So I'm replacing my exhaust with the Gibson exhaust. I'm looking to replace the Cat's with high flow cats, is it recommended that I replace the front & rear cats or just the rear? Also any good brand reccomendations. So far I have Pace Setter and possibly Magnaflow but not sure if the Magnaflows are high flow.
Also are there any Headers out there for the Pathys?
Looking for High Flow Catalytic Converters
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HoneyMonster256
- Posts: 60
- Joined: Tue Jul 01, 2014 11:43 am
- Location: West Jordan, UT
I'm not really sure if so-called "high-flow" converters really have much less restriction than "regular" converters. The rear converters are not monitored by the O2 sensors, so you could even got them if backpressure is a concern, or have a straight pipe made with an O2 bung and flanges to replace the front pipes with the converters, also called a "test pipe." Of course, check with your state regulations in regards to emissions testing. Headers are out there, but you failed to mention whether it's a V6 or V8. You can Google it and come up with some hits. Nismo made some for the V6 and JBA makes them, as well. You can also check Stillen's site.
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Zen_master
- Posts: 276
- Joined: Fri Apr 12, 2013 7:42 pm
Can anyone confirm if the cats are necessary?
Put another way, if I live in a state without e-check can I essentially just "punch out" the honeycomb to increase flow? Have heard of this done on other makes and models. Wondering if it will result in a dash light coming on or some other adverse engine effect.
Put another way, if I live in a state without e-check can I essentially just "punch out" the honeycomb to increase flow? Have heard of this done on other makes and models. Wondering if it will result in a dash light coming on or some other adverse engine effect.
If you have no catalytic converter, it will trigger P0420 & P0430 trouble codes unless you use some kind of rear O2 sensor simulator. The ECM wants to see a 2:1 cycling ratio from front to rear to tell it that the converter is working efficiently. Also, if you gut the converters, make sure you get every bit of the catalyst substrate out. The Pathfinder uses the variable timing to accomplish EGR rather than a conventional EGR valve. It cracks open the exhaust valve during the intake stroke, pulling exhaust gas back from the exhaust system into the combustion chamber. If there is any bits of honeycomb loose in the system, it can be sucked back into the cylinders, scoring the cylinder walls, much like what happened with the early L31 Altimas with the QR25DE engine when the front converter started to break down.
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HoneyMonster256
- Posts: 60
- Joined: Tue Jul 01, 2014 11:43 am
- Location: West Jordan, UT
A high flow cat is basically a emissions legal cat but with less restrictive flow. I'm from the import world so removing the cat or putting in a test pipe isn't possible in my state.
I will look at NISMO or JBA as I have the 4.0 V6 I will need headers as the plan is to install the Stillen's Supercharger
I will look at NISMO or JBA as I have the 4.0 V6 I will need headers as the plan is to install the Stillen's Supercharger
Nmex, you aren't showing the right drawing.NmexMAX wrote:There are no sensors behind these cats, at least in the Vu8 version. I've replaced mine with Cajun B-pipes with no cats and no SES here.
Remember that there are 2 sets of Cats on the R51. The primary cats (20802 and 20900+A) have sensors before and after. The post-Cats don't have any sensors (20010 and 20020 on the drawing you posted).
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