded wheel" test portion." This is where small blocks drag as they bog down the engine. Porsches are not some low RPM American Big block and expect it to run correctly at 1500 RPMS.

I saw the best posting from a honda guy for visual Cats. He said just slam the car so low they can't look under it. Might be correct for your friend and us race cars.

[flash968]

i just went through this on the blue car - i have tried a number of aftermarket cats - NONE of them cleaned it up enough, and ALL of them cost me torque (probably a pulse timing thing due to the dual resonance intake manifold unique to the 968) - i was able to get it hot and pass with one of them, but it was right on the edge

i put an OEM cat back in, and it runs so clean now that they had to run the test again, thinking the sniffer fell out - i also gained back the torque i had lost

[ScoobySteve]

Originally Posted by flash968

i just went through this on the blue car - i have tried a number of aftermarket cats - NONE of them cleaned it up enough, and ALL of them cost me torque (probably a pulse timing thing due to the dual resonance intake manifold unique to the 968) - i was able to get it hot and pass with one of them, but it was right on the edge

i put an OEM cat back in, and it runs so clean now that they had to run the test again, thinking the sniffer fell out - i also gained back the torque i had lost

I understand the point of view that aftermarket cats are largely unregulated and you don't know what you're going to get. My friend recently developed a set of headers for the BMW M5/M6 V10. He ended up sourcing cats from a German company that is OEM for most of the German manufacturers. They look beautiful, actually work, and cost an arm and a leg. They also came with datasheets and all kinds of other things which imply actual engineering.

On car parts you tend to get what you pay for...or less. Sometimes, it's an insignificant part and and a lower level of quality will do. Other times, not so much.

[flash968]

i was quite shocked at how poor a job the aftermarket cats did - i spared no expense either, trying anything anybody i could find would recommend - no soap - admittedly i don't think i tried the ones you are talking about though - after 5 different ones, all showing better flow, but all showing torque loss, and none of them passing the test, i gave up