Muffler modification...
 

I recently saw a dyno chart with some increased HP numbers from a gutted (i.e., cut open & rip out) muffler. I'm curious what exactly such muffler hack involves -- gut the entire thing, or perhaps just open up certain parts..? It would also be interesting to know how different the sound would be compared to the stock muff. So, has anyone here done this gut-out hack?

-- peer

I haven't done it but have talked to the guys who does it. Apparently it's a old trick that was done to old 911 mufflers.

The muffler is cut into two halves,stripped on anything on the inside. They then install two pipes,one on each inlet and lead it to the exhaust tips.

if you're gonna go trough that whole procedure, why not just take off the whole heave muffler, store it away or sell to someone, and just fab up some pipes and put nice tips on them. no need to have all that weight on the car if the muffler is pretty much a straight pipe in a big box.

yeah, but I'd expect that your car is too loud for normal traffic (Harley drivers will look mad at you ;) and you will have brutal resonances betw 2,000 and 3,000 RPM

The dual muffler styled exhaust already have enough resonance. I wouldn't want to see what straight pipes are like. :confused:

When i was modifieing my exhaust with bypass pipes and the mufler was out of a car i started it with just headers on and gave it quite a few revs.......O MY GOD!!!! :dance: It blew my ears off....there is no way you can drive that on a streets and not get a ticked....i would sure love to thou because it sounds just amazing

Same here. I tried a straight through 2 muffler type, too loud for me. I want quiet absolutely no resonance with best possible flow. The "Korda" mod introduces some resonance back in. Don't know the specifics of the mod, but it must've changed the Hemholtz resonator in the OEM unit.

I ran straight pipes on my 99
 

Yes I am guilty, i had straight pipes on my 99 Boxster for about a year, there is a video at www.youtube.com/gwhand

was it loud?? Yes...so loud that after a 2 hr drive I would get a headache and talking on the phone was near impossible.

I am glad I tried it but i would not do it again.

I've modified my muffler by cutting holes in the inlet pipes so that some exhaust gases skip a chamber in the muffler. The sound is very nice. There is a bit of resonance right at 2800rpm if the car is under load, but otherwise it isn't bad.

Below you'll find a dyno chart for a hacked muffler. I'm just curious what they exactly did to it, since it's quite an improvement, especially the torque.

-- peer