[SOCAL.M6.ZLE]

Originally Posted by KingLT1

You should have stated that in your prior post because it reads like you are implying the GESI Gen 2 4.5" cats are the culprit....which had me scratching my head. The ones that came with your AR headers I don't believe are the same. Honestly these high-end header companies need to start offering the Gesi Gen 2 4.5" for forced induction applications imo. Standard high flow cats and cars >700whp is No Bueno.

Thanks KING, I just edited my comment. I agree, wish I would have known that these cats are not rated for anything over stock power levels :(

I dont have high hopes for the sound changes dropping the cats.


Quick question; is it safe to assume that the car will adjust after removing the cats? or do I need to adjust my tune at all?

[Joshinator99]

Originally Posted by KingLT1

You should have stated that in your prior post because it reads like you are implying the GESI Gen 2 4.5" cats are the culprit....which had me scratching my head. The ones that came with your AR headers I don't believe are the same. Honestly these high-end header companies need to start offering the Gesi Gen 2 4.5" for forced induction applications imo. Standard high flow cats and cars >700whp is No Bueno.

Yep, that’s why I asked… something didn’t add up lol

[SOCAL.M6.ZLE]

Well, I have put a few miles on the car with no cats and well... YUCK.
The tone has shifted away from deep, I lost some of the cool popping, and I really didnt want the extra volume... but most of all, the SMELL is terrible. I think I will be ordering some GESI Gen2 4" HO cats rated at 350-500 per cat... or the 4.5" UHO rated for 850 per cat...

Anyone try the 4.5" yet?

[Joshinator99]

Originally Posted by SOCAL.M6.ZLE

Well, I have put a few miles on the car with no cats and well... YUCK.
The tone has shifted away from deep, I lost some of the cool popping, and I really didnt want the extra volume... but most of all, the SMELL is terrible. I think I will be ordering some GESI Gen2 4" HO cats rated at 350-500 per cat... or the 4.5" UHO rated for 850 per cat...

Anyone try the 4.5" yet?

I just bought a set of 4.5” ones rated at 850 per side. They’ll be going in on v-bands for street use and I’ll keep the “test pipes” for the track. I’ll let you know how it goes. But I won’t use the cats for track use…I just think the car will sound (and smell lol) better with the cats. My Magnaflow center muffler is coming out too…getting to the point where I think it’s a bit restrictive at my level.

[SOCAL.M6.ZLE]

Originally Posted by Joshinator99

I just bought a set of 4.5” ones rated at 850 per side. They’ll be going in on v-bands for street use and I’ll keep the “test pipes” for the track. I’ll let you know how it goes. But I won’t use the cats for track use…I just think the car will sound (and smell lol) better with the cats. My Magnaflow center muffler is coming out too…getting to the point where I think it’s a bit restrictive at my level.

Thats a great idea... I use V-bands on my system also. I was also worried about excessive back pressure with the small cats, and (3) mufflers. Would be cool if everything was removable, so we could get some back to back to back dyno testing.... hmmmmm

[Joshinator99]

Originally Posted by SOCAL.M6.ZLE

Thats a great idea... I use V-bands on my system also. I was also worried about excessive back pressure with the small cats, and (3) mufflers. Would be cool if everything was removable, so we could get some back to back to back dyno testing.... hmmmmm

I wouldn’t do anything less than the 4.5” ones on a boosted car FYI.

[BunnyBoy]

Originally Posted by SOCAL.M6.ZLE

Thats a great idea... I use V-bands on my system also. I was also worried about excessive back pressure with the small cats, and (3) mufflers. Would be cool if everything was removable, so we could get some back to back to back dyno testing.... hmmmmm

Link to correct V-Bands for kooks into cats? I dont know if Im looking at the right ones and I'm getting annoyed with the exhaust leaks on the collectors to cats.

[JSH]

Hennessey put Green cats on mine at 700whp. I think they lived at that level but I had to fish them out of my AB when I jumped up to 800. I see GSport sells a 1200hp version now.

[SOCAL.M6.ZLE]

Originally Posted by BunnyBoy

Link to correct V-Bands for kooks into cats? I dont know if Im looking at the right ones and I'm getting annoyed with the exhaust leaks on the collectors to cats.

Assuming you have 3" tubing... this is what you need. A proper performance muffler shop will have what you need.

https://www.summitracing.com/parts/v...BoC4tkQAvD_BwE

[SOCAL.M6.ZLE]

Originally Posted by Joshinator99

I wouldn’t do anything less than the 4.5” ones on a boosted car FYI.

Just ordered them! I'll make sure my muffler shop gives me a matching set of off road pipes to swap out when I dyno... etc...

[SOCAL.M6.ZLE]

Ordered from CSP.... But this is from the GESI website.

[Joshinator99]

Originally Posted by SOCAL.M6.ZLE

Just ordered them! I'll make sure my muffler shop gives me a matching set of off road pipes to swap out when I dyno... etc...

Originally Posted by SOCAL.M6.ZLE

Ordered from CSP.... But this is from the GESI website.

Yep, that’s the route I went as well.

For street use only, I don’t think I could melt them if I wanted to lol. Just can’t get into the car long enough at this power level without going to jail.

[khcoaching]

Question that is bit of thread hijack. On my 2019 ZLE with 16k miles, it is all stock but a Weapon X catback (sec cat delete) tune and Weapon X intercooler. I have already blown the stock cats once, replaced with another stock set and am looking to the future. The car is 99% road course use and I'd like to end up at 650 wheel - ported stock blower, LTs and I would prefer to keep cats on it. The current catback is horrendous...the drone is driving me insane, can I find a used stock catback to go back on and use it with the above mods?

Ken

[Joshinator99]

Originally Posted by khcoaching

Question that is bit of thread hijack. On my 2019 ZLE with 16k miles, it is all stock but a Weapon X catback (sec cat delete) tune and Weapon X intercooler. I have already blown the stock cats once, replaced with another stock set and am looking to the future. The car is 99% road course use and I'd like to end up at 650 wheel - ported stock blower, LTs and I would prefer to keep cats on it. The current catback is horrendous...the drone is driving me insane, can I find a used stock catback to go back on and use it with the above mods?

Ken

Yes, you can. The NPP/ valves need to be open when in track duty. Also, you should run E85… biggest thing you can to.