Carpokes Porsche Forum

Well I passed my smog test today, which is always a huge relief. Looks like the NOx numbers are creeping up, so I may add a smidge more gas next time. Stock chips, AFM, injectors, etc. This is still with the DEC cat I bought in 2018, which is starting to get close to the end of its 5-year warranty period. But that's a worry for another year. Today, all is good.

Congratulations! It's always a point of concern in California and a reason to celebrate after you pass!

Hi Tom - where did you do your test?
I used Smog and Run in Los Gatos in 2020 and they were pretty patient with my tweaks between tests. Passed after putting in a Walker Cat (NO went to 2 PPM!).
Mike

I went to SmogIt in Sunnyvale, on Evelyn. I've taken it there before. He's just a straight-up, honest smog tech. No special favors but no game playing or hyper nit-picking either. I've been going there for several years now after the last guy tried to shake me down for money to pass my car, claiming my 100% CA legal cat wasn't legal. When I argued that the cat was CARB approved for the car, he started pointing at other things like my j-hot coated factory headers -- basically letting me know he wanted $50 to pass the car (even it had already sailed through the tailpipe dyno test). Karma caught that guy though -- or should I say the state did. He was on the lamb for a while, then suspended, and now has resurfaced at another gas station smog shop in Mt. View.

Happy to report my car passed smog today. Yippee!! This was with the DEC cat I bought in 2018 -- so apparently it lasts longer than I feared. I was worried the NOx would keep creeping up like last time out, so in additional to my normal tune-up ritual, I added a little extra fuel this time (careful to stay in closed-loop); did the test in the morning before it got hot (~25 degrees cooler than last time); and ran the car on the freeway for a solid 45 minutes before the test to really heat-soak the cat. Results were fantastic -- probably the lowest overall numbers I've seen yet!

Great news - same place in Sunnyvale?
My turn in a few weeks....

Nice, the additional factor of measuring for NOx while under light load is something we don't have to deal with in Santa Barbara. It is becoming more and more difficult to find quality CA/BAR-legal catalytic converters that last a decent amount of time. This is a constant struggle with our '90s BMW customers in particular. My 951 is somehow scraping by with its original cat with over 180K miles, at least 10K of them track miles while I ran the engine in stock form . . . . I am able to make the thing pass the idle/2500 RPM tests in neutral with the VEMS engine management and 830cc injectors, which demonstrates the power of even a basic standalone engine management system.

whalenlg wrote: Sat Aug 10, 2024 2:39 pm Great news - same place in Sunnyvale?
My turn in a few weeks....

No, their dyno was down for repair. He said it would be fixed in a week. Assuming they are up and running again, I'd go back to them. I went to Le's Auto Repair on Evelyn, down the street from the other place, which was recommended by a car friend with a shop in the area. They were good in the sense that they were not looking for reasons to fail the car and/or take advantage -- been there and done that. But I was not a fan of their actual dyno, which sat above the ground. And they made me wait 30 minutes while they worked on an old jalopy, despite having an appointment, and despite the fact that they could have stopped anytime to smog my car. In the end, everyone was very nice, but the shop and parking lot had kind of a junk yard vibe. They also charged $135 for the certificate, which is above market I believe, but there were not a lot of options and I just wanted to get it done. I was surprised how many Star stations refuse to do dyno tests anymore. When I called around, most said no, presumably because they just want to do 10 minute OBDII tests and collect their $40 with very little time and effort.

cda951 wrote: Sat Aug 10, 2024 3:15 pm Nice, the additional factor of measuring for NOx while under light load is something we don't have to deal with in Santa Barbara. It is becoming more and more difficult to find quality CA/BAR-legal catalytic converters that last a decent amount of time. This is a constant struggle with our '90s BMW customers in particular. My 951 is somehow scraping by with its original cat with over 180K miles, at least 10K of them track miles while I ran the engine in stock form . . . . I am able to make the thing pass the idle/2500 RPM tests in neutral with the VEMS engine management and 830cc injectors, which demonstrates the power of even a basic standalone engine management system.

Aftermarket CA-legal cats must carry a 5 year, 50k mile warranty. My theory is that caused a race to the bottom, where all the mfg's try to make the cheapest cat possible that will still last, if barely, 5 years. These dyno tests are run at very light load (13 in. HG vacuum according to a log I once made during the test), but even that adds the challenge... But in the end, it's all about a good state of tune and a good cat.

Congrats on the successful test!

That testing is something I actually miss from my car's time in Cali, something that might surprise or even amuse some folks. Local smog guy at his gas station near a property in OC was a car guy, so every visit for the car was a chance to visit and socialize. Most important was the learnings from the various tests over the decades. Slowly creeping tailpipe NOx offered clues about injectors that needed cleaning, for instance. Maybe extra valuable was his willingness to use the two pre-cat test port pipes in the engine bay, which offers the ability to isolate symptoms to one bank on the V8.

Now, out here in the wilds of central Oregon, I'm not aware of anyone who even offers that simple level of diagnostics, and certainly not for the relatively low test fees in OC. I can add a wideband CO sensor for fuel/air mixture, but unfortunately there's no no similar cheap-and-easy option for HC and NOx.

After living through the ugly times in the L.A. basin and watching the slow but steady improvements in air quality over the decades, I'm still a big fan of testing and compliance. Here, I can regularly get a reminder about 'the good old days' with the windows down at a stoplight. I suspect we are a substantial market for Cali cars that wouldn't pass inspection.