Wife says she needs Earplugs!

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Woody'sScamp

Woody'sScamp

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Hi all. I need your expertise on "droning". It doesn't bother me too much because I love the car, but my wife says she wants earplugs, and she's a car lover, maybe my classic car lover? From 20 to 90mph (WOT) it's fun! No problems there.
I'll try and provide everything I know about the engine rebuild and exhaust system. From about 30 to 40 major droning, up to about 2K RPM, driving around the town and countryside, city, hit the gas it's gone.
Here's what I have.
Car - 1975 Valiant Brougham 2- door
Rebuilt 1975 318 - (only 32,000 miles, but I wanted more than that "smog engine") .30 over with iron 340 heads, not sure if X or J", worked on a little bit" is what I'm told!
The Engine with headers dyno'd at 404HP (at 5,5500), 419 TQ (at 4,100)
Cam - Comp XR280HR-10 (2,2200-6,000rpm)
Manifold - LD4B
Holley - Dominator? Carb 750
Trans - Rebuilt 904 2,500 stall.
Exhaust manifolds - 72-73 340 manifolds
Exhaust - 2 1/2" TTI head pipes, full TTI exhaust with turn downs out the back, Dynomax Turbo mufflers. (The standard TTI kit.)
8 1/4 rear end with 3:55 sure grip.
Back Tires - 245/60/15

Will putting Exhaust Tips out beyond the bumper help or not? Different mufflers? Suggestions please.

Thanks all.
 
get up to speed with the drone there, put the car in neutral, does the drone go away?
 
H pipe?
Do you have room for bullet style resonators in the tailpipes?
Find out what rpm the drone occurs at.
(I may be wrong, but I don't think tips will help.)

Mom's Duster post while I was typing.... slowly.lol.
 
You need different mufflers. Those are bad about that.
 
RustyRatRod said:
For that kinda dough, they better come with a really high end call girl to install um for me and then give me a happy ending.
Click to expand...
Lol. My point was really just to point out that you can do some math and build a Helmholtz resonator with just a couple of U bends and some exhaust tubing.
7E35AE7B-0584-4E38-A226-71B30070D00F.png
 
or get her some ear plug music playing some Al Green, makes for a good time when you get home. lol
 
All,
Love the pics and comments! So, I forgot to mention, brand new balanced driveshaft, and I have the TTI x-pipe. Any other muffler suggestions I should look at? Aren't the Dynomax Turbos the quieter mufflers? I would go for louder as long as I get rid of that low-speed drone.
(Hooker Aero chamber - I'll look these up)
 
I have TTI headers to 3inch collectors, to 2.5 TTI pipes with a H cross over with moroso spiral cores then to the up bends over the rear end and out the back. They are a little loud when your hard on the gas, but just cursing at 2500 they are not too loud and can have a conversation.
 
Any different with windows open or closed? Any chance the exhaust is touching the body at that rpm? How is the exhaust attached in the back?
 
Good point, I will check the whole system. Seems worse with windows closed. TTI tail pipe hangers are on the back, (1 foot? from the end) also the turn downs are not past the bumper. About even with bumper.
 
Woody'sScamp said:
. I need your expertise on "droning".
Click to expand...
Btw define "droning" there can be a heterodyne caused by two sounds that are similar in frequency.

Like a 1000 htz and a 900 htz sound will produce a 100 htz sound. Typically it will be like a slow wobbbb, wobbbb, wobbbb. Some people can hear it some can not.
 
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