Okay. I've been around long enough to know that back pressure is no good and gas velocity is the key to a better performing exhaust, but I've been thinking (uh-oh) and I have a question regarding this principle.

Suppose you had two exhasut systems. Both are 2.5" ID (for NA applications). Both systems are identical with one exception: one system has a single 36" glass pack resonator, the other a 36" and a 24" in line. Now the length of the glass pack is not important. The question is will the system with the additional length of piping that runs through a perforated core in the glass pack have a lower gas velocity than the other, thereby lower performance? Or will they be similar, if not identical?

I'm asking as I'm pretty sure that, the more resonated (perforated) piping the exhaust blows through, the quieter the exhaust will be, but I wonder if it will result in a noticeable decrease in power output?

the velocity would be less in the system with two glass packs, but it shouldn't make any kind of noticeable difference

Originally posted by DR1665
Okay. I've been around long enough to know that back pressure is no good and gas velocity is the key to a better performing exhaust, but I've been thinking (uh-oh) and I have a question regarding this principle. Suppose you had two exhasut systems. Both are 2.5" ID (for NA applications). Both systems are identical with one exception: one system has a single 36" glass pack resonator, the other a 36" and a 24" in line. Now the length of the glass pack is not important. The question is will the system with the additional length of piping that runs through a perforated core in the glass pack have a lower gas velocity than the other, thereby lower performance? Or will they be similar, if not identical? I'm asking as I'm pretty sure that, the more resonated (perforated) piping the exhaust blows through, the quieter the exhaust will be, but I wonder if it will result in a noticeable decrease in power output?

There actually isn't a definite answer to your question.. Here's why. Sound frequencies travel in pulses from the cylinders firing within the exhaust gases.(think of it as blowing through a straw while humming and placing your hand at one end) As the exhaust gases exit rearward, the frequencies want to osolate up and down. If there isn't an opening to disipate the frequency effectively as it expands around the pipe, the frequency will stay contained within the pipe and create a resonant tone. This is why a second resonantor would be used. (to cut down on boom/sound) However, as the sound pulses expand, the exhaust gases will still travel in a linear motion and will not actually enter the perforated section...(flow should still be the same) Yet, this is ONLY if the system is the same diameter all the way through with an EFFICIENT RESONATOR DESIGN that does not have anything "cupped" into the exhaust path. I hope this is of help, however if you want more insight www.corsaperf.com .. this is what I do every day. ;)

Santiago



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know me as santiago
boosted 420a and ej2o..(my 2liter v8 eaters)

Excellent info. I think I might just do the twin resonator thing when I build my exhaust this spring. }(

If any of you play paintball, you know that spiral ported barrels help release the gas faster, thus shooting the ball faster,straighter, etc. I wonder if you could spiral port a catback. On cold mornings u would have a sideways tornado coming from your exhaust....lol :scratch

The spiral cuts on the barrel of a gun are to control the spin of the projectile (bullet or paint). By spinning the projectile parallel to the path of movement, you get consistant accuracy. The bullet doesn't spin up and down allowing the bullet to sink or rise at a faster rate than normal.

But they do make spiral core resonators.



Exile Racing Technologies: http://www.exileracing.com
una salus victus
It's holding down the garage floor right now.

Originally posted by DR1665
Excellent info. I think I might just do the twin resonator thing when I build my exhaust this spring. }(

only if the second resonator is designed to cancell the original resonators frequency will it not slow velocity otherwise the single glasspack would be better *but not noticeable*

Originally posted by Skrilla
only if the second resonator is designed to cancell the original resonators frequency will it not slow velocity otherwise the single glasspack would be better *but not noticeable*

So is this to say if I bought 2 of the Cherry Bomb glass packs, they wouldn't cancel each other out? How do you know if they cancel out the frequency? Thanks!