My exhaust is too loud - how to make quieter?

[Jeff Frigo]

Originally Posted by patrickt

Gary, I think the absolute truth of the matter is you're going to have to get new pipes made. I have the Stainless Specialties "quieter pipes" and they do pretty well. Short of new pipes, everything else is a just a gimmick.

I have talked to guys in who race A Production cars (see below) in vintage races that swear that these work well with little to no loss in power.

Dynatech Accessories - Auger Style Muffler



A-Production

AC Cobra (427cid)
1970-72 Chevrolet Corvette 350cid
1965-67 Chevrolet Corvette 427cid
1968-72 Chevrolet Corvette 427/454cid
DeTomaso Pantera 351cid
Ford Boss 429 429cid
Shelby GT-500 428cid

[patrickt]

Originally Posted by Jeff Frigo

I have talked to guys in who race A Production cars (see below) in vintage races that swear that these work well with little to no loss in power.

Dynatech Accessories - Auger Style Muffler

I've heard that too. But there have also been threads on here where guys have tried them and said just the opposite. I also suspect that the psychological force of "believing they work," after you've gone to the trouble of buying and installing them, might also come in to play. I know I had been around more than one Cobra that just plain hurt my ears (from both outside the car, and inside) so I dealt with the issue when SS was fabbing the pipes. I really like their "quieter pipes" on my FE, but it's going to cost him a couple of bucks. On the other hand the auger inserts are only $15, so WTF, he might as well give it a shot I suppose.

[Dwight]

I replaced my 2 1/2" x 24" mufflers (louvers facing away from motor) with Classic 3" x 28" (louvers facing the motor). They are a lot quieter and still sound like a Cobra, deep rumble at idle.

Dwight

[Jeff Frigo]

Originally Posted by patrickt

I've heard that too. But there have also been threads on here where guys have tried them and said just the opposite. I also suspect that the psychological force of "believing they work," after you've gone to the trouble of buying and installing them, might also come in to play. I know I had been around more than one Cobra that just plain hurt my ears (from both outside the car, and inside) so I dealt with the issue when SS was fabbing the pipes. I really like their "quieter pipes" on my FE, but it's going to cost him a couple of bucks. On the other hand the auger inserts are only $15, so WTF, he might as well give it a shot I suppose.

Patrickt:

I have not been able to find anybody on the forum that has tried them. I have searched. Do you think you could find that thread. I was planning on trying them this winter, but if they are NG, I would like to save my money. $15.00 is no biggy, but the rest of the process for existing ceramic coated pipes are.

[undy]

I had the "auger" style mufflers on my ride and picked up 40 rwhp (and a small amount of noise) when I went to the Classic Chambered exhaust. There's just too much exhaust impingement with the spiral style...

[Jeff Frigo]

Originally Posted by undy

I had the "auger" style mufflers on my ride and picked up 40 rwhp (and a small amount of noise) when I went to the Classic Chambered exhaust. There's just too much exhaust impingement with the spiral style...

What was the hp diff with the chambered? Pleases explain exhaust impingement.

[undy]

Originally Posted by Jeff Frigo

What was the hp diff with the chambered? Pleases explain exhaust impingement.

I gained right at 40 rwhp with the CC pipes. I also added true merge collectors that may have skewed the results a bit too.

As the exuast travels down the muffler it's constantly "bouncing' off the angular augers. Just that fact that the exhaust is repeatedly "hitting" the spiral center section creates undue back pressure, ie; impingement.