Just had my first NJ emissions test on my 2000 I30. The readings seem really good and I was wondering how they compare to other VQ engines.
They look so good, could I remove the cat. conv.?

NOx standard 625
NOx reading 1

HC standard 78
HC reading 0

CO% standard 0.44
CO% reading 0.00

CO2% reading 15.4

O2% reading 0.0

Just curious, does anyone have their readings handy?

 

The cat is exactly why they are good.

Without it...they would be bad.

 

how about the pre-cat? Is it needed?

 

If the car is warmed up well (ie driven for 15 minutes or so) before the emission test(s), then you should be ok without the pre-cats. I think they are most useful (emissions wise) when the car is cold.

 

Yup, I took my 2000 Maxima SE a few weeks ago to the Paramus inspection station. My numbers were:

NOx reading - 0

HC reading - 2

Co% reading - 0

Co2% reading - 15.4

O2% reading - 0

Looking good!

 

and if you care about the thing we affectionately call THE OZONE

 

Thank you.

 

Well, the way I figure it is that if all those freaking trucks and SUV's can basically run around with emissions equipment nowhere's near as effective as new cars must be, I can run without pre-cats. I seriously doubt that the extra emissions a Maxima with no pre-cats has doesn't even compare to a Ford Excursion cruising around creates.

 

True, but its been proven time and again that you can make plenty of power with cats and emissions stuff in place. The cats we have today are very efficient, not like the behemoths they used in the 70s that killed power output.

A friend of mine dynoed his modded Impala SS with cats, and without. Without the cats, he lost 12 ft/lbs of torque across the entire RPM band. Torque wins races, any way you slice it.

Another example is my Monte SS. We ditched the stock carb, build a modified 305 V8, and bolted on a fuel-injection setup from an '87 IROC. An antique by todays standards, but worlds better than a carb. My car passes emissions with flying colors, and the next motor will also.

My $.02

 

Steve, I'm not advocating removing the main catalytic converter. My issue is that a 2002 Maxima vs. a 2002 SUV has way more controlled emissions than the truck does. Why is it okay for them and not for us? By removing the pre-cats, the Maxima is only emitting more than it is supposed to for the first 15 minutes or so of a start, the rest of the emissions system is left in place and works normally for the majority of the time. In the grand scheme of things, how bad is that really? If someone out there took the time to design a Y-Pipe that still had similar flow characteristics of an aftermarket one but retained the pre-cats, I'd be all for it. I'm probably in the minority though.

 

here are my numbers from 9/2001 with the following exhaust mods:

stillen hi flow in take (should have no impact on emissions)
gforce ECU upgrade

I passed the test without problem. here are the details:

state standard: (hydrocarbons) 0.8000 gpm
my test result: (hydrocarbons) 0.0467 gpm

state standard: (carbon monoxide) 15.0000 gpm
my test result: (carbon monoxide) 0.2325 gpm

state standard: (oxides of nitrogen) 2.0000 gpm
my test result: (oxides of nitrogen) 0.0725 gpm

state standard: (carbon dioxide) N/A (no standard??)
my test result: (carbon dioxide) 34.7453 gpm

I live in MD

 

dose not make it right
Leave you cat a lone

 

the fact of the matter is that the internal combustion engine is very inefficient. not only that, but current energy delivery mechanisms are also inefficient--ever think about how much energy it takes to extract, process, refine, and transport gasoline from some sea bed in the gulf of mexico to gas stations across the US??

besides car emissions, many people don't know that the majority of CO/CO2 are contributed from electricity generation. most people have NO IDEA how their electricity is produced. but the majority of it is produced by burning COAL. it's cheap and plentiful here in the US.

So if you really wanna make a difference and save the ozone, then reduce your electricity consumption. in laymen's terms, turn that TV off when you're not watching.

ok i'm officially off my environmental soap box

 

I hear your point. The SUVs get away with it 'cause the parent companies like GM and F**d have enough vehicles that pass with LEV standards to offset the pollution of their bigger vehicles - in the eyes of the Feds anyway.

Hey, I'm a treehugger at heart, I'd be all over a larger Y-pipe that had pre-cats too. I don't think you're idea is really bad for the environment, but from a performance standpoint, you may lose a little bottom-end torque if you make that Y-pipe too large.