Kooks High-Flow Cats Failure

[Robottrainer]

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.

GESIs aren't cheap but I think the lower cell count and that they do not have cerium oxide which stores oxygen is the main issue. I used them on a 2013 Shelby and had no issues. Somewhere along they way I think they reduced the threshold.

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[stang17]

Spirited driving?

Mustang is my daily, but whenever I hit an on ramp or go over a bridge and the road is open, Ill do a nice 3rd gear pull up to 7,000ish rpm. I must have 100+ trips down the 1/4 mile and 1/3 mile Racemotive roll races on them.

As far as stock cats, they started to fail at 2,000 miles before I ever even hit the track for the first time. The regular Kooks cats didnt even last 700 miles before they started to get the same sulfur smell and show signs of melting/closing up.

 

[mtr5.0]

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.

how much clearance do those GESI G sport series gen 2 UHP cats have underneath the whipple coyote car? they have the UHP listed at 4.5 inch body on the GESI website, the HO is listed at 4.0 inch body.

 

[Robottrainer]

how much clearance do those GESI G sport series gen 2 UHP cats have underneath the whipple coyote car? they have the UHP listed at 4.5 inch body on the GESI website, the HO is listed at 4.0 inch body.

Much more than oems

 

[mtr5.0]

With the stock manifolds there is a lot of room because where the cats are located. ,but with long tube headers the cats will be more down stream which limits the size . I can see a 4 inch fitting but 4.5 inch looks like it would hit maybe.

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