Ok so I'm hearing you guys say you didn't seem to get much of a difference from a hi-flow cat to a cat removal but I also didn't hear anyone complain about losing power, so I'm going to go ahead and put in my straight pipe. Thanks for the fast responses.

 

No offense to neon, but I would like to see dyno results instead of butt dyno results on the high flow to the gutted cat difference. Like I said, not to cause offense, but I believe an increase in sound always tends to fool us into thiking we are getting more than we are.

In all honesty, the difference, if any, will be minuscule. Now, gutting (w/ the use of a pipe as previously mentioned) the stock cat is a much more substaintial difference. I personally don't see you getting 5 ponies out of replacing your hi-flow with a straight pipe.

I have pretty much everything you do except the headers and kegger mod and I'm running a 5.2. I have a pipe instead of cat because the stocker went to the junk yard and it was cheaper to do than a hi-flow. If I already had a hi-flow though, I'd probably save the $10 and start towards getting some rockers.

 

Did you find that your exhaust note got raspier? Did you notice a change in tone at all? other than it getting louder.

Oh and I found a simulater that I thought was interesting and with a mild cam it showed a 10hp increase by removing the cat. I know thats not real world so please guys dont jump me too bad here, I just thought it brought a little validity.

 

In regards to your exhaust note, you will defiantly hear the differance. I mean,that's the reason I gutted my cat. I didn't do it for horsepower, I did it because I want to louden up my exhaust even more, and I just love the sound of a gutted cat going into a chambered muffler. It really does become more raspier.

As for h/p results, I obviously don't have any dyno results. But I recalled racing my brother before the cat and he would always beat me off the line. Then, I had the cat gutted, and sure enough, I beat him by an entire truck length from the line on multiple occasions, there is no bluffing there. Like I said though, I did it mainly for sound. It was just a bonus that it freed up some extra horsepower, but nothing too noteworthy. If your doing it for h/p, don't aim too high, but if your doing it for noise and more of a rasp, then defiantly do it, you'll notice it man

 

I did it on a 96 5.9L the cat ad the 2 in from the motor 1 out to muffler so we had to hollow it out becuase it got cloged sounded good felt more power

 

RM Indy's page states that he dropped .15 sec off et's with a gutted high flow cat.

 

Too bad you can't do a before and after dyno test to see what you actually get. It would put a lot of arguments to rest once and for all.

That car you see in my avatar had a cat. I had it cut off and they put in a smaller diameter pipe than the what the car had on. Took it to Car-X and the young guy walked around andaround my car. He said "I think I can get 73 Chevelle pipes on this. I was one huge piece but he worked on it until he got it in. THEN I could really tell a difference (low restriction muffler of course). That gave that 75 Grand Prix its voice.

 

Tell me about it, I would have loved to do a before and after dyno run.

Well isn't that interesting, I think I'm gonna go to his website and check things out.
Do you know offhand if he did a gut or a pipe replacement?

 

Yeah but if we're talking about a race truck then it doesn't really apply to big 4x4 trucks. Our trucks, especially I know this now[8D]....aren't meant for speeding, so your not even going to notice any loss of horsepower, because your not going to be running quarter mile times lol. I just think it's pretty simple. If you want your exhaust to be louder and it to be more raspier, do it. It's why I did it. And I defiantly felt a little gain in h/p, it whats made me beat my brother off the line.

Here's the diff. between my truck with a catback system with the magnaflow cat last summer.
And then another video of my truck after I gutted it in the fall.

http://youtube.com/watch?v=aQyPmZY_ZsY (pre-gut)

http://youtube.com/watch?v=r5GrnL6kGzA (gutted cat, I mean you can just hear the rasp, love it!)

 

The pipe is in and its pretty f***'n loud. I'm going to give it a week but if I still can't stand it after that the cat is going back in. It does seem to drive a LITTLE different. This one hill it always downshifted on it actually didn't but I don't know if it made all that much difference.
But hey, I did make a crappy video of driving with open headers because I had to take the tail section down to my uncles shop for a little work.
http://www.youtube.com/watch?v=AzBwyRV_FMo Damn I'm good at making crappy vids
Heres another ****ty one with the cat removed and the rest of the system re-installed
http://www.youtube.com/watch?v=AzBwyRV_FMo
Don't forget to turn up the volume cause my mic sucks hard core.