cat converter punched out..how much Hp gain?

i recently had my cat converter go bad and just had it knocked out and was wandering how much hp i would gain from this...any one know? stock LT1 in a 94 TA GT Conv.

Probably nothing. As a matter of fact, you probably lost some low end torque. I've never heard of anyone actually gaining HP by doing that, only losing. You need some back pressure for one, and I believe the shape of the hollow converter has a tendency to cause some odd pressure waves as the exhaust bounces around in it. I did it on my 90 Formula just to avoid replacing 2 converters since it had the 2 converter set up, and seat of the pants felt like I lost some off the line.

Yup, The older cars with the cats. gained some power having this done but the newer cars are designed with the cats. in mind and yes, they do need some back pressure, I doubt you lost very much, maybe a couple hp but I can almost certainly tell you it didn't help.

in my 84 i gutted the cat and noticed no gain or loss, but my exhaust tone did change a little bit

last year headin down to ecoean city maryland to do a little deep sea fishin, me and my dad were in his 95 ram pickup with a 5.9 v8 magnum in it and right as we're goin through the toll booth in dover deleware his truck loses power. My dad bein a sick mechanic, used to be in nascar, figured his cat was clogged right away. We called up my cousin who didnt live far away and had him bring a hack saw.....cut the exhaust off right in front of the cat and waddya know at least a 25hp gain!!!

last year headin down to ecoean city maryland to do a little deep sea fishin, me and my dad were in his 95 ram pickup with a 5.9 v8 magnum in it and right as we're goin through the toll booth in dover deleware his truck loses power. My dad bein a sick mechanic, used to be in nascar, figured his cat was clogged right away. We called up my cousin who didnt live far away and had him bring a hack saw.....cut the exhaust off right in front of the cat and waddya know at least a 25hp gain!!!


See i have had different oppinions about this, ive had people tell me i'll gain nothing and those who say i should gain a little. personally i thought i should gain a little because the exhaust would be flowing a little better, but then again i didnt think about the back pressure. it definetly sounds a lot meaner that's for sure. anyone else out there have this done to the LT1?

your going to lose low end torque, i promise you. but you might see a gain in high end HP.

i did this to my car, and my 60 foot times dropped a bit, but overall, ran the same ET. the best thing to do would be to replace the cat with a hollow tube the same diameter as the rest of the exhaust