Muffler replacement huge horsepower gains!

[cdnus]

Dean
If you look closley at mickmate's photo you will see that rather than the end washer/baffle being welded directly to the perforated core there is now a solid sleeve welded to it. Now the perforated core fits over the sleeve on both ends allowing it to float when it expands and contracts. That's what was the problem with the old version, you would get cracks at the welds on the perforated core & all the packing would get sucked out.
Now with the two pieces not welded together the core can expand all it wants and will not crack or split.

Craig

[BMEP]

Great thread! I'd love to hear more about the flutter. When exactly does it happen? Seems like it's heard any time the engine is losing revs - is that right? Is it a constant sort of slapping/flapping sound or is it more of a random popping?

I've read every muffler thread I can find because I'm about to build a set of sidepipes for my FFR. I want minimal power loss and noise is okay as long as it's not crazy. I'd been planning on the same sort of setup (except with merge collectors) that RedBarchetta has but now I'm wondering if that's the right thing to do...

Rob

[dont]

Mine only makes the fluttering noise during the time when the clutch is depressed until it reaches idle RPM's. If I leave it in gear during slow down it sounds fine. To me it almost sounds like the motor is inhaling instead of exhaling.

[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?

[Dwight]

I changed my mufflers last winter from 2 1/2" x 24" Lone Star mufflers to 3" x 28" COBRAPACK MUFFLER. My 302/354 dyno'ed at 402 rwhp 416 rwtq. I do not know how much I gained with the new muffler because I changed heads, cam, intake, TB, mass air, etc.
But I love the sound, loud but not to loud. I can cruise at 70 and talk to the passenger. I could not do that with to old mufflers. Nice deep rumble.

I highly recommend the Classic Cobrapack mufflers.

www.classicchambered.com/

Dwight

[Dwight]

DRBB

About 4 or 5 years ago I removed the fiberglass packing from a friend's Unique side pipes. He bought the kit in early 90's maybe 91 or 92. The pictures tell the story better than I can.
Another friend, Mike had his Unique side pipes replaced with the Classic Cobrapack last fall and love the power (seat of pants) and sound.
Dwight

[KarlCSX2498]

Hello, I had Nick replace the mufflers in my side pipes with the CC 2.5" packed mufflers. I just started the car for the first time (it is a brand new car, scratch built) and the pipes sound fantastic. Not loud but a low rumbling sound and the idle sound is perfect. If I can get a few details complete, I should have a test drive this weekend. I hope to have a video on the club cobra site in the next couple days so everyone can hear.
Nick did a great job and I highly recommend his services.
regards, karl