2004 6.0 NV4500 Tahoe

[Dantheman1540]

I usually just call them when the app won't let me do something.

Call them what Facktards?

ive got a 5.5>6" silicone coupler i needed to put

even if i did - i wouldnt take advice from me

Good advice

Canadian heritage. I like it. Sadly, I'm not fluent in the metric system


I'm no help in that department.

I'd make a cardboard template and use that as a guide then trim to fit so you aren't welding up a big gap.

Ewww don't tell people about that canadian thing

 

[randeez]

Call them what Facktards?

Good advice

Ewww don't tell people about that canadian thing

i dont need the coupler anymore, cause i had a 5.5 to 5.5 coupler that i stretched over the 6" velocity stack - nearly poked my eye out tho. i had the stack on my belly, the coupler went on like 5/8 of the way so i was prying it on the rest of the way with some screw drivers like i was getting a tire over the bead, one slipped and screwdriver poked me about 1/4" (6mm) between my eye and bridge of my nose. at the time it hurt like a sonofabitch and i slammed my eye shut cussed for about 2 mins afraid to open my eye in fear that i just wouldnt be able to see. but i still have both eyeballs

 

[George B]

Anyone have a good way I can fish mouth this 3" pipe to fit the hole I cut into the 4" exhaust? I don't mind getting wild with the grinder but a template would be sweet.

What kind of angle you coming in at?

 

[George B]

How about this?

Online tube notching calculator

www.jockeyjournal.com

 

[Dantheman1540]

How about this?

Online tube notching calculator

www.jockeyjournal.com

Your the man! I should be coming in at a 90* as that is supposed to be the most effective.

That should be a sticky somewhere

 

[pwtr02ss]

How about this?

Online tube notching calculator

www.jockeyjournal.com

Some useful info that this thread needed. I like it

 

[iamdub]

So let me ask you this if someone straight piped their truck and decided to just make multiple J tubes of different lengths would it be tame enough to drive or does it only effect the drone persay?

Drone is just an exhaust sound, which is a resonance. Drone is the term given to that sound which we find offensive since it's so prevalent instead of smoothly blending in with the rest of the exhaust notes. It's a particular sound wave (frequency) that resonates in just a way that it pierces the cabin floor and maybe even vibrates other pieces, adding to the offensiveness. The Helmholtz chamber(s) very effectively cancel out those offending sound frequencies since they target them. So, if you had a bunch of them to attack a range of frequencies, then, yes, you could very effectively muffle your exhaust volume. You could fine-tune it to cancel out all the lows and pass the highs and make it sound like a weedeater or cancel the highs and make it have a deep rumble. Your average chambered muffler (stock or aftermarket) has a bit of a Helmholtz effect by design. They typically break up the sound waves while reflecting them. A packed muffler is designed more to absorb all the sound waves to attenuate them rather than to reflect them onto themselves to cancel them. A lot of mufflers use both methods. Different sound absorption materials and amounts (usually determined by length and size of muffler) will determine what frequencies are absorbed the most and how much they're absorbed. A resonator's purpose is to attack any "stray" and unwanted frequencies that the muffler wasn't capable of attenuating.

 

[Dantheman1540]

Drone is just an exhaust sound, which is a resonance. Drone is the term given to that sound which we find offensive since it's so prevalent instead of smoothly blending in with the rest of the exhaust notes. It's a particular sound wave (frequency) that resonates in just a way that it pierces the cabin floor and maybe even vibrates other pieces, adding to the offensiveness. The Helmholtz chamber(s) very effectively cancel out those offending sound frequencies since they target them. So, if you had a bunch of them to attack a range of frequencies, then, yes, you could very effectively muffle your exhaust volume. You could fine-tune it to cancel out all the lows and pass the highs and make it sound like a weedeater or cancel the highs and make it have a deep rumble. Your average chambered muffler (stock or aftermarket) has a bit of a Helmholtz effect by design. They typically break up the sound waves while reflecting them. A packed muffler is designed more to absorb all the sound waves to attenuate them rather than to reflect them onto themselves to cancel them. A lot of mufflers use both methods. Different sound absorption materials and amounts (usually determined by length and size of muffler) will determine what frequencies are absorbed the most and how much they're absorbed. A resonator's purpose is to attack any "stray" and unwanted frequencies that the muffler wasn't capable of attenuating.

