cfr865

I just had a built 302 stoker installed this past week, when we put it on the dyno for the tune it wouldn't make more then about 350 whp, the tuner decided to un-hook the exhaust from the manifold and it picked up 100 whp, he said the cats are plugged up. We odered a new catted pipe today and will install it on Monday. I have had my Paxton on for about 20k it seemed to run good, the Paxton was installed and dyno tuned by Brenspeed. What would cause the cats to clog up, wouldn't I have noticed some power loss prioir to the engine swap.

aclass

I'd be interested to see what the cats look like. I wonder if the heat melted the "stuff" inside causing it to deform.
FI cars are recommended to have the cats that will endure the heat from the blower.

Just a thought.
I just put the Pypes High Flow cats on my car and had to buy the more expensive ones.

Keep us posted.

bigray327

I melted two sets before switching to an off-road pipe. You will continue to melt cats, no matter what the brand or type, and put your engine at very serious risk in the process. A couple of guys have blown engines to prove that.

cfr865

I was thinking about going with the off- road pipe , how noisy is it.

candymanjl

there's the guy on here with the blown motor from his catted X pipe clogging, I forget the brand. honestly I've never seen anyone with an issue with stock cats, only aftermarket ones.

IMO don't waste your money on "high flow" cats, they're not worth the money or risk for minimal power gains. just go with an off-road setup or keep your stocks.

jerjan

I've been running stock cats since day one with my KB. No meltdowns. Lean fuel conditions can cause excessive exhaust temperatures that can fry cats. Candyman is right the stock cats have been tested by KB to work well up to 575 RWHP. There are plenty of used ones available from guys who put off-road pipes on. Oh, and off road pipes are way louder. I tried both the X and H styles and they were too noisy, could hardly hear my stereo. The stock system is back on and quiet.

candymanjl

on my buddy's 04 GT he had the offroad pipes and it was pretty loud, sounded good, but loud, too loud for me to put on a daily driver.