Catted long tube headers safe for boost?

[Desert Dog]

They are a ticking Time Bomb, its not if , it's When. You can look at My previous post on this. I wadded up high flow cats on my Edelbrock Supercharged 18., Broke 3 Pistons. Its was on the Half Mile car went 165 mph on the pass. It's not worth the risk Pay now or Pay more Later. If your just cruising around and never get on it. Why supercharge it in the first place.

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[Q6543]

If smell is what you’re worried about, just run E30.
The ethanol seems to kill any noticeable fuel smell.

if i run full 93 or race gas I get smells again, and tail pipes make it less noticeable too.
My old fox with off-road dumps was pretty bad, so I understand.

 

[Farmer Fran]

So, if the cats are failing how the hell does Ford sell it as an authorized accessory?

 

[robvas]

So, if the cats are failing how the hell does Ford sell it as an authorized accessory?

The real trick is how they get everyone to believe "it doesn't affect your warrantee"

 

[smurfslayer]

Ok, I think I have some extra data here. I checked my stainless works cats and they are made by GSport / GESI, part number HPPL-00100. According to the vendor, they're supposed to be good for 500 hp per cat. Sounds cool, right?

How much hp does your whipple Coyote make at stage 2? 700+ with headers, easily. How much is that at the crankshaft? about 825-ish? Figuring about 18% driveline loss.

Now I understand why my shop was saying don't do it. At stage 2 + headers and 1 other mod-give or take, you're easily pushing the limits of those cats.

They do have some cats rated to significantly more - 1k per cat and they cost about $1k per cat.
Zoinks.

 

[ZXMustang]

I took the easy way out and gutted the cats. Wow what a massive difference in power now. Not too much louder too.

 

[cbrtrx]

I took the easy way out and gutted the cats. Wow what a massive difference in power now. Not too much louder too.

The one side that is connected one piece to the header how did you gut that one? Did you cut it off then weld it back on?

 

[ZXMustang]

The one side that is connected one piece to the header how did you gut that one? Did you cut it off then weld it back on?

Yeah, the whole manifold had to come off. Then you cut the front of it off and it’s a straight shot right into the cat. Lots of work but worth it.

 

[smurfslayer]

I took some db readings yesterday. Stainless Works headers, no cats, stock resonator, stock mufflers. I have her set to start on quiet mode 24x7.

Cold start: Spike to 105.5db, settles to 92-94db cold idle and idles down to ~75db.

in cab, windows up quiet mode. idle 56db, 75db at in town speeds.

take off and accelerate to about 65mph 84db. This was gently applying throttle, max 6k rpms.
76db at speed. this is smooth asphalt.

rough pavement and it increased to around 78db at speed. This section of road is just abrasive asphalt.

Sport mode: 79db at speed.

The at speed numbers are only a few db higher than stock. The real noise comes in when you're taking off or caning the car. I put it in track mode after getting fuel, and saw 95db just leaving the HEB parking lot and a moderate take off from a light was over 100db

Quiet mode definitely takes the edge off that attention grabbing noise when you stab the throttle, but it's still plenty loud.

This can be a feature. For example, my wife was crabbing at me for something a few days ago so I just put it in sport mode and kept rpms up.

 

[Junkyard Dog]

Thats not ideal. I took a blood vow with myself many years ago to never again own a car with no cats. I cant stand how awful the raw exhaust smells, plus the coyote becomes so ratty sounding with headers and no cats. Its just not on my playlist.

LOL, that didn't age well.

 

[Junkyard Dog]

They are a ticking Time Bomb, its not if , it's When. You can look at My previous post on this. I wadded up high flow cats on my Edelbrock Supercharged 18., Broke 3 Pistons. Its was on the Half Mile car went 165 mph on the pass. It's not worth the risk Pay now or Pay more Later. If your just cruising around and never get on it. Why supercharge it in the first place.

Desert Dog, I read all of your posts on this site. There are not very many, but I could not find this information. Was it maybe on the 6Gmustang site?

Did you try anything like the Gen 2 Gesi G Sport UHO+ Part Number 85600 6 inch cats, rated at 1200 hp, for 2017 and newer vehicles?
https://www.gsportbygesi.com/g-sport-emissions-systems-products#GEN1

You may have to scroll down at the link.

But it seems like they tailor make some of these cats to take the exhaust of a boosted engine.

 

[Billycar11]

 

[ZXMustang]

Yep thats what mine did with my ESS car after about 800 hard miles. RIP stock cats.

Mine are hallowed out now. Car sounds good with the complete stock active exhaust. Stinks, but sounds good and isnt as loud as headers with no cats.

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