Very well said and thank you for the detailed response! Now my next questions is, if I make a single long tube and decide it needs another pipe of smaller length can I T directly off the existing J tube and create another smaller J tube? Obviously taking into account the extra length added depending on the position I would T into.

 

[Dantheman1540]

Got some time tonight to play with J pipe location and chopped the remainder of the spare tire bracket out. There's plenty of room now and it will all be way tucked up out of sight. Also ended up using the old bracket to cut the end cap for the j tube since I was having trouble finding any on Amazon.

Lastly my 408 Denali buddy came over and we practiced Bozozuko or whatever it's called with the crazy exhausts lol.

 

[iamdub]

Very well said and thank you for the detailed response! Now my next questions is, if I make a single long tube and decide it needs another pipe of smaller length can I T directly off the existing J tube and create another smaller J tube? Obviously taking into account the extra length added depending on the position I would T into.

Interesting thought! But, it don't think it works that way. Or maybe it does? I guess if the other tube was targeting a widely different frequency, it'd work. Although, I'm inclined to think the resonator on a resonator would likely disrupt the movements of the waves in each tube and make both less effective. Besides, why would you branch off of one J-tube when you could just branch another J-tube off of the main trunk line?

 

[Dantheman1540]

Interesting thought! But, it don't think it works that way. Or maybe it does? I guess if the other tube was targeting a widely different frequency, it'd work. Although, I'm inclined to think the resonator on a resonator would likely disrupt the movements of the waves in each tube and make both less effective. Besides, why would you branch off of one J-tube when you could just branch another J-tube off of the main trunk line?

limited space to put a branch off the main exhaust where it's 4" and I really don't want to have to do two equal length pipes on up at the Y pipe area. I don't think it's necessary but for conversation's sake, I thought it was an interesting point. I am so excited to hear this thing with the J pipe I can hardly wait!

 

[Dantheman1540]

I used that spectroid app the guy in the video suggested and got exactly what his excel spreadsheet guessed, 100hz at 1,500rpm. which means a 42" J tube, it's so odd the drone totally clears up at 1,700-2,050 but at 2,100 it creeps back just not as bad as at 1,500. Hopefully the 42" pipe will help at the higher rpm as well, I do have an idea to make a slip fitting and play with length a tad so that will be fun.

 

[pwtr02ss]

I used that spectroid app the guy in the video suggested and got exactly what his excel spreadsheet guessed, 100hz at 1,500rpm. which means a 42" J tube, it's so odd the drone totally clears up at 1,700-2,050 but at 2,100 it creeps back just not as bad as at 1,500. Hopefully the 42" pipe will help at the higher rpm as well, I do have an idea to make a slip fitting and play with length a tad so that will be fun. View attachment 344840

An exhaust trombone. Nice!

 

[George B]

An exhaust trombone. Nice!

Add a cable to control it....

 

[pwtr02ss]

Add a cable to control it....

Power window motor, change notes as you drive...


Here Dan is being all serious and I come in and joke up the thread.

The adjustable thing is a pretty damn good idea. All you to fine tune with minimal effort and then when you get it where you want, just welder-up

 

[Dantheman1540]

It won't be that adjustable! I just happen to have some 3" couplers, so I am going to fish mouth one and weld it directly to the pipe that way I can simply clamp on my J tubes and see how they sound. That way I can make the long 42" and I think I will have enough left over for a 24-32" which is about what I'd need to target the 2,100 rpm drone. It will be fun to collect some data on this and prove this theory to myself. I also have room for an additional pipe down the side of the Gibson so I'm sorta preparing for the possibility of a second pipe.


@iamdub What do you think about adding a pipe to the side of a muffler? The Gibson is not much more than a box with some tubular louvered baffles that IMO don't do a whole lot. I think space-wise it would be cake to add some different length tubes down the side of it tight hugging the case. Just not sure if the turbulence from the louvers would disrupt the sound waves (Probably the whole point to the design) and cause the wave length calculation to be off or less effective.

 

[randeez]

you guys are making my 3" longer with all this sciencey talk

 

[pwtr02ss]

you guys are making my 3" longer with all this sciencey talk

Such a tease

 

[Dantheman1540]

I really want that lab coat I was talking about a few weeks ago because it will double as a flasher coat.

 

[George B]

I really want that lab cot I was talking about a few weeks ago because it will double as a flasher coat.

Like this?