[Camaro1973]

Originally Posted by Z OH 6

When I pulled my OG green cats because I was concerned about them failing, I went with offroad pipes and immediately disliked the additional volume and tone, so I added the Magnaflow muffler in the center as many have done which helped with the volume but the tone still wasn't as good as it was with the green cats, but then I got concerned about the flow of the double Y design so I pulled it out and installed a Jones X pipe muffler and the sound got worse, much sloppier and raspy. I had it on the car about a month and now I'm back to my original green cats again and it sounds great again. I bought a set of the Kooks HO green cats which I will swap out with the original green cats when they arrive.

Yeah those are the upgraded version of the original gen 1 cat and hold up
Better. It just sounds so much better with them on and I’m Still making 850rwhp through the gen 2 ultras so not really sure what kind of power I’m losing if I took them
Off.

[JSH]

First I've heard about Fabspeed cats (200 cells)

https://www.autoevolution.com/news/f...ss-148346.html

[Z OH 6]

Originally Posted by JSH

First I've heard about Fabspeed cats (200 cells)

https://www.autoevolution.com/news/f...ss-148346.html

I knew about these last year when the C8 came out. They were one of the first companies with a high flow cat for the C8 but they're insanely expensive.

[h018871]

Post 50
https://www.camaro6.com/forums/showp...3&postcount=50

It's taken a while, short version........

Kooks blamed E85 for causing the cats to fail
I contacted Gesi and they stated that their products are designed for E mix
Kooks said that the tune was wrong, causing failure
Tuner jumped in (thx Ted!) and said no way
Kooks sent two Gesi GE-90147 for me to weld in
I sent back the original Gesi GE-90140 cats to Kooks

Kooks volunteered to send cats with the connection pipes. But since I had welded them in, eliminating the rear clamp that was not an option. I had to prepay for the new cats, they agreed to refund the charge this week. The welding is on me.
Kooks states on the replacement invoice they are 850hp cats, but their website says 425. Not real promising, but we'll see how these do.

[JSH]

What are your mods and hp?

Originally Posted by h018871

Post 50
https://www.camaro6.com/forums/showp...3&postcount=50

It's taken a while, short version........

Kooks blamed E85 for causing the cats to fail
I contacted Gesi and they stated that their products are designed for E mix
Kooks said that the tune was wrong, causing failure
Tuner jumped in (thx Ted!) and said no way
Kooks sent two Gesi GE-90147 for me to weld in
I sent back the original Gesi GE-90140 cats to Kooks

Kooks volunteered to send cats with the connection pipes. But since I had welded them in, eliminating the rear clamp that was not an option. I had to prepay for the new cats, they agreed to refund the charge this week. The welding is on me.
Kooks states on the replacement invoice they are 850hp cats, but their website says 425. Not real promising, but we'll see how these do.

[Gunkk]

Originally Posted by h018871

Kooks states on the replacement invoice they are 850hp cats, but their website says 425. Not real promising, but we'll see how these do.

They're the same? 2 * 425 = 850. Reading your other thread I presume the car is up at that level as well road-course use, so yeah you're probably going to break 'em if anyone is.

[Z OH 6]

Originally Posted by Gunkk

They're the same? 2 * 425 = 850. Reading your other thread I presume the car is up at that level as well road-course use, so yeah you're probably going to break 'em if anyone is.

It looks they sent him the replacement for the older standard Green cats which are rated to 425hp per bank. The new Kooks Green HO cats are designed to hold up to 850hp per bank.

[Z OH 6]

Originally Posted by h018871

Post 50
https://www.camaro6.com/forums/showp...3&postcount=50

It's taken a while, short version........

Kooks blamed E85 for causing the cats to fail
I contacted Gesi and they stated that their products are designed for E mix
Kooks said that the tune was wrong, causing failure
Tuner jumped in (thx Ted!) and said no way
Kooks sent two Gesi GE-90147 for me to weld in
I sent back the original Gesi GE-90140 cats to Kooks

Kooks volunteered to send cats with the connection pipes. But since I had welded them in, eliminating the rear clamp that was not an option. I had to prepay for the new cats, they agreed to refund the charge this week. The welding is on me.
Kooks states on the replacement invoice they are 850hp cats, but their website says 425. Not real promising, but we'll see how these do.

That's 425hp per bank so 850hp is correct.

[h018871]

Originally Posted by JSH

What are your mods and hp?

Car hasn’t been on a dyno
Mild cam, ported blower, ported heads, occasional E and bolt ons
When this started it was only the bolt ons w/ E

I should now be close to the limit

[SHE'Z 18]

Originally Posted by h018871

Car hasn’t been on a dyno
Mild cam, ported blower, ported heads, occasional E and bolt ons
When this started it was only the bolt ons w/ E

I should now be close to the limit

Hey HO,
Any updates on how the replacement Kooks cats are holding up? Are we missing something, or are the replacements that they sent you also rated for 425/bank? It seems like Kooks just shipped you the same ones, just with a different part number. But, I may be missing something. Thanks everyone for all this outstanding feedback. I’m in the beginning stages of a build and suspect that I’ll end up in the 750-ish WHP range. That said, it seems like the GESI HO cats may be the best/only option

[h018871]

The construction of the medium is different. I neglected to take a picture ��*♂️
Anywho instead of a simple spiral from the center, it is a dual spiral. Looks like the ying/yang symbol.

[Marozl1LE]

Hi guys i have now uho cats from gesi 85032 gen1 i hope this cat's doesn't gone bad too like the first green cat's

My HJS cats going bad after 6 months only bolt on my car
Kong ported blower with x port 16 psi ~ 22~ degrees timing
On pump gas fuel 97 octane no track use i think middle high 6xx whp
Is 1le package 60-130 times 6.1 ~ sec

[radz28]

That's a bummer...

[Marozl1LE]

I hope gesi do it better i don't wanted melted cats again ****ing expensive too or I immigrate to the USA and drive without cats yessir American dream life.
In my greda fan country you can't do nothing so sad here ��

Also my afr was alwaYS at wot 0.79-81 ~ not leaner