The latest Buschur Racing dyno test..........a wash.
The latest Buschur Racing dyno test..........a wash.
Very interesting stuff this morning.
I have a few cars. One of which is a 1987 Turbo Buick. On this car I was running the ATR single 3" exhaust. It was LOUD. Sounded good but loud. A couple years ago I moved the muffler from the rear where they had it to where the cat is suppose to go. To my surprise this quieted the car down quite a bit.
A year later I bought a beautiful 1995 Durango Copper, AWD Eagle Talon. It also had an ATR exhaust on it when I bought it. I also moved the muffler to where the cat was and again, was surprised at how much quieter the system got.
Next up was my brothers 1940 Ford Pick up. He runs a 4g63 in the truck and I put the muffler in the middle of the truck and built a tailpipe, it is 2.5" and is SO FREAKING quiet.
This brings me, finally, to my point. I just ordered a JDM EVO9 rear bumper cover for my RS. I was thinking about building the exhaust custom for this fascia so the muffler wasn't visable after the rear bumper cover swap. Then I got to thinking about all the above situations and the quieter exhausts.
Today I did fresh DB testing of my RS and dyno'd it. (poor freaking car) After this I pulled it off the dyno, installed a new bullet muffler where the cat usually goes, built a new section for the rear to replace the old muffler and repeated the testing.
Very odd finding. First thing I thought when I started the car was WOW it is A LOT quieter. My brother said the same thing. I then put it on the dyno and got the meter out.
Before at idle (1200 rpm on my car) was 91.5 DB's.
Before at 4500 rpm was 106.6 DB's.
After at idle was 92 DB's.
After at 4500 rpm was 107 DB's.
The meter moves around a bit from the pulsing of the exhaust but the point I am making is as much as it sounds quieter the meter says it is not.
Next oddity. Dyno. The low end (under 5,000 rpm) lost power and some boost. However after 5500 rpm or so the car gained power. The two comparisons made me very "confused" and unable to choose what I wanted to do, leave it like it is now or change back. I ended up choosing to leave it as the new rear bumper cover is going to look sweet with it like it is.
I then went for a road test. Took the decibel meter with me and held it up where my head is. At 55 mph in 5th gear, cruising, the car was at 82 db's inside with the windows up. Odd again, I rolled the window down and to me it sounded quieter in the car, I could barely hear the exhaust. Decibel meter told a different story, it went up to 86 db's.
These readings seem high so before anyone jumps the gun, my car has absolutely NO sound deadener in it what-so-ever, a very stiff suspension, solid motor mounts etc. The car is loud even if I shut it off and coast.
So this was suppose to be a huge break through but with the DB's outside the car and the power being a wash I am going to call it just another Buschur Racing test. Gained some a knowledge and maybe a car that is a little quieter on the inside.
I think I am currently out of things I want to try
I have a few cars. One of which is a 1987 Turbo Buick. On this car I was running the ATR single 3" exhaust. It was LOUD. Sounded good but loud. A couple years ago I moved the muffler from the rear where they had it to where the cat is suppose to go. To my surprise this quieted the car down quite a bit.
A year later I bought a beautiful 1995 Durango Copper, AWD Eagle Talon. It also had an ATR exhaust on it when I bought it. I also moved the muffler to where the cat was and again, was surprised at how much quieter the system got.
Next up was my brothers 1940 Ford Pick up. He runs a 4g63 in the truck and I put the muffler in the middle of the truck and built a tailpipe, it is 2.5" and is SO FREAKING quiet.
This brings me, finally, to my point. I just ordered a JDM EVO9 rear bumper cover for my RS. I was thinking about building the exhaust custom for this fascia so the muffler wasn't visable after the rear bumper cover swap. Then I got to thinking about all the above situations and the quieter exhausts.
Today I did fresh DB testing of my RS and dyno'd it. (poor freaking car) After this I pulled it off the dyno, installed a new bullet muffler where the cat usually goes, built a new section for the rear to replace the old muffler and repeated the testing.
Very odd finding. First thing I thought when I started the car was WOW it is A LOT quieter. My brother said the same thing. I then put it on the dyno and got the meter out.
Before at idle (1200 rpm on my car) was 91.5 DB's.
Before at 4500 rpm was 106.6 DB's.
After at idle was 92 DB's.
After at 4500 rpm was 107 DB's.
The meter moves around a bit from the pulsing of the exhaust but the point I am making is as much as it sounds quieter the meter says it is not.
