Cutting 2nd cats off

Yea I did

yea I had already built an exhaust form the cats back since I have a panhard in the way of where the old muffler would’ve sat. Didn’t want to spend too much money on tubing autozone so just tools out those 2nd cats. I had a small exhaust leak after welding and closed it up. Sounds pretty well now. Startuos are the worst but other than that I can control the sound throughout my neighborhood. I live out in St. George so eveyone got an Offroad truck and a loud RZR. Was definitely thinking of going the urd route and then just pop a muffler on. Cruising at 5-6k rpm through whoops wasn’t loud enough, I wanted the truck to be louder and gain a bit more power maybe along with a tune. Do want to try and melt down those cat metals and see what I can get haha.

 

I still have cats so technically still a legal setup. The 2nd cats are literally just for sound deadening. The first cats are what prevent any sort of fire coming out the exhaust. Little less weight now up front too. I remove my front diff and reinforced the front 3 cross members with some tubing. Better weight balance now and don’t have to run as much pre load up front making for a smoother ride. Going to throw the diff back in once I can fix my cv axles and not be limited on travel. The extra 3” of down travel I get in 2wd really helps balance the truck out in hot deep whoops and it doesn’t dive down into as much now with the extra down travel. My next project after king of hammers is to install my te designs engine cage. Then we’ll be 4 linking the rear and deleting the panhard so I can get more up travel out back. The rear likes to buck with how low the hydro bumps are set. I have more up travel up front then a the rear which is my biggest problem currently. I’m not a rock crawling so I need to have more travel out back so the truck can kind of lean back throw the whoops and and really stay planted. Tag along for a wild adventure in not building this truck into a proper race vehicle. Hoping to get into the 1450 class once I get a different engine in after the other mods.

 

The 2nd cats are certainly considered emissions equipment. They do a second burn of your exhaust gases.
Legality depends on state and if it’s even registered

 

Sure they might help with exhaust burn. If a big block v8 is legal with only 2 cats than I’m sure most states would consider my setup legal.if I had a muffler. Muffler and 2 cats is all you need to pass most state emissions tests. 4 cats is overkill especially for a little v8 making pretty low compression lol.

 

Removing those cats is illegal in all states if driven on the road. In reality if your state does inspections you'll fail if they notice.

 

You lose low end torque when you remove the cats, increase the size of the exhause pipe, etc.... Only possibly beneficial if you are super charged.

 

Most aftermarket y pipes for our trucks remove the 2nd set of cats, but include a bung for the 2nd set of O2 sensors. You may or may not have to use O2 adaptors to keep the specs in line and avoid dash lights.

Back pressure seems to always be a huge argument. In my experience with the y pipe and a proper exhaust, the truck does feel a bit more peppy on the lower end and it's holding the gears a bit longer both street and highway. No, I don't have any numbers just what it feels like.

 

Wow

 

Agreed, i definitely think it hold gears much longer now without the 2nd cats. It doesn’t matter what compression ratio your engine runs or if you have a supercharger guys. It has been proven on multiple YouTube channels that cats limit power no matter how many cylinders you have. I’m on 35s with 3.91 gears weighing about 5000lbs. The truck climbs up to 70-80mph no problem. Sounds soo much roudier in the whoops. The stock exhaust manifolds are really what limits our trucks from stock capabilities without boost. The urd extractor pipes paired with no cats and a resonator would be the perfect exhaust setup to get the most power out of an exhaust system. A tune would also help out a lot. You can add back in a bit more timing with some 91 octane fuel paired with that exhaust setup . A supercharge on top of that would do wonders! But Id rather keep the motor/trans reliable, especially since I already snapped soo many studs don’t need the extra power till I’m on a full floater.

 

Oh look a wild Tacoma . Don’t trust the 1.97$ wheel studs from oreillys in the whoops.