Cats that can handle the power?

cidsamuth

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Once you get into the 800RWHP range, are there any cats we can use and be confident they won't melt down or break up?

I'll go catless if I have to, but would love to find a universal cat I can weld in.
 

Klaus

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gas or corn? my understanding is that there are no issues with corn since it burns cooler. I am >1000hp and still running cats.
 

cidsamuth

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Engine being built now, but my intention was to be able to run both on two different tunes.

But, staying at the 800 mark or below so that I don't have to go to a return style fuel system.

Are you on stock cats?
 

Tob

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I honestly don't think the typical aftermarket cat can live behind that kind of power. Even with a perfect tune they fail, eventually.

I'd look for an OE cat from a Hellcat, etc. They are more restrictive than what you'll find from the aftermarket but they are far more robust.
 

axo250

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Supposedly the Kooks green cats are made a lot better than most aftermarket cats. Per Kooks, they will handle a high horsepower, high boost supercharged car but I don’t know what the limits really are. I put them on my car recently but I’m only pushing 600rwhp and haven’t had them on long. There is a good YouTube video that can be found about the green cats and how they are manufactured relative to most aftermarket units.
 

cidsamuth

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Yea, my intention was always to go with the Kooks green cats. I just couldn't find anywhere where they claimed it was suitable for high HP, so I was starting to second guess myself. It doesn't surprise me that they wouldn't put in writing how many HP it was designed to take, since there are so many factors. But, it would be nice to get SOMETHING.

I also considered the Vibrant 7840. Supposedly, it can withstand 850 HP per bank, for a total of 1700 HP when you install one on each side. 7840 Vibrant Performance | 4" Inlet|Outlet GESI UHO-Series 500-850HP Rated 4.5" O.D. x 7.5" Long Round Catalytic Converter
 

enormous

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I have 5 seasons and 28,500 miles on my Stainless Works headers and supplied SW cats which Van recommended and could not be more pleased after 5 running seasons.

Last November we used a flexible camera through exhaust sensor hole to inspect both cats and they looked as "NEW".

My car was tuned perfectly by Lidio at Alternative Auto in Mi. 740 RWHP and 730 RWTQ.
 

cidsamuth

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Supposedly the Kooks green cats are made a lot better than most aftermarket cats. Per Kooks, they will handle a high horsepower, high boost supercharged car but I don’t know what the limits really are. I put them on my car recently but I’m only pushing 600rwhp and haven’t had them on long. There is a good YouTube video that can be found about the green cats and how they are manufactured relative to most aftermarket units.

This is probably the Green Cat video you mention. Very informative. Of note, they said it would take 2700 degrees to melt those cats. And, they are double locked to hold the substrate in place, should it come loose.

The only "fuzzy" I see . . . they say verbally it is meant to handle upwards of 1000RWHP. However, behind them, it says "up to 850 HP." Perhaps that is "per bank" and likely crank HP. But, there is some "fast and loose" going on with the numbers.

 

axo250

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This is probably the Green Cat video you mention. Very informative. Of note, they said it would take 2700 degrees to melt those cats. And, they are double locked to hold the substrate in place, should it come loose.

The only "fuzzy" I see . . . they say verbally it is meant to handle upwards of 1000RWHP. However, behind them, it says "up to 850 HP." Perhaps that is "per bank" and likely crank HP. But, there is some "fast and loose" going on with the numbers.


yep that’s the one. I spoke with a seemingly knowledgeable older gentlemen at Kooks and he said he’s seen guys run them on 1k horsepower cars (unsure crank vs rwhp) without issue. He did state their standard cats won’t hold up to supercharged cars and they frequently get calls from people that bought them against their advice. While I cannot speak to the validity of max horsepower claims, Kooks puts out a high quality product and I tend to trust their input. I put more faith in them than a majority of exhaust manufacturers.
 

Tob

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If you look, I think you'll find that Kooks and Vibrant are using some of the cats made by GSPORT.

About Us - G-Sport - High Performance Aftermarket Catalytic Converter

Scroll down their facebook page and you'll see shots of them being manufactured.

GSport

Think they'll live when pushed, say, at VIR? I I honestly doubt it. One guy that used them had this to say...

Mine and my buddies Kooks green cats burned up in about 10 minutes of running at VIR in ZL1’s. These CANNOT be used for HPDE’s even short sessions. Completely hollow now. Had to cut the pipes to find the guts. Very disappointed.

I'm no big fan of Alejandro Flores but I agree with what he says here about failing cats.


"Furnace brazed" or otherwise, if you actually put this type of cat to the test, I don't think many here would be happy with the results. Short bursts on the street? A dyno test here or there? You may get by. Hit a roadcourse with the kind of power talked about here in conjunction with these aftermarket cats...hopefully you don't lose an engine.
 

PM-Performance

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This was my point. I was told specifically by Lund it’s not worth chancing it. They said they have seen too many cats fail on cars that are actually ran hard into the 600’s+
Again if you race, proceed with much caution. It’s not worth losing a motor or the car burning down over.
If you hit it once in awhile for a single or 2 gear pull, not nearly as much an issue.
I think you will find a lot of guys like to make big HP just to do it and don’t actually race or run the car hard. For them, cats will probably be fine for awhile as they won’t ever have a chance to get hot enough.
 

axo250

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Rob, PM,

Ya’ll are probably right. I wouldn’t expect any cats to take that kind of extended punishment. Track abuse can and will tear up just about anything.
 

cidsamuth

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If you look, I think you'll find that Kooks and Vibrant are using some of the cats made by GSPORT.

About Us - G-Sport - High Performance Aftermarket Catalytic Converter

Scroll down their facebook page and you'll see shots of them being manufactured.

GSport

Think they'll live when pushed, say, at VIR? I I honestly doubt it. One guy that used them had this to say...



I'm no big fan of Alejandro Flores but I agree with what he says here about failing cats.


"Furnace brazed" or otherwise, if you actually put this type of cat to the test, I don't think many here would be happy with the results. Short bursts on the street? A dyno test here or there? You may get by. Hit a roadcourse with the kind of power talked about here in conjunction with these aftermarket cats...hopefully you don't lose an engine.

I appreciate the input but .... you are quoting one guy who made one comment on YouTube, reference the Green Cats. I saw the comment, and I don't ignore it. But, I don't take it as gospel either.

And the guy in the video .... he references the dangers of "aftermarket high flow cats." Well, he doesn't say what brands, and those dangers are what Kooks/Virbrant claims to have addressed. In the video, they expressly state it was a problem in the aftermarket, muscle car community, and there was a demand in the market for a fix.

So, I get that many of the high flow cats would be dicey at best. But, other than the one comment on YouTube, are these Kooks/Vibrant cats known to fail?

I'm not arguing. Just trying to sort through the background noise ....
 

cidsamuth

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Okay . . . let me be more specific about my goals and use for the car. See if that changes your opinions.

700 to the wheels on 93. 775-800 on E85.

The car will not be tracked. Sorry if that offends you. I am building it for the hobby of building it, not racing it. It will be used to have fun on winding back roads with my daughter strapped in next to me, around town on a Saturday night, and the local cars and coffee. Maybe even a show, though I don't know if I want to go down that road or not.

Does that change anything about your feelings on whether the Green Cats (or similar) will work? I don't have emissions, but I do have inspections. So, if I go catless, I'd either have to switch them out at inspection time, or gut them. With either, I then have to worry about the car being obscenely loud and raspy, then invest time and money into resonators/mufflers.
 

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