Next oddity. Dyno. The low end (under 5,000 rpm) lost power and some boost. However after 5500 rpm or so the car gained power. The two comparisons made me very "confused" and unable to choose what I wanted to do, leave it like it is now or change back. I ended up choosing to leave it as the new rear bumper cover is going to look sweet with it like it is.
I then went for a road test. Took the decibel meter with me and held it up where my head is. At 55 mph in 5th gear, cruising, the car was at 82 db's inside with the windows up. Odd again, I rolled the window down and to me it sounded quieter in the car, I could barely hear the exhaust. Decibel meter told a different story, it went up to 86 db's.
These readings seem high so before anyone jumps the gun, my car has absolutely NO sound deadener in it what-so-ever, a very stiff suspension, solid motor mounts etc. The car is loud even if I shut it off and coast.
So this was suppose to be a huge break through but with the DB's outside the car and the power being a wash I am going to call it just another Buschur Racing test. Gained some a knowledge and maybe a car that is a little quieter on the inside.
I think I am currently out of things I want to try
This is part of the reason a lot of people on here like you and respect you so much. You dont mind spending your free time testing things and sharing your results since most people cant do these tests themselves. Thanks for always helping us out.
David, very cool experiment.
There is a straightforward explanation.
While moving the muffler may not have attenuated the volume of the sound, it may have shifted the frequencies of the noise generated downward in the spectrum, to a range where they are not as noticeable to your ears.
Recently, our local transportation board performed a similar experiment involving grinding a section of highway that passed near a residential neighborhood (in an effort to quiet the highway noise).
While the absolute sound level did not change markedly (only 1-2dB as I recall), subjectively the community felt the noise had abated, because the grinding process had removed a lot of the high-frequency noise that had been getting emitted by cars passing over the rougher roadway.
This theory can be tested using a spectral analyzer, similar to the ones used to judge EQ contests in sound competitions.
Good stuff.
There is a straightforward explanation.
While moving the muffler may not have attenuated the volume of the sound, it may have shifted the frequencies of the noise generated downward in the spectrum, to a range where they are not as noticeable to your ears.
Recently, our local transportation board performed a similar experiment involving grinding a section of highway that passed near a residential neighborhood (in an effort to quiet the highway noise).
While the absolute sound level did not change markedly (only 1-2dB as I recall), subjectively the community felt the noise had abated, because the grinding process had removed a lot of the high-frequency noise that had been getting emitted by cars passing over the rougher roadway.
This theory can be tested using a spectral analyzer, similar to the ones used to judge EQ contests in sound competitions.
Good stuff.
Originally Posted by ez76
David, very cool experiment.
There is a straightforward explanation.
While moving the muffler may not have attenuated the volume of the sound, it may have shifted the frequencies of the noise generated downward in the spectrum, to a range where they are not as noticeable to your ears.
This theory can be tested using a spectral analyzer, similar to the ones used to judge EQ contests in sound competitions.
Good stuff.
There is a straightforward explanation.
While moving the muffler may not have attenuated the volume of the sound, it may have shifted the frequencies of the noise generated downward in the spectrum, to a range where they are not as noticeable to your ears.
This theory can be tested using a spectral analyzer, similar to the ones used to judge EQ contests in sound competitions.
Good stuff.
I was thinking the exact same thing. Although the sound level did not change, the frequency probably did.
-Paul
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THe key isn't necessarily the ability to hear the frequency, but the wavelength of the frequency. The frequency should not really change much since the velocity and volume of the port (exhaust) is constant. It may be related to the fact that ther pressure is more consistent when the muffler is further from the exit. Moving the frequency down an octave would double the distance that the sound wave would complete and be heard.
I could sample volume at 4 distances simultaneously with my test equipment but I would rather not subject the $750 mics to the heat and soot coming from a tail pipe.
I could sample volume at 4 distances simultaneously with my test equipment but I would rather not subject the $750 mics to the heat and soot coming from a tail pipe.
ok maybe this is offtopic and im not trying to me mean in anyway but, Y THE HELL DOES UR BROTHER RUN A 4G63 IN HIS 1940 FORD PICKUP????? im sorry but that just seems assinine to me.
David,
Any chance you could try using one of these "spectral analyzers?"
It would be awesome if it allowed the bullet to be less "noisy" to law enforcement.
I think you could even just hook up a microphone to your computer and record the sound that way. Then you, or some one on this board, can use software to do the rest.
Any chance you could try using one of these "spectral analyzers?"
It would be awesome if it allowed the bullet to be less "noisy" to law enforcement.
