catalytic converter questions

[di_rosa]

looking for a new cat. there seems to be a couple of different kinds, and i was wondering which is more efficient. there are three different converter substrate materials, ceramic, monolithic, and metallic. anyone know which one is better?

and there are ones meant for 4500 lbs vehicles, and 6000 lbs vehicles. would the 6000 lbs cat filter out more than the 4500 lb one then ?

thanks

 

[lewis15498]

If you dont have to pass emissions anymore, id skip the cat and just get a test pipe. I got mine from rich (sipracing) for like 60 bucks iirc. if your worried about visual inspection, you can cut the housing off the old cat and weld it over the test pipe to make the pipe look like a cat.

 

[di_rosa]

i would still prefer to have a functioning cat on my car.

 

[Supra0089]

Jack at suprasport sells a random technology cat that I use/like very much. 3" in "3 out. http://www.suprasport.com/RT-High-Flow-Metallic-Substrate-Cat_p_17.html

 

[S.A. supra]

I bought a 3 in 3 out high flow cat and two 3 inch flanges from drift motion took them to a muffler shop and had them weld them together. cost about $ 130 for everything. It was a spun metal works great.

 

[Supra_Sensei]

I would put nothing in my car...Im not from the US so prob law's here are different IDK

 

[di_rosa]

my car is a 1986.5, and the laws in canada allow me to be exempt from emissions. however, i feel guilty driving around with a non-functioning cat. i originally bought a magnaflow one 3" in/out, only to find that it is a 2-way cat, not a 3-way cat. i also bought the same cat for my volvo, and it failed soooooooo bad on the NOx, which lead me to figure out it was a 2-way, not 3-way.

so, thank you to the 2 guys that actually answered my question. i do not want opinions of putting on one, i have a dump that i use when i hit the dyno, so i don't care about a little bit of backpressure.

EDIT:

what i was looking for was something like this:

# Metal Monolith is much more resistant to the effects of vibration than traditional ceramic bricks.
# Capable of withstanding higher operating temperatures.
# 300 cell per Sq. Inch catalyst flows at 578 CFM, up to 40% better than a typical ceramic core converter.

what else is interesting, is that they tested ceramic against metallic, and found that the ceramic was better at lower rpms than the metallic (because of its lower thermal conductivity) and the metallic was better at higher rpms (because of its larger geometric surface area and lower transverse Peclet number). but that only applies to CO and HC, not NOx. the difference for NOx is insignificant apparently.

i think metallic is the one for me.

 

[turbotoy]

I'm also using the metallic substrate RT cat sold by Jack at Suprasport. The lack of odor is easily worth the $300, especially if you sit in traffic at all. Build quality is excellent.

I have no data on pressure drop across the cat, but the car is more than fast enough as-is, so it's irrelevant at this point for me.

 

[paradox616]

If you dont have to pass emissions anymore, id skip the cat and just get a test pipe. I got mine from rich (sipracing) for like 60 bucks iirc. if your worried about visual inspection, you can cut the housing off the old cat and weld it over the test pipe to make the pipe look like a cat.

yaay for global warming.

i can hardly talk i welded a cat shell over my 3" test pipe

 

[Poodles]

Only reasons for not running a cat:
-You're running leaded race gas
-You're a cheap ass

There aren't any others.

Now, back to the question, you'll be fine with just about any cat, though the metal core high flow cats tend to be a bit more durable (hence why I run one).

 

[Hmong_1G]

Running rich on a new catalytic converter can reduce its life or damage it. As most turbo tuners will know and understand is that its better to be rich then lean and staying stoich is a tuning question. The only question you will want to ask your self is near future mods or whats your supra main purpose? If you read up on catalytic converters that sometimes is able to revive a bad cat from aggressive driving, but I see no point in one only for smog. I say test pipe. I went through a maganaflow universal cat and random technology cat from meltdowns. I'm not stating that having a cat is bad, but solely what is the purpose of your vehicle.

PS... luckly cats for our cars are replaceable without denting our wallets and have a huge variety to chose from.

 

[Poodles]

If you're destroying cats, you have issues that are unresolved.

 

[lewis15498]

Only reasons for not running a cat:
-You're running leaded race gas
-You're a cheap ass

There aren't any others.

Now, back to the question, you'll be fine with just about any cat, though the metal core high flow cats tend to be a bit more durable (hence why I run one).

Yes i am!

 

[Poodles]

Don't be surprised when you piss people off at a cruises then.

 

[lewis15498]

Don't be surprised when you piss people off at a cruises then.

True. I guess I'll just follow up the rear.

 

[dumbo]

Why would that piss people off? Other than emissions?

 

[Poodles]

Safe tune = some unburnt HC = burning eyes & running nose

 

[92nsx]

Only reasons for not running a cat:
-You're running leaded race gas
-You're a cheap ass

There aren't any others..

Ummm. Me, me, me, me........ Because I dont want to I took a screw driver threw mine and a spair I bought, well it just sits in the corner with it's nose in it.

Also never heard any complaints about the smell either.

 

[lewis15498]

Ummm. Me, me, me, me........ Because I dont want to I took a screw driver threw mine and a spair I bought, well it just sits in the corner with it's nose in it.

Also never heard any complaints about the smell either.

Me either, glad I'm not alone.

 

[dumbo]

x3...