I was wondering what (if any) advantages there are from removing the cat. Some tell me that low end power will rise where as you'll lose high end power. I'm just wondering if anyone out there has removed their cat and how it is effecting their performance (for example hp gains, noise, etc)...

Harpreet
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Re. 1

It is usually not adviseable to remove the cat. converter. The engine itself is tuned to accept a certain amount of back pressure. There would not be a significant increase of horse power unless it is a turbo charged engine. I would suggest to replace a free-flow cat converter, cat-back exhuast and matching headers.

Choon-wei Ong
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Re. 2

According to california state law, it is illegal to remove a cat if it is performing properly. i know there are companies that sell free-er flowing cats. but as to their california applications, i don't think it's legal. i  don't know about other states, but my cal. 96 240 has 2 cats.

christopher j. dunn
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Faq:

Does removal of thecat provide more power?

Solution:

I live in Australia and we call the car a 200SX eg SR20DET engine (turbo 2.0L). Most laws state that removal of the cat is illegal and so on but I can tell you that Power increases are very notieable as well as the odd flash of flame at night! My advice is smash out the inners off the cat or if you want to keep it replace it with a straight through pipe.

Name: michael bernhardt
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ARE THERE ANY BENIFITS TO REMOVE THE CATALYTIC CONVERTER

PDM RACING (WWW.PDM-RACING.COM) HAS A STRAIGHT THRU PIPE FOR 240SX'S, THAT REMOVES THE CATALYTIC CONVERTER.    THIS IS NOT FOR STREET     APPLICATIONS AS IT WILL AFFECT YOUR EMMISIONS. BUT FOR THE TRACK IT GIVES YOU AN EASY 5HP,    PLUS EXHAUST NOTE IS LOUDER. I WOULD     RECCOMMEND IT IF YOU ARE NOT WORRIED ABOUT EMMISSIONS AND EXTRA NOISE.     AND ANYONE WHO SAYS IT DOES NOT MAKE EXTRA POWER IS LYING.    

ADAM HUTCHINSON
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DOES REMOVING THE CAT PROVIDE AN INCREASE IN HP?

REMOVING THE CAT DOES NOT MAKE A NOTICABLE IMPROVEMENT IN HP. BUT THIS IS ONLY TRUE IN MOST APPLICATIONS OF STREET DRIVEN 240SX'S. YOU ACTUALLY LOSE TORQUE, BECAUSE TORQUE IS AFFECTED BY BACK PRESSURE, THAT IS TO SAY UP TO A CERTAIN ENGINE RPM. HOWEVER, REMOVING THE CAT IF YOU HAVE A TURBO WILL IMPROVE TOP END POWER, ALSO IF YOU OPERATE YOUR ENGINE IN THE 6500-9000 OR HIGHER RANGE, HP WILL INCREASE. THE LESS BACK  PRESSURE A TURBO HAS, THE FREER THE TURBINE WILL BE ALLOWED TO SPIN IN TURN RESULTING IN INCREASED HP. HOWEVER THE STOCK 240 ENGINE DOES NOT BENEFIT FROM A REMOVED CAT. BESIDES, THE 240 ENGINE HP FALLS WAY OFF AFTER 6000 RPM UNLESS YOU HAVE NEW CAMS, OR A TURBO. I SUGGEST BUYING A RANDOM TECHNOLOGIES CAT BECAUSE IT BOLTS RIGHT IN PLACE, LOSES NO HP AND GAINS 2 LB-FT OF TORQUE. COST IS ABOUT 200 DOLLARS. OR YOU COULD PURCHASE A CATCO CAT FROM SUMMIT RACING FOR ABOUT $70 IF YOU DONT MIND DOING A LITTLE CUSTOM FABBING. I KNOW BECAUSE I BUSTED THE INSIDES OUT OF !

MY CAT AND MY 240(KA24DE) FEELS LESS POWERFUL. IM GOING TO BUY A HIGH FLOW LEGAL CONVERTER FOR MY CAR THIS SUMMER. HOPE THAT EXPLAINS IT FOR YOU. I DRIVE A '93 240SX-SE TWIN CAM, NO MODS YET, BUT I PLAN TO SUPERCHARGE IT.

ERIC ROY
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