I think you could even just hook up a microphone to your computer and record the sound that way. Then you, or some one on this board, can use software to do the rest.
I don't have a spectrum analyzer, don't even know what it is The sound coming from the car is definetely different than it was.
deadbeattrec,
Well everyone is entitled to their opinion. He could have used a small block Chevy like everyone else does, made a bunch of noise and gotten 10 mpg. Instead he used the 4g63 that we make our living from gets 27 mpg, has cruise control and a/c and is the fastest of all of our streetrods on the highway. I built a 1949 KB2 International pick up, no a/c, no power steering, 462 cu. in. Big Block Buick, from a 55 mph roll he kicks my ***. Really ticks me off. I get 10 mpg at best.
I went back and printed the dyno sheet off from this testing.
From 3000 rpm to 4500 rpm there is at most at any point a 5 whp loss, if that much. From 4500 to 5800 rpm the two lines are identical. After 5800 rpm moving the muffler to the center of the car improved power all the way to 7,000 rpm. At 7,000 rpm the power is up about 7-8 whp.
As I said, a wash more or less. It sure is going to look good from the rear though.
The other good side of this is the cops. I think it is getting more common for them to look for cats. The cat is always under the center of the car. If they look now it is going to appear to have a cat on it. I'd rather get hassled for no muffler than no cat
Another very interesting test I am thinking of getting off my butt and doing (and I thought I was done testing just a few posts ago) is to take the bullet muffler I removed from the back and put it back on and re-dyno the car. It would be interesting to see how much quieter it gets and if it looses power. I don't think it is going to drop power as in other testing the car makes as much or more with the bullet muffler on than it does with an open exhaust.
The sound coming from the car is definetely different than it was.deadbeattrec,
Well everyone is entitled to their opinion. He could have used a small block Chevy like everyone else does, made a bunch of noise and gotten 10 mpg. Instead he used the 4g63 that we make our living from gets 27 mpg, has cruise control and a/c and is the fastest of all of our streetrods on the highway. I built a 1949 KB2 International pick up, no a/c, no power steering, 462 cu. in. Big Block Buick, from a 55 mph roll he kicks my ***. Really ticks me off. I get 10 mpg at best.
I went back and printed the dyno sheet off from this testing.
From 3000 rpm to 4500 rpm there is at most at any point a 5 whp loss, if that much. From 4500 to 5800 rpm the two lines are identical. After 5800 rpm moving the muffler to the center of the car improved power all the way to 7,000 rpm. At 7,000 rpm the power is up about 7-8 whp.
As I said, a wash more or less. It sure is going to look good from the rear though.
The other good side of this is the cops. I think it is getting more common for them to look for cats. The cat is always under the center of the car. If they look now it is going to appear to have a cat on it. I'd rather get hassled for no muffler than no cat
Another very interesting test I am thinking of getting off my butt and doing (and I thought I was done testing just a few posts ago) is to take the bullet muffler I removed from the back and put it back on and re-dyno the car. It would be interesting to see how much quieter it gets and if it looses power. I don't think it is going to drop power as in other testing the car makes as much or more with the bullet muffler on than it does with an open exhaust.
Originally Posted by davidbuschur
deadbeattrec,
Well everyone is entitled to their opinion. He could have used a small block Chevy like everyone else does, made a bunch of noise and gotten 10 mpg. Instead he used the 4g63 that we make our living from gets 27 mpg, has cruise control and a/c and is the fastest of all of our streetrods on the highway. I built a 1949 KB2 International pick up, no a/c, no power steering, 462 cu. in. Big Block Buick, from a 55 mph roll he kicks my ***. Really ticks me off. I get 10 mpg at best.
Well everyone is entitled to their opinion. He could have used a small block Chevy like everyone else does, made a bunch of noise and gotten 10 mpg. Instead he used the 4g63 that we make our living from gets 27 mpg, has cruise control and a/c and is the fastest of all of our streetrods on the highway. I built a 1949 KB2 International pick up, no a/c, no power steering, 462 cu. in. Big Block Buick, from a 55 mph roll he kicks my ***. Really ticks me off. I get 10 mpg at best.
Originally Posted by PA-silver03evo
This is part of the reason a lot of people on here like you and respect you so much. You dont mind spending your free time testing things and sharing your results since most people cant do these tests themselves. Thanks for always helping us out.
