Will headers cause me to not pass smog?

[FRSBRZGT86FAN]

Originally Posted by 67corvette

So I'm stuck just putting my stock headers back on in five years or however long it is. Or finding a place that will just take some extra money an let me go that would be the ideal situation

6 but yes, pretty much, or you need to go aftermarket Catted EL headers and catted headerback, and then a tune again or keep your current tune to cover up the CEL. Then hope to god it passes the sniffer in CA. We shall drink to your horsepower loss

[FRSBRZGT86FAN]

Originally Posted by Nevermore

This is a question I've been curious about. I want to do a whole exhaust eventually, but I don't know how many cats the car has stock, or where they are. I see people always wanting the catted headers, but they seem to be pretty rare.

2 Cats, one primary and one secondary. The primary cat is important its connected to O2 sensors before and after it, the secondary can easily be removed without a CEL (hence a catless headerback exhaust can gain 10-20 hp), because that catalytic converter (secondary) is not connected to the car electronically in any way. The reason some people want catted headers is that they don't want to go full catless for whatever reason so they can run catless headerback.

[skye67]

Here is one way around all that. Get a PO box and register to car in Bishop or Maraposa CA. No smog in ether of those places.

[67corvette]

What do you mean we will drink to my horsepower loss

[Gusto]

Headers will not pass smog in California, a cat back exhaust will. They will pass the visual test but not the actual smog test. Anything from the cat up will cause you problems with cel, smog test, and pigs.

[Gen]

They don't use the sniffer on newer cars in CA--OBDII and visual only. You will fail the visual in CA as others have said.

From what I'm hearing, even a tune will potentially cause you to fail in a few years. Supposedly various voltages will be compared to a specified OEM range.

[uspspro]

Mod the heatshields to fit the header, do what it takes to have complete monitors and no CEL, and bring the car in warm.

[nakamur21]

So if the O2 sensors are in front and behind the primary cat in the exhaust manifold, can you ditch the secondary cat in the front pipe and still pass the OBD-II smog test?

I understand newer vehicles are not getting the sniffer test and are OBD-II only, so even though you can't get a header in CA and still pass smog, you may still be able to get a catless front pipe and pick up 5-7hp.

[FRSGeek]

I didn't want to mess with CEL and future issues with any smog tests here in WA or where I live (never in the Socialist Republic of CA.)!!!!!!!

I am going FA20Club w/CAT. I dropped the 2nd CAT on my Invidia front pipe, but for noise control added a resonator in the hope it would drop a few db.

Originally Posted by FRSBRZGT86FAN

2 Cats, one primary and one secondary. The primary cat is important its connected to O2 sensors before and after it, the secondary can easily be removed without a CEL (hence a catless headerback exhaust can gain 10-20 hp), because that catalytic converter (secondary) is not connected to the car electronically in any way. The reason some people want catted headers is that they don't want to go full catless for whatever reason so they can run catless headerback.

[FRSBRZGT86FAN]

Originally Posted by FRSGeek

I didn't want to mess with CEL and future issues with any smog tests here in WA or where I live (never in the Socialist Republic of CA.)!!!!!!!

I am going FA20Club w/CAT. I dropped the 2nd CAT on my Invidia front pipe, but for noise control added a resonator in the hope it would drop a few db.

No problem, I would reccomend an Ecutek tune though in case you get any CEL it removes and blocks all the ones caused by catalytic issues.

[wparsons]

Originally Posted by nakamur21

So if the O2 sensors are in front and behind the primary cat in the exhaust manifold, can you ditch the secondary cat in the front pipe and still pass the OBD-II smog test?

I understand newer vehicles are not getting the sniffer test and are OBD-II only, so even though you can't get a header in CA and still pass smog, you may still be able to get a catless front pipe and pick up 5-7hp.

A proper sized high flow cat costs VERY little hp compared to a catless pipe. The big restriction is from higher cell count OEM cats with smaller diameters.

A 2.5" catted front pipe will probably make about 1hp less than a 2.5" catless front pipe, plus the catless pipe will be raspier and louder. It might not be noticeable with the stock header, but if you go aftermarket you'll hear it for sure.

[Cesium Rainbow]

Originally Posted by FRSBRZGT86FAN

http://www.dmv.org/ca-california/smog-check.php
In LA because california has some of the strictest emissions laws in the country it won't pass smog certification. You can only get catted EL headers, and a catted header-back exhaust, as well you will need to get a tune so the CEL will dissapear and no codes will be shown in the ECU during inspection before the smog certification test. That being said if your vehicle is six or less model years old, you are not required to obtain smog certification as long as you pay the annual $20 smog abatement fee, so you will be good going cat less for 6 years if you pay $20 every year, but honestly you would still need a tune to make sure the UEL or EL headers you get don't kick up a CEL otherwise every inspection will fail in that 6 year period, also some officers can smell the fact your car is cat less and will right you a nasty ticket, its not worth it, stay catted if you can with an aftermarket exhaust you will still get gains.

Why EL headers and not UEL? Is there an EGT temp difference between the two that affects the cat?
And if both cats are swapped for high flow, will the sniffer be satisfied? I only swapped one cat for a Cobb high flow on my WRX and failed miserably. Pissed me off.

[FRSBRZGT86FAN]

Originally Posted by Cesium Rainbow

Why EL headers and not UEL? Is there an EGT temp difference between the two that affects the cat?
And if both cats are swapped for high flow, will the sniffer be satisfied? I only swapped one cat for a Cobb high flow on my WRX and failed miserably. Pissed me off.

I only said EL headers because those are the only headers so far I have found that have a cat, I don't think the EGT temps would have a difference because they all collect at one point so. I do believe with a tune and two cats being swapped the sniffer will be o.k. but only in the case of the FA20.

[Cesium Rainbow]

Oic. FA20club came out with a UEL catted set not too long ago.

Originally Posted by FRSBRZGT86FAN

I only said EL headers because those are the only headers so far I have found that have a cat, I don't think the EGT temps would have a difference because they all collect at one point so. I do believe with a tune and two cats being swapped the sniffer will be o.k. but only in the case of the FA20.