Hi-flow Cats - how much louder??

[DJCV]

I know that the OEM cats are a constriction point for Crown Vics, if not all Panthers. I also know that high-flow cats increase the flow as well as the exhaust note volume.

Who's running these, and about how much louder is your interior and exterior exhaust note as a result------10%, 25%, 50% or what?

[Ktorres1]

I do not know if high flow cats will actually increase the volume any by much but I know guys report a very nice increase in rumble by removing the rear cats.

[Taemian]

The SW high flows made my set up about 25% louder. SW headers were another 25%, all other exhaust bone stock.

[burt ragio]

Swapping out the oem cats for the s/w high flow metal matrix cat will not alter the db by any significant level maybe additional 5 -7 db. You can still hear your music talk on the phone ect. no drone. It will make a significant increase in flow. Could be one of the best mods in the exhaust system on a none aspirated motor under apx 400 hp. That and a cold air intake.

[musclemerc]

Save some cash and get Magnaflow #94106 high flow cats. I got a set last year for 90.00 shipped from performancepeddler.com. There will only be a slight diffrence in sound and will flow more efficient that stock

[fastblackmerc]

As the others have said, you might hear a little more sound if you replace the 4 OEM cats with 2 hi-flo cats. Not enough to make a real difference. You will notice a little more power and slightly better gas mileage.

[DJCV]

Gents,
Thank you for the good advice.