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Secondary Cat Delete on 3.3T

CoconutRob

Registered Member
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Genesis Model Type
No Genesis Yet!
I am interested in doing this...but something that can easily be put back to stock since I have a lease car.

Is it possible to simply replace the 2ndary Cat (I assume it is a fairly short piece) with a straight pipe? No welding...just undo screws/clamps on either side of the Cat...and replace with new.

That way...very easy to put them back. No welding, etc, etc.
Jun.bl makes a midpipe for g70
 

CoconutRob

Registered Member
386
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63
Genesis Model Type
No Genesis Yet!
I do not own a g70 yet but when I do I will try to contact jun.bl directly. I have all my mods chosen just need the car lol
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Beefer

I’m faster
3,682
2,977
113
Richmond, VA
Genesis Model Type
Genesis G70

nimasis

New member
13
11
3
Genesis Model Type
Genesis G70
I am interested in doing this...but something that can easily be put back to stock since I have a lease car.

Is it possible to simply replace the 2ndary Cat (I assume it is a fairly short piece) with a straight pipe? No welding...just undo screws/clamps on either side of the Cat...and replace with new.

That way...very easy to put them back. No welding, etc, etc.
Yes the pipes are short and Im pretty sure you can unbolt the cats and replace them with straight pipes
 

nimasis

New member
13
11
3
Genesis Model Type
Genesis G70
@nimasis Would it be too much to ask for a full throttle example/outside the car drive by? just so we can see what it sounds like at around 5-6k rpm. I know this might be a pain in the ass so no worries if you cant, especially since its cold as balls out haha
I'll try my best to get some drive by and I'll post it here
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CoconutRob

Registered Member
386
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63
Genesis Model Type
No Genesis Yet!
Catalytic converters are such an effective air pollution control, it's a shame to delete these for so little benefit. Speaking only for myself, I would not feel good about doing this.
You still have primary cats and they say it's a 30 horsepower increase
 

CoconutRob

Registered Member
386
262
63
Genesis Model Type
No Genesis Yet!
Ok...so I am new to this. So looking at that pic...the original setup would have a secondary cat somwhere in the middle of that straight pipe?

$520 seems not bad. Looks like I could even replace it myself.

Update: Almost $200 for shipping. F that. I will wait for a USA company to have something similar.
SSR performance in USA makes a set also for the stinger not sure if dimensions are the same for G70 . I feel a little strange calling them without owning A G70 maybe someone with interests can call them.
Side note that also was a seller through eBay maybe if June. BL is contacted directly maybe they have a better price with shipping
 

Toddasaurus

REEEEEEEEEEEEEEEE!!!!!
1,753
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Portland, OR
Genesis Model Type
Genesis G70
We got 2 more primary cats to take care of that

But by removing 50% of the catalyst you're still increasing emissions significantly.

Personally, I like replacing all of them with higher flow models. Also, if something happens and my car has to get a surprise inspection, then I still have all of them on and no laws broken.
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joschneider

G70 Member
492
484
63
Las Vegas, NV
Genesis Model Type
Genesis G70
just to clarify: secondary cats are only for cold start emissions and have no sensors
But by removing 50% of the catalyst you're still increasing emissions significantly.

Personally, I like replacing all of them with higher flow models. Also, if something happens and my car has to get a surprise inspection, then I still have all of them on and no laws broken.
cats don’t work like that. Seconadary is just to catch anything the primary misses during cold start, other than that it’s not doing much compared to the primaries. You pollute more by accidentally dropping a piece of trash and the wind gets it before you can pick it back up, it’s all relative. Also what is a ‘surprise inspection’? Serious question, wondering if it’s something I didn’t think of. I have smog checks and inspections required, but only for older cars and the smog check is only OBD2 checked, not anything else
 

Toddasaurus

REEEEEEEEEEEEEEEE!!!!!
1,753
1,882
113
Portland, OR
Genesis Model Type
Genesis G70
just to clarify: secondary cats are only for cold start emissions and have no sensors

cats don’t work like that. Seconadary is just to catch anything the primary misses during cold start, other than that it’s not doing much compared to the primaries. You pollute more by accidentally dropping a piece of trash and the wind gets it before you can pick it back up, it’s all relative. Also what is a ‘surprise inspection’? Serious question, wondering if it’s something I didn’t think of. I have smog checks and inspections required, but only for older cars and the smog check is only OBD2 checked, not anything else

Certain states, like California, can require inspections if a police officer believes you have illegally modified your car (such as removing cats). If they see you've removed emissions control components you'll receive a fine, and in certain situations can even have your car impounded.

Also, secondary cats are not for cold starts - it's actually the closest cats to the exhaust ports that are designed for cold start emissions (ie the primary cats). The closer they are to the exhaust ports, the quicker they heat up. They may not have an o2 sensor downstream (primaries usually have an o2 sensor before and one after the cat), but they still have a significant impact on emissions.

Case in point, my last car (OBD-1) I added a second cat slightly further down the line because I wasn't able to pass the sniff test (emissions) even though it was only designed for one cat (I had a built engine with a more aggressive camshaft) - the second cat made a big difference in emissions to where I was able to pass. This is all after everything is warmed up.

The secondary cats may not have as big of an impact as the primary set, but it's still a vital part of emission control.
______________________________
 

Beefer

I’m faster
3,682
2,977
113
Richmond, VA
Genesis Model Type
Genesis G70
Certain states, like California, can require inspections if a police officer believes you have illegally modified your car (such as removing cats). If they see you've removed emissions control components you'll receive a fine, and in certain situations can even have your car impounded.

Also, secondary cats are not for cold starts - it's actually the closest cats to the exhaust ports that are designed for cold start emissions (ie the primary cats). The closer they are to the exhaust ports, the quicker they heat up. They may not have an o2 sensor downstream (primaries usually have an o2 sensor before and one after the cat), but they still have a significant impact on emissions.

Case in point, my last car (OBD-1) I added a second cat slightly further down the line because I wasn't able to pass the sniff test (emissions) even though it was only designed for one cat (I had a built engine with a more aggressive camshaft) - the second cat made a big difference in emissions to where I was able to pass. This is all after everything is warmed up.

The secondary cats may not have as big of an impact as the primary set, but it's still a vital part of emission control.
How many people do this? Few handfuls? Not going to effect anything in regards to the environment. There are bigger environmental issues out there...like the fucktard at the very top.
 
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