[TheOldGuy]

Have a good look at the pictures. What this is, Is a small weight swedged into a bracket and welded to the factory pipe on a 2014 Dodge Ram pickup truck. This is a factory setup. We removed the stock pipe between the Y pipe and the muffler to install an exhaust cutout. It works, but with the cutout closed, now there is a drone that was not there before just like you get when you install Blastin Bob's Resonator delete on an RT Challenger.

Well now... WTF is going on? After doing much research, I found out that without this weight hanging on the pipe, the standard exhaust will start to drone and drive you crazy. Why? This is because the Hemi engine sets up a sort of vibration in the pipes that can only be quelled bu the addition of the attached weight. Because of the particular mass of the weight, it cannot resonate at the same frequency as the pipes and therefore cancels the vibration.

I looked at another truck with a 6.4 on a new car dealer's lot and it has the same thing, just set up a little different.

I am in the process of creating a duplicate weight setup to weld to the rear pipes on my Challenger and install them just ahead of the glass-pack resonators on my Blastin Bobs pipes.

I will let you all know the outcome. Stay tuned...

-John

 

[jackal]

Subscribed.

 

[stig]

Interesting...I will stay tuned.

 

[2014core]

Very interested as well

 

[BAD GRANDPA]

Me too^^^

 

[beas62]

:smileup:Subscribed.

 

[hellsfire]

ok now i am looking at this post as well

 

[Darth]

Really cool, nice post.

Seems like such an afterthought, I wonder why they don't simply make one side of the pipes heavier so the thing cant vibrate uniformly.

What do I know, I make logos.

 

[Home Theater Guy]

That would solve a lot of issues for the automatic folks and open the doors for more brand purchases all around.

 

[ply67cuda]

Alright John - we are all waiting with bated breath! I am especially interested because my drone is fierce after I changed motors out!!!!

 

[TheOldGuy]

Alright John - we are all waiting with bated breath! I am especially interested because my drone is fierce after I changed motors out!!!!

I'm waiting for my garage propane heater to get fixed. They can't seem to find the correct limit switch for this unit. (It's really old) They don't want to take the responsibility of adapting a new model switch and simply modifying the bracket to hold it in place. They seem to have no engineering skills whatsoever. I'm too old to lay down on garage floors in the Winter anymore.
I have all the parts I need to weld on the Challenger. It's really cold up here in Maine.

-John

 

[Scat Pack]

Normally, drone is created due to exhaust resonance at particular frequencies in the system . The weight apparently counters drone akin to muffling a small bell by grasping it with your hand after chiming it.

 

[dz302]

Subscribed...

 

[ply67cuda]

I am wondering is there is a quick way to test this. I drone between 1500-1900 with my new motor. I am thinking I can take a pipe wrench weighing about 2 pounds and just clamp it onto the exhaust just tight enough so it does not fall off and let it hang there. Then start the car and raise the RPMS to the drone range and see what happens (although I suppose I will need a wrench on each pipe...)

 

[InfernoTim]

Subscribed!

 

[HemiMetal]

I am wondering is there is a quick way to test this. I drone between 1500-1900 with my new motor. I am thinking I can take a pipe wrench weighing about 2 pounds and just clamp it onto the exhaust just tight enough so it does not fall off and let it hang there. Then start the car and raise the RPMS to the drone range and see what happens (although I suppose I will need a wrench on each pipe...)

Andres, I think your results might be less than optimal. Chrysler chose to weld that bracket along 2 fins when it would have been easier and cheaper to clamp the bracket on, so I figure that the length and thickness of the fins has a lot to do with dissipating the drone resonance, as do those large metallic "buttons" which probably serve to arrest the vibrations.

But since I'm not a mechanical engineer, my post is nothing but pure speculation. It certainly wouldn't hurt to give it a try. :smileup:

 

[chizzle1]

subscribed. my drone at cold start is severe.

 

[jklotz10]

This almost sounds like the 'fix' they used to subdue the whine folks with the TR-6060 manual trans had. They installed a mass damper kit on the rear cradle.

http://www.challengerforumz.com/showthread.php?t=83854&highlight=whine+rear

 

[Matt W]

I have to imagine that anything that reduces vibration would in fact reduce the drone issues. Even an extra clamp or two would reduce resonance much like a drummer grabbing a cymbal to quieten it...

Don't have any bad drone issues with current set up but interested just the same..

 

[BAD GRANDPA]

Alright John - we are all waiting with bated breath! I am especially interested because my drone is fierce after I changed motors out!!!!

Just curious. Did you use the solid steel motor mounts?