well I gutted my cat because I couldn't get it off. Why take it off? I had a strut nut inside it rattling around from when I did my front suspension. Well I tried propane torch, MAPP gas torch, and then gave up. So I just rammed a screwdriver and rod inside and pulled all that crap out. Got the nut out! It was black as could be.

Well my car sounds a lot better, but of course it stinks. I'm carbureted, and I get fair mileage (15-18 average, city/hwy combo) with my mods, but am I running rich? Is exhaust smell any indication of rich/lean status, or is it always going to smell funny due to the way a catless car will smell? I'm just wondering, because it could lead to better tuning if I am rich.

Yeah it smells alot better

but yeah compared to the way a catted car smells it'll be alot different.

Thanks

does it smell like old muscle cars? i love that smell

and you could beable to tell if its rich or not by smell. strong fuel smell would be more rich i would say.

but dont stand there and keep smelling it

How does a hollowed out cat sound compared to a straight pipe in placement? Its gonna be about = as loud right? but ive heard hollowed out cats dont sound very well?

sounds pretty much the same in my experience. The hollowed cat will lower hp output by ~3 hp however vs a pipe.

the cat that was in her car was hallowed
i didnt know at the time
the straight pipe i put in sounds much better and the car felt better too

i might hollow it and shove a smaller straight pipe threw it then.

Be careful with catalytic converter substrate. It has a TON of metals that should not come in contact with skin.

good to know

When i put my hooker catback on the iroc, i hollowed out my cat. The insides were broken up into 4 or 5 pieces, so I shoved a metal pipe into the inside and broke it all out, then reinstalled the cat.

I don't know how much gutting the cat had anything to do with sound level, but it definately sounds nice when you get on it.

Im getting a hooker catback for my car in the spring. Was thinking about getting a hi-flo cat but now i think im gona spring for some 4th gen interior so thats not an option now. How much HP/sound would i gain from gutting my stock cat vs. keeping it intact. Also, will my car smell different (TBI) and will it hurt the environment even if the smog/AIR is still intact??

youll pollute more. but if your cat is stock, and you don't have to worry about emissions, i'd say hack the d*mn thing off, and run a straight pipe. just have the welder tack the air tube into the side of the pipe if you plan on keeping the air system. i did that, and haven't had any problems.

Then I guess all those fairly hollow type designed mufllers like Flowmaster and IMCO and etc are hurting performance too ?
I agree a straight pipe is the way to go but if you have only a visual inspection to pass leave the gutted cat and don't worry about it. I like the way ALL of my gutted cats sound.

when i purchased my car it had a gutted (factory original) cat on it. i put a new hi-flo on, i think it sounded exactly the same if not better then a gutted cat.

but dyno did'nt notice any change in performance.

Actually Flowmasters are HORRIBLE mufflers! The WORST of all aftermarket brands. They earned their name "Flowstoppers!"

The reason a hollow cat is worse than a straight pipe is because the air must first expand to fit the now hollow cat, then contract to be squeezed back into the pipe. It creates a turbulence that slows the air down.

Please here we go again, somebody don't like the sound of a FLOWMASTER so it hurts performance, it does not hurt performance. To say an open free flowing muffler or gutted cat hurts performance is like saying a larger diameter exhaust pipe will hurt performance. I am not saying putting dual 3 inchers on a v-6 wouldn't hurt performance but you all get the point, right ?
Got any dyno numbers to substantiate your claims ?

Are you saying your BUTT dyno didn't notice a change or an actual dyno did not see a change between a gutted cat and a high flow cat ?

I know I will keep my gutted ones, I don't have to worry about them plugging up or breaking apart AGAIN. One time deal and it is done forever. Mostly some people think they sound differently, depends on the size of the cat's case....a very large CASE will slightly alter the tone. This is based on experience not conjecture too.
I have never felt a loss of any power gutting a cat. Even if I somehow lost one or two horses it would be worth to me not to have to worry about another one of the damn things plugging or breaking up and pieces lodging in my muffler. AgAIN SPEAKING FROM EXPERIENCE.