Catalytic Converters (Brands and Questions)

[PHOENIX]

I am getting ready to buy a few more of my exhuast components and trying to figure some pricing.

Catalytic Converter Requirements for my exhuast plans:
3" In and 3" out (no exception)
Quantity Required = 1

First my question:
What does the air tube on a catalytic converter do?
Does it allow the flowing exhuast gases to suck fresh air into the cat to help it work (air helps heat, cats work when hot)?
Is there an advantage to getting one with or without an air tube?

I believe my current catalytic converter does not have an air tube, but I have not checked in awhile.
Eitherway it doesn't matter what I have know.
The question is about the air tube; what is it for and is it an advantage?

Brands:
I would like to get something nice like a Random Technologies catalytic converter because they are very high flow and would work well with the high flow muffler.
But they are not cheap at $199.99 each.

Any comments (good, bad, etc.) about these units (no specific order):
(1) Dynomax Super Converter ($130-$140 each)
(2) Magnaflow Performance Hi-Flow Converter ($110 each)
(3) Catco ($66 each)

Thanks!

[Tom]

I used catcos on my 79. They were $95 a piece though. Where'd you'd find them so cheap? Anyways they were nice. But they glowed like a torch and eventually melted. One of them was replaced with some type of high flow after market and the other was left on there. Im gona hollow it out after I have the weld removed. I do remember that about 2 yrs ago the highest flowing cat onthe market was from a 98 tahoe w/ 350cid. It flowed better then a vipers cat, a vettes cat, and several types of aftermakets.

[Slonaker]

I have nothing useful to add, but that has never stoped me before...

My truck has dual "Charlie Brown" brand converters. No, I am not making that up. I did a double take when I read that...

When I got the truck 2 years ago, I did an internet search. They are, apparently and IIRC, made in Alabama.

Slonaker

[PHOENIX]

Tom:
The Catco I was looking at didn't have any tech. info.
After looking some more, I think the correct one was $98 from Summit Racing.
The $66 one would probably not work correctly for a 5.7L.
I overlooked the other Universal 3" Catco converters, they were on page 2

[swervin ervin]

Not but one converter as far as I'm concerned. Random Technology. It's supposed to be the highest flowing converter built. Of course it's around 200 bucks too.

[sbc350gearhead]

I have no experience with high flow cats. The air tube is for air injection.

[apstguy]

You don't need the air tube, so if you get a cat w/ one, just keep it capped. It serves and acts exactly as the AIR sytem hooked up to the exhaust manifold. It has no performance advantage, probably makes it worse. It is for SMOG purposes on newers cars. Their AIR system is hooked up the the manifolds and the cat. It puts in air into the middle of the mediums of the cat causeing the hydrocarbons to become less harmful. I hate SMOG. Did I mention I hate SMOG?

[PHOENIX]

I hate inspection enough for all of us
Would having a cat with the air tube (open) make my truck run cleaner (emissions wise)? I hate having problems with emissions and if it will give me a little advantage in passing I'll do it, unless I have to pump air into the cat, is that the case, do you have to pump air into the cat like the manifolds?

Thanks

[apstguy]

Yes, the AIR pump or an electric pump brings air into the cat. just like the manifolds. Just having the air tube open would be a bad idea. Exhaust would come out of it not treated by the cat, you won't pass inspections, and it won't be muffled. I doubt it really does anything anyways, as does most emissions stuff. The air tube on the cat is also tuned that when the oxygen sensor behind the cat is triggered (which these trucks don't have), it will trigger the AIR pump to start air flow, which invloves a computer (we also don't have that and don't want it) and all that other emissions crap. Just drop the idea of hooking it up on an old truck, it is useless. But that is why we have older truck right? I hate emissions. Have I mentioned that yet?

[PHOENIX]

Thanks for explaining it.

I was thinking that maybe the exhuast flow created a suction and pulled air in by itself without a pump. I figured maybe it had a check valve or something to stop exhuast leak. Now I know better

I'll probably end up getting the Random Tech.
Cat is not something I want to skimp on.
I would hate to go to emissions and have it fail or have the cat restrick my exhuast flow. I guess peace of mind is worth the extra cash.

Thanks for all the responces!

[bigblock73]

what is a catalyc converter??

...Jeff

[PHOENIX]

you b*stard

[AirMale]

I just got 2 Catco 3inch converters off of Ebay for $95.00 shipped to my door. God bless Ebay. And as for the flow ratings....that is a bunch of crap invented to raise prices. Keep the AIR tube capped and you won't be disapoited!

[swervin ervin]

Originally posted by AirMale
And as for the flow ratings....that is a bunch of crap invented to raise prices.

Not true, but you can keep on believing it if you want to. I'll continue using Random Technology cats. You get what you pay for.

[PHOENIX]

I am not saying the random tech is worth the money they charge.
But I do believe that some cats flow better then others.
Random Tech. states on their web site that they manufacture the highest flowing cat. If this was not true, they would be guilty of false advertising.

[AirMale]

Show me some dyno sheets cause for the money Catco clearly wins. And how much of a horsepower gain from this extra flow are you gonna feel? For an extra $150per converter, sorry. Unless you are trying to scavage every single hp., then don't waste your hard earn money on advertising. I own two 2-1/2 inch Catcos now and am here to say they are premium quality and the obvious choice over random-tech.

[apstguy]

Sure - I enjoy sharing my knowlage! I HAVE to learn about all this stuff because no one will tell you about it - you just have to learn it on your own. My friends all come to me for that kind of stuff because no one else will explain it! The industy sucks. But maybe I put too much effort into learning about things. Leave it to me to over-analize things. Anyways, EMISSIONS SUCKS! I had to say it one more time for good measure.

I'm not getting into the Random Tech vs. Catco thing. I'm just telling you you usually get what you pay for. I have gotten burned way too many times to ignore it. Don't half-ass things. You'll be sorry.

[PHOENIX]

I have nothing bad to say about either as I have never delt with either. I ran some searches on a few engines and found mixed opinions on Catco, but didnt find one bad thing about Random Technologies.
I do take into consideration that Catco probably sells more cats then random due to price.

Airmale:
Do you have 2-1/2" or 3" catco converters on your truck?
You have dual 2-1/2" but your about to go to dual 3"?
How long have you had the Catco's on?
The word online seems to be that a lot of them give out after about a year or so of everyday driving.
Have you driven your truck for 5 days a week for more then 2 years with these cats on?
Tom, what about you, how long have you had the catco cats on and how often is the truck driven?

Thanks again guys

[AirMale]

I'm running 2 1/2 dual converters and have had no problems with them in 3yrs. I just bought two 3inch converters for my BBC conversion.

[jimfulco]

If cat airflow is a crock, then I've got a bead-type cat from a 77 Nova I'll sell you.

[TIMSPEED]

Actually, for the best price/flow...Carsound is the best deal. That's what I have on my vette.

[apstguy]

Originally posted by jimfulco
If cat airflow is a crock, then I've got a bead-type cat from a 77 Nova I'll sell you.

Bead type is bad! That is what came stock on our trucks. They plug up easily and restrict flow. Monolithic-type converters are much more efficent, flow better, and don't plug as easily. Make sure to get 2-ways not 3-ways (air tube).