I've seen a few Evo vendors selling high flow cats, usually Random or Catco stuff which I believe is composed of a 200 cell brick. I'm REALLY trying not to go to a straight pipe for emissions (I have a rotary to spoil the environment) and noise. There are a few high end German shops selling 100 cell cats for various cars but I have no idea who makes the actual converter unit itself. Apex-i Japan also has a 108 cell high flow cat that's being used on some very high hp turbocharged cars (600+wheel hp). Looks like those are going to run in the $600 range.

Does anyone have a source for 100 cell high performance/flow cats? I wouldn't mind doing a custom weld job to save a few hundred $$$$. I have a feeling the "normal" high flow cats are worth maybe 5hp over stock and are still 20hp down on a straight pipe (cat delete). If any vendors are listening, I think there'd be a real market for a cat which allows you to pass emissions and is only 5hp or so down on a true straight pipe, especially for the 350whp and under crowd. Anyway, links or leads appreciated!
Michel

 

I don't think anyone is going to provide a high cell density aftermarket cat.
These supposed high flow aftermarket cats create more restriction than your stocker, your better off just going with a strait pipe.

 

A 100 cell brick, designed correctly, would be considered a low density cat, not high. What I'm asking would actually reduce the cell density over what's currently offered. Whereas the stocker might be a 300 cell unit, the Random is a 200 cell. The Apex-i is about 106 or 108 and there are numerous Porsche shops using 100 cell units which flow much more than the OEM units. The new 100 cell units apparently use special rare earth elements and super-efficient designs to scrub exhaust as well as a high cell count cat brick while offering far less restriction.

Power-wise, you're correct, it'd just be easier to go to a straight pipe. While that may seem logical for you, it's not for me, hence my post. I have no desire to make the car any louder (daily driven) nor stain the rear bumper. Some of us have to be environmentally friendly!

Out of curiosity, do you have any proof the aftermarket cats sold by say Buscher Racing or Vishnu, Ultimate, etc...rob hp compared to the stock unit? I can see them performing marginally better but to say they actually flow less?

 

I use Random cat and the catalytic element core size is fraction of other HF cats- maybe a fistful size. It pretty much resembles a test pipe and a center fistful bump. I was told by TT that Random cat is one of the highest flowing cat around - short of test pipe. I got mine used for $100. GL

 

I'll see if I can find the message. I had someone from Europe/UK contact me a while back. He said he could ship me 100 cell cats for around $350.

 

Awesome, I'd appreciate it. Any tech info on the cells would be appreciated as well!