Will you or won't you PASS SMOG without cats?

[Cop Magnet]

I always thought a properly tuned car didn't need cats to pass smog, hence the visual cat-check on most cars (best design feature of the Viper, period). I keep hearing yes and no, and believe me I've searched.

Quote:

dump the cats! Lots cooler and will sound mean at WOT!


Ya won't pass smog, hi-flow cats are a great compromise, keeps sills cool, sounds good and passes smog, I used Randomtechs.

And this brings me to my issue, specifically.

In IL, they do the sniffer test, gas-cap, and OBD check only. The used to do some pulls on a dyno type thing but after I sent the last drum crushing over the three cars behind me, I guess they stopped. Okay, kidding about that part.

I removed my cats last summer. Used the MGW O2 sims from JonB. Car runs fine although I have gotten check engine lights on and off. I had trouble with my valve stem seals, and the codes show misfires not 02 sensor problems.

Since then, I must have put 200 miles on the car in varying conditions and road speeds, with no check light. And I've been to the freaking Smog Station 5 times. I don't fail, but each time they read the car as not ready, and tell me to drive it some more. And here's the DMV Irony of Illinois...they suspended my plates for not passing smog. But the solution is to put more miles on the car. Go figure.

So, am I doing something wrong? Will my car pass smog without cats at all or have I screwed up? Is there something I should do to prep the car beyond what I'm doing? Are my 02 sims at fault?

 

[SoCal Rebell]

I can't speak for Il. but you would fail miserably in Cali

 

[viperdude118]

Prior to going to the smog station you need to check with an OBD II scan tool to ensure that all your readiness monitors have been set to ready!

Generally speaking yes you can pass both a ASM test (dyno/sniffer) and or a OBD II test without cats.

Fortunately for the viper that cats are hidden so a visual test isn't easily possible. Most reasonable inspectors will let this slide if the car passes one of the above two tests. The EPA wouldn't like it, but who cares what they think.

If your interested in more specific details on these tests and how to possibly get your monitors to the ready state pm me. Otherwise I won't type too much here.

I am not as familiar with O2 simms, so this particular fact may prohibit some monitos such as the O2 monitor and O2 heater monitor from ever being set. But that doesn't mean you still can't get through this.

 

[my viper]

Viperdude118, can you please post the specific details here? I am very anxious to go catless and would like to know as well.

TIA

 

[Mccarlin]

For anyone in IL that never wants to worry about emissions ever again you can PM me.
I've been emission exempt for 3 of my cars for many years now as well as have many friends who are too.

GO CATLESS AND NEVER LOOK BACK AGAIN

 

[Ulysses]

Your car does not pass the ready tests because you have 02 sims. The readiness tests on the 02 sensors checks for certain voltages. Your O2 sims most likely can not emulate this.

 

[SoCal Rebell]

Your car does not pass the ready tests because you have 02 sims. The readiness tests on the 02 sensors checks for certain voltages. Your O2 sims most likely can not emulate this.

What do you know about Vipers Ulysses It's good to see you again, been a long time, you still drag racing at Carlsbad or did they finally shut that place down?

Ron

 

[Johann]

When I took my stock GTS in for its first California Smog Check I told the tech that the cat's location prevented visual inspection; his exact quote "If they're not there I'll know it, it'll show up on the sniffer".

 

[Paul Hawker]

No way you are gonna legally pass smog in California without cats. Even cars with one of the cats removed only pass until you get some miles on them.

There are ways to trick the system with gas additives, etc, but if you get caught the penalties are severe. Fraud is not looked kindly upon when discovered.

Even cars with high flow cats will pass for a while, but in a few years they tend to fail also.

Modern cats are less restrictive than earlier models. Often you can get better results with deleting the mufflers than deleting the cats. No cats often get you that rotten egg smell, and the risk reward is relatively unpalatable.

 

[Ulysses]

What do you know about Vipers Ulysses It's good to see you again, been a long time, you still drag racing at Carlsbad or did they finally shut that place down?

Ron

Ron! Howzit? Unfortunately, they shut the place down. Heard the insurance costs were just too much for the owner to handle. Plus, developers were really pressuring the city. Just as well, work has got me swamped. Funny thing is, I now work right down the street where the track use to be.

Hope all is well up your way.

 

[SoCal Rebell]

No way you are gonna legally pass smog in California without cats. Even cars with one of the cats removed only pass until you get some miles on them.

There are ways to trick the system with gas additives, etc, but if you get caught the penalties are severe. Fraud is not looked kindly upon when discovered.

Even cars with high flow cats will pass for a while, but in a few years they tend to fail also.

Modern cats are less restrictive than earlier models. Often you can get better results with deleting the mufflers than deleting the cats. No cats often get you that rotten egg smell, and the risk reward is relatively unpalatable.

I managed to pass the Cali sniff test with Randomtech hi-flow cats with a full Belanger exhaust and 17,000 track miles, cats were about 2 years old.

 

[viperdude118]

Modern cats are less restrictive than earlier models. Often you can get better results with deleting the mufflers than deleting the cats. No cats often get you that rotten egg smell, and the risk reward is relatively unpalatable.

For the record..mufflers have absolutely positively no influence on emissions testing. They are strictly to regulate sound and are not even required by the EPA.

 

[KWIK96]

I managed to pass the Cali sniff test with Randomtech hi-flow cats with a full Belanger exhaust and 17,000 track miles, cats were about 2 years old.
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Me too

 

[Casey]

Passed NO Problem in Indiana, Twin turbos and all! :grin:

They Can't see that the cats are missing! LOL

 

[Martin]

I've run into the 'drive it some more' advice from the smog check station. If you have anything weird going on with your system, the controller will apparently not settle into a steady-state that the scanner is looking for. They tell me to go out and drive at exactly 50 mph for 20 miles and then re-check. So far, it's worked every time. That apparently gives the system enough time to settle into a set point.

 

[got one]

small town, a few extra dollars...it's amazing how emission friendly these cars can be.

Seriously, if your area has the smog check station, then just get the cats...its not going to make a huge difference on your performance and you can feel better knowing that just in case...

 

[Cop Magnet]

Your car does not pass the ready tests because you have 02 sims. The readiness tests on the 02 sensors checks for certain voltages. Your O2 sims most likely can not emulate this.

Is this true? So 02 sims are worth nothing except to keep the check engine light from coming on? I thought the whole idea was to give the OBD the signals that all was well downstream.

I've run into the 'drive it some more' advice from the smog check station. If you have anything weird going on with your system, the controller will apparently not settle into a steady-state that the scanner is looking for. They tell me to go out and drive at exactly 50 mph for 20 miles and then re-check. So far, it's worked every time. That apparently gives the system enough time to settle into a set point.

I see you are in Cali, and am assuming you do not have cats. Is this correct? If so, this is contradictory to what others have posted. If not, I have already driven way more than 20 miles at 50MPH etc, so that leads me to believe that Ulysses' post may be correct.