Flowmaster Drone on LS3

[VR Baron]

Originally Posted by Sleez

shape doesn't matter, length is where it's at, ahem!!!

it's also a good idea to make an end cap that gives you a bit of adjustment, +- an inch or two. the diameter effects the volume of air mass, and effects the usefulness a bit.

"When air is forced into a cavity, the pressure inside increases. When the external force pushing the air into the cavity is removed, the higher-pressure air inside will flow out. The cavity will be left at a pressure slightly lower than the outside, causing air to be drawn back in. This process repeats with the magnitude of the pressure changes decreasing each time.
The air in the port (the neck of the chamber) has mass. Since it is in motion, it possesses some momentum. A longer port would make for a larger mass, and vice-versa. The diameter of the port is related to the mass of air and the volume of the chamber. A port that is too small in area for the chamber volume will "choke" the flow while one that is too large in area for the chamber volume tends to reduce the momentum of the air in the port."

see more here; http://en.wikipedia.org/wiki/Helmholtz_resonance

There you go!

[BigRed585Lbs]

J-pipe shape is usually determined by what space you have available for them. Pipe diameter, in my case, was determined by what size and material tubing was available. You guys are right on with the theory you're using.

[VR Baron]

Originally Posted by ddunerider

I must be crazy I dont hear drone.....

True, you're crazy, we all know that

[PMJ]

I appreciate everyone's comments, i know this topic is covered frequenlty in this forum. 1 more question...

Has anyone successfully removed the drone from a Flowmaster American Thunder cat-back system on a LS3 using j-pipes? If so, can you post pictures?

I have found picture of successful Flowmaster Outlaw j-pips, and pictures of unsuccessful American Thunder...but yet to find a picture of a successful American Thunder j-pipe.

I'd like to make sure i have a chance of success before modifying my current system...the alternative of course to resell and go with Corsa or Solo...but i really like the American Thunder sounds...

[PMJ]

So it seems like i talked to everyone in town, and no one recommended J-pipes to fix my drone. I could not even get anyone to give me an estimate...they wouldn't even try on my dime. Finally I found a place that would give it a go...Christian and Wayne at a local Meineke Muffler on Jones Rd in Houston.

I think they thought I was crazy, but they were willing to humor me; so we started cutting and bending pipe to the specification of the Helmholtz chart...my drone was worst at 1900, so we built to 26.5" exact (see chart above).

Below i have the pictures of my j-pipe design and some install pics. We used 2.5" stainless steel pipe. I'm happy to say the drone is gone!

Christian and Wayne are now open for j-pipe business in the Houston area!
================================

Here is the J-Pipe i designed...we cut the pipe at 28.5", made the first bend ~65 degrees, and then cut 2" off the short side of the bend. The second bend is 90 degrees and at an angle to go around the muffler at an upward angle...



Muffler before:


In progress:


Final results:


Completely hidden from behind:

[Sleez]

very cool, good job, glad it worked, knew it would!!

[BigRed585Lbs]

And the beat goes on!

Let those who will cut and bend pipe have great sounding vehicles (this stuff works on anything with an exhaust and a drone problem).

Really glad it worked out for you and the muffler guys who were willing to try something "new" to them. Now they "know",too.

[Camaro_hx]

Changed my American Thunder cus of the drone and got me CORSA. Wish you had this info up before hand lol

[VR Baron]

Glad it worked. Your experiance with people looking at you as if your crazy is probably normal, most dont know about J pipes though GM uses them on our car's and others for years. I love my outlaws now, at a show yesterday two members and a new guy heard mine and want to switch from super 40's to the outlaw!

[v6sonoma]

I'm glad it worked for you. You'd think Flowmaster would just start selling them like that since it's such a problem.

[Camaro_hx]

Flowmaster's intension is to have the DRONE! lol otherwise you have other alternative exhaust systems

[BigRed585Lbs]

Two words: profit margin.