Anyone ever TRY to quiet down a 428?

[65srpnt]

I need new pipes for my SPF with a 428. I saw some stainless ones on the web that actually have mufflers. Does anyone have anyother ideas? I live in a quiet neighborhood with bored cops. I want a little quieter car without giving up too much performance..
Thanks

[A Snake]

Before I actually read your post, I would have said "why would you want it quiet?"

I too live in a quiet neighborhood, but my neighbors just smiled when I drove into the driveway and it was loud enough to set off car alarms 100 feet away.

As to how to quiet it down, the stainless might look good but it is actually very often louder than plain steel. It seems to have a more piercing sound.

You might look into "supertraps" like racecars use. With these you can add or subtract layers to change the noise level. The down side is that the quieter it is the more back pressure there is, which is true of any exhaust system.

Just my thoughts

Al

[Tom White]

How about inviting the local police for a spin.

[misfit41]

I have a set of stainless pipes,,they sound sort of "tinny" to me ,anyone else experience this ?as for me,,this isnt my milk runner,so I want to set off car alarms and wake up babies,,it is still quieter than my 113 stroker on the chopper.Tim

[A Snake]

Tim,

Tinny sounding is what I was talking about. I guess I was being too polite. If a guy likes the silvered look, powder coating can be an answer. Hi temp paint doesn't last.....I've tried it. Chrome definitely is not good because it turns blue when it gets hot. Only good for show cars that never get started and driven.

If a guy likes loud, Ron Butler of Butler racing makes a really good "muffler" for side pipes. They're basically straight through, but have a helix wrapped around the center pipe that "kinda" kncks the edge off the noise. The great thing about them is they don't burn out like glasspacks do. They're loud when they're new and stay that way.

A side note on the Butler's is that when I had my 427 S/O on the dyno, I later learned that the mufflers cost about 50hp compared to open headers.

Our poster is looking for quiet, and I don't know of an answer other than the supertraps that will work with side pipes.

I only got pulled over once in my car and it wasn't noise that did it. The cop was just curious and said something feeble like, "Did you know you were going 35 in a 30?" Never even asked for my license. Just walked around and around the car and asked a ton of questions.

Methinks the constabulary won't bother you if you don't do stupid crap in your car....even if it's a little loud. All cops know a Cobra is loud and expect it. The neighbors can learn to live with it unless somebody is freewinding the engine at 3 AM in his driveway.

I don't think stealth is meant to be part of a Cobra's persona......

Al

[65srpnt]

I guess what I meant were these guys.....
http://www.stainless-specialties.com/products2a.htm

I agree, I don't want to give up 50 hp....but this is my grocery getter and it puts out over 500hp....so I am sure I will get there....thanks for all your help. just looking for the best new pipes.

S

[BMK]

Hi all



I asked this question some time ago on the forum and received a Post that identified a cone shaped perforated insert.

I tried this making one at the local engineer shop it does quiten down but changes the sound to whistle like sound. Perhaps someone may Post the site again ( Exhaust manufacturer in US)



Perhaps a purchased one from the manufacturer may have a different sound and reduce the noise dB level.

Cheers

Bernie

Bernie Knight
Mt. Gambier South Australia Driving in the sun

[era427tp]

Like hearding cats,it can't be done

[Cobra Dude]

I actually changed my exhaust pipes from glasspacks to custom-made sidepipes using the Stainless Specialties pipes. I agree with misfit41 ... they do sound a bit more tinny (lost a bit of that rumble), but were a bit quieter as well. The good thing is that the SS mufflers are actual mufflers, so will not burn out over time like glasspacks would.

I looked into SuperTrapps as well, and the only thing that bothered me was that it would not look like a "regular" Cobra sidepipe. But I know from experience with other cars that Supertrapps work excellent, and are very adjustable. Sometimes I wonder if I regret not going that route.

Cheers,
-Neil.

[65srpnt]

So are you happy with the Stainless pipes? Does it make a difference that I am running a 428 CJ? I just can't imagine it sounding tinny... I had them increase the muffler by about 6 inches. The guy told me that they use a 21/2 inch pipe instead of a 2 incher like the Standard Superformance....ah who knows...