11-24-2005, 05:26 PM
[quote name='sayporsha' date='Nov 24 2005, 11:55 AM']Good thing the longitude/latitude weren't displayed on your GPS!
You Bet!
Is there a better way to cut that thing out? I'm reluctant to take a torch to mine. It would be ideal to divide the plate/perforated pipe into thirds, then cut the segments off near the flange & remove them one at a time.
[right][post="12764"]<{POST_SNAPBACK}>[/post][/right][/quote]
I was thinking about this last night and there are actually two ways to do the mod, 90% and 100%. The 90% mode would probably allow the use of a suitable hole saw to drill/cut out the diverter. Most likely the cutout would stay on the hole saw and save a lot of time trying to pull cut material out of the resonator.
The 90% route would for sure improve the gas flow in the resonator but would not increase the second chamber volume like doing the complete mod. I do think that increasing the chamber volume does benefit full throttle high RPM performance more than just cutting out the diverter. The lower the pressure in the resonator (or any muffler for that matter) the less restriction and most cases, more power. If someone were interested, they could measure the pressure in the resonator front chamber before and after by welding a fitting to the resonator can. I know the difference would be dramatic.
To cut the entire first chamber out requires additional work. I used a cutoff wheel, (actually two cutoff wheels that were ground down to fit inside the pipe, which wore them out very quickly) to make a cut in the circumference of the perforated tube in the first chamber and then an air chisel to push the tube and first chamber cap (which is welded to the perforated tube) to the back of the second chamber. From there it's pretty much a bend, cut, saw, burn process to reduce the pieces to something small enough to allow removal from the resonator inlet.
You have to realize that Porsche had very tight design constraints to muffle a very loud 4 valve high compression 4 banger. If you've ever heard an S2 or 968 engined racecar at full song, you'll know what I mean. They make a 911 with open exhaust sound streetable. Anyway, German mufflers are typically very large and there is simply no room on our cars for the usual rectangular "suitcase" sized boxes used by most German car makers. Look under a BMW or Cayenne and you'll see what I mean. The diverter was probably the only EASY way to drop the full throttle db levels without some major redesign work. I also think the power claimed by Porsche is SAE net, without an exhaust system, so this mod just moves you closer to claimed hp/tq.
I simply love the car with this modification. The engine sound is greatly improved and free revving nature of the engine is enhanced as well.
![[Image: bits.jpg]](http://i30.photobucket.com/albums/c313/sgr100/bits.jpg)
You Bet!
Is there a better way to cut that thing out? I'm reluctant to take a torch to mine. It would be ideal to divide the plate/perforated pipe into thirds, then cut the segments off near the flange & remove them one at a time.
[right][post="12764"]<{POST_SNAPBACK}>[/post][/right][/quote]
I was thinking about this last night and there are actually two ways to do the mod, 90% and 100%. The 90% mode would probably allow the use of a suitable hole saw to drill/cut out the diverter. Most likely the cutout would stay on the hole saw and save a lot of time trying to pull cut material out of the resonator.
The 90% route would for sure improve the gas flow in the resonator but would not increase the second chamber volume like doing the complete mod. I do think that increasing the chamber volume does benefit full throttle high RPM performance more than just cutting out the diverter. The lower the pressure in the resonator (or any muffler for that matter) the less restriction and most cases, more power. If someone were interested, they could measure the pressure in the resonator front chamber before and after by welding a fitting to the resonator can. I know the difference would be dramatic.
To cut the entire first chamber out requires additional work. I used a cutoff wheel, (actually two cutoff wheels that were ground down to fit inside the pipe, which wore them out very quickly) to make a cut in the circumference of the perforated tube in the first chamber and then an air chisel to push the tube and first chamber cap (which is welded to the perforated tube) to the back of the second chamber. From there it's pretty much a bend, cut, saw, burn process to reduce the pieces to something small enough to allow removal from the resonator inlet.
You have to realize that Porsche had very tight design constraints to muffle a very loud 4 valve high compression 4 banger. If you've ever heard an S2 or 968 engined racecar at full song, you'll know what I mean. They make a 911 with open exhaust sound streetable. Anyway, German mufflers are typically very large and there is simply no room on our cars for the usual rectangular "suitcase" sized boxes used by most German car makers. Look under a BMW or Cayenne and you'll see what I mean. The diverter was probably the only EASY way to drop the full throttle db levels without some major redesign work. I also think the power claimed by Porsche is SAE net, without an exhaust system, so this mod just moves you closer to claimed hp/tq.
I simply love the car with this modification. The engine sound is greatly improved and free revving nature of the engine is enhanced as well.
(This post was last modified: 11-24-2005, 05:33 PM by orphanowner.)
