Want to get rid of drone?

[dds78910]

I saw a thread a while ago about people running 2 mufflers or a muffler and a resinator. But I dont remember anything about the the out comes and what brands people used. I have a 3" turbo back on my R/T with no cat and a Magnaflow muffler and it is fine in town but cruising on the interstate at 80 for a couple hours can get a little noisy. I was thinking of adding a resinator unless someone else has any better ideas. Any input would be appreciated.

[contraption22]

Is your exhaust tip extended beyond the bumper?

[Reaper1]

This is the exact reason I actually still have a catalytic converter. It helps with the drone and the overal decibels and doesn't hurt performance very much due to it being a high flow unit.

[PunKid]

I dont have the solution but would like to hear some more opinions.

I have a full 3" system, no cat, going on my Omni that will be DD for the most part. I have yet to order the muffler because I want to fit the largest one possible back there.

I to was planning on leaving the test pipe removable so a resonator could be installed if the drone was too much.

[mr glenn]

Is your exhaust tip extended beyond the bumper?+1on the exhaust tip beyond the bumper, Most of the Drone comes from the sound bouncing off the car body They sell the 3'' turn downs at auto zone

[2.216VTurbo]

In Cali we have the tailpipe emissions every 2 years but to keep from killing cats on my *race cars* (I would never illegaly modify the emissions equipment on a street driven vehical:p)I use a 3 flange bolt in/bolt out set up. Each one is set up at the same length so the same OBDII cat can be used:thumb: Funny thing is, the exhaust note on the red TC and the White TC although done by the smae guy, at the same shop, with the same muffler is different:confused2: Red car, no problem on the highway, white car, drone city:( So I got a cheapy 'bullet style'(glasspack-ish) perforated core strait thru muffler that bolts in place of the cat. It's the style that has little raised triangles of metal in the center thru pipe that partly exposes the fiberglass packing material in the outer core. It kills the drone nicley and was cheap. Not that the manufacturer name is coming to me right now:o I'm sure they are pretty generic.

Two things to consider though, I've tried the kind of glasspack that just has a perforated center with little holes. That one didn't kill the drone or much sound. Second thing is the raised material type is uni-directional for best exhaust flow. Install correctly;) On my Shelby Lancer I used to have 40 series single chamber 'race' Flowmaster in place of the cat. That worked but was heavy and expensive.

[turbovanman²]

I saw a thread a while ago about people running 2 mufflers or a muffler and a resinator. But I dont remember anything about the the out comes and what brands people used. I have a 3" turbo back on my R/T with no cat and a Magnaflow muffler and it is fine in town but cruising on the interstate at 80 for a couple hours can get a little noisy. I was thinking of adding a resinator unless someone else has any better ideas. Any input would be appreciated.

If you searched, you'd find like 10 threads from me on it, :p

Yeah, I run 2 mufflers and a cat, the cat made a big difference in drone. I have run a large body Walker cat and currently run a large body OEM GM cat off a 3.8. You can feel the difference in power but for the street, big whoop. Resonators I found did nothing.

The 2 mufflers are an oval Magnaflow up front and a round Magnaflow in the rear. I had a Walker Ultra-flo up front but the Magnaflow is alot quieter, all are straight thru designs. I did try a Super turbo and the rear muffler but still droned enough to piss me off, and i didn't have room to put the cat in, that would be a nice combo, as the exhaust rocked and the power came up.

[Turbo3Iroc]

I have a full 3" system on my daily driver Spirit with a SS Ultraflow muffler. I also do the same cat mod Alan mentioned. I have a turn down on the tail pipe and it isn't bad even on the highway. Get a little popping on decel but it doesn't bother me. My muffler broke off at the flange a few weeks ago and HOLY DRONE CITY! But at cruise on the highway it wasn't all that bad but any accel or decel it was ridiculous. I attributed it to the sound waves bouncing off the inside of the bumper but the odd thing was at cruise it wasn't much louder than with the muffler back on.

[contraption22]

Another question... do you have stiff motor mounts and/or bobble strut?

[turbovanman²]

Another question... do you have stiff motor mounts and/or bobble strut?

Good points, they do transmit alot more "noise" than stock mounts.

Years ago, had a stock exhaust system from a caravan, I would use it for emission's testing until a scrap guy took it away without permisssion, :banghead: anyhow, it was soooo quiet, it was unreal, lol, so smooth, you could hear pin's drop, lol but man, did it hold the engine back, :rolleyes:

[dds78910]

If you searched, you'd find like 10 threads from me on it, :p
I did a quik search and did see some info on your van, just wanted to hear some other ideas.


