CA Smog Success!
 

I passed CA smog today with the lowest numbers I've seen yet!

15mph:
HC was 19 (max allowed was 115)
CO% was .01% (max allowed was .57%)
NOx was 20 (max allowed was 1069)
no typo: NOx reading was twenty!

25mph:
HC was 11 (max allowed was 75)
CO% was .02% (max allowed was .43%)
NOx was 130 (max allowed was 669)

Car used bone stock engine management (chip, injectors, FPR, AFM, everything) and was running safely in closed loop at 14.7 AFR for the entire test. I used NGK BRP6ES plugs, fresh O2 sensor, cap, rotor, and wires, with a brand new DEC CARB-certified catalytic converter (fully warmed up with highway drive before test). Special thanks to PEvans for his endorsement of that cat -- it sure worked well, with significantly lower results than I got a few years back with a brand new SFR catalytic converter.

With Zeitronix's new remote logger (no laptop needed), I was able to log the entire test. See screen shot below -- left half is 15mph test, and right half is 25mph test. If you have ever wondered how much load they use on the test, the logs show it's very little. On the 25mph test, the vacuum is at near idle levels, and it's not much higher during the 15mph test. I thought the vacuum, rpm, and AFM signal (user1) might be particulalry useful for those wondering where to concentrate when tuning for the test.

Also snapped pics showing how I installed the DEC Cat. The Cat is DEC PO82609B. First thing to know about this cat is that, although it is CARB certified for the 944 turbo, is doesn't actually fit. The wastegate pipe is all wrong. It comes with a flared-out wastegate tie-in pipe that is the wrong length and shape to mate up to the factory dump tube. By dumb luck, however, I stumbled on a cheap and easy way to make it work. I was going to get out the welder and make up some connection but discovered along the way that the factory dump tube is just big enough to slide over the tie-in on the cat. So, I just cut the flared end off the DEC tie-in pipe with a sawsall, slid that pipe into the factory dump tube, and used a 2" lap joint band clamp from Summit Racing (Part DEP L20SA). Fits like a glove and seals perfectly. For under $20, this way you can install the DEC converter yourself without needing to go to an exhaust shop, etc.

Sorry for the long post, but I'm happy to have passed, and thought this might help others... :thumbsup:

wow those are excellent results Tom. Each year I worry about this.

Congrats.

Well, I endorsed the DEC cat but also expressed hope that you would have better luck than I did with the fitment, and it sounds like you did not. Nice fix though. Now if I have to get a new one at least I'll be prepared.

Take care of the warranty paperwork now while it is fresh in your mind. I'll let you know shortly whether I got the guaranteed 5 years out of mine.

Congratulations.

Interesting, my 15 and 25 mph NOx numbers on a fresh DEC cat were 116 ppm and 12 ppm respectively, so the opposite of yours. Two years later I barely passed the 15 mph NOx test even in first gear and 2500 rpm. The 25 mph NOx reading was still very low.

Now I am really wondering if there is something up with my car that is causing high NOx at the 15 mph operating condition. Is this the kind of thing a wideband could help me figure out? Or is it just a bad 02 sensor?

Is all California just a 15 and 25mph test? (besides visual)

All the populated areas have the "enhanced" smog test, which is the 15/25mph 'dyno' test. In some rural areas, they still have 'basic' idle-only test. In very rural areas, there is no bi-annual test required at all -- only test is when you transfer title.

Here's the map:

http://smogcheck.ca.gov/80_BARResour...rogram_Map.pdf

I forgot to mention, I did have a wideband port welded into the DEC cat so I could watch the AFR and make sure it was in closed loop at 14.7 under test conditions. If the AFR was the cause of the higher NOx, then yes a wideband would have shown you.

Hi Five Tom
Now all you have to do is get your cholesterol numbers to match that smog test and you will live for-ev-ver !!
:roflmao:
Great job

Way to go Tom! The stock management setup was the way I went too this year, and passed with very good numbers too, though I'm not sure as good as yours. I think this is a good option for us California guys with mods, even if it is a bit of a pain to put it all on then take it off again... Good to know it's a viable option for even a significantly modified machine. :)

Great post Tom, thanks!

Fast forward two years and happy to say I passed the test again today with the exact same set up! The emissions numbers were higher in every category at both speeds, even though I changed nothing, and even though the logs (AFR, RPMs, vacuum, EGT, etc.) from 2 years ago looked virtually identical to the logs for today's test. The NOx was getting up close to the limit on the 25mph test. Since HC, CO, and NOx were all higher than last time, it looks like the DEC cat doesn't last long at all (it's only two years old and has very few miles on it). PEvans said the same about his DEC. It would be a shame if the ONLY direct fit CA smog-legal cat loses its effectiveness so quickly...

Congrats Tom
You have to be the most meticulous, anal, detailed smog statistician, the world have ever know :bowdown:
Way to go ... I can't wait to do mine ...
I may be toast :(

Well done! I'm jealous...

I am still struggling to get my '87 to pass due to high NOx. Thanks to this post though for the DEC suggestion. I did end up getting one. Though, I didn't have to do the flange modification as you did so maybe they corrected the design since then.

I had the same issue with the Walker cat I tested with in "11. In "11 I passed with miles to spare, but in "13 I failed on the 15mph test. Had to retest and BARELY squeaked by. And I only used the cat for testing. It was on the shelf for the 2 years. WTH? Attachment 849622

Attachment 849623

Great info!