Exhaust With High Flow PSP Downpipes

[Jramos44]

If I remember correctly Dballz/ Pinnaclebuilt said the opposite. They tone down the start up idle sound level.

They might tone it down a bit but the rpm’s on start up are so high that I’m sure the valves are open anyways. It’s my understanding that the valves are there for freeway drone.

 

[rpr]

The issue with resonators is they do nothing for the drone in terms of the frequency that causes drone they only take down the higher frequencies, trust me I know I have 4 resonators in my current set up and there’s still slight drone (livable) the way I see if if I add the valence s back in but get rid of the swished pipe under the transmission then I’d call the flow loss/gain a wash.

Did you ever pinpoint the problematic frequencies?

Also, do you or does anyone else know if MagnaFlow’s SPEQ exhaust has true Helmholtz resonators? I believe those can be designed to eliminate the lower drone related frequencies but no way to know how MagnaFlow has tuned them. They don’t use Helmoltz terminology, they refer to them as “No Drone Technology (NDT) chambers” but they sure look like Helmholtz resonators.

 

[D&Sadventure]

They might tone it down a bit but the rpm’s on start up are so high that I’m sure the valves are open anyways. It’s my understanding that the valves are there for freeway drone.

That would be easy enough to verify. Just slide under the truck at idle and look at the clock spring position. I would look at mine except for mine have been clamped open for the last 10,000 miles. The reason I clamped them was because the rattle sound they made at an idle drove me nuts. I’ll bet they open a little, maybe 25% at idle, but that’s about all.

 

[Rubodee83]

The issue with resonators is they do nothing for the drone in terms of the frequency that causes drone they only take down the higher frequencies, trust me I know I have 4 resonators in my current set up and there’s still slight drone (livable) the way I see if if I add the valence s back in but get rid of the swished pipe under the transmission then I’d call the flow loss/gain a wash.

Looks like I’ll be adding resonators lol. Took it for a spin and got on her a bit. Felt like the truck morphed into a Honda. Great power. Horrible rasp.

 

[Jramos44]

Did you ever pinpoint the problematic frequencies?

Also, do you or does anyone else know if MagnaFlow’s SPEQ exhaust has true Helmholtz resonators? I believe those can be designed to eliminate the lower drone related frequencies but no way to know how MagnaFlow has tuned them. They don’t use Helmoltz terminology, they refer to them as “No Drone Technology (NDT) chambers” but they sure look like Helmholtz resonators.

Yes frequencies were 110-120 hz mostly , I couldn’t find anyone to make me a Helmholtz resonator to fix this for me so I just settled with have a quest stock exhaust. Only problem is without the valves I now have a bit of drone it’s just livable because my exhaust is inky loud when your really getting on it. I am change to a x pipe to see if I can get away with not having the valves. Plus in all my experiences the power was much smoother with the x pipe vs the h pipes.

 

[rpr]

Plus in all my experiences the power was much smoother with the x pipe vs the h pipes.

The power was smoother or the sound was smoother?

 

[Jramos44]

The power was smoother or the sound was smoother?

Power was much smoother.

 

[Dtom05]

I have tried everything for this truck, chasing a reasonable exhaust tone.. finally have settled on dual 2 (3") into 1 (4") mufflers with a 4" single pipe center section. Got this idea from the BMW guys.

I originally thought I could leave the exhaust alone, but after downpipes I was not happy with how much louder the shitty tone was. I started by adding the flowmaster fx as suggested here, then resonators where ever I could fit them, plugging the factory screens, and variations of all this... I was close to giving up and just going back to a hemi 1500 (had a '20) . The wife has a grand wagoneer (same motor) that sounds perfect, and I love everything about this motor so thought I'd try the 2-1-2 as a last resort. I so far think this is the ticket. Sounds like the wagoneer with a bit more sputter, but otherwise pretty quiet like I wanted and I even think I picked up some top end.
Point of all this is to say I dont think keeping the dual exhaust is ever going to sound good to some of us, after downpipes, and wanted to offer up this as an option.

 

[Dtom05]

 

[Dtom05]

the mufflers i used..