By removing the cats, i know i should get a lot better airflow... But will decrease my MPG's? and or Mess up my Performance or whatever the computer does? Pros and Cons Welcome.

Thanks

 

When the cats where removed, What was noticed, and what was the biggest regret???

Someone reply to this...

 

I have no cats.... no regrets! Love the way my car sound with LTs, o/r y and borla exhaust.

 

car sounded alot better. no regrets,but im now upgrading to longtubes and tsp ory. best thing is you wont have to replace rear o2's

 

No regrets here, but if you don't like the raspy sound it's not for you

 

Half the people here probably don't have cats, I myself don't have them either and never will, sounds great with true duals also

 

at certain rpms i hate the rasp but at WOT i love the sound. i still have my stock cats with an lm1 and i love how its a smooth sound throughout the rpms. if i put on ory then i would probably hate it on the acceleration between 1500-3000

 

My buddy had it with ORY and LT's...

For about a week

 

i have no regrets i like the way mine sound

 

Lovin it here as well - no cats = less restrictive = more power!!

 

have the back O2 sensors deleted and better tune installed.you can mail your ECM to some tuners ,cost 125-150.are you going to do a full exhaust install?

 

Yes definetly!
Im thinking more on the side of a Y pipe upgrade instead of an X, x Is more expensive, and im also looking into getting an electronic cut out. Which will be cheaper to just have to mess with one pipe instead of two.

Do you have the website info or place of BIZ to send the ECM?

 

Hey!
No one said anything about my gas mileage messing up without the cats... Did anyone notice the difference or same thing?

 

mine gets 25+ on the highway if i stay out of the throttle.

 

Just did mine a couple days ago. Car sounds VERY aggressive now with manifolds, Flowmaster cat-back and hollowed cats. Not raspy because of the Flowmaster (yeah I know they aren't that good).

 

CATs are not a huge restriction on these cars, been plenty of dyno's showing not a tremendous difference over stock.

On a stock car, with at most a cat-back will notice a difference in sound. When adding LT's it gets louder and when adding as cam it gets a little too much.

The only time I would consider removing CAT's on these cars is for the installation of a 2-Step or if I was building a track only car. Cops just looking for reasons to break *****, especially with the economy.

You will need to have the computer tuned to either ignore or turn off the rear set of O2's as now the PCM cannot read there difference of the upstream and down stream O2's, the values will be nearly the same and your going to get a SES/Engine light. It can effect gas milage. Also since air flow has changed more fuel maybe needed, it all depends on the car.

I was pulling Knock Retard on a 2002 T/A with a Lid, Headers, catted Y pip and a Corsa. Fuel needed to be added to help compensate.

 

No regrets of getting rid of the cats. The only use for them is if you have to pass emissions. Not having them will give your car better flow of exhaust and increase performance, but really its not that much. If you have emissions where you live, I would think twice about dumping them. Just my $.02 tho, there are ways around that as well.

 

I hate the high pitch "rasp" from 2500-3000 rpm, I love the growl when punching it. I have Pacesetter Long Tubes/TSP off road Y/hooker Muffler. I miss the "deep muscle car rumble" and torquey feeling it had with stock exhasut and flowmaster muffler.

I asked TSP what can I do to get some deepness back/less rasp they said try a magnaflow muffler..what do you guys think?

 

I disagree. I would remove the cats any time headers are being installed. I do agree that removing cats on a stock manifold car won't show big gains and isn't really worth it unless you're just doing it for the sound. But since the purpose of headers is to increase power, I can't see spending additional money for less gains (even if it is a small amount) by adding cats. Having said that, I can understand adding cats if you have to pass a sniff or visual inspection, but LTs won't pass the most strict visual inspections even WITH cats.

Hooker mufflers are usually known to reduce rasp over other mufflers. Maybe you need a better quality Y-merge, like the Flowmaster Y. Another option would be to also add some Dynomax race bullets to the Y-pipe (or one in the I-pipe, if you don't have space elsewhere).

If you are willing to do a different system entirely, true duals with your headers, no cats and something like round/oval Magnaflow (or Borla XR-1) mufflers will give you a very nice "deep muscle car rumble".

 

I have passed many times. Depends who is doing the inspecting.

Again depends on the preference of the owner and what motor your using. For example....

http://www.hotrod.com/techarticles/e...ock/index.html

Catalytic Converters
Everyone knows catalytic converters suck for performance-no true hot rodder wants to plug up the engine. Back in the days of crude, first-generation pellet-style converters, there was some validity to this belief. But engineers have had 30 years to refine converter technology, and as technology goes, 30 years is a lifetime. Dynatech makes some high-tech catalytic converters designed to be used with its headers. Installing dual miniconverters after the headers but still running through 211/42-inch dual pipes into the dual Flowmaster 40 mufflers cost only 0.3 hp and 7.1 lb-ft at the peak, and just 2.6 hp and 3.8 lb-ft on average between 1,600 and 5,700 rpm. Overall, the engine ran so well with the cats that they were left in place for all subsequent mods.



Read it and see what I mean, you can run CATS and have a good balance. If people want max effort there should be nothing more then a turn down off the header and tuned accordingly.