I had this really bad rataling coming from my cat and the shop said i could hollow it out and i might could get some power out of it.Any one have this done,sould i hollow it out or just replace it? Iv got a 97 sh,lots o bolt ons and zex 55 shot??

 

Uh, don't expect to pass emissions, but sure...go for it. Just stick a big *** stick into it and twist it around. Afterwards, pound it against the ground to get all the bits and pieces out of it. I'm sure it'll help out with the ZEX.

 

oh yeah it'll help, but you'll have to pick up a new one before your next smog check

 

yeah, i've done it before on my old prelude and a 6hp gain showed on the dyno.
with all the bolt-on's you got, plus the nitrous, it would help. you will get some power for sure.

 

I'd have a test pipe made up instead, I got one for 30$ US installed.

I'm gonna go to a high flow cat sooner or later when I can afford a full custom exhaust.

 

i heard once i think from some guys at atomic, that if you hollow out the cat, the air when it travels through will sit more in a empty cat instead of going straight through. i may be wrong though.

 

a buddy of mine hollowed out his and it sounds like *** now. the noise you hear might be the heat shield above the cat, it might be loose.

 

That's somewhat correct. A hollowed out cat is just that, a huge emtpy chamber. Now when the exhaust flows through, it'll try to fill up the chamber and cause some turbulence. The BEST way to keep the exhaust flowing is to get a testpipe of the same diameter as your exhaust piping.

 

I had the cat hollowed out on my old car a 95 honda Civic.....and yes it is a good idea, real big gains...and sorry your incorrect about the big chamber. When I hollowed mine out it was a perfectly round 2.25" pipe all the way through. just like a test pipe...It was awsome.....I am going to do it to my new prelude as well...And I think it made my civic sound even better...I highly recommend

 

Your car will smell like ****, sound like a fart and gain about 3whp. Just get a carsound high flow instead $95. You'll be much happier.

 

Big gains? Did you dyno it before and after? How much HP did you realize?

EVERY Honda that I've heard with a hollowed out cat sounds like crap. But that's just my personal experience. To each their own I guess?

 

to each their own it is........ Hey RCR, do you ever run out at commerce?


[Modified by GudeH23a, 5:07 PM 6/2/2002]

 

ya what that hell i think il do it,and and if its sounds bad il just get and a stright pipe

 

Atlanta Dragway is ok. I like Silver Dollar better though. You'll shave at LEAST 2/10ths just switching tracks man!!

But yea, I go there pretty often. Were you there a few weekends back at the Import weekend with Mahdavi?

 

smell, not really, mine didn't. as far as it sounding like a "fart", that all depends on the exhaust you got. i had a tanabe hyper medalion and it was hella quiet. i didn't even notice any sound changes... it was not loud at all.