Bronco Forum - Full Size Ford Bronco Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
146 Posts
Discussion Starter #1
i know cats have been talked about on here 38516538 times and all but here is my question...
i live in Oklahoma and we do not have to get sniffed. my bronco has 2 inline cats. i have already chopped the muffler off after the cats. what would it sound like if i just cut off one of those 2 cats? would there be any noticeable performance/mpg gains?
 

·
Banned
Joined
·
5,463 Posts
Considering yours is a 96 it probably runs pretty good. I would replace both cats with a highflow. Look into a bassani y pipe.


Cutting off one of the cats will just make it louder and have more in cab noise.
 

·
Registered
Joined
·
146 Posts
Discussion Starter #3
if i chopped both cats and put on the bassani y-pipe and ran pipes out the back, would it be just ungodly loud/annoying? im trying to get to maximum breathing that is still tolerable for mpg purposes
 

·
Convicted Drunk Dialer
Joined
·
2,521 Posts
I finally threw on a pair of flowmasters recently after running straight pipes for several months. Yes, its ungodly loud.
 

·
Satyr of the Midwest
Joined
·
17,734 Posts
Remember the factory PCM calibration is dependent upon some things, e.g. catalyst(s) in the exhaust stream, exhaust gases passing the HEGOs at a certain rate, etc. This means that, especially since your setup is OBD-II compliant with a HEGO after the reduction catalyst, that you should have a catalyst in your exhaust.

I would second the idea of using a Bassani Y-pipe or fabricating your own for much less, AND using a single-shell three-way converter (TWC). High flow would be an option, but I also advise people to save some cash by just getting a converter that's rated for a much higher GVWR and/or engine size. The one I'm running on my 5.8L is rated for >8500lb and a 460 engine, 3 inches in and out. The cool thing is that a modern single-shell converter can take the place of those two MASSIVE ones that come factory and separate the reduction and oxidation catalyst beds. Plus the newer ones flow better and reduce pollutants more efficiently.

Don't throw the factory setup away; they contain rare elements (platinum, palladium, rhodium) that can be sold to scrap yards OR sold to other FSB'ers that need them in states where emissions testing is done.

If nothing else, please keep a catalytic converter on to keep our air clean AND to preserve your truck's driveability. Removing them will have a temporary effect on power, but only at WOT, and mileage will sufffer.
 

·
Banned
Joined
·
5,463 Posts
The stainless steel highflow bassani cat is just like a honey comb... you have to be shooting out emissions the size of bolts for it to catch anything. So maybe a cat like Sigepblue is talking about might be a better idea.
 

·
Convicted Drunk Dialer
Joined
·
2,521 Posts
The stainless steel highflow bassani cat is just like a honey comb... you have to be shooting out emissions the size of bolts for it to catch anything. So maybe a cat like Sigepblue is talking about might be a better idea.
Its not a filter, its a converter.
 

·
Registered
Joined
·
146 Posts
Discussion Starter #11
Sig, i didnt think that cutting the cats would effect the PCM. i knew there is an O2 sensor back there but i thought it was just a trigger for the check engine and didnt do anything as far as fuel:air ratio? and thanks for the heads up on not just throwing the cats away. thank you guys for your help, as always, i appreciate it.
 

·
It's BTW Not AKA!
Joined
·
5,354 Posts
Talked about alot? I have never heard of you?
 

·
Registered
Joined
·
146 Posts
Discussion Starter #13
also, i just looked at a magnaflow high-flow cat and it looks JUST like my cat thats on their. when i had my 81 camaro, the cat on it was just a stinkin honeycomb in their. The one on my bronco has that dang screen inside so that i cant poke out the innards like my camaro's.
 

·
Registered
Joined
·
4 Posts
i have a catless exhaust system on my 94 with a 3inch magnaflow and tailpipe....really isnt that loud at all. I like it. The truck feels more responsive.
 

·
Registered
Joined
·
146 Posts
Discussion Starter #15
GT, i used the search feature before posting to see that cats were talked about a million times. never saw any questions about cutting off one of the two inline cats so i asked. and yes i am new to posting, but not to reading the posts.
 

·
crank trigger
Joined
·
8,150 Posts
i thought trucks with 2 cats had to keep them both or they would throw a mil and not run as well, unless you do a mil eliminator on one of the hegos
 

·
Registered
Joined
·
146 Posts
Discussion Starter #17
yah, my back o2 is already throwing a code. i plan to program it out. but if the broncos are like most cars, the back cats dont affect any fuel:air or anything else. they just throw the warning code
 
1 - 17 of 17 Posts
Top