Stop the Drone - Helmholtz Style

[outlaw2]

Originally Posted by orange-prince

what the hell is this !!!

Yes officer those are "Bongs" hanging from my car and they only have "HP" resin in them...test em if you must but I'm telling the truth

[MillerTime]

Originally Posted by SSTony

What is the overall length of your pipes?

I believe his are 28" as well. Just a straight shot. Only Down side to them being up front is haveing to move them to drop the transmission... but that's not big deal really. Either way 28" seems to bee the sweet spot on length. 0 drone with that... The shop did mine for 60 bucks... 30 for materials and 30 for labor.. decent price if you ask me..

[Inferno LSX]

What's up with everyone talking about the length of their pipe? I thought the longer the better! Lol

[Roger Ramjet]

Here are the calculations again. This time I included the V6.

Drive the car and find the worst drone RPM. Use that RPM in the table below to see suggested pipe length in inches. Interpolate as necessary.

[gatorlover]

I'm going today to have some pipes put on to try and eliminate the drone I get from my borla "s" type catback. I'll be using 28 inch pipes. I'll take pictures to share with everyone and let you know how it works.

[gatorlover]

Ok, guys, here's more proof this really works.

I have a ss a6 with a k&N cai and a borla "s" type catback. I "HAD" a pretty bad drone in the 1600-2000 rpm range when the car was under load or cruisin on the highway around 70. Following the guidance of all the great info in this thread I went to the local muffler shop with pictures and info from this thread in hand.(actually just brought my laptop.)
They were a little skeptical at first but, after talking with them and showing all the info, they said they would give it a go for 120 bucks. I agreed, and off they went. When they put the car on the lift, I snapped a few pics of the stock axle back portion just for reference. Not a whole lot of room to work with. We used 2 1/4" pipe and the length goal was 28".

Again the first 3 pics are just my borla catback shots.




The next 3 are of the end result. These are not the best because I was using my cellphone. The shop I used didn't have a mandrel machine so we improvised a little. The thought here was, it's not so much the shape but the length that is really important. The location that was used is completely hidden when looking at the car from the rear. They tucked up nicely behind the borla mufflers.




So I went for a test drive and used the paddle shifters to get the car in 4th gear and slowed down so when I gave it gas the rpm's were around 1500 to load the engine. This is where I usually get the drone. Sure enough, it was gone. all the way through 2000 rpm's, no drone!!!!! I then hit the interstate and got it up to cruising speed around 68-70 mph and it was really quiet, no drone!!!!

One thing I will say is that it does, very slightly, quiet the overall exhaust tone down maybe 2-4 decibals at idol, which is really not that bad. You don't lose the growl when you get on it.

So there you have it. More proof this works! Thanks to everyone that contributed to this thread!

[Mark Myles]

Thank you for taking the time to post pics and share your experience with the rest of us.... I for one greatly appreciate it!

Now I feel comfortable enough to purchase headers with the confidence of deleting the drone.

M

[Padre]

This thread delivers.


Padre

[BigRed585Lbs]

The heavens rejoice when another believer enters the fold. This is one time when "We told you so" is appropriate and not meant to put anyone down. Welcome, and go out and drive some more!

[BigRed585Lbs]

Can I get a "bump"?

[Darth Martel]

hopefully I'll be taking my Camaro in either tomorrow or Monday to get Jpipes installed.

[inrandy]

The only thing I am unhappy with my SS is the wimpy sound. I have rode in a friends with the rear mufflers removed and the sound is okay, but I would like louder and more of a lower rumble sound.
I talked to my local exhaust shop and they say the same thing I have heard here it is hard to get a good overall sound with the active fuel management system.
I had a 2003 Silverado SS and had the old school 40 series Flowmasters installed and the truck was the best sounding vehicle I have ever owned. It did have some drone at cruising speeds, but I was okay with it.
My last car was 2007 Daytona Charger, because it had the fuel management I had the catback Flowmaster complete system installed and was not happy with the loudness or tone.
Does this J pipe help with the sound when the active fuel management kicks in or is it only for the normal drone sound when cruising?
Because I have a slow Sat internet connection I have not read all the pages so please be kind if this has already been covered.
Thanks,
Randy

[BigRed585Lbs]

If it were me just starting out with a new car, I'd have to give Solo a shot and go for a built-up, tunable exhaust set-up. But that's just me; old and lazy.

http://www.camaro5.com/forums/showthread.php?t=133901

[mpiper]

Stupid question:

The V6 has an H-pipe before the resonators. What would happen if you were to add another similar pipe connecting the exhaust right behind the rear gears. Basically a 45 degree bend, straight pipe across and another 45. It's not a J-pipe or a Helmholtz, but would the added volume and cross-flow help reduce drone, maybe not eliminate, but maybe cut in half??

By the way, this would be on a V6, not the larger V8 engine. Just curious of what everyone thinks.