cat converter cores?

[oldcorollas]

for work we needed soem catalyst cores, so we went off to toyota and ordered the cheapest ones (hoping they were ceramic cores.. easy to work with)

what we got was toyota part number 18450-74450
thanks to Wilbos L33T EPC skillsorz, that is from ST202/206, 93-97

it has inlet/outlet of 50mm and 65mm (50mm side has a sender hole that looks too small for O2 sensor)

it has 2 cores insode. both are 97mm diameter (almost 4") and 113mm long.
the cores are slightly different colours, one is more yellow, one is mroe white, and they have different numbers printed on the core, 3043, and 3051 (more yellow one).
so it looks like a 2 stage core. we'll do analysis to see what the catalyst has in it shortly..

there was gap between them, but i can't remember what it was, maybe 40mm?

absolute buggers to get out as well, the whole thing is made in 1.5mm steel with a seperate layer of 1.5mm steel around each core... the core sections seem to have been seperate, and then welded to the ends..

the core itself has a metal support, with the catalyst in a thin ceramic coating on top of the metal (metal is probably FecrAl type)

i'm wondering what is so special abotu the "metal cats" and other aftermarket "performance" catalysts, and if the internal core size is significantly bigger or not?
what is internal core size for aftermarket cats? inlets and outlets? why not get a stock core and weld bigger ends on, or is a 4" cat core not big enough?

here is crappy phone pic of core. looks like cardboard.. wound around centre bit. each layer is abotu 1.2mm (ie, 10 layers = 12mm)

[JustCallMeOrlando]

(50mm side has a sender hole that looks too small for O2 sensor)

Probably for a temp sensor.

[Golberg]

Probably for a temp sensor.

Yeah, some (I've only seen it on JDM vehicles) Toyotas have a temp sensor warning light in case the exhaust is getting too hot. And it'll get hottest at the cat so hence they put it there.

[TERRA Operative]

Ya, my JDM AE101 Levin has a temp sensor at the cat, throws a warning light if the cat overheats.

Probably a safety due to the supercharger or something.

[oldcorollas]

the temp sensor is not really a question it is there to see if cat is blocked or not basically... or if mixture is so rich it will cause cat damage (while cat is being damaged)..


anyone got an aftermarket cat lying around they can have a peek at?

i'm wondering if there is any real difference in flow between stock toyota cats and aftermarket cats, apart from inlet/outlets...
granted most aftermarket cats are single stage type, and not double, but it seems to make sense to use a good quality cat like the toyota stock ones, and change the in/out based on new exhaust sizes?

[rob]

good call i like where this is going

[Jabtronic]

I've got a MetalCat sitting around.. what do you need to know? It's pretty much a 3.5" diameter core I think (whole thing is 3.5"). Not sure if it's 2 stage, I'm not going to cut it up

[oldcorollas]

hmm, size of core (or external size minus any layers of steel)
picture of core.
measurement of layer thickness (they are similar design?.. count 10 or 20 layers and measure is easier)
is the metal core coated with ceramic? what colour? etc
in and out pipe diameters.
length of core (measure from both ends and subtract from total length)

that kind of thing....
oh and cost. I'll find out what this cat cost when i go to toyota next...

[wilbo666]

I've got a MetalCat sitting around.. what do you need to know? It's pretty much a 3.5" diameter core I think (whole thing is 3.5"). Not sure if it's 2 stage, I'm not going to cut it up

Take pic looking down the end for the man

So he can compare design of cat material.

Cheers
Wilbo

[timbosaurus]

Hmm... interested in the comparison. I'm looking into a cat for my car now, and it's hard to know if a $3-400 cat is any better than the $150 ebay jobbies.

The only comparison you seem to hear is from expensive company's marketing department, or some kid racer claiming he now gets 13 extra psi from his new superdoopercat... and he must do, because we all know killerwasps are directly proportional to pineapples.

[oldcorollas]

well.. put it this way, there can't be that many companies making cores, that don't supply to the OEM market.
good cores that is.
so chances are, a good aftermarket cat has same cores as some OEM product.

of course there are probably also cheap aftermarket cores that DON'T have any catalyst in them either!!!

if you look at the metal cat page (not that there is much of it) it looks like say.. 3" inlets and 4" core.... so the core is that free flowing? if so.. is it any different to stock cores.... and can7t you just weld big inlets to your stocker?
http://www.metalcat.com.au/images/17092008025.jpg

on the surefloe(?) page they have some good pictures.. they have a 5" single stage metal, which would be an improvement on a 2 stage 4".. but the core material looks identical to toyota.
http://www.surefloexhaust.com.au/cc.htm

their metal cat looks exactly same as the one used by toyota is at least 1993 except this is single stage, and toyotas is two stage (i forget the proper word for that)
like this.. but in metal
http://www.surefloexhaust.com.au/cat03.htm

the ceramic cats are usually wider.. in oval shape.. and the extra size seems to be to offset the thickness of the walls of the ceramic cells, wherea the metal is much thinner...

edit: three way, not two stage http://auto.howstuffworks.com/catalytic-converter2.htm
first stage is reduction, second stage is oxidation.... i wonder which type the single stage aftermarket cats are?

[BLACKCAT]

Here is a picture of a 4 1/2" body Hurricane brand metal cat.

[thanhngo]

I got a Vibrant Power Inc 2.5" metal cat (well thats what I was sold and not sure if it is a metal cat?). Pics included, it has a yellowish colour on the mesh and looks identical to the aboves. Got it fairly cheap off fleabay (when currency was strong .

Single core and I think 4" in diameter. It has 28 layers. TThe width between layers is around 1.5mm but hard to judge.Core lenght seems to be only 8cm.

he toyota one looks pretty darn similar. Does feel like there is an oem alternative now. Whats the cost of them like?

[Gary]

so you're asking if it would be an option to open up the inlet and outlets to something larger, instead of going for an aftermarket highflow?

i wouldnt think stock catalyst flows better than an aftermarket metalcore cat, say we're comparing your average cat (not a GTR cat for instance)

if oem didnt flow as much for the area used as aftermarket cores, im guessing they just make em bigger to compensate? if that makes sense, then perhaps simply opening up the inlet and outlets on a stock one would do little to improve flow, as its the catalyst holding things back rather than any restriction due to size

edit; the difference ive found on my celsior cats are the same as the pic you posted, stock ones have tiny holes, and my metalcats had nice big ones