Muffler replacement huge horsepower gains!

[cdnus]

It would be interesting to find out if this "flutter" is associated to engine displacement & muffler size. Do the members with big displacements encounter this noise (427+) ?
Is it only smaller (408-) that encounter it?
When I had the original VERY restrictive mufflers I did not have any "flutter" but as soon as I installed the S/S 2.5" mufflers I started getting it.
It's almost as if the flow capacity of the muffler is too much for the engine @ lower RPMS & you get a "sucking effect" that causes the fluttering.
I suspect that if I installed 2.5" turnouts the problem would go away--would look rediculous but might solve the problem. (not going to happen)

Not being a engineer & not knowing anything about expansion-contraction-heating-cooling-velocity of exhaust gasses this is my best shot at the problem.

I am sure that someone here is & can answer with a more accurate solution/cause/effect.

Craig

[undy]

Originally Posted by cdnus

It would be interesting to find out if this "flutter" is associated to engine displacement & muffler size. Do the members with big displacements encounter this noise (427+) ?
Is it only smaller (408-) that encounter it?
When I had the original VERY restrictive mufflers I did not have any "flutter" but as soon as I installed the S/S 2.5" mufflers I started getting it.
It's almost as if the flow capacity of the muffler is too much for the engine @ lower RPMS & you get a "sucking effect" that causes the fluttering.
I suspect that if I installed 2.5" turnouts the problem would go away--would look rediculous but might solve the problem. (not going to happen)

Not being a engineer & not knowing anything about expansion-contraction-heating-cooling-velocity of exhaust gasses this is my best shot at the problem.

I am sure that someone here is & can answer with a more accurate solution/cause/effect.

Craig

I have it now with a 600hp 482" s/o and 3" Classic Chambered exhaust.. I didn't have it before with the other 3" CC exhaust. The other set flowed as much as this set.. I'm not really complaining as I've grown used to it and others outside the car don't seem to hear it.

[CobraEd]

I have stainless steel glasspacks that I had Lucien Donofro of Arizona Exhaust make up for me about 7 years ago. 4" outer diameter, 3" inner diameter. Louvers facing backward. From the time I put them on I noticed a SIGNIFICANT increase in power, but upon any deceleration of engine RPM, you get the sound like papper fluttering in the wind at the outlets.


Who cares.


.

[T E Lewis]

I keep waiting for the final solution on this thread, but it doesn't really sound like there is going to be one definative anwser. I am running the same engine in my Spf that I took out of my E-Morrison, and the loss of power is really noticeable. I can't stand it any more, and ready to make a change just not sure what. I really only want to do this once. Where is anyone sourcing the different muffler choices?

[767Jockey]

Originally Posted by T E Lewis

I really only want to do this once. Where is anyone sourcing the different muffler choices?

I got my 3" core Cobra Pack mufflers from Eric at Classic Chambered, and I'm having Nick Acton from Acton Customs ("Mickmate" on Club Cobra) do the work to put them into the old sidepipes. The mufflers I took out were stock from Contemporary, and were about the most restrictive I have ever seen, they were much worse than I ever imagined.

Both Eric at Classic Chambered, and Nick Acton from Acton Customs are straight shooters and a pleasure to deal with. Stuff costs what they say it will cost, it looks the way they say it will look, it works the way they say it will work, and it shows up when they say it'll be there. You can't beat that. I highly recommend both!

[T E Lewis]

767..

Thanks for the source on the mufflers. We can do all of the work in house, and I have a guy down the road from our shop that powdercoats all of our marine parts for us. I may watch this thread a little longer before pulling the trigger. Thanks to everyone for their input.