cib24

Last year I had the stock cat on my car but the honeycomb began to crack so I replaced it with a used RE-Amemiya 150 CPSI cat found through the UK RX-7 forums. It's doing alright except for the fact that I can no longer legally pass emissions, and we tried! We welded a bung ahead of the cat which we attached the airpump to so the cat would see a good amount of oxygen at low RPMs and leaned it out as much as we could reasonably do for the test and it wasn't enough, as we sort of expected.

The thing is, I can get it passed through a few people but it's such a hassle each time and besides my car smells now more than it did before which my wife hates. So, I'm thinking about what my alternatives could be as I'm not that worried about losing a few horsepower for a slightly more restrictive exhaust, plus my exhaust temps should improve a bit once my water injection system is installed and that should help extend the converter's life a bit and keep the EGTs in check when on the track (or at least I hope).

I have thought about chopping the converter out of a RX-8 but it is a ceramic piece and it might not hold up so well under occasional track use even with the use of water injection.

I am also looking into metal substrate cats but it seems to be that every single one I can find available from a shop (keep in mind I have been limiting myself to parts available in the EU) is either 100 or 200 cell which won't pass. I think if I can find a cat that is 400 cell with a decent surface area I may be able to pass.

Has anyone come across a 400 cell or higher metal substrate converter that can work with 3-inch diameter piping?

gracer7-rx7

iTrader: (16)

Try contacting these guys: Universal fit converters - Random Technology
The universal used to a 300 cpi. They might have other densities.

cib24

Great, thanks. Any other companies or known metallic converters out there with 300 CPSI or more?

HJS makes some nice high quality stuff but the best they do is 200 CPSI.

gracer7-rx7

iTrader: (16)

I noticed some Magnaflows with metal cores when I was searching yesterday. Take a look.

cib24

Yeah, but my research tells me they are generally pretty cheaply built and I think only up to 200 CPSI.

primerGrey

iTrader: (13)

Does anyone have any experience with this Flowmaster PN 2000130 metallic cat?

3" inlet and outlet
5" diameter
14" long
200 cell

From page 4 of the catalog:
• Compact case design allows it to fit into tight places.
• Stainless steel, seamless spun case for an ultra-clean look.
• Perfect for extreme temperature situations that occur in racing and highly
modified vehicles.
• Stainless steel substrate will hold up under severe-duty applications better
than the ceramic substrates used on traditional replacement converters.
• 200 cell construction provides maximum exhaust flow.
• State-of-the-art precious metal loading process and materials to maximize
emissions reduction.

See page 19 in the catalog for specs, here

Moe Greene

iTrader: (2)

Not sure how harsh testing is in the UK, but from my understanding everyone here state side has had good success with the Bonez cat in passing emissions.

primerGrey

iTrader: (13)

BTW, Random Technologies reports they no longer provide "automotive products".

gracer7-rx7

iTrader: (16)

Good to know.

Are you interested in the above mentioned cat for smog or for other reasons?

primerGrey

iTrader: (13)

The last tuning session made clear that I've got the car to the point where flow is becoming a limiting factor.

So I'm looking for a higher flowing exhaust that can survive track sessions, with at least some effort to reduce pollution. The 5" diameter and smaller cell count have me hoping that the Flowmaster might survive if the car is reasonably tuned.

Also, it is cheaper than the SMB option. Cheap enough that I will probably try it unless I hear from others.

j9fd3s

iTrader: (3)

i'm interested too. i'm under the impression that a metallic cat will handle more abuse than a ceramic, and that is where i'm interested.

i can get em from Japan but they are $600, seems like we should be able to get em cheaper in the US

gracer7-rx7

iTrader: (16)

primerG - what cat are you running now?

If you are running one of the usual high flow ceramic cats like the Bonez, you probably do want to switch to a metal cat. However, b/c of Laguna sound you'll probably need to add an additional muffler to the exhaust stream.

Many years ago when I added a Random universal 3" in/out metal cat to a cheapo mid pipe, it did indeed hold up to track use better than a regular ceramic. It also offered more flow, less stink and helped control boost better. The butt dyno didn't register any difference from the straight mid pipe.

The problem I had with that setup was noise. It was loud as all unmuffled mid pipes are. The metal cat does little to nothing to decrease exhaust noise like a big, stock style ceramic cat. I eventually switched to the SMB mid pipe which had a metal cat just after the flange to the downpipe and a muffler. That was nice and quiet and had the metal cat.

If you have the budget, look into getting that combo metal cat + muffler mid pipe from SMB from AU.

jpfd3s - Like most catalytic converters, the cores are made by a select few global players then customized to different car models by the retail oriented companies. I think you can safely buy one of the universal cats and customize as needed. Or just press the easy button and buy a setup that bolts into our cars

WANKfactor

iTrader: (1)

This mob make amazing quality mufflers so i would assume their cats are good too.
SMB Catalytic Converters

primerGrey

iTrader: (13)

An ancient Pettit "high flow" cat that looks like the other high flow cats. It is light, at least. And as near as I can tell, it hasn't clogged. While I was running stock turbos, I never thought it was worth it to upgrade.

Thanks, that is extremely helpful input. I was worried about making sound, and was about to pull the trigger on the SMB cat+resonator. But it is expensive. So I started reviewing other options and found a surprising number of these spun metallic cats, many never mentioned here, e.g. Flowmaster and Magnaflow. The Flowmaster seems to be the only one that is 5" dia though, like the SMB.

So your SMB held up at Laguna? There was a thread here that showed an SMB that had ejected spools of metal cat out the tailpipe. I wonder if putting the cat AFTER the resonator might reduce the temps the cat sees. Seeing if that was possible was another reason I was looking at DIY options.

j9fd3s

iTrader: (3)

i was playing around with the FC cats today (my FC-REW passed smog!) and i notice that the S4 and earlier cats have a piece of perforated metal in the inlet of the cat. i'll post a pic later. based on the condition of the S5 cat without this thing and the S4 cat with this thing, i think it might be there to absorb the pounding from the engine

i actually WANT to run a cat, but i don't want to have to worry about it melting either

cib24

Was just looking at cats and checking out Magnaflows website. What about just running a high flow Diesel converter which is say 4" or 5" inlet/outlet diameter and 200 CPSI? Whilst the CPSI is low, the larger size of the cat would mean that more surface area is available to treat exhaust gases and therefore that could mean that the FD would run a bit cleaner with one of these than your traditional 3" 200 CPSI cat?

http://www.magnaflow.eu/02catalytic_...niversal=60012

Maybe I'm wrong and someone can correct me?

primerGrey

iTrader: (13)

I ended up buying the SMB cat with the resonator. It came in the mail a week a ago. The craftsmanship is exceptional.

When I get around to installing it, I'll try to remember to post how it does at Laguna.

cib24

Any pics of the core? And pics of its size compared to the stock cat?

It is only 200 CPSI right?

primerGrey

iTrader: (13)

PART NO.: MRMSC3M
5" dia
100 cells per square inch

I can take pics when I get home if you really need them.