Daul Cat Question

okay Im contemplating converting my car to dual cats. The car is an "86 but

the motor has been change to a 350TPI. Now my brother inlaw works at a

performance shop and I asked him if there are any aftermarket set-ups that

are just y-pipe and not header y-pipe combinations. He said no and I'm

better off sticking to just one cat because two cats are more

restrictive.... Now I'm no genius but that statment goes against all ever

ever learned...... lets face it if you put 2 straws in your mouth and blow

theres going to be less restriction then if theres only one. So what should

I do I'm hoping you guys can help me not make a mistake. and If duals are

better is there any aftermarket set-up available

thanks TOM

Reply to
Tom
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I would have to agree with you that dual cats would be better, but

unfortunately it's not legal to convert your car from single to dual cats.

The "hot" legal setup for your car would be to replace the stock cat with a

high flow aftermarket cat, then buy an aftermarket cat-back exhaust system.

Gary

Reply to
Gary - KQ6RT

Maybee it is restrictive.

after all there is some kind of filter inside the can.

if only one side of the motor is running through it then that would be half

the presure to force the gasses through the filters.

Maybee it does need two banks of the engine to force the gass through at a

stady flow. ?

dunno I do agree with the Straw idea though. Why not do away with the Cats.

Regards

Wombat.

Reply to
WombatPPC-NEWS

Replace the 2-1/2" cat with a 3" one like I did. There's plenty of

flow through the 3" unit. My pipes from the exhaust logs are 2-1/2"

each side to the Y-pipe, then the 3" cat., then a Flowmaster 3" cat

back exhaust. American Thunder is what Flowmaster calls it, I think.

Maybe that's the system in my 68', either way you can upgrade the

exhaust to handle it and won't have to worry about the constricted

area that you'd have to run 2 pipes down. The last thing is that the

system uses all of the original mounting points.

...Ron

--

68'RS Camaro 88'Formula 00'GT Mustang
Reply to
RSCamaro

Well These are all good points but the thing is I've already Put a 3inch

Dynomax superflow cat on there and a 3inch Edelbrock Performer RPM cat back

coated with JetHot. Problem is that the stock Y-pipe, has a big crack in it

and is leaking pretty good at Idle so I'm guessing that its probably really

pouring out at high RPM even though the majority of the exhaust note is

coming from the rear.... Your probably thinking big whoop change the pipe

right. But the cars seem to have way more balls with the crack and I know

Mac makes a nice single cat y-pipe, but hears the thing... 1996 formula

Single cat' rated at 275hp '96 T/A daul cat 285hp.... And think about this

if your forcing out say 3000cubic cm per min' through a 6"X10" cat// or the

same amount of cubic cent-per-min through two 6"X10" cats thats double the

amount of flow. I would think????

Tom

Reply to
Tom

Take a look at the page below.

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Find someone who can use all of the information about your engine and

drive train and have them design the system that will work best with

what you have. There is more to look at than just the cm3 of the

pipe, you have to look into how well exhaust gasses will flow through

those pipe with the least amount of restriction.

Most of the sites I've read have said that a 3.5" equals a dual 2.5"

but the sites I was reading had vehicles that were talking about

engines that exceeded 400 hp. I've put in a dual exhaust on an 83'

Z28 and it was the most difficult fitting system that I've ever had to

put in.

...Ron

--

68'RS Camaro 88'Formula 00'GT Mustang
Reply to
RSCamaro

I installed a full dual exhaust with headers and dual cats onto an '84

T/A. The local inspection people said it was okay because a later

model F-Body came from the factory with dual cats. Thankfully there

was no sniffer test in the area because there was no way it would have

ever passed. Sure, a later model came with duals, but the two 2 1/2"

cats I installed couldn't have possibly gotten hot enough to light-off

and clean the exhaust. Not to mention there just isn't enough room

under the floor to fit all those parts. It used to scrape and bottom

all the time.

My recommendation:

Edelbrock T.E.S. headers and Y-pipe.

Stock H.O. 2x3 oval catalytic converter, or a high flow aftermarket 2

1/2" 3" Flowmaster cat back exhaust

That'll be 50 state legal, very high flow, and you can sleep well at

night knowing the emissions won't kill any spotted owls or desert

tortoises.

-rev

Reply to
The Reverend Natural Light

(Update) Well after all the help and throwing around different senarios I've

come to the conclusion that it'll be more of a headache to get daul cats on

the car all for maybee a few more horses, not really worth it if you ask me.

I ordered the High flow Y-pipe from Mac Performance today and the way I look

at it this pipe alone will out flow the stock one by far and probably

wouldnt have gain more than a couple give or take if I had gone through the

trouble of setting up dual cats. Thanks for the help

TOM

Reply to
Tom

I would recommend replacing the cat with a high flow model at the same

time. Making everything else flow better is a little bit of waste if

you don't do the same with the cat.

Reply to
Cy Welch

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