Can you run longtubes with stock cats?

[Bluemustang]

I am thinking about installing headers for the sound and the low end torque bump. But I live in a state where emissions test is required. Can I run them with stock cats and still pass emissions?

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[wireeater]

You can purchase aftermarket headers WITH different types of catalytic converts but I you won't be using stock. One side is welded to the complete header.

 

[Bluemustang]

You can purchase aftermarket headers WITH different types of catalytic converts but I you won't be using stock. One side is welded to the complete header.

So you can't use stock ones? I'm given tonunderstand that aftermarket cats will not pass emissions making them somewhat pointless, besides the smell. Is this true?

 

[Terminator2]

So you can't use stock ones? I'm given tonunderstand that aftermarket cats will not pass emissions making them somewhat pointless, besides the smell. Is this true?

Is your test a sniff test or is it visual or is it based on scanning for DTCs and cat readiness?

 

[Bluemustang]

Is your test a sniff test or is it visual or is it based on scanning for DTCs and cat readiness?

I'm not sure what the requirements are in my state. I need to do some research on that.

 

[stoli]

I'm not sure what the requirements are in my state. I need to do some research on that.

About the MD Inspection Program
MD emissions testing consists of a gas cap test, an on-board diagnostics (OBD) test, or an idle tailpipe test.

Gas Cap Test
All vehicles are subject to a gas cap test unless the OBD test is used to determine fuel emissions output.

On-Board Diagnostics (OBD) Test
OBD tests connect emissions testing equipment to the vehicle's computer system to determine whether the vehicle's emissions components are working properly.

The following vehicles undergo OBD testing:
Passenger cars and light-duty trucks model year 1996 and newer.

http://www.dmv.org/md-maryland/smog-check.php

 

[Kahboom]

Stock cats and long tubes will be a lot of cutting to try and get it too work. Possible? Yes. Stock cats are restrictive and might negate the long tubes. You could get Kooks 1 7/8" short tubes and run stock cats for emissions and run cat delete or high flow cats for the rest of the time with similar gains of long tubes, or get long tubes and green cats from kooks or gesi (gesi vendor that makes ultra high flow cats that meet or exceed federal mandate but pricy).

 

[SVT-DADDY]

Is your test a sniff test or is it visual or is it based on scanning for DTCs and cat readiness?

Will aftermarket cats pass a scan?

 

[2015 Silver GT]

Will aftermarket cats pass a scan?

Not in Connecticut.

 

[wireeater]

Best solution if you really want to go this route but are worried, MAK cat deletes and keep stock ones and bolt them back up when it's time for inspection. Have them weld a flange on the passenger side catalytic after they cut it so you can bolt it back up. The driver side already has a flange on the catalytic and header so good there. I couldn't imagine it being more than an hour job switching them out when you need to.

 

[D.Brown]

Not in Connecticut.

Interesting. So I'm guessing the aftermarket cats wouldn't pass a scan in Rhode Island either. That's a huge bummer. What's the way around this? Would green cats work?

 

[Terminator2]

Will aftermarket cats pass a scan?

Normally no.

 

[Terminator2]

Best solution if you really want to go this route but are worried, MAK cat deletes and keep stock ones and bolt them back up when it's time for inspection. Have them weld a flange on the passenger side catalytic after they cut it so you can bolt it back up. The driver side already has a flange on the catalytic and header so good there. I couldn't imagine it being more than an hour job switching them out when you need to.

I think he wants the sound of long tubes and the torque gains they give and while using the stock cats with long tubes will decrease the gains some cat deletes will not give the sound of long tubes so if that is a big factor for him....

 

[Bluemustang]

I think if I go headers with high flow cats I should be OK in Maryland as long as I can trick to ECU not to throw any codes. And if they look for cats they will see evidence of them being there.

 

[Bluemustang]

I just want to know if I go long tube headers can I get it to pass the emissions test/inspection whatever you wanna call it. Looks like they just plug into the OBDII to check for codes or component readiness and possibly a quick visual inspection.

I just brought up the stock cats as a possibility of helping me pass. But if that negates the effectiveness of the headers than there's no point in having stock cats.

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