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About the Thrush system...

Allen Chan (

The high flow cats are made by Thrush and they cost about $110. You can get them at many speed shops since many of them offer after market cats. I don't have the model number, but their the Thrush catalog was quite accurate and helpful.

The performance gains seems to be across the power band. There seems to be a 5+ HP gain from this mod. The effects are quite noticable in the low RPM range. It acts like a simple resistor in an electric circuit (for all you EE types). I got a cat that fit exactly to the pipe diameter of the exhaust. If I were to do this again, I would get the largest cat that would fit in the space, regardless of the pipe diameter. The bigger the cat's core, the less the resistance.

Mounting it was a nice hack. The flange of the old cat was too rusty to salvage. So I cut out the flanges and used pipe sections and pipe clamps to mount the cat. My mechanic friend does quality work, so there has not been any exhaust leak problems at all. There is no additional noise from this mod.

This is my opinion: a high flow cat seem to reduce as much exhaust back pressure as the high flow mufflers. Both seem to offer about 5 - 10-ish HP improvement. You can achieve Stage 1 with a high flow cat instead of a high flow muffler. The benefit is the reduce noise levels. I don't know of the EPA/emission laws about replacing cats in your state though.

I need a new cat, but the NISSAN one costs $724! Any ideas on where to go?

Daniel Paik (

Try Random Technology. Phone number is (770) 978-0264. Turbo magazine used their cat on their turbo SE-R, cuz the stock one got fried. Supposedly high flow, and you can get different sized inlets and outlets. Don't know how much they cost though.

Robert Szczepanski (

I got a Random Technology cat. I ordered a 2" thi nking it was smaller but it is not. The price...$175. A hell of alot cheaper than NIssan wanted. Also, it is Stainless Steel inside and out and THEY say it flows a lot better than stock. The gentleman on the phone claimed 5-7 HP over the factory. I am happy with it. I don't know of any other places that sell good high quality converters. This is what they say in there TURBO magazine ads.

  • Stainless Steel Construction
  • Brushed finish
  • High efficiency monolothic brick (just like stock)
  • 50-State legal
  • 5 year, 50K warranty
  • For 2", 2.25", 2.5", 3" and 3.5". Custom inlets and outlets also available.

They did not have a direct replacement for the SE-Rs, so if you want one, just order a 2.5 in and out and take it to your local muffler shop to install.

Kinjeo Yeung (

You can get a Dynomax Hi-Flow cat for about $120. Another $30 bucks to have a shop to weld the flanges on. I have the Dynomax cat. It appears to be the same as one from Random Technology.

Maintained by Ronald S. Chong (