OK so everyone is saying that removing the secondary cats you will loose TQ but then recomending high fow cats......ummm yeahhh

Obviously this is fiercely debated, but I don't think cutting the cats out alone will hurt your power, if anything the engine will be able to expel exhaust gasses faster... especially if your cats are clogged. From my understanding though, if you don't "tune out" the O2 sensors, they'll freak out and the car will go into a fail-safe fuel/air mix that may not be the optimum.

You will lose torque if you expand the exhaust beyond what the engine can flow though... think of a garden hose. Yeah, you could get a fire engine hose and hook it up to your regular faucet to wash your car but it's going to take a lot longer for the water to get out. A smaller diameter hose may not have as much capacity for flow, but it will move the water your faucet is capable of pumping quickly. You want the exhaust moving out of the engine as quickly as possible. That's delta pressure. Delta pressure = good.

How could one find out the delta pressure (rating?)... Obviously you want best flow. But you want minimal restriction (back pressure) to keep the engine performing it's best. My plan has been to go with 2.25 or 2.5 inch cat back 304 stainless. No muffler no nothing after the cats though still keeping the H pipe design or possibly turning it into an X pipe. So what I am wondering if only having the bends and the pre-cats on the exhaust system though still going all the way back factory length. Would it hurt the system to remove the mufflers and cats?

Australia doesn't use cats on their cars to my knowledge they do just fine. The old school muscle cars didn't have cats, they didn't seem to have a problem, definitely with torque production.

A catalytic CONverter is nothing more than an exhaust restriction. What happens when you remove restrictions? You gain more power.

If this isn't true then why do so many people change out the single exhaust for duals?

Holy Sheet. you guys must have some massive frostheaves there

^^^^^^^

All I know is I ran 14.9s with stock exhaust & then with hollowed out rear cats & glasspacks dump'd I have gotten a best of 14.7s. I picked up 2 tenths on the little exhaust mods I made. I definatly didn't lose any power hollowig those rear cats out.

yes you will gain a little power as long as you keep back pressure you wont loose low end TQ.

think of a motor as an air pump. The more efficient you can pull air in and expell air the more power you make.

THIS.

Not to rain on anyone's parade but I know New Jersey frowns on removing cats. Any of you from the "Garden State" ever watch how they inspect vehicles in their inspection stations? I lived there from 1969 to 2003. A mirror on a pole was put under the car & the exhaust system was examined closely, the gas cap was removed to check the size of the tank inlet & older vehicles were put on a special line that picked up the front wheels & shook the car to check the front end.

In Massachusetts, it's not unusual for an inspector to crawl under the front and rear of the car to check for cats if your exhaust is too loud.

In select counties they just plug the car in here and check for codes.

HA here in newfoundland when having an inspection there is no emissions checks.

This made me laugh...hysterically

here in ohio, when i had an off-road pipe on my 98 GT i had 3 different cops compliment me on how my car sounded over the time I owned it.