Re: Need help with exhaust drone
[Re: General 68]
#2728387
12/30/19 08:00 PM
12/30/19 08:00 PM
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Joined: Aug 2011
Posts: 2,853
Pattison Texas
CSK
master
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master
Joined: Aug 2011
Posts: 2,853
Pattison Texas
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70 Challenger 440 cr close to 10:1, Lunati Voodoo 60303 cam:
Drone from idle to about 2500 rpm. Almost unbearable low drone.
1-3/4 shorty headers, 3" x-pipe, 16" Dynomax Super Turbo's, 10 or 12 " glass packs along tank, standard rear valance so the pipes bends down about 30 degrees to get outlet under valance.
Rubber hangers, no interferance with body.
Strange thing: When we got the car it had a 512 stroker in it and the same drone, but only between 40 to 60 mph, not from idle. I then added the glass packs and they helped a lot but drone was still there.
After swapping in the milder 440 it got worse than to begin with. It will ring the ears from a low tone at idle and way past 5
All floor pans are covered with Dynomat sound deadener.
The Super Turbo's shouldn't be the worst mufflers. Do the shorty headers play a role? Or the down bends at the outlet? Or is it just a unlucky mismatch of parts?
Any ideas to fix this? What is the ign timing set at & the curve, Vac advance ?
1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5
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Re: Need help with exhaust drone
[Re: CSK]
#2728391
12/30/19 08:15 PM
12/30/19 08:15 PM
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Joined: Jan 2007
Posts: 401
Norway
General 68
OP
mopar
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OP
mopar
Joined: Jan 2007
Posts: 401
Norway
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18 initial, 35 total. Starts at about 1000 rpm. All in by 2500 rpm.
No vacuumn.
Last edited by General 68; 12/30/19 08:15 PM.
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Re: Need help with exhaust drone
[Re: General 68]
#2728395
12/30/19 08:20 PM
12/30/19 08:20 PM
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Joined: Aug 2011
Posts: 2,853
Pattison Texas
CSK
master
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master
Joined: Aug 2011
Posts: 2,853
Pattison Texas
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18 initial, 35 total. Starts at about 1000 rpm. All in by 2500 rpm.
No vacuumn. bump it up 2 deg & see how it does
1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5
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Re: Need help with exhaust drone
[Re: CSK]
#2728418
12/30/19 09:28 PM
12/30/19 09:28 PM
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Joined: Jan 2003
Posts: 20,752
A collage of whims
topside
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 20,752
A collage of whims
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Pac is onto something, as I've done a similar deal adding 2.5" tailpipes behind some 3"-X-Flowmasters and the car got pretty pleasant, no drone.
That was a 512" Duster, TTi headers.
Also had a 406" SB Duster: full headers, 2.5", H, Flowmasters, tailpipes & tips, never droned at all, which is supposed to be impossible.
Droniest car I ever had was a wagon with 3" system, tried 3 different mufflers and the Dynomax Super Turbos had the least drone but there was still some.
That was 446" full headers, 2.5" tailpipes.
I think the wagon body amplifies any droning, so you may want to disregard that comparison.
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Re: Need help with exhaust drone
[Re: General 68]
#2728513
12/31/19 12:20 PM
12/31/19 12:20 PM
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Joined: Jan 2003
Posts: 8,393
Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,393
Highland, MI.
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I have a buddy with a 70 Challenger 440-6 car that went with a TTI 3" system with the 3" x 16" Super Turbos. Exhaust sounded great for about the first two years. Then, the fiberglass mat started going away inside the ST mufflers & now the car is so loud, it's almost unbearable to drive or ride in.
My suggestion would be to replace with different mufflers & add a pair of GOOD quality glasspack-type mufflers (resonators) that have a body length of 18" at the rears. If you can't find something, I can build you the resonators. 3" dual exhaust is LOUD - there's no two ways about it. Also, you don't really need dual 3" exhaust unless you are over 500 HP, & even at that you can run dual 2.5". I have customers with 800 HP running dual 2.5" & they don't notice loss in HP or flow until they go over 4800 RPM.
Last edited by Sunroofcuda; 12/31/19 12:22 PM.
No Man With A Good Car Needs To Be Justified
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Re: Need help with exhaust drone
[Re: RealWing]
#2728572
12/31/19 03:13 PM
12/31/19 03:13 PM
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Joined: Jan 2003
Posts: 3,122
Auburn WA
Dave_J
master
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master
Joined: Jan 2003
Posts: 3,122
Auburn WA
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With a warmed over 360 and stock 2 1/2 inch H pipe on my LRT, my son installed FlowMaster 40's with 2 1/2 mandral bends to go up the stacks. At idle its not so bad but at 2500 RPM I need ear plugs as that drone sounds like a nest of 50 birds are in the cab. Can NOT go on the freeway at 80 MPH as its so bad. Forget opening the slider rear window and rolling the windows down.
While I'm putting my new 410 Stroker Magnum 5.9 in I am going to Magnum SS shorty headers, 2 1/2 inch 14ga SS pipes and SS mandral bends, SS X pipe and Magnflow muffs.
Retired, US ARMY 1973-1994
ASE mechanic, Electrical 1994-1997
Retired GTE/VERIZON/FRONTIER 1997-2015
Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.
03 Suzuki Burgman 650(Burger King) Scooter
65 Formula S Cuda
78 Little Red Express Truck
98 Buick Regal (wifes car)
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Re: Need help with exhaust drone
[Re: Dave_J]
#2728622
12/31/19 05:25 PM
12/31/19 05:25 PM
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Joined: Jan 2007
Posts: 401
Norway
General 68
OP
mopar
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OP
mopar
Joined: Jan 2007
Posts: 401
Norway
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Thanks! Keep it coming👍
For your interest I have ran both engines that have been in the Challenger in a 68 Charger without any drone.
The Charger has 2" TTI headers and 3" TTI x-pipe and Dynamax mufflers. No glass packs.
This system has been used 13 seasons now.
Last edited by General 68; 12/31/19 05:26 PM.
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Re: Need help with exhaust drone
[Re: General 68]
#2728657
12/31/19 08:21 PM
12/31/19 08:21 PM
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Joined: Jan 2003
Posts: 4,712
Moved to N.E. Tennessee
GomangoCuda
master
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master
Joined: Jan 2003
Posts: 4,712
Moved to N.E. Tennessee
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70 Challenger 440 cr close to 10:1, Lunati Voodoo 60303 cam:
Drone from idle to about 2500 rpm. Almost unbearable low drone.
1-3/4 shorty headers, 3" x-pipe, 16" Dynomax Super Turbo's, 10 or 12 " glass packs along tank, standard rear valance so the pipes bends down about 30 degrees to get outlet under valance. Thanks! Keep it coming👍
For your interest I have ran both engines that have been in the Challenger in a 68 Charger without any drone.
The Charger has 2" TTI headers and 3" TTI x-pipe and Dynamax mufflers. No glass packs.
This system has been used 13 seasons now. The shorty headers on the Challenger have 2 1/2" collectors dumping into 3" pipes. The 2" TTIs on the charger have 3 1/2" collectors dumping into 3" pipes . See where I'm going with this? Pipes bigger than collectors is asking for big time drone. You either need bigger headers or smaller pipes on the Challenger. Probably both.
Last edited by GomangoCuda; 12/31/19 08:30 PM.
In theory, there is no difference between theory and practice. In practice, there is.
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