https://www.rx7club.com/showthread.php?t=635738&page=3

if you are running a stock cat or hi-flow, you need one

if you are running a resonated MP (or worse yet, a standard midpipe), you need one

 

 

I'll be curious to see the lifespan of these cats. Every metallic cat I've seen installed on an FD hasn't held up too well.

 

Grant claims 5+ years for these....I admit I'm skeptical of that claim, but he says there are several examples

 

Air injection happens after the cat???

 

I plugged mine

Grant claims the air pump is largely superfluous for metallic cats

 

Exactly what does that mean? No cat (of any type) can oxidize excess hydrocarbons if you don't have enough O2. The purpose of the air pump is to provide that oxygen (note that it is normally injected downstream of the stock metal [pre]cat). Too much O2 ahead of a metallic cat can lead to overheating and its early demise...

It will be interesting to see how these perform under US/Cali emissions tests--I don't know how tough their standards are over there.

 

so it stinks a little at idle, big deal...still far better than it was, and emissions are drastically reduced during higher rpm use (i.e. 99% of the time I spend driving)

without the air pump, it may not pass a sniffer, but I'm not concerned about that

 

I will be getting there cat back eashust end of the summer when my cousin goes to austrailia!

 

Mine should be coming in the mail tomorrow....since I have to pass inspection in a few days I'll probably throw it on and see how she does. I'll post results. I do not have an air pump at this time, but may need to install the corvette pump....we'll see.

-Dan

 

I just ordered one up to have welded into my rx7store resonated midpipe...was at the local in-n-out a few nights ago, and I was getting tired of stopping/restarting the car while in the drive-thru line because I felt bad for the cars behind me.

This will hopefully clear my conscious somewhat. =]

 

^ I'm in the process of doing the same thing

 

I've had mine for well over a year now - just looked through it this weekend, core is holding up great. I put a LOT of miles on my car too.

The SMB cats are REALLY built well, top quality across the board, and you can't beat the quality for the price. IMHO, this is THE high-flow cat to get.

I love the new one with the resonator as well - that is SO nice looking!

Dale

 

I ended up getting the setup with the resonator built in, and I just received it! It took just over a week to get here in San Francisco! I haven't taken the bubble wrap off of it yet, but I'm already getting excited to take it to the muffler shop to have them put it on. (I need to get a wideband O2 sensor bung welded in, and I think I'll have the air pump connection hacked off since it seems to be pretty useless, even if I had an airpump, and I also have to have the rear hanger chopped off or moved because the differential brace I have won't fit with it.

I currently have the RX7store resonated midpipe installed, so I'll let y'all know how it sounds in comparison.

 

It wouldn't technicly be legal in the US especially in Cali. Its not legal to replace 2 cats (precat + oem cat) with one.

so if a cop/emmisions tech knows there are 2 cats in the car stock (it says so on the emmisions label) and recognises that the premuffler is not a cat then they will fail it in a state with visual inspection (ca).

t

 

Does this cat contain serium? Serium is a substance that collects O2, to aid in oxidation of HCs and COs, as well as NOX. All OBD2 cats contain serium, and that's why new cars don't have air pumps. Without serium in the cat, it cannot be run without an airpump.

That cat seems really small. Kind of hard to believe it would greatly reduce the emissions on our gross polluting cars.

Does anyone have a weight for it compared to OEM?

For those of you guys that are running it, are you running a PowerFC or other ECU? Since our cars run so damn rich (my car idles at 11:1) on stock ECU's, that would lessen the life of the cat greatly. Once I'm tuned to much leaner idle AFR's, I'm going to be looking into getting a new cat.

How well do these hold up to burnt oil? I know on a regular catalytic converter, burning oil is a quick way to kill a cat. Since our cars purposely burn oil, I'm curious to see how well these resist getting "coated".

 

I just weighed it...was 15lbs on one scale, 17lbs on another.

Regarding legality, this mod is definitely not about legality. Particularly in Cali with our ridiculous laws, removing the pre-cat is definitely illegal, as is pretty much any engine mod. I failed a visual because I had a small K&N on my air pump once. The laws here are only getting more strict too...sigh...

Most of the time, one can find a friendly smog technician that would overlook the inane visual tests. IMHO, it should be all about what comes out the tail pipe. Period.

AFAIK the quality of these units are supposed to be second-to-none as they have lifetime warranties on their exhausts and have had no returns yet.

 

I agree that many visual inspection criteria are retarted. But bieng that the car is pre obd 2 it actually is legal even in cali to run a custom downpipe with 2 OBD1 carb legal cats in it. There are many other mods that are by the book legal, with and without carb numbers, and several others that they will never see durring visual (such as a PFC).

 

Perhaps that's why they have the air-pump connector AFTER the cat-element ?

I know my metallic-cat with a very RICH tune and the air-pump connector before the cat-element was burned-up/melted and clogged after approx. 6-months of use.

:-( neil

 

Neil,

What brand cat?
What A/F ratios?

That thing is pretty burnt up alright. Good job killing it!

 

The metallic-cat core (300 cpi) was from Dave Sport:
http://www.davesport.com/cgi-bin/davesport/DCAT300.html

He now has a 100 cpi core:
http://www.davesport.com/cgi-bin/davesport/DCAT100.html

Unfortunately, I don't know the A/F ratios.

:-) neil

Steve Kan tuned PFC; 4x850cc injectors; DP; resonated MP; Trust cat-back; Y-pipe; SR Motorsports SMIC; Spec '99 air-handler & intercoler shroud.

 

That is odd. I'm running a Steve Kan map also with A/F ratios down in the 10.5:1 area. I'm also premixing. My Random Tech metal substrate cat has held up well over almost 10k miles. It is a 300 CPI model. I am not running an air pump or air inlet.

 

sure smb metal cats are a work of art.
but if your financial is limited check out
performance curve.
thunderbolt hi-flow 300 cell metal brick for around $60 bucks delivered to your door sizes 2-3 inches
get yourself a midpipe and a resonator take everything to a muffler shop
i spent about $150 labor and parts already about 7 months and holding up great
no issues

 

I installed the SMB unit last week and have been very pleased with it. There's a slightly noticable increase in lag over the RX7Store midpipe, and the sound of the SMB is just about the same...maybe a tick quieter.

The difference in odor however is incredible...almost forgot how a catalyzed car should smell!

 

so running two high flow cats after a custom midpipe is cali street legal?