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JL8Jeff · 02-24-2006, 07:09 PM

You guys must have had damaged cats or damaged them with tuning. I've gone through a bunch of tests that show that high flow cats will not affect performance. Tim, your example is a single incident and you can't use it as a standard. With all the mods you were doing to the car I'm sure you somehow damaged the cat. And since removing cats is illegal it's not really an argument on a street driven car. For a track only car, no, you don't need cats obviously. I would like to see some real test numbers that show a high flow cat is robbing more than 2-5 hp.

This test result shows that the TTS Bullet cats were poor flowing but the others flowed very well and better that most mufflers. And the passenger side cat was modified to a 2.5" opening to make it an equal test and it flowed better because of the increased opening size.

Table 1
Inlet Diameter (in.) Outlet Diameter (in.) CFM @ 20.4” H2O CFM @ 28” H2O
Passenger Side
Catalytic
Converter 2.5 2.5 299.5 350.9

Driver's Side
Catalytic
Converter 2.5 2.5 268.3 314.4

TTS Bullet Catalytic
Converter 2.5 2.5 277.1 324.6

Carsound Catalytic
Converter 2.5 2.5 372.7 436.7

FLP Catalytic
Converter 2.5 2.5 376.0 440.5

Another test done on a Mustang.

02-24-2006, 07:09 PM	#22
JL8Jeff Hippy Mod, Bergermeister Meisterberger, Moderator Join Date: Aug 2004 Location: Ewing Posts: 6,216 iTrader: (3)	You guys must have had damaged cats or damaged them with tuning. I've gone through a bunch of tests that show that high flow cats will not affect performance. Tim, your example is a single incident and you can't use it as a standard. With all the mods you were doing to the car I'm sure you somehow damaged the cat. And since removing cats is illegal it's not really an argument on a street driven car. For a track only car, no, you don't need cats obviously. I would like to see some real test numbers that show a high flow cat is robbing more than 2-5 hp. This test result shows that the TTS Bullet cats were poor flowing but the others flowed very well and better that most mufflers. And the passenger side cat was modified to a 2.5" opening to make it an equal test and it flowed better because of the increased opening size. Table 1 Inlet Diameter (in.) Outlet Diameter (in.) CFM @ 20.4” H2O CFM @ 28” H2O Passenger Side Catalytic Converter 2.5 2.5 299.5 350.9 Driver's Side Catalytic Converter 2.5 2.5 268.3 314.4 TTS Bullet Catalytic Converter 2.5 2.5 277.1 324.6 Carsound Catalytic Converter 2.5 2.5 372.7 436.7 FLP Catalytic Converter 2.5 2.5 376.0 440.5 Another test done on a Mustang. __________________ 69 Z28 JL8 4 wheel disc brakes - being restored 09 Silverado Z71 Last edited by JL8Jeff; 02-24-2006 at 07:31 PM.