the stock muffler is so huge but does almost nothing for the noise......damn those cats...lol

I agree with you Semtex. I think most people are just amazed that it doesn't make an atrociously terrible sound. I wouldn't think for one moment to do this but I'm still really surprised that it actually results in a somewhat decent tone.

it doesnt sound bad, but it you put HFC's on and leave no muffler...man, that's gonna be loud....lol.....do it with some \/ pipes with tips.

Oh I agree about being surprised that it doesn't make a terrible sound. Don't get me wrong -- like I said in my original post to this thread, I think this little experiment yielded some valuable information, and I'm glad batman_4 did it. Specifically, if we remove the mufflers and it still sounds reasonable, I think we can infer that the stock cats are really, really restrictive. I think we've all pretty much known that for a while anyway. But this just confirms our belief.

While I do agree that there is likely not much of a gain to be had by deleting the muffler...there is, however, quite a bit of weight savings in dropping that thing off the *** end of the car. Now, it's not dropping weight where we would prefer (front end), but it is dropping weight none-the-less. No HP gain but a reduction in weight is still considered a performance increase. :nutswinger:

I disagree about this being a rice mod. As pointed out, the weight, but also, it's like taking a Lamborghini Gallardo and putting aftermarket pipes on it. Sure, you only gain 10hp on 560, but it makes such sweet music. It's a more satisfying mod than removing my Bose sub and adding a 12" speaker and amp. To some it's just noise. To me, it is music. Unfortunately inline 4's don't sound like music unless they spin faster than 10,000 rpm. For that reason, my Yaris, which is lowered, has aftermarket swaybars, shocks and Momo wheels, has a STOCK exhaust.

It's not that it changes the ammount, it could potentially be a problem dropping CO under the floorboard instead of out the back, especially when idling.

Stock exhaust has 2 cats, 2 diffusers and one muffler. I don't think it's neccesarily fair to say it's the cats cutting the noise. You've got me curious enough to unbolt the rear section of my stillen exhaust to see if it's the cats or the diffusers....

Yeah, I have to admit that I neglected to take the weight-savings aspect into account, so I guess it's not entirely rice. I still think it's a poor substitute for getting a proper aftermarket exhaust though. Just my opinion.

Replacing just the stock cats with HFCs and leaving the stock cat-back in place produces a significantly louder exhaust note. DDMotorsports has a vid clip showing this. From this alone it's obvious that the stock cats are having a noise-suppressing effect. Are you suggesting otherwise? That the stock cats aren't cutting any noise? Yes, the resonators are cutting noise as well, but if the stock cats didn't cut any noise, I don't think the HFCs alone would produce as dramatic an increase in sound as they do.

I agree, but it's a personal opinion. Some people really only enjoy the sound that the exhaust gives and don't mind if there are no power increases. Just wanted to point out the weight factor since weight reduction is definitely a big topic for the track. :tup:

well when i got home from work today i grabed my 14mm wrench and went to town, sprayed the hangers with wd40 and took off the 4 bolts, slide it off the 3 hangers and Bam~! took maybe 8 mins. started it up and wow, sounds great!! kids next door said it sounded like a superbike at wot.

oo that bi#ch is heavy.. guessing 25ish pounds

Woot!

Isn't it a blast? I love how it sounds like that.
:driving:

I will probably try this this weekend when I am doing some other work on the car.

Dropped my muffler today (because of the rear JDM fog install) and drove around.. it's really loud.. but it sounds pretty nice when you get high into the rpms.. lots of droning at 40-45 mph.. haven't gotten up on the highway yet. Will do more driving without it on tomorrow.

loving it still lol. just went to a meet and most of the 350 guys where amazed at how good it sounded. also raced a mustang on the way out (which i beat with ease i must say) and man does the exhaust scream!!! hadn't redlined the car like that without the muffler.