Yet another PSE style exhaust mod
03-04-2007, 01:46 AM
#1
Yet another PSE style exhaust mod
The 996 is an awesome machine, but many of us long to have a more aggressive exhaust note while at the same time keeping the tone reasonable. Last year for a few track days I removed the mufflers and fabricated some slash-cut 3" polished tips. The sound going down the main straight at NHIS was heaven, but it was barely streetable and my wife refused to ride in the car. 
So I wanted to do a modification that would sound similar to the PSE - either mkI or mkII.
I decided to go with the mkI style where a small bypass pipe is cut in, between the inlet and outlet of the muffler. Searches on the forum will reveal a lot of detail on the PSEs and other similar mods for comparison. I went with a larger and more direct design for the bypass using 1-1/4" 304 SS U-bend tube obtained from Classic Tube below:
Classic Tube 1-800-882-3711
http://classictube.com/
Item #65-180-125-20
Part: 16 Gage - .065" Wall
Description: 180º "U" Bend 2" Radius Legs 6" x 6"
Make/Type: 304 Stainless Steel
Model/Size: 1-1/4"
The U-bend tube was about $30 and cutting it in half produces stock of the appropriate size for each muffler. After laying out the best location to minimize clearance issues, the two tightest being the header-cat flange and the chassis, I used a hole saw with a 1/4" center guide to cut the openings. After a bit of fitting to shape the openings and the tube ends, I welded in place.
I'm pleased with the end result, both from the standpoint of the modification and the resulting sound. The exhaust really comes alive with a nice rumble and a bit of a bark when tapping the throttle. Being in the northeast, I have not had the opportunity to bring it out on the road yet, but hope to in the next few weeks.
I have attached before and after sound clips and pictures of the steps in the fabrication. Hopefully the quality of both will be adequate as I only used my treo to record the clips and photos.
-Wayne
So I wanted to do a modification that would sound similar to the PSE - either mkI or mkII.I decided to go with the mkI style where a small bypass pipe is cut in, between the inlet and outlet of the muffler. Searches on the forum will reveal a lot of detail on the PSEs and other similar mods for comparison. I went with a larger and more direct design for the bypass using 1-1/4" 304 SS U-bend tube obtained from Classic Tube below:
Classic Tube 1-800-882-3711
http://classictube.com/
Item #65-180-125-20
Part: 16 Gage - .065" Wall
Description: 180º "U" Bend 2" Radius Legs 6" x 6"
Make/Type: 304 Stainless Steel
Model/Size: 1-1/4"
The U-bend tube was about $30 and cutting it in half produces stock of the appropriate size for each muffler. After laying out the best location to minimize clearance issues, the two tightest being the header-cat flange and the chassis, I used a hole saw with a 1/4" center guide to cut the openings. After a bit of fitting to shape the openings and the tube ends, I welded in place.
I'm pleased with the end result, both from the standpoint of the modification and the resulting sound. The exhaust really comes alive with a nice rumble and a bit of a bark when tapping the throttle. Being in the northeast, I have not had the opportunity to bring it out on the road yet, but hope to in the next few weeks.
I have attached before and after sound clips and pictures of the steps in the fabrication. Hopefully the quality of both will be adequate as I only used my treo to record the clips and photos.
-Wayne
Last edited by waynesworld; 03-04-2007 at 01:58 AM. Reason: Added Attacments
03-04-2007, 07:58 AM
#2
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Wayne - Good job! It sounds great! 
Very similar in sound to the PSE MK II on 3.6L mufflers. It is certainly better sounding than the PSE MKII on 3.4L mufflers.
Very similar in sound to the PSE MK II on 3.6L mufflers. It is certainly better sounding than the PSE MKII on 3.4L mufflers.
03-04-2007, 08:37 AM
#4
I used the original 3.4 mufflers on my 2000 C2. I think the increased diameter and more direct route (as compared to the mkI PSE style) helps make the tone a bit more throaty. It is also relatively easy to do once the design was determined. Being able to purchase the mandrel bent tubing also helps simplify the fab.
