final word on metallic cats?
 

So, Whats the conclusion to metallic cats?
Do we need to retain somre sort of air pump to keep them from burning up?
Does anyone sell a metallic cat MP with a resonator built into it?
If yes to the question above, has anyone tried it and how does it work?
I know there has been quite a few threads about this topic before, but after reading them I did not come to a solid conclusion. It's been a little while since a thread like this has come up, and I'd like to know how current metalic substrate cat users cores are holding up.

-Dan

I've had my Random Tech Metal Substrate cat for a few years now and prolly less than 10k miles of driving. I'm running very rich throughout with AFR in the 10s and idle in low 12s. No air pump. Pre-mixing. Flame-age out the exhaust etc. Basically the perfect recipe to kill a cat.

I just pulled it off over the weekend. I'll go shine a flash light in there to see how its holding up and let you know.

I just finished my "custom" cat(random-Tech))/resonated mid-pipe. I don't have any pictures yet...or milage of course, but the idea is to have a replace-able cat section with v-bands (also fit a "test" pipe - straight 3" SS with v-bands as-well)

I will be placing a "final" EGT probe in the end of the DP to monitor temps going to the cat, so I can keep my street tune in check.

Also as a note: I believe air pumps increase heat going thru the cat...maybe I should see it I can fit the final EGT in the mid pipe after the air pump check valve.

Carson,
Would you be willing to make another one to sell? I would be interested in something like that.

gracer,
That would be great, post em up if you get a chance.

Thanks,
Dan

I would if I owned a shop (and was better than average at welding :lol: )...seeing how my extire exhaust is custom until the RB cat-back, I couldn't just copy mine and have it bolt up to your car.

I really have too many car projects going on to take on work...outside of work.

MP makes a big difference, dunno what a difference pipe diameter or the OEM cat makes because I bought the car w/ 3" turbos back.

Scrub, there are a ton of VERY NICE aftermarket metallicats, such as KS and Sard.

Ramy,
If you can't call me by my real name you'll never see my kittens again!! Anyway, those cats you mentioned are a LOT of money correct?

-Dan

Sard is a beautiful Cat' and it's sectional. You can replace the cat itself with another strait pipe if you make it with flanges then just bolt it in. I beleive Apexi make the longest cat'.

I have a metalcat by Arvin Meritor and when I remove it to weld in my Moroso spiralflow it was fine, no problems and my tune was very rich I just found out.

Air pump is not needed except to be legal becuase it came with one. the original cat was actually two cats. air was injected before the 2nd cat raising the temperature back up like an afterburner to burn NOx or anything that made it past the 1st cat. Metal cats dont need to be air injected. The reason Knsightsports and other JDM metal cats have the air pipe is becuase its needed to be legal. the car was sold with an air pump connected to the cat, if you change that it's illegal. You can go to a referee and get a sticker approving the cat but they wont approve the removal of the air pump, so whats the point.

The final word is that cats are for pussies :bigthumb: :bubrub: :git:

(cali boys exempted)

c'mon Rich, we all know that you're not happy until the car is hard to steer, roasts you in the summer, and is loud enough to peel paint off a wall.... :D :pokestick:

There is another metalic cat thast also has a resonator in back of the metalic cat. It's made by Revolution Tune (www.revo-tune.jp). It comes in 80mm and 90 mm. Here's the link for the actual cats:

80mm
http://revo-tune.jp/catalogue/detail.php?id=45

90mm
http://revo-tune.jp/catalogue/detail.php?id=43

Hope this helps!

for pussies that don't want their date to smell like exhaust :fawk: ;)

I have an SMB high-flow metal cat from Australia on my car. Fit and finish is second to none - all stainless, PERFECT fit, has a nice flange for the air pump hookup, and flows great and makes great power.

Best part is it's CHEAP - $387 for the 3" version, $460 for the 3.5" version.

Check it out here -

http://www.smb.net.au/fullsystemsmazdarx7.htm

I believe SMB made the exhaust for the Aussie RX-7 SP car, too.

I've had mine on the car for probably 10-20,000 miles now, still looks brand new. I'm tellin' ya, this is the way to go.

Dale

^

That is a nice highflow and their Ti catback looks nice and is cheap.

I don't really get it.

US people talking about putting HF cats on the car either because of the higher performance or environmental issues (ehm, forget about that last one)

Those cheap ass cats don't do a thing, except for providing some backpressure to keep boost spiking controlable other than to be really functional.

HF cats like from SARD or Knight sports are not bettrer than any of them, just more expensive.

