I know this question has been beaten to death but after reading as many post as i can i am still confused on this issue.People claim that the best cat for power is no cat and it makes sense.Now others claim that removing the cat leave you without back pressure and that is vital for 3rd gens.My cat is almost rubbing the floor and i am trying to decide between no cat or high flow cat.There are no emmisions in miami no more so that shouldnt be a problem....PLease respond and help a novice out.....: :

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1988 Trans am.......best 600 bucks ive ever spent...305 5.0 but will save my lunch money and every penny to swap for a 350 tpi in the coming two years

 

I swear that if you can get rid of the cat do it! it costs 50+ for a catco cat+ an hour for a muffler shop to weld it in. your looking at 150 bucks. it will probably cost you about 50 to have a muffler shop bend and install a pipe in its place. If back pressure was a seroios issue do you think these people here would be using headers and highflow cats that reduce backpressure on my 82 in my sig i cut the cat off and am running a muffler that is just a little louder than a stock one. and i gained power from removing the cat. try this in the morning. Take a screw driver and punch a big hole in the plug on the bottem of the cat. your going to get rid of that one any way, make it a big hole. clean up the little ***** that come out and dispose of them in a plastic bag. then go out on the street and clean the rest out by driving.
you will notice a big difference in power. just imagine if the damn thing was completly off. try this bro and post your results of this little test tomorrow. sory if i got a little wordy here


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85 Camaro RS 350/350 stealth intake, holley street avenger 670
true dual exhaust. "ButtStang killer"
82 firebird 305 all original - the cat and smog crap."All show No go"

 

third gens needing backpressure?
LOL...
how fast are they running with this so called "needed backpressure"?

 

I just had a muffler shop cut my cats out and repipe the gap- it cost $60 and was worth it- it sounds a better and has a more power. It doesent make a huge difference but if your gonna do a full exhuast its a must.

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1992 Z28 W/5.7L. Teal with unpainted cowl hood,18" Billet Specialities Rims,Eibach Sportline Springs, Leather int., B&M Mega Shifter, Headman Headers, Flows,No Cats,K&N,HyperTech air foil,Custome Burned Chip,MSD Ignition,Shift Kit, Billet Corvett Servo my Back License plate reads "ALL UL C"

Here's a pic of my car
http://www.geocities.com/jonnyarson/maro.jpg

" WHAT DOES THE BACK OF A MUSTANG LOOK LIKE "

[This message has been edited by BigMike 92 Z28 (edited March 20, 2001).]

 

The torque you lose by removing the cat is insignificant. By the way did you get your lights to flip up?

 

I was told that as long as you run a muffler, you can run with out a cat and still have sufficent back pressure. I think the main reason you want back pressure is to slow the pistons down on the up-stroke of the exhaust cycle, it will make the engine last longer.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

Soon to Come: 7.625" 10 Bolt with 3.42s and Accel TPI Intake Base

 

I am with dan on this one. I have seen a artical (in PHR I think)where they took 700 hp 10 sec camaro (low tens to high 9's)ran it open headered and then put like dual four inch and some borla race mufflers and ran better times with the exhuast. So I think that have an nice exhaust with a free flowing muffler may produce better power but I don't see how a cat fits into that picture.

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"I don't trust anything that bleads for five day's and doesn't die"
88 iroc slp headers,borla catback,procharger to come soon.

 

Thanxs guys..I am going to run a pipe and get rid of the cat and if i dont like it (which i doubt) i will just buy a new cat....I wasnt able to get my lights to go up but ill keep trying but i think the motors are shot

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1988 Trans am.......best 600 bucks ive ever spent...305 5.0 but will save my lunch money and every penny to swap for a 350 tpi in the coming two years

 

all this talk about cats....... the truth of the matter is that a cat is about as equal as a slight bend in exhaust tubing, its virtually unrestrictive, the honey comb ones anyway, the pellet type on the other hand are slightly more restrivtive, the removal of the cat will be even less than the difference you would feel running your car on a hot day versus a cool day, and if you can take it off, to all you emission free people, by all means do it, (it sounds much cooler) but if you cant, dont, its dumb, you can get into trouble and its not even all that restrictive!