Exhaust

[Walt]

Hey are there any guys that built the augers for the mufflers, and if so do they cause any problems from added heat or anything?
Thanks

[Norm B]

Here’s a thread where I outlined my auger installation. https://thefactoryfiveforum.com/showthread.php?35690-Exhaust-decibel-level&highlight=Exhaust+augers

There is no added heat or other issues with the exhaust.

Norm

[NAZ]

I experimented with the 11" auger inserts, even stacking two in series -- no problems, just lightened my wallet and made no significant difference in the sound, save your $$. I also tried the perforated cones and using two in each collector at least worked to some degree, they attenuated the sound pressure by a few db. I've tried perforated discs and with enough of them they reduce the sound about as much as the cones but I suspect they create more back pressure than the cones. If you go with the perforated cones install two of them in each collector with the pointy ends touching.

But the system I have settled on is the Supertrapp mufflers, the type that you have to weld the flanges on the end of your collector (or exhaust pipe) and use a stack of SS plates. These you can tune until you get the sound reduction you like. Supertrapp makes different designs other than the one I used so take a look at their products and maybe they might have something that works for you.
140910

[bobl]

Walt,
I did some dyno testing of various mufflers back when I built my engine. I tested the augers on a set of flowmaster mufflers. They reduced noise quite a bit, but cost about 30 HP at the 500 HP level. Probably not much loss on a mild 302 though.

Bob

[bobl]

Here's a pic of the new augers I built! That ought to quieten it down. I actually made these for my dyno out of some 3/4" thick, 12" pipe. They weigh about 300 lbs apiece. They really work well. They will hold 500 HP down to under 80 db at WOT. So the auger concept works pretty well.

[CraigS]

I used augers in mine that I bought from Summit it along w/ an add-on turndown. I cut the original pipe as long as possible so the turn down added length and I rotated it 45 deg down toward the road. This is a copy of the text from a long ago post.

JEGS Performance Products 30645 JEGS Exhaust Turndowns
I had gotten the turndowns since a new set of FFR sidepipes helped but the exhaust was still too loud. So I cut the original turndowns off leaving the pipes as long as I could and installed the Jegs turndowns and angled the outlets downward. These helped a little bit. I have read and saved a bunch of stuff on other's exhaust mods and figured I would probably do the chambered pipes at some point. Then I came across these spiral inserts at Summit.
Patriot Exhaust H3843 - Patriot Muffler Inserts - Overview - SummitRacing.com
These are cheap compared to $60-90 each for either cones or CC inserts so ordered a pair. Found they are 3.5 inch OD and so are the pipes so needed to mod them a little so they would fit inside the pipes
Test drive was an hour ago and these things are fantastic.Very obvious noise reduction from the first start in the garage. Only about a 20 minute drive but I am very satisfied w/ the noise reduction and my butt dyno says they didn't hurt power.

Additional info. Over the years it became obvious that welding the augers in always eventually cracked loose. So drilled through the pipe from the bottom and into the core of the auger. Pulled the auger out and welded on a 1/4 in nut. I dimpled the outer hole some and got a 1/4 in flat head machine screw. Put it back together and installed the screw. Once every 1-1.5 years I tighten it a little.

[Avalanche325]

Quite some time ago there was a thread where you made a flexible auger that you could install and remove without cutting the pipe. They made my car, with a 500hp 347, sound like a tractor. A rumble with an overtone of phut phut phut. My wife who REALLY wanted me to quite the car down came outside and said "That sounds like s***! Get those out of there." Sound is a very tough thing. Go to a Cobra event and no two sound the same.

If you are a decent welder, it would be fun to experiment.

[Walt]

I built a set of augers last year and drove it once , I thought it made the mufflers a lot hotter in front of the augers, but it might have been my imagination, I'm thinking of trying them again, it's getting where my hearing is not so good and when I have the soft top on it really sounds loud.
Thanks for the replys!
Walt

[Avalanche325]

.....when I have the soft top on it really sounds loud.

I discovered the same thing. I wasn't expecting that.

[GTBradley]

I’m guessing that the exhaust is more pronounced with the top on because the top blocks other sounds and makes the exhaust note that much more noticeable.

[Norm B]

With the top on I find the wind noise greatly reduced and any other noises that would normally be drowned out by that are much more noticeable. That and the top traps noises that would normally go straight out into the atmosphere.

Norm