macadoo

I'm having mine replaced when I get the money. When this happens I will let ya'll know if I feel a difference. The plan is middle of Jan. Does any one know if there is a cat that can be installed to replace both of these? another words just have one on there? Will it mess up the mpg? I like my 28 mpg and want to keep it that way.

92lxsleeper

yeah just cut one off, you don't need both of them. its just a heat issue thing, if you put one big cat on it, there will be alot of heat generated, they put two on them (4 on the V8's) to help lower the heat due to how close they are to the floor pans.

Rustang Racer91

I have to dissagree with 92 lx sleeper, the purpose of the dual cats was that each cat was to "treat" a different type of emission, due to the fact the "monolith" type that are used currently were still in it's infant stages...

Rustang Racer91

the current hi-flow cat replacements that you can get for like a integra or honda replacement will function just as the dual cats did with only one instead...as far as the heat goes, as long as it is still located under the oemheat shielding it will be just fine...or a reputable exhaust shop can construct a suitable replacement heat shield. Besides, if you remove one of those cats, then the emissions it was suppose to "treat" are un treated, greatly increasing your chances for failing the sniffer (I used to be a California licensed smog inspector/repair technician).

Rustang Racer91

for example the 5.0 mustang original H-pipe has four cats, but all the replacement hi-perf units have only two. That's because all of the hi-perf replacements come with the hi-flow monolith style ( looks kinda like a honeycomb). As silly as it sounds, there are a ton of suitable ones that will work perfectly sold for hondas and integras- the integra one is usually better because it's designed for a turbo.

Rustang Racer91

a high flow monolith cat will out perform your old dual cats hands down, and will probably help your gas mileage due to the better flow characteristics. definately won't hurt. I know it made a huge difference on my old 5.0, and my Toyota when I upgraded the cats

sleeper_inc

Non of that testing goes on where I live, and my car doesn't have a cat right now low

Rustang Racer91

then you got nothing to worry about...unless your o2 sensor gets too cold...

MustangGuy93

Taking the secondary cat out might reduce the effectiveness of the emmision control... but it would still be legal. Both my parents cars only have one cat, and both engine are way bigger than mine. Dad has a 4.3 V6 and mom has a 3. something V6.

sleeper_inc

the 87-90 2.3's had only one cat and they passed also[&:]