Originally Posted by davidbuschur
I don't have a spectrum analyzer, don't even know what it is The sound coming from the car is definetely different than it was.
deadbeattrec,
Well everyone is entitled to their opinion. He could have used a small block Chevy like everyone else does, made a bunch of noise and gotten 10 mpg. Instead he used the 4g63 that we make our living from gets 27 mpg, has cruise control and a/c and is the fastest of all of our streetrods on the highway. I built a 1949 KB2 International pick up, no a/c, no power steering, 462 cu. in. Big Block Buick, from a 55 mph roll he kicks my ***. Really ticks me off. I get 10 mpg at best.
I went back and printed the dyno sheet off from this testing.
From 3000 rpm to 4500 rpm there is at most at any point a 5 whp loss, if that much. From 4500 to 5800 rpm the two lines are identical. After 5800 rpm moving the muffler to the center of the car improved power all the way to 7,000 rpm. At 7,000 rpm the power is up about 7-8 whp.
As I said, a wash more or less. It sure is going to look good from the rear though.
The other good side of this is the cops. I think it is getting more common for them to look for cats. The cat is always under the center of the car. If they look now it is going to appear to have a cat on it. I'd rather get hassled for no muffler than no cat
Another very interesting test I am thinking of getting off my butt and doing (and I thought I was done testing just a few posts ago) is to take the bullet muffler I removed from the back and put it back on and re-dyno the car. It would be interesting to see how much quieter it gets and if it looses power. I don't think it is going to drop power as in other testing the car makes as much or more with the bullet muffler on than it does with an open exhaust.
The sound coming from the car is definetely different than it was.deadbeattrec,
Well everyone is entitled to their opinion. He could have used a small block Chevy like everyone else does, made a bunch of noise and gotten 10 mpg. Instead he used the 4g63 that we make our living from gets 27 mpg, has cruise control and a/c and is the fastest of all of our streetrods on the highway. I built a 1949 KB2 International pick up, no a/c, no power steering, 462 cu. in. Big Block Buick, from a 55 mph roll he kicks my ***. Really ticks me off. I get 10 mpg at best.
I went back and printed the dyno sheet off from this testing.
From 3000 rpm to 4500 rpm there is at most at any point a 5 whp loss, if that much. From 4500 to 5800 rpm the two lines are identical. After 5800 rpm moving the muffler to the center of the car improved power all the way to 7,000 rpm. At 7,000 rpm the power is up about 7-8 whp.
As I said, a wash more or less. It sure is going to look good from the rear though.
The other good side of this is the cops. I think it is getting more common for them to look for cats. The cat is always under the center of the car. If they look now it is going to appear to have a cat on it. I'd rather get hassled for no muffler than no cat
Another very interesting test I am thinking of getting off my butt and doing (and I thought I was done testing just a few posts ago) is to take the bullet muffler I removed from the back and put it back on and re-dyno the car. It would be interesting to see how much quieter it gets and if it looses power. I don't think it is going to drop power as in other testing the car makes as much or more with the bullet muffler on than it does with an open exhaust.
Are you saying run 2 bullets?
Originally Posted by ez76
David, very cool experiment.
There is a straightforward explanation.
While moving the muffler may not have attenuated the volume of the sound, it may have shifted the frequencies of the noise generated downward in the spectrum, to a range where they are not as noticeable to your ears.
Recently, our local transportation board performed a similar experiment involving grinding a section of highway that passed near a residential neighborhood (in an effort to quiet the highway noise).
While the absolute sound level did not change markedly (only 1-2dB as I recall), subjectively the community felt the noise had abated, because the grinding process had removed a lot of the high-frequency noise that had been getting emitted by cars passing over the rougher roadway.
This theory can be tested using a spectral analyzer, similar to the ones used to judge EQ contests in sound competitions.
Good stuff.
There is a straightforward explanation.
While moving the muffler may not have attenuated the volume of the sound, it may have shifted the frequencies of the noise generated downward in the spectrum, to a range where they are not as noticeable to your ears.
Recently, our local transportation board performed a similar experiment involving grinding a section of highway that passed near a residential neighborhood (in an effort to quiet the highway noise).
While the absolute sound level did not change markedly (only 1-2dB as I recall), subjectively the community felt the noise had abated, because the grinding process had removed a lot of the high-frequency noise that had been getting emitted by cars passing over the rougher roadway.
This theory can be tested using a spectral analyzer, similar to the ones used to judge EQ contests in sound competitions.
Good stuff.
the frequency has changed to a more acceptable range for the ear.
Last edited by stevEVO8; Jul 11, 2006 at 12:56 PM.