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More hp and performance?

1K views 14 replies 8 participants last post by  poncho62 
#1 ·
Monday I am getting the catalytic converter off my car and putting a glass pack on it. Will this increase the hp of my car and will i be able to tell a difference? I dont quite have enough for duels so im going to get the other side done in a couple months.

I also wanted to ask if it would sound okay with just the single exhaust glass pack. The motor is a olds 307
 
#6 ·
cutting the cat

I dont recommend cutting off the cat as it may effect the 02 sensor in your exhaust system. I have 3 vehicles that all have cats on them and I run straight pipes out the back from there. The sound is very non objectionable. In fact it just gives them an exhaust sound like having massive turbo mufflers on it. Having done this I have noticed an actual increase in gas mileage by at least 1-2 mpg. I am not however going to make any claims of any substantial horsepower increases. BTW, we dont have vehicle inspection in our state, other than in the state capital, as it is over run by wanky liberals and they demand everyone adhere to their phony political correctness,there.
 
#10 ·
which is better?

I like a nice sounding exhaust as well as the next guy, but just consider this. Loud exhaust, like loud sterios are cop magnates, most places. Again, I refer to the three vehicles that I have that run straight exhaust from the cats back. They have very nice tones to them, yet are unobstrusive. Since your engines fuel control system is calibrated for operating with said cat or cats, to remove them my cause detrimental performance to your vehicle.
If you have a plugged cat or cats, my advise is to replace them. As it is, most reputable muffler shops wont remove a cat unless they are going to reinstall it or replace it. Some shops wont even put dual cats on if your vehicle came equiped with just a single exhaust system and a single cat. I fear that you are only going to disappoint yourself with what you are wanting to do. If its just the noise you are after, also be prepared to attract a lot of unwanted attention.
 
#13 ·
Removing the cat will increase noise, but the glasspack will be quieter than a straight pipe. A long glasspack (or two in a row) will be quieter than a short one. I have a 77 Nova (parts car) with a 305, gutted converter, & no muffler, and it sounds a whole lot like my '63 Ford pickup (292 V8) sounded with a single glasspack. Quieter than a V8 with duals & glasspacks, and a smoother, more pleasant deep tone, something like duals with an X-pipe. The truck still had some of that "blat" when you let off the gas, though. You should get a little better power than with the restrictive cat & stock muffler too. Be sure to use a good non-restrictive (smooth internal pipe, no louvers) glasspack like the Thrush Magnum. They're under $20 at the mail-order places.
 
#15 ·
When I had a plugged up cat, before we had emission testing, I took the pipe off and with a long bar and knocked the guts out of my cat. That put a hole right through the honeycomb. It was basicly a straight pipe after that, but still looked like I had a cat on it. Of course, you still need a muffler.

Glasspacks are quieter than straight pipes.
 
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