what would be the down side of running with a hollow cat and straight pipes. I'm looking for more sound. I've got 80 series on now. But I'm not to thrilled with it.

But I also don't want to much attention from cops.

 

no muffler or cat will get LOTS of attention from cops. if you want, just keep your system and get a cutout. that way you can switch back and forth.

 

try hollowing out the cat and try that first before you run strait pipes because if you run strait pipes and hollow cat your a cop magnet....

 

I have heard that hollowing out the cat will cause you to lose power and torque. Is that true?

 

if you don't put a pipe through it...yes it will. It will cause a lot of turbulance in the exhaust stream. Just get a high flow cat. Its smog legal, no loss of power, and a mellower sound.

 

the cat in place with the honeycomb stuff inside will cause it to have turbulance also, so hollowed cat over stock cat would be better, and create a little more horsepower and torque by letting the cat flow better, but a straight pipe in place of the cat would have more velocity over hollowed cat, its your choice on what you do.

 

just take the shields off an old cat and tac weld em over a piece of pipe. stright pipes will gain you torque and noise though. bends tone and exaust nicely. you will want a little back pressure if your on the street also. i had open headers on my GTA and it was a dog while accelerating. i put the exaust back on and it seemed to accel faster with it than without. after that experience, i will never run open pipes again.

 

Sorry dude....you never want any backpressure! That is common misconseption. Read any car book that talks about exhaust or do a search on it here....all will show how the less the back pressure the better.

 

And i do agree on the cut-out. Really good idea. You get the best of both worlds!

 

I've got hooker headers -> high flow cat -> full flowmaster exhaust, all 3".

Was planning on taking the cat off completely after it's smogged (good for 2 years) and then putting a straight pipe (with shields to satisfy cops) still leading out to the Flows.

Will removing the cat add some power?
Anyone with a similar setup know if it sounds better or worse? Thanks!

 

i dunno dude... i believe you want a certain amount of backpressure in order not to have all low end go to crap...

 

please dont let this turn into a back pressure arguement, there are many threads about back pressure. do a search

 

https://www.thirdgen.org/techbb2/sho...t=backpressure