Japan and the rest of Asia (together with the US) are the most environmental unfriendly parts of the world when it comes to exhaust gas emissiosns.
Why would they care about catalytic converters for performance cars?

In Europe this is different. Smog tests are really hard and if your cat has no European type approval, you can simply forget it. Tis means that cats are being tested on EURo emissions norms (currently Euro4), backpressure and performance gain.

Companies like SARD and KS are active in the aftermarket/performance business, but can they back their products with OEM standard quality and research? I don't think so.

Please have a look at this company in Germany.

http://www.hjs-motorsport.de/english/home.php

HJS Motorsport is one of the biggest suppliers of High performance exhaust parts but they have a background which stands for research and development

http://www.hjs.com/english/

Being one of the major and leading suppliers in the OEM business.

All products have European approval and for motorsport, FIA-apporoval/recommendation.

If you really want to invest that kind of money and be sure that it will work in every way this product was designed for, you better talk to them.

No disrespect but I don't think people driving FD's in the U.S.A or Japan give a flipping burger's meat about meeting European emission standards.

The only reason people want Highflow's as you put it "because of the higher performance or environmental issues (ehm, forget about that last one)".

Well tell me in the U.S if a Highflow can prevent boost creep and has a CARB number what more could they want. For Pete's sake they drive FD's not Prius'. Same goes in Japan if they can meet emissions and safely run high performance from there motors why would you want more?

Sorry if this is a rant but I hate those people that are like "If it is European/German it must be better" same as "If it is more expensive it must be better" kind of people. Those people own BMW 318's,324's and 525's, Merc 240's and the likes. I hate hate hate hate those people, think they are all good with base model stuff that they paid a fortune for because it is made in "Europe".

Back to what Dale was saying although that Highflow is very nice would it accentuate boost creep?

Alex

Ehm... I understand your point of view. But I work in the european OEM HYundai and KIA accessorry department and we have plenty of experience with stuff like this.

Performance and environment do not match, everybody knows.
So Why even care about a cat anyway? if emissions are no issue, just delete the cat, buy a boostcontroler and/ or a resonated midpipe for boost/noise control.

Turbo's don't need backpressure so why install a restrictive (even if it's less than the original one) cat anyway?

I'm not telling anybody to meet any emission norms, you probably never will with a RX7 anyway (hell, mine allmost didn't pass with all OEM exhaust parts on it).
I'm just telling you that if you want to spend money on it, you better spend it on something with decent background otherwise I just don't know why you need a cat at all.

In the end you will fry 1,2 or 3 cats before you decide to buy something decent and spending more in the end

A boost controller will do you no good with a MP if you don't have your wastegate ported, and not everyone has the tools/ability/time/or money to do that.
Because some people hate dealing the with smell of excessive hydrocarbons, both on themselves and their passengers.

Not really sure where you're getting this idea that US FD owners are looking at hi-flow cats purely for environmental reasons. The only reason the vast majority of them use hi-flow cats is because they at least clean up the exhaust emissions enough to keep the hydrocarbon smell from permeating everything in the cabin when the car is stopped in traffic. If they can do that while getting some performance increase, and pass emissions tests without spending a fortune for an "OEM supplier/Euro 4 approved" cat, then so much the better. Otherwise, for those that don't have to deal with annual/bi-annual emissions tests, and don't care about the smell, a MP (with the proper boost control methods) is the "non-cat" of choice.

Not sure why you're getting so worked up about this.

I would very much like to hear from someone that has put 50K miles on one of these metal cats. Durability is a concern when buying one of these.

Is the OEM pre cat a "metal cat"?

No, ceramic, just like the main cat.

My Dynatech Metal Cat lasted about 10,000 miles. The spiral insert shrunk inside the casing, due heat and rich a/f (11.5-1) per the engineering department. I am presently running a midpipe with a Car Chemistry 2 Disc insert. Additionally, I have deleted my OMP and have been running Klotz Benol 2 stroke oil (castor oil) at 160-1. The castor oil has a sweet smell, similar to a motorcycle or snowmobile which is reasonable.

The quality of their work is awesome. I got the 4" Ti tipped exhaust, metallic cat and 3.5"-3" downpipe. The cat has a pipe on for the stock air pump as well. I ended up selling it as it's not required for my car here in the UK. But have kept the exhaust and downpipe. Car is currently in pieces so haven't actually tried it yet :)

Interesting article about High flow cats, with some info about metalic cats, not rx7 specific but still interesting:

http://www.importtuner.com/features/...val/index.html