How much Horsepower/Torque losses can you expect from adding a catalytic converter to a straight pipe to pass emmisions testing? I would be adding a 2.5 " high flow cat. Know of any muffler shops in the Seattle Area that would make me a test pipe too? Thanks for your help!

 

they make some good flowing cats liket he carsound cats it flows almost as good as a str8 pipe. for all motor it doesnt matter much as turbo. there is a dyno with the carsound against a test pipe the test pipe made 1 hp more but the carsound had 1 torque more.

 

thanks zad5 for the info - I forgot to ask if I need and OBD I or OBD II cat caonvertoer. According to the muffler shop I spoke to there's a significant difference in price ($260 installed for OBD I vs $400 installed for OBD II). Using the wrong one will apparantly cause the cat to be blown up or worn out prematurely - can anyone verify if that is correct? My motor is a 95 GSR Head and Block with a stand alone AEM EMS. Thanks!

 

it won't really matter unless you are in CA and have to do smog. OBDII cats just have a better filter that the dyno smog machine will pick up. The only time you would need a OBD II cat is if you car is 96+

 

There was a dynosheet comparing a straight pipe and a high flow cat. The difference was only a SMALL gain. I would suggest just keeping the high flow cat instead of going with straight pipe. Killing the environment isn't worth the 1-2hp. I still need to install the 2.5" cat and get the custom piping done soon.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by D1703 &raquo;</TD></TR><TR><TD CLASS="quote">it won't really matter unless you are in CA and have to do smog. OBDII cats just have a better filter that the dyno smog machine will pick up. The only time you would need a OBD II cat is if you car is 96+</TD></TR></TABLE>

it does matter on some applications. some header do not have an o2 bung and so the obd2 cats have a bung before the cat and after the cat. you can always get an obd1 cat and get a bung welded. if you get an obd1 cat make sure it is a three way cat. also the price the guy gave you are ridcilous buy a carsound cat from ebay are you 2.5" if you are get the 94066 should be around 70 dollar or so should be less then 100

 

Don't buy the 94005, 94006, 94035, 94036, 94065 or 94066 cats.

 

Thanks everyone for your input - I am a little confused though... For my application (95 GSR Block and Head with AEM EMS stand alone ecu), I should use a OBD I Cat correct? As far as the price to install, the $260 was installation including the price for the muffler. How many hours worth of labor or how much in labor costs should it be to install a cat converter? As far which cat to get, should I get a carsound 94066 (OBD I ?) or a SMSP high flow cat? OBD I or OBD II? Thanks again and sorry for the confusion...