Better exhaust or new cam?

[vector1]

if i was to look at sidepipes here is what i would consider

http://www.coastfab.com/index.html

[xlr8tr]

Originally Posted by vector1

if i was to look at sidepipes here is what i would consider

http://www.coastfab.com/index.html

These look interesting- do you have any pics? I didnt see anything on their website.

[Dwight]

I had Lone Star sidepipes with 2 1/2" core and 24" long mufflers. The louvers were facing so they did not catch air. This would give max air exiting the muffler. I replaced them with Cobra Pack 3" x 28" mufflers. I installed them so the louvers would scoop the air into the muffler. Four inches longer gave more volume.

Before you could heard me from 1 1/2 miles away. I've got witnesses. Lots of them including one police office, pictures in my gallery. No ticket.

After I changed the mufflers, it's a "lot" quieter and I "think" it makes more HP. I made other changes between dyno runs so I don't know what the muffler change gained me. But I feel very confident the new sidepipes help.
I now have a quieter exhaust system with a deep health rumble. I like it.

It's that air in - air out thing. I have larger mufflers to handle the same amount of air, so it should be quieter.

A muffler is a place to store air till it can sloooowly exit the muffler. The reduced speed of the air exiting the chamber reduces the noise.

IMHO

Dwight

[Dwight]

this is a pic of the core out of Unique's sidepides. Note the louvers.

Dwight

[CobraEd]

Originally Posted by Dwight

A muffler is a place to store air till it can sloooowly exit the muffler. The reduced speed of the air exiting the chamber reduces the noise.

Dwight

I don't believe this is correct, . . . . Uhhhhh, . . This is 100% wrong.

Exhaust gas and sound waves are two completely different things. You never want to make an effort to slow or reduce the exhaust velocity. You will lose power (backpressure). The mufflers job is to absorb and/or cancel out sound waves. The better it can absorb/cancel sound waves relative to maintaining a free flow, the better it is at its job.

Mufflers like glasspacks absorb sound waves and mufflers like Flowmasters cancel out the sound waves inside small resonance chambers within the muffler.

(just as an aside, . . . . good backpressure is like good cancer)

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[vector1]

Originally Posted by xlr8tr

These look interesting- do you have any pics? I didnt see anything on their website.

i haven't used these, just brought over from another site, thought they looked interesting. i've read the guys will make anything you want, they also have a discounted list of stuff.

[Dwight]

I removed the fiberglass and re-installed them.
It was a friends Cobra.
Dwight

[Dwight]

CobraEd, I think you use the word absorb and I used the term "place to store air till it can sloooowly exit the muffler" to describe the same thing.
All the air that enters a muffler has to exit. Nothing is absorbed. A large muffler is quieter than a small muffler on the same car.

Stock vs glasspacks (Cherry Bombs).

The large muffler has more room to store the air till it exits the muffler.
Glasspacks have fiberglass in them and Flow Master uses metal baffles to slow down the air.

This same theory is used to build/design suppressors for firearms.

I don't design or build mufflers for a living, but this is what I think happens inside a muffler.
Dwight

[CobraEd]

Originally Posted by Dwight

CobraEd, I think you use the word absorb and I used the term "place to store air till it can sloooowly exit the muffler" to describe the same thing.
All the air that enters a muffler has to exit. Nothing is absorbed. A large muffler is quieter than a small muffler on the same car.

Stock vs glasspacks (Cherry Bombs).

The large muffler has more room to store the air till it exits the muffler.
Glasspacks have fiberglass in them and Flow Master uses metal baffles to slow down the air.

This same theory is used to build/design suppressors for firearms.

I don't design or build mufflers for a living, but this is what I think happens inside a muffler.
Dwight

You cannot store "absorb" the exhaust (air as you put it) or the muffler would get bigger and bigger as you drive. You can absorb SOUND WAVES only.


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[RestoCreations]

Quote from Dwight

" A large muffler is quieter than a small muffler on the same car. The large muffler has more room to store the air till it exits the muffler. Glasspacks have fiberglass in them and Flow Master uses metal baffles to slow down the air."

Im going to disagree with you on that one when referring to the sidepipes for cobras and cobra replicas-> Larger internal diameter=more straight through flow=louder. The larger ID pipes also equal less packing material to absorb the SoundWaves.

[CobraEd]

Dwight,

More food for thought:

Picture a car accellerating at full throttle at 7,000 rpm. Lets say hypotheticaly that the exhaust is entering the muffler at 600 mph. By your way of thinking the exhaust would leave the muffler at 200?, 300?, 400mph??? I think not. That would mean the muffler was holding all that exhaust and getting bigger and bigger. If the exhaust goes in at 600mph. it comes out at 600mph.

EXHAUST has VOLUME and MASS. To store it the muffler would have to grow and get bigger as you drive. Sound waves have NO VOLUME and NO MASS. They are what get absorbed and/or cancelled out within the muffler.

I think you are trying to compare this with a gun. It is not the same thing. A gun is an instantanious discharge. Exhaust is a continual flow.


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[RestoCreations]

Originally Posted by Dwight

I removed the fiberglass and re-installed them.
It was a friends Cobra.
Dwight

Why? Did he want them louder? Eventually the fiberglass builds up with so much carbon/exhaust gunk that it doesnt absorb the noise anymore anyway.