Catalytic converters and boost

[Olddudesrule]

After I finished my dyno tune Tuesday, was talking with the shop owner and the tuner, and they asked if I was planning on continuing to road race the car. I told them "sure, from time to time", and they both advised my cats wouldn't survive it. Both are very experienced in FI, specifically with LS engines (not that it makes a big difference to the core question). They know I have Kooks standard HF cats, and I asked if changing to the green cats, rated up to 900 hp, would make a difference. Both said they did not think so, and advised I remove them and just run an off road pipe since the rear 02's are tuned out anyway. On a side note, they said it's just the prolonged on-throttle time that is the issue, obviously causing excessive heat in the exhaust, and that daily spirited driving, or 1/4 runs, wouldn't be an issue.

My question is two fold. How are owners who want/need to keep their cats, but road race a FI car, handling this issue? Also, if SC's specifically on OEM cars, are coming with OEM cats, why aren't they failing too. My set up is really no different from a ZL1, so why isn't it an issue for that OEM set up?

[jeff657756]

I would get rid of them before they clog and take your engine out too. If you have a bone stock lsa install (i.e. no headers, not pullied, etc) you would be fine. You may even be OK with what you have in your sig, but why risk it?

[ecreps]

You could pick up a set of offroad pipes and swap them in before a track day.

If it was me, i would get rid of them before they melt.

[stevieturbo]

Cats need heat to work effectively...so they are mounted fairly close to the engine.

However, cats will die with excessive heat....like when mounted close to the engine on a high power turbo setup.

Obviously they can be made to work reliably, as there are millions of turbocharged factory vehicles that have cats fitted.....with lots of money, R&D to make them all work.

Largely it's finding the balance of power, tuning, cat location etc etc to make everything happy.

[Olddudesrule]

Originally Posted by stevieturbo

Cats need heat to work effectively...so they are mounted fairly close to the engine.

However, cats will die with excessive heat....like when mounted close to the engine on a high power turbo setup.

Obviously they can be made to work reliably, as there are millions of turbocharged factory vehicles that have cats fitted.....with lots of money, R&D to make them all work.

Largely it's finding the balance of power, tuning, cat location etc etc to make everything happy.

I thought about moving them further downstream as well. Don't really want to deal with the smell caused by removing them completely, but may try it for a while since it's an easy fix.

[stevieturbo]

Moving them further away will help them survive excess heat better.....of course if they are not hot enough it will hamper their job as a catalytic converter though which in turn may reduce its lifespan

I guess there's no room under the car to do a cutout setup but as a cat bypass rather than a full blown external cutout ?

[BiggFoot]

My Kooks green cats made it for about 3 years at 10 psi but as I continued going up in boost pressure I finally blew them out.

If you are concerned about passing inspection because the cats are missing, then gut them but leave in place.

If you are concerned about the smell, then make the switch to E-85 if it is available in your area.

[Bildo]

My SLP high flow cats shit themselves @ about 10k miles 1k miles after nitrous install. They shot the element into the Xpipe. Just gut them and save yourself the headache.

[Olddudesrule]

Originally Posted by BiggFoot

My Kooks green cats made it for about 3 years at 10 psi but as I continued going up in boost pressure I finally blew them out.

If you are concerned about passing inspection because the cats are missing, then gut them but leave in place.

If you are concerned about the smell, then make the switch to E-85 if it is available in your area.

I was wondering about the Kooks green. Heard they can handle up to 900hp. Good to hear real world experience. I'm not too worried about the emissions inspection, as it's OBD hook up only. Now if the exhaust smells like hell, maybe they'd look. Thinking about going E-85, but the main drawback is it's not widely available in the area. Probably 10 stations throughout the valley if my research is correct.

[patternpilot]

My goal is to reduce the smell as I am cat less now. Iv'e done a lot of research on aftermarket cats. What I found out is that the stock cats are 400 cell ceramic substrate. They do not handle pressure or heat very well and one or both can cause failure. Metallic substrate and less cell count will handle pressure and higher heat better. I finally settled on a 200 cell count metallic substrate converter. The down side is they have to be welded into the pipe which may be a roadblock to some as what iv'e read on here is most want bolt in replacements. I bought mine from Bear River Converters and just waiting for the weather to warm so I can start the installation. I will weld them in my self (Iv'e done a lot of modifications to the exhaust myself already)
I have high hopes they will hold up. There even are some 100 cell count converters available. Perhaps this may help those who are struggling to find a suitable solution to this converter problem.

[SS PANTHER]

Look at the Dynatech Supercats. Jannetty Racing uses them on many of their supercharged builds. And he runs them on his own ZL1, which he road races. http://www.camaro5.com/forums/showthread.php?t=438731

[Olddudesrule]

Originally Posted by SS PANTHER

Look at the Dynatech Supercats. Jannetty Racing uses them on many of their supercharged builds. And he runs them on his own ZL1, which he road races. http://www.camaro5.com/forums/showthread.php?t=438731

Thanks, appreciate the info. Problem I see is the connection at the header. I'll check the Supercats out, but I'm willing to bet the Kooks style connection (I have the older "ball and socket" connection) will not work with those.

[GHOSST2012]

I'm not sure what emissions test you need to pass where you're from. In nj they only visually check to see if there are cats on the car. I had mine hollowed out. Therefore I pass emissions cause it looks like they're there and don't have to worry about them busting.

[Olddudesrule]

It's mainly an OBD hook up, and if none of the emissions monitors are showing in a "not ready" status and you have no CEL's, you're good. I purchased a set of Kooks off road pipes to swap out the cats, as I really would rather keep them if needed later. I've never run a car without cat's (well, not since my younger days when gas was leaded...), so I'm thinking all the talk I've read about the smell running catless may be a dead give-a-way at the emissions testing site.....

I'll run the catless pipes for racing, and likely switch back to the cats for testing, but that's not for another couple of years.