Thinking of going back to exhaust manifolds...

No. Not at the headers. On the pipes closer towards the center of the longest runs.. They arn't designed correctly if they have excessive drone and that is the part of the conversation I am commenting on. What is the solution to reducing the drone if tieing the pipes together isn't designing them correctly? I don't see that adding a brace is not a proboble design. It could prove cheaper and less restrictive than adding resinators. I am still looking at the pipes as a tuning fork. I know that tieing the two tines of the fork together in the center and then at the end there will barely be a tone if any at all.
I am no expert on the subject so I am not saying what is or isn't a correct design or solution. Just trying to give some alternative ideas.

 

You know, there are some good experiments to be had here...

I could even "tie" them together using baling wire or similar, and move it around on the pipe to see if the drone changes or goes away.

Still, if it is true that I have lost power with the 2-1/2" pipes, about the same as I would have lost with the manifolds, that might be something to consider...

 

Come on Scooper.................bailing wire? Why not try some chewing gum?

 

just don't get it rolled up on it's side...
I have test driven a lot of mods, but never any bailing wire...

my suggestion is to test something you would/could leave on if it works. if the bailing wire works you will still have to take it off and find something less embarrassing...

 

blugene's idea has merit but the bailing wire won't do anything. The pipes would need to be welded to the braces because vibrations (and resonance) are waves, they cycle, so you need to rigidly mount the brace so the pipe won't move in any direction. Then there is the embarassment factor...:16suspect

 

Put adjusters on the wires and you could tune them for some nice harmony.

 

Oh Oh ...and some wire nuts...(multi-colors) for the Dopie effect...

 

Hey Scooper,

Looking at the pictures you have shown of your exhaust............it looks like you only have hangers at the very end of your exhaust system in back of the mufflers..................how about using some of the same type of hangers and putting one on either side just after the collector flange to help support the headers??????????????? The collector was never designed to support any weight and this transfers fatigue directly to the flange at the exhaust port.
Certainly would be better than using bailing wire............don't yeh think?

 

Ok so from what i have read so far from header removal to trying to tune the exhaust like a banjo the most reasonable cure so far has been to try and put tail pipes on the car.The headers are not the cause of resonation,the exhaust is hardly huge it just 2.5 pipe and im assuming not mandrel bent probaby squishes to 2" in spots.Flowmasters maybee contributing to the problem but for sure not the cause,my dads old 64 falcon 289 with manifolds duals and thrush turbo mufflers (not loud) and dumps would resonate so bad your ears would hurt.
Resonation is frequency.So exhaust frequency is bouncing off of shocks,fuel tank,the ground etc..The answer as it was mentioned before is move where the exhaust exits idealy out the back away from the car.But Scoop i know you like to experiment so try this one.Point the dumps almost at each other a sound cancelling effect is suppose to happen.I only tried it once on a 86 ford pickup and it worked
P.S My car has Headers 2.5 pipes 2 chamber 40 series flows and dumps (they are around a 30 deg angle and point past the axle) and i have no resonance, it's loud but tolerable

 

Derek has a good idea here............although I still think you need to anchor down the exhaust a little better like I posted earlier..............I have been a SCCA racer/member for a few years and actually have my SCCA license for working sound management..................every track, like Laguna Seca, Sears Point, and others have a sound limit to comply with..........Laguna Seca has a limit of 90db which is measured 50' feet from the car (yes, the sound limit at Laguna has a maximum of 105db, but that is only for a short time during the day) and lot of guys were having problems not meeting it (yes, most all SCCA cars run mufflers with durn outs/downs behind the headers). What we found is that they were pointing the turn downs directly at the pavement.............they did try aiming them at each other and that actually made it worse.........then they pointed them directly to the side..................and most guys who were unable to make the 90db........were able to make that or less.
Just a thought if you like to experiment..................???????

 

You guys are hilarous . Made my day reading this stuff.

 

I do notice a difference when the dumps are moved to the side in front of the rear wheels verses down in front of the axle underneath. .. I agree that the direction and location of exit has alot to do with sound, but I am trying to adress the resonance at the point of where I feel it is playing it's tone. I'd like a way to adjust the location as Scott was trying to get at. But I also feel any means other than a solid fastening would be causing a false read to the theory.
Edit: That is a solid fastening of the two pipes to each other not to the body of the car.

 

Joking aside, securing the pipes at different places might be a good diagnostic technique. Wires might dampen the vibrations or maybe have some tell tale vibrations of their own. Hope you do it.

 

ok. so I have spoken to 4 exhaust shops 1 being where I go. 3, including my guy, say that the exhaust does not have enough back pressure. The one guy said he has to look at it and didn't want to "speculate". So in discussions with these guys they say the exhaust is too big that it can be addressed by using a different muffler and in some cases using a glass pack before the muffler. My guy suggested the glass pack that bolts to the flanges because that would be less than making all new down sized pipes. I did not tell him who I was so I could get an unbiased or a general answer.

 

For whatever it's worth... My exhaust is 2.5," long tube headers, cheap Summit 2-chamber race mufflers, and turn-downs before the rear axle. It has just two hangers, attached at the output end of the muffler.

About as basic as can be, and by all rights it should drone and resonate and just generally be terrible but it's not. It's much quieter inside the car than outside. Stand beside my car while it's running and you can feel it in your chest, sit inside it though and hold a conversation at a normal volume while idling, cruising, any RPM unless of course I've got my foot in it. There's just no drone or annoying resonance at any speed.

As far as I can tell, my setup is just like Scooper's except for two things - My mufflers, although the same type design, are a different brand. And the second difference, my trunk floor is covered in Peel-N-Seal.

Just stuff to think about. Every factor thus far that has been proposed as a cause for the resonance is also present on my car...

Well I guess engine displacement is also different, but if anything I'd expect mine to be worse.