Smog Legal Mods

CDsDontBurn said:

What are they? I know from working on my Accord, that we can change the intake, mufflers, get headers, but not the cats unless they're California legal cats like the Magnaflow ones.

I'm just curious to know what we can do to our cars in regards to emissions and still have them able to pass smog.

Click to expand...

CARB exempt mods are legal. You cant change the headers or intake unless they are CARB approved. Air filter and Muffler are OK - cats need to be OBD2 certified for 1996 and newer vehicles - and Cats are only necessary if your stock ones are bad, heres a little fact .. aftermarket "high flow" cats wont do anything for your performance, and may even make you fail the smog test when they diminish after a couple years, then youre out another $600 to get new ones all over again. These are all just "visual" items, they dont affect your smog test in any way whatsoever. As far as performance gains, they are VERY minimal, really not worth it in my opinion. Maybe you'll gain a couple miles per gallon, but then you do something that actually makes a big diference like gears - and your MPG goes out the window.

Yes you can do PI heads / intake, tune your car accordingly - although technically they are not legal even though they come off newer cars, you're not supposed to mess with ANY emissions control devices. None of these things will affect the emissions results on the 5 gas analyzer in any way. Smog tech wont know you made any changes either. Probably the best thing you can do - internal engine modifications / power adders are the only way youre going to see a big improvement.

Really getting hard to find a "smog guy" now, they are cracking down a lot more and the fines are really steep if they dont take your license away completely - the BAR issues a report and lists the names of smog techs who got caught and their fines / punishment - we're talking about $15,000 fines. If you do find a guy to pass you - its going to be more expensive, upwards of $300 for them to overlook the $200 Intake on your car that is not CARB approved, so thats $500 you just spent on a modification that might get you 1 more mile per gallon, depending on how you drive of course, people do mods like this to see how much better their car performs under WOT conditions, and then your miles per gallon just went to nothing.

Oh and even if you manage to cheat the smog test, if you get pulled over for street racing, the cops can pop your hood and if they think your car has been modified they can impound your car.

As for the smog guy, yea, I know a guy. He's also (what you guys just said basically) told me how now that they're doing that STAR Certified thing that it's much harder for them to overlook something. He'll at least tell me what's going on with my car before he even runs it on the smog machine if he thinks it'll pass or not.

Anyways, the performance related mods I'm thinking of - for now at least - are more "butt dyno" and audible mods. I know that things like a SRI / CAI, gears, and under drive pulleys can improve my MPGs a small amount as long as I don't go WOT all the time.

But yea, I'm just concerned on what mods can be done that won't impact the emissions of the car. I did do both CATs a while ago because one had failed so I decided to both because, well, why not? Since I'm still on the OEM exhaust tubing and the center cat, I haven't noticed any performance increase, however I have noticed that the exhaust has a very slight "grumble" to it; particularly at lower speeds / RPMs. I know that if I went with a full on cat-back system that she would sound a helluva lot better .

Oh, and speaking of the 3rd CAT. Will removing the 3rd CAT affect smog performance at all? Like, will removing it cause me to fail smog? Or is it's purpose more for noise reduction? And the mods I'm thinking of specifically are SRI / CAI, PI intake (which I already have just need to install ), Magnaflow Hi-Flow CATs (already installed), and true dual exhaust.

CDsDontBurn said:

As for the smog guy, yea, I know a guy. He's also (what you guys just said basically) told me how now that they're doing that STAR Certified thing that it's much harder for them to overlook something. He'll at least tell me what's going on with my car before he even runs it on the smog machine if he thinks it'll pass or not.

Anyways, the performance related mods I'm thinking of - for now at least - are more "butt dyno" and audible mods. I know that things like a SRI / CAI, gears, and under drive pulleys can improve my MPGs a small amount as long as I don't go WOT all the time.

But yea, I'm just concerned on what mods can be done that won't impact the emissions of the car. I did do both CATs a while ago because one had failed so I decided to both because, well, why not? Since I'm still on the OEM exhaust tubing and the center cat, I haven't noticed any performance increase, however I have noticed that the exhaust has a very slight "grumble" to it; particularly at lower speeds / RPMs. I know that if I went with a full on cat-back system that she would sound a helluva lot better .

Oh, and speaking of the 3rd CAT. Will removing the 3rd CAT affect smog performance at all? Like, will removing it cause me to fail smog? Or is it's purpose more for noise reduction? And the mods I'm thinking of specifically are SRI / CAI, PI intake (which I already have just need to install ), Magnaflow Hi-Flow CATs (already installed), and true dual exhaust.

Click to expand...

Exhaust wont do anything for your car "performance wise" .. it just makes it sound different.

THe 3rd cat is there for HC reduction and to combine the CO with O to CO2. You will fail visually with the 3rd cat removed - I can get away with only 2 cats on my SC because the 5 speed SC's only came with 2 cats from the factory, the automatics had 3 ( the smog guy has to look this up in his book every two years I take it in). Marginally, it affects your emissions results - if your first two cats are borderline, you may not pass with the 3rd one removed on the analyzer, you will Fail the visual. I failed with my 1994 4.6 with a 3rd cat gutted and dual exhaust .. for some reason there wasnt enough back pressure for the EGR to operate correctly, I put a stock exhaust back on and the emissions came way down again. Your engine really doesnt push enough exhaust gasses to make a full exhaust system beneficial unless youre supercharged .. its mostly for sound. The resonator after the 3rd cat is for sound reduction, the cat is for emissions.

funderbird said:

In san diego on coronado island, the had what looked like a moble smog station. Of course this was 2007 or 08. Not sure if that is what it was or not. CARB LEGAL stuff would be the safest bet. I know a LA county sheriff that told me he could tell by smell if a car was too far off legal smog. It could have been bogus. You never know. A p.i. engine swap would be the best way i think. But that has its limitations too. A smog guy in murrieta ca told me that i could not.legally put an explorer motor in, it had to be from a similar car. Such as a crown vic, mustang etc...again not.sure if it is crap or not. He.said i should by a caprice haaahaaaa.

Click to expand...

Not BS.
Generally, when you tune an engine for performance vs. emissions, you make it run slightly rich to protect the engine under load.
This can be smelled by a human and easily detected by a machine.

It's even more obvious when you gut a cat; I know from experience with my track car that the catless cars "stink" (b/c he unburnt fuel goes out the tailpipe instead of collecting on the catalyst and burning off.)

Hwy monitor work and are no joke. See what Colorado does:
http://aircarecolorado.com/rapidscreen/how-i/

In comparison, it looks like CA tests (at least in the Bay Area in 2013) were for information only (surveys + users) and NOT punitive.
http://www.mercurynews.com/ci_23219778/surprise-bay-area-drivers-have-cars-examined-at

CA also does roadside screenings (much like DUI checkpoints).
I believe they have held up in court b/c driving is a privilege and not a right and by doing so you accept the rules the state has placed on the upkeep of your vehicles.

While I totally agree with enforcement of emissions standards for roadgoing vehicles at any time (vs every 2 years), I object to the complete BS of CARB exempt numbering. That's a revenue tool.

-g