-Wayne
-Wayne
03-04-2007, 05:32 PM
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That sounds amazing! How does the car sound when it is not accellerating? I am very tempted to do the mod but I want it to remain a daily driver yet sound throaty when I accel.
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03-05-2007, 01:31 AM
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Originally Posted by Tool Pants
This has come a long way from the original design.
I love the "On/Off Switch" on the original design!
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03-05-2007, 10:31 AM
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This mod is very akin to what the C5 Vettes are doing. It was the best sounding mod at a fraction of the price of aftermarket systems.
And you have done a great service in recommending a place to get a hold of the by-pass tubes.
You could make a business out of pre-cutting them and selling them. Several vendors have on the Vette side.
And another business can be buying up take-off cans and modding them and selling them with a core exchange.
Just in case, how much would you charge to apply the mod to my original cans sitting in the attic?
And you have done a great service in recommending a place to get a hold of the by-pass tubes.
You could make a business out of pre-cutting them and selling them. Several vendors have on the Vette side.
And another business can be buying up take-off cans and modding them and selling them with a core exchange.
Just in case, how much would you charge to apply the mod to my original cans sitting in the attic?
03-05-2007, 08:00 PM
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Can you put out a sound bite of what the car sounds like INSIDE the car during normal driving and also one while driving the car all out? I am still not sure if this is a mod that I can live with during every day driving. 
03-05-2007, 11:09 PM
#14
ToolPants, that original dsign certainly set the bar in creative use of plumbing supplies. 
Melchior, unfortunately I have not had the car out to try it because of the salt covered roads around here. I will be sure to post the results and sound bite when I do. I can't wait to hear it under load as I have high expectations based on the sound so far in the shop.
PorschePRH, the fabrication is fairly simple using the mandrel bent tubing. I would expect that a local muffler shop could do the job if supplied with the pictures and the tubing. I just don't have the time to go into production. To busy dreaming up other mods!
-Wayne
Melchior, unfortunately I have not had the car out to try it because of the salt covered roads around here. I will be sure to post the results and sound bite when I do. I can't wait to hear it under load as I have high expectations based on the sound so far in the shop.
PorschePRH, the fabrication is fairly simple using the mandrel bent tubing. I would expect that a local muffler shop could do the job if supplied with the pictures and the tubing. I just don't have the time to go into production. To busy dreaming up other mods!
-Wayne
03-10-2007, 04:19 PM
#15
Added new sound clips as requested
It finally warmed up and the roads were clear enough to bring her out for a test drive of the PSE mod described above. All I can say is it rocks! 
The sound is perfect -imho- with just the right tone and sound level. I did not detect any drone or vibrations. It is exactly as I hoped it would turn out as the mod accentuates the sound when you are accelerating, but much less so when at constant speed. I wish I had thought to grab some sound clips while driving before the mod for comparison, but ...
I have attached three additional sound clips; one with windows down and stationary, one windows down and driving, and one windows up and driving. The windows down recordings are with my treo held up to the driver's side window and for the windows up recording I put the treo on the rear seat back folded down.
I hope this is helpful to those considering doing the mod - a flat6 symphony awaits.
-Wayne
The sound is perfect -imho- with just the right tone and sound level. I did not detect any drone or vibrations. It is exactly as I hoped it would turn out as the mod accentuates the sound when you are accelerating, but much less so when at constant speed. I wish I had thought to grab some sound clips while driving before the mod for comparison, but ...
I have attached three additional sound clips; one with windows down and stationary, one windows down and driving, and one windows up and driving. The windows down recordings are with my treo held up to the driver's side window and for the windows up recording I put the treo on the rear seat back folded down.
I hope this is helpful to those considering doing the mod - a flat6 symphony awaits.
-Wayne