LateApex
12-09-2022, 11:26 PM
I've posted recently in a thread titled "Another comment about hearing protection" about some of my efforts to handle noise in the Coupe. I thought I would share my efforts to become a muffler engineer separately ... here
There are times when you clench your jaw and make a cut. One such time for me is when I cut the turnouts off the twin pipes. Here is a photo of that:
176560
This shows a couple things: The Borla band clamps that I am using to re-attach the turnouts after I do cruel and unusual things to the "mufflers", and how I cut the turnouts off maybe 1/4" too short. There is a bit of a flare coming off the belly of the side pipes that needs to be better considered when determining where to put an effective clamp. The clamps are first class however, and torque solves most problems, even in parts that are exposed to temperature extremes. Also maybe of note is the patina the pipes take on after 900 miles :-)
Here is a photo looking "up the tailpipe" - I hope this doesn't draw too many colorful comments ...
176561
One of the twins has not been altered. You can see in that pipe that these are as close to straight pipes as one might imagine. I imagine that not too many coupe owners have had this view ;-) I can talk about i.d., o.d. and other dimensions of this little project on request, but some of this follows anyway
The other twin has been stuffed. I contacted Ryan Westdorp at HighFlo Performance, and he sent me 4 baffles that are ~ 30" long and 2" in diameter, not including flanges at both ends. The original HighFlo design intent is to wrap the baffle with a 1/4" 12 psf ceramic cloth. This intent met reality with the fact that the turnout i.d. is ~ 2.13". There is no way to wrap a 2" baffle and stuff it into the belly of these pipes. So I turned the problem on its head. If you look carefully at this photo you can see that the i.d. of the belly is ~ 2.5". What if one inserted the ceramic material first, and then slid the baffle home?
So here is another photo of that prep:
176562
I cut the ceramic fabric to the interior length and diameter of the belly. It is fragile stuff, even if it does cut easily with a box knife. And then I "carefully" rolled it and inserted into a Mylar shipping tube that is, ... you guessed it ... 2" in diameter and let it settle. Then slid it through the tight *** end of the tailpipe until it was in the belly. A piece of ~ 2" PVC pipe was then tapered at the business end and used to press the ceramic cloth into place. This is VERY important, as the next step of sliding the baffle up the pipe is fraught with peril, such as any sharp edges or bad luck that can catch the ceramic cloth, rips it, and become a real PITA. I used some packing tape at the tip of the baffle, and even a little grease (which will smoke later when you fire the beast up ...)
In the second photo, I have successfully inserted the baffle on one of the twins.
I am also pinning the inserts / baffles with a 3/16" SS rivet. You can see this placement in the first photo (the twin without the turnout attached) if you look carefully. There is a second hole in the turnout that you should ignore. I have tried other inserts, which I can neither recommend or mention.
So, does this amount to a hill of beans, or does hacking the twin pipes produce real results?
The basic answer is yes. Using a super-sophisticated free Decibel meter on my iPhone, I have been recording sound levels. Drum roll please ...
I have 85dB measured one meter from the exhaust tips at idle. The tone is deeper and not as raw or edgy as the straight pipes.
I have purchased a "Steelie" which is a smartphone magnetic mounting ball I have installed on the tranny tunnel just North of the shifter. I have the dB meter running and am still collecting info. I was surprised to find (despite observations from others in related threads) at how loud the car is even coasting at 60 mph. I was not surprised at how loud the car is when one gets on the right foot, regardless of exhaust mods.
I like the tone better with this hack. A bit more civilized. I will still wear some hearing protection in this vehicle at all times
Thought I would share
There are times when you clench your jaw and make a cut. One such time for me is when I cut the turnouts off the twin pipes. Here is a photo of that:
176560
This shows a couple things: The Borla band clamps that I am using to re-attach the turnouts after I do cruel and unusual things to the "mufflers", and how I cut the turnouts off maybe 1/4" too short. There is a bit of a flare coming off the belly of the side pipes that needs to be better considered when determining where to put an effective clamp. The clamps are first class however, and torque solves most problems, even in parts that are exposed to temperature extremes. Also maybe of note is the patina the pipes take on after 900 miles :-)
Here is a photo looking "up the tailpipe" - I hope this doesn't draw too many colorful comments ...
176561
One of the twins has not been altered. You can see in that pipe that these are as close to straight pipes as one might imagine. I imagine that not too many coupe owners have had this view ;-) I can talk about i.d., o.d. and other dimensions of this little project on request, but some of this follows anyway
The other twin has been stuffed. I contacted Ryan Westdorp at HighFlo Performance, and he sent me 4 baffles that are ~ 30" long and 2" in diameter, not including flanges at both ends. The original HighFlo design intent is to wrap the baffle with a 1/4" 12 psf ceramic cloth. This intent met reality with the fact that the turnout i.d. is ~ 2.13". There is no way to wrap a 2" baffle and stuff it into the belly of these pipes. So I turned the problem on its head. If you look carefully at this photo you can see that the i.d. of the belly is ~ 2.5". What if one inserted the ceramic material first, and then slid the baffle home?
So here is another photo of that prep:
176562
I cut the ceramic fabric to the interior length and diameter of the belly. It is fragile stuff, even if it does cut easily with a box knife. And then I "carefully" rolled it and inserted into a Mylar shipping tube that is, ... you guessed it ... 2" in diameter and let it settle. Then slid it through the tight *** end of the tailpipe until it was in the belly. A piece of ~ 2" PVC pipe was then tapered at the business end and used to press the ceramic cloth into place. This is VERY important, as the next step of sliding the baffle up the pipe is fraught with peril, such as any sharp edges or bad luck that can catch the ceramic cloth, rips it, and become a real PITA. I used some packing tape at the tip of the baffle, and even a little grease (which will smoke later when you fire the beast up ...)
In the second photo, I have successfully inserted the baffle on one of the twins.
I am also pinning the inserts / baffles with a 3/16" SS rivet. You can see this placement in the first photo (the twin without the turnout attached) if you look carefully. There is a second hole in the turnout that you should ignore. I have tried other inserts, which I can neither recommend or mention.
So, does this amount to a hill of beans, or does hacking the twin pipes produce real results?
The basic answer is yes. Using a super-sophisticated free Decibel meter on my iPhone, I have been recording sound levels. Drum roll please ...
I have 85dB measured one meter from the exhaust tips at idle. The tone is deeper and not as raw or edgy as the straight pipes.
I have purchased a "Steelie" which is a smartphone magnetic mounting ball I have installed on the tranny tunnel just North of the shifter. I have the dB meter running and am still collecting info. I was surprised to find (despite observations from others in related threads) at how loud the car is even coasting at 60 mph. I was not surprised at how loud the car is when one gets on the right foot, regardless of exhaust mods.
I like the tone better with this hack. A bit more civilized. I will still wear some hearing protection in this vehicle at all times
Thought I would share