Kooks High-Flow Cats Failure

[2021 Mach 1]

Any pics of the damaged cat? Curious as the whether the material dislodged itself from the walls of the cat housing like my Ultimate Headers cats did?

Not yet

Sponsored

 

[Robottrainer]

GESI Gen2 UHO cats are the only way to fly

Mine kept throwing cat efficiency DTS codes. Ended up going back to OEM. Im debating whether to sell them as I might use them one day if pressed.

 

[Joshinator99]

Mine kept throwing cat efficiency DTS codes. Ended up going back to OEM. Im debating whether to sell them as I might use them one day if pressed.

Those are 49 state legal and I’ve never heard of that happening to those for that reason. Interesting.

 

[Robottrainer]

Those are 49 state legal and I’ve never heard of that happening to those for that reason. Interesting.

2021 GT. 3" GENSI UHOs. They have an EPA number but not a CARB number.

 

[junits15]

Those are 49 state legal and I’ve never heard of that happening to those for that reason. Interesting.

EPA legal is kind of a funny thing, its not quite what is required to make the car not throw a CEL.

 

[robvas]

For the states that follow CARB (there quite a few now), does that not apply to aftermarket mods?

 

[Joshinator99]

2021 GT. 3" GENSI UHOs. They have an EPA number but not a CARB number.

Correct. That’s what they mean by 49-state legal lol… ;)

 

[Rhyanski]

Here in Europe, the sensors at the high-flow cats are disabled. Reason is the high flow and higher temp of gases confuse the sensor as if there's no cat at all and it throws errors. Turning it off gets the car running normally.
When you run the emissions test with high-flow cats, everything is in the norm, so they work, it's just the sensors that get confused... And trust me, here the emissions / gases tests are at par or more strict than California.

 

[Robottrainer]

Here in Europe, the sensors at the high-flow cats are disabled. Reason is the high flow and higher temp of gases confuse the sensor as if there's no cat at all and it throws errors. Turning it off gets the car running normally.
When you run the emissions test with high-flow cats, everything is in the norm, so they work, it's just the sensors that get confused... And trust me, here the emissions / gases tests are at par or more strict than California.

Turning off the sensors in North America is an instant fail in some area. The emissions monitors will never go ready plus most tuning software will not allow you to turn any of that stuff off .

 

[Rhyanski]

Turning off the sensors in North America is an instant fail in some area. The emissions monitors will never go ready plus most tuning software will not allow you to turn any of that stuff off .

Do you do yearly road-worthiness tests in US? On those tests, do they inspect the car software for modification? Here we do the test yearly, commercial vehicles (meaning cars registered on legal entities, not on physical person) should pass the road worthiness test every 6 moths, however they measure the gases without probing / checking the car software in any way. They just take 2 measures on the exhaust - 1st measure at idling, 2nd at around 3500 rpm and this is it. Nobody cares if there's a tune or sensors disabled.

However, if we're talking car warranty - then it is a completely different topic.

 

[Robottrainer]

Do you do yearly road-worthiness tests in US? On those tests, do they inspect the car software for modification? Here we do the test yearly, commercial vehicles (meaning cars registered on legal entities, not on physical person) should pass the road worthiness test every 6 moths, however they measure the gases without probing / checking the car software in any way. They just take 2 measures on the exhaust - 1st measure at idling, 2nd at around 3500 rpm and this is it. Nobody cares if there's a tune or sensors disabled.

However, if we're talking car warranty - then it is a completely different topic.

Depends. State to State, Province to Province. In those area that require a yearly inspection or when you buy and sell a car, they plug into the OBDII port and read if it's ready or not. If 2 or more criteria is not ready, it's a fail. They also do a visual. You may br required to have oem cats. Missing sensors is definetly a fail.

 

[Rhyanski]

I see, well, then it won't work... Here they don't plug anything to OBD. Don't read car sensors or computer whatsoever. In Germany however, they have much more strict rules to what you can add to your car. In general, in case the part (whatever part it may it is - e.g. headlights, tailpipes, etc) is TUV Certified, the car is considered road legal. They will still check the car, but you'll pass. If it is not TUV Certified then they may not even consider checking, or if it checks out, they may issue some "remark" regarding road worthiness...

 

[robvas]

Here in Europe, the sensors at the high-flow cats are disabled. Reason is the high flow and higher temp of gases confuse the sensor as if there's no cat at all and it throws errors.

I don't think it's flow or high temp gas but simply that the cheaper "high flow" cats just don't clean the exhaust as well as the OEM ones so the tests still fail. Most people will see catalyst inefficiency codes with them here in the USA. The larger more expensive cats usually perform better.

 

[stang17]

The GESI G sport series gen 2 UHP cats with 4 inch body and 3 inch in/out will support up to 850 hp per cylinder bank. Kooks sells them rebranded as their High Output or Ultra Green Cats. We have run them on a 1070whp hellcat and and 800+ whp whipple coyote for a few years now without any issues. Leave COT protection turned on in tune and don't use a 2 step and they should hold up.

FWIW I had both the stock cats and regular high flow non green Kooks cats both fail rather quickly on me running the stock whipple tune.

 

[JoeCee]

The GESI G sport series gen 2 UHP cats with 4 inch body and 3 inch in/out will support up to 850 hp per cylinder bank. Kooks sells them rebranded as their High Output or Ultra Green Cats. We have run them on a 1070whp hellcat and and 800+ whp whipple coyote for a few years now without any issues. Leave COT protection turned on in tune and don't use a 2 step and they should hold up.

FWIW I had both the stock cats and regular high flow non green Kooks cats both fail rather quickly on me running the stock whipple tune.

Spirited driving?

Sponsored