+1on the exhaust tip beyond the bumper, Most of the Drone comes from the sound bouncing off the car body They sell the 3'' turn downs at auto zone
Tip is past the bumper.


Another question... do you have stiff motor mounts and/or bobble strut?
I do have solid motor mounts, I guess that could be the problem.

---------- Post added at 12:55 PM ---------- Previous post was at 12:52 PM ----------


Good points, they do transmit alot more "noise" than stock mounts.

Years ago, had a stock exhaust system from a caravan, I would use it for emission's testing until a scrap guy took it away without permisssion, :banghead: anyhow, it was soooo quiet, it was unreal, lol, so smooth, you could hear pin's drop, lol but man, did it hold the engine back, :rolleyes:

I have a stock Spirit R/T also with nothing done to it and it is amazing the difference in the sounds between the 2, or the lack of sound in the stock R/T.

[turbovanman²]

I did a quik search and did see some info on your van, just wanted to hear some other ideas.

Just bugging you, I am the only one that seems to complain about it, lol.

[DevoBuzz]

I'm running a full 3 inch system with a cat (http://www.summitracing.com/parts/MPE-94109/) and Magnaflow straight thru muffler (http://www.summitracing.com/parts/MPE-12619/) along with a dual resonator tip (http://www.summitracing.com/parts/PSM-95-9919/). But I do have this vibration only at 2200 rpm. Maybe because of the mounting?

[turbovanman²]

^^^^^^^^NO balance shafts?

[DevoBuzz]

^^^^^^^^NO balance shafts?

It's a 2.2. And it's exhaust related - never happened before I put the 3 inch system on.

[turbovanman²]

It's a 2.2. And it's exhaust related - never happened before I put the 3 inch system on.

2.2's came with BS's, depends on which engine you have, :p

I think the larger piping causes the exhaust to bounce around per say, causing more drone, :( I find 2.5 inch have much less of a drone issue.

[chryguy]

Like Simon says...from my experience, 2.5 vs 3in makes a big noise difference.

1st example...Spirit R/T with 2.5 and no muffler or cat. She was slightly drone-y on the highway, but not unacceptable. Sounded very good at idle and WOT.

2nd...Spirit R/T w/3in and two long Dynomax race bullets (about 23") was awesome. No drone at speed, sounded great at idle and WOT. Had several people at meetings comment on how good it sounded at idle.
I parted that car and still have the complete exhaust.

Both of those R/T's had full exhausts all the way to the rear bumper.

I'd suggest a second muffler in the resonator position, after the axle. I didn't have any problem fitting a DM long bullet in that spot. That should make it sound sweet...:thumb:

Make sure the tailpipe clears the rear bumper so you don't melt it. :D

CG

[DevoBuzz]

2.2's came with BS's, depends on which engine you have, :p

I think the larger piping causes the exhaust to bounce around per say, causing more drone, :( I find 2.5 inch have much less of a drone issue.

Hey I didn't know that - which 2.2's had shafts? The Masi motor?

Yeah I bet the 3 inch causes some resonating frequency - in my case for my layout right at 2200 rpm.

[Turbo3Iroc]

TIII and TIV 2.2's had balance shafts.

In my TIII cars the resonation usually peaks around 3000 rpm.

[Ondonti]

Since it is an AA, what is the condition of the sound deadening behind the rear seat?

[DevoBuzz]

That may help somewhat. I just put 40 sq ft of Damplifier underneath/behind my rear seat and the package tray in my 72 Pontiac to lessen the drone.

[contraption22]

Did it work on the Pontiac?

[DevoBuzz]

Yes it did help, but not as dramatic as replacing the mufflers would have helped. On old cars like that there is a lot of unsupported sheet metal. Not sure how much an effect it would have on our unibody cars.

[DUGZSHELBY]

I had a 3" exhaust put on my minivan straight out the back. It had terrible drone noise from 40-60mph. I took it back and talked to the guy about it. All he did was put a slight downward bend in it and it made a HUGE difference!

[johnl]

Yeah, turn down positioned so the sound cannot rebound back up under the car, and soft motor mounts/dog bone. Then you can add sound deadening material in the spare tire well and around the trunk floor; just patches is all you need, in the middle of the big panels that might resonate.

[turbovanman²]

Sound deadener is my next purchase. I added some more timing at the cruise table and it really helped, did this on Saturday.