Gundo or Fister Mod on aftermarket exhaust like Agency Power on a 996
#1
Gundo or Fister Mod on aftermarket exhaust like Agency Power on a 996
Hello All - I have been jumping around searching for the perfect exhaust - Tried the Fabspeed Supercup that sounded awesome between 3-7RPM's but left my ears ringing between 2-3K. I tried the Fister Mod which sounded great but those cans weigh a ton. I recently scooped up a pair of Agency Powers for fairly cheap but I think I need somebody to follow me to let me know if it sounds any different than stock. Great news is Drone is basically non-existent but so is increased sound......Long way to the point but has anybody tried the gundo or fister mod to an aftermarket exhaust like the Agency that is too quiet for my taste but love the no drone and the 20 lbs off the back of my already to heavy Cab.
Any responses appreciated
Any responses appreciated
#2
You can do a modified PSE and get a decent sound. Its a little louder than the PSE mod and different than the bypass pipe mod (not the muffler bypass pipes you see for sale that eliminate the muffler).
While you have the two muffler outlets open for your mod (one is a "plug" if you dont have factory PSE) and can see inside the muffler, there is a solid wall seperating the chambers. You can experiment with different size "holes" in the wall until you get the sound you want. Your actually doing an internal muffler bypass instead of external one. I know it may be hard to understand without seeing pictures. I was able to do this myself. I will probably just cut the muffler skin open next time to make it easier. I got this idea from another poster who opened his muffler to repair it not mod it.
Its a little louder than a PSE but not annoying. No drone. I plan on experimenting by enlarging the hole in the muffler wall until I get the perfect sound I want. I will try and dig up some photos or post a sound clip on Renntech if you want. I had the PSE "hack" done first but was not happy with the quality of work or the sound. Thats why I re-did it myself and added the internal mod.
While you have the two muffler outlets open for your mod (one is a "plug" if you dont have factory PSE) and can see inside the muffler, there is a solid wall seperating the chambers. You can experiment with different size "holes" in the wall until you get the sound you want. Your actually doing an internal muffler bypass instead of external one. I know it may be hard to understand without seeing pictures. I was able to do this myself. I will probably just cut the muffler skin open next time to make it easier. I got this idea from another poster who opened his muffler to repair it not mod it.
Its a little louder than a PSE but not annoying. No drone. I plan on experimenting by enlarging the hole in the muffler wall until I get the perfect sound I want. I will try and dig up some photos or post a sound clip on Renntech if you want. I had the PSE "hack" done first but was not happy with the quality of work or the sound. Thats why I re-did it myself and added the internal mod.
#6
Im working on making a set of stock mufflers with an easily removed access panel where you can remove or put back in the internal muffler wall. Might even try a half wall. Im using stock mufflers even thought their heavy because their cheaper to destroy. Ive seen crappy used stockers for @$100 a pair.
#7
I did the Fister mod on my gemballa cans with a 1" piping. It sounds good with no drone but still not loud enough for my taste. I think im gona go with 2" next time i have my cans off.
Last edited by 996pp; 06-20-2013 at 02:48 PM.
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#8
I've contemplated on doing this mod when I had my Agency Power mufflers but ultimately sold them and now have the Tubi's.
I've also contemplated on just gutting the stock cans as others have reported some weight savings doing that, but I was concerned that I might get highway droning as well.
If you're finding the levels still too quiet for your tastes, many have reported additional sound gains by replacing the stock cats.
I'm going to be using my Tubi's with aftermarket crossover pipes and hoping it will be a good balance without being "too loud".
I've also contemplated on just gutting the stock cans as others have reported some weight savings doing that, but I was concerned that I might get highway droning as well.
If you're finding the levels still too quiet for your tastes, many have reported additional sound gains by replacing the stock cats.
I'm going to be using my Tubi's with aftermarket crossover pipes and hoping it will be a good balance without being "too loud".
#9
Hi alpine003
I have also been considering getting race cats but the darn things are so freaken expensive. If i come accross some used ones that i can pick up for a few hundered bucks i think ill go with that.
I have also been considering getting race cats but the darn things are so freaken expensive. If i come accross some used ones that i can pick up for a few hundered bucks i think ill go with that.
#10
I guess you can always hack up your stock cats and replace them but then you still have the pipe bends and such that is still not optimal.
This site lists them under $200 each so for a Porsche system, you're probably paying close to $1000 for the piping/bung holes/flanges by my calculations.
Edit: Forgot to include link: http://www.mil-spec.org/2.5-200-Cell-Weld-In-Cat.html