Bad cat plugging exhaust?
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Bad cat plugging exhaust? I bought FLP headers a few years ago with cats. The cats are cheesie and no longer work to scrub the air.
Question; Can these get clogged up so the exhuast is restricted; how do you tell if there is a restriction? Is it necessary to remove the cats which sucks?
Is it a bunch loader if I take the cats off and replace them with the straight pipes. Yeh, I have neighbors too. Cops also.
Question; Can these get clogged up so the exhuast is restricted; how do you tell if there is a restriction? Is it necessary to remove the cats which sucks?
Is it a bunch loader if I take the cats off and replace them with the straight pipes. Yeh, I have neighbors too. Cops also.
Teching In
Joined: Feb 2004
Posts: 47
Likes: 0
I had the cats on my FLPs, and when i switched them for the offroad pipes I definately felt the difference in power.
It wasn't really all in my head, as a friend was also there and agreed. I guess if the HP difference is noticeable it must have been close to 10hp right??
Anyway, yeah it got louder... but not by a huge amount. It is definately noticeable, but as long as you aren't going through your streets at WOT, it should be ok.
It wasn't really all in my head, as a friend was also there and agreed. I guess if the HP difference is noticeable it must have been close to 10hp right??
Anyway, yeah it got louder... but not by a huge amount. It is definately noticeable, but as long as you aren't going through your streets at WOT, it should be ok.
I flow-tested (in an uncalibrated, but apples:apples manner)
cats and offroad tubes with a leaf blower and a water-tube
manometer made of hardware store vinyl tubing. If you see
more than a couple of inches H2O across the cat then it's
definitely a restriction; if you see a big difference between
the two of them than the high-pressure-drop one is congested.
Did you ever manage to find the FLP offroad tubes that bolt
in in place of the cats? That's your optimum-flow ticket.
Or you can remove any obstructions with a long masonry bit
and a crowbar, just to be on the safe side.
cats and offroad tubes with a leaf blower and a water-tube
manometer made of hardware store vinyl tubing. If you see
more than a couple of inches H2O across the cat then it's
definitely a restriction; if you see a big difference between
the two of them than the high-pressure-drop one is congested.
Did you ever manage to find the FLP offroad tubes that bolt
in in place of the cats? That's your optimum-flow ticket.
Or you can remove any obstructions with a long masonry bit
and a crowbar, just to be on the safe side.
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Oh yeh; the FLP headers come standard with a section of straight pipe betweent he header collector and the Y-pipe. If you want cats which are sold separately for $300, you remove the stright pipes and clap on the cats.....
I recently passed BYS inspection which killed the sniffer test and replaced it with the PCM code test. Consequently, I am very happy and no nlonger need cats...
I recently passed BYS inspection which killed the sniffer test and replaced it with the PCM code test. Consequently, I am very happy and no nlonger need cats...
Staging Lane
Joined: Mar 2005
Posts: 82
Likes: 0
From: georgetown tx
The easiest way to check restriction of cats is remove front o2 sensor and install a psi gauge (snap on sells one with adapter) start the car and see if the psi is greater than 2 psi (stock muffler ). If the gauge jumps way up when you snap the throttle then the cat or whatever else behind the cat (muffler ) is causing a restriction. To test after the cat remove your rear o2 and check psi there
