I've finally reached the point in my FD where I want to add a cat because the smell is part of the reason I don't drive my FD more often. Anyone have experience with a high flow cat on a single turbo FD? My local muffler shop that has done a lot of exhaust work for the FD and other cars I've owned sells Magna Flow. They said for my car, they would go with the spun body style cat. Since this is aftermarket and non OEM setup and on a rotary, they said they will not warranty it though. Any one have experience with this style of cat or recommend any others? I assume the high EGTs might be a real issue with the life of a cat?

 

I've had good luck with the Magnaflow 59920 metallic cats on the 3.5" systems I made. To use them on a 3" system, just weld on 3.5 > 3 reducers on each end.

They won't survive a track day but will absolutely clean up the smell for street driving.

 

Seems like twin cats might be the only way to get decent life of out a performance setup.



That said, I don't have any personal experience - YMMV.

 

15ish years ago, I welded a 300 cell metal core cat into a straight midpipe. The company is no longer around but the design is common. I ran it like that for a couple of years maybe 10k miles on the street and track days until I decided I wanted it both less stinky and quieter. At which point, I bought the SMB that had a metal cat and a muffler.

Check out the options from Magnaflow, Vibrant and other big names.

 

Look on Buyee for used JDM aftermarket cats. You can always find a few.
SARD and a few other companies make high-performance cats for the FD.

 

Thanks for the feedback. I am not running an OEM exhaust so whatever I had would need to be universal and weld in or vBand.

 

Thanks for the feedback. I am not running an OEM exhaust so whatever I get would need to be universal and weld in or vBand.

 

I have the Vibrant SHO metal cat. I like it a lot. Most of the smell is gone once warmed up. I do recall someone in the forum having theirs clog. I have had mine off recently for a rebuild and it was still fine. Only one track day on it several years ago with my old engine. They state in their literature it can take much higher heat than most metal cats. I had my old SMB melt before switching to the Vibrant.
Mike

 

Here are some pics.

 

thanks for the intel. What is SMB?

 

A vendor out of Australia. I don’t think the newer SMB has cats anymore but I’m not sure. I think the original vendor used the owners initials.
Mike

 

HJS weld in catalytic converters, fabspeed sells the cores if you don't want to import a fully built cone assembly. It's the only catalytic converter AFAIK that is able to withstand rotary engine EGTs.

 

Those are great cats but are quite expensive. I looked at those when I bought my Vibrant. Over 3x the price. They will take up to almost 2,000 degrees F but are only 200 cell. The vibrant will take up to 1,500 degrees F and are 300 cell. If you are over 1,500 degrees F in the midpipe area, where we place out aftermarket cats, on a street car, you have more problems on your hands than melting the cat. You would need to worry about the higher heat at your engine tearing up your seals and prematurely destroying your turbos. Your exhaust manifold EGT’s would be way higher than you would like to see on any street car. My point is for all practical purposes, unless your car is a track car, the Vibrant is fine. Way cheaper. Worked for me.
Mike

 

Do something like this so you can easily swap back and forth in the midpipe... These magnaflow cats work great on the street.

 

How is everything going?

 

Haven’t pulled the trigger yet on a cat but plan to soon. Likely vibrant or magnflow spun body high flow cat.

 

yes. I was thinking same thing but with vBand clamps so I can swap out cat with my current mid pipe resonator in case I want to go back to tracking my FD a few times a year.

 

The only thing i have to add is that there are two types of converters.
the OE style ceramic, which melt around 650c

and the metallic substrate converters, which melt at 1100c. the metallic substrate is also thinner, so at the same cell count they flow better.

also i'm jealous, in California we can't run anything except the stock converter

 

I wonder how race cars with catalytic converters (e.g. GT3, F4) manage to not melt them? Maybe they are just running them further downstream.
Or they just aren't as hot as rotaries...

 

this is super useful because I can’t find specs on cats for the temps they support. Only cell count and substrate type. At least I know to get metal now.

 

Thanks for the pictures.

 

Not as hot, and WAY less horsepower.

 

That's true for something like an F4 car, but GT3 cars have more horsepower than, let's just say, most rotary cars.
Couldn't you deal with the heat by just putting it further downstream of the manifold?

Of course, it would be less effective from a cold start, though, and that's half the reason to install a cat...

 

GT3 cars are ~500hp and other than the M4, they all have two exhaust banks and cats. Each cat only has to deal with ~250hp.

EGTs kill cats. Mounting them further away from the engine/turbo will help them live longer. Like you said, they will just be less effective at reducing emissions prior to them getting up to temperature.

High EGTs and more HP per cat is why it's more difficult to make a cat live on an rx7 than a GT3 race car.