We are getting into 4 things here:

1.) That "dyno number" is not reality, but you will need to put the car on a dyno to see.
2.) Our cars are making the sound I expect from a glasspack muffler when you let off the accelerator.
3.) The earlier sidepipe style (as shown in photo above) had baffles which would rattle loose and could be addressed with the screws.
4.) Current pipes are less restrictive and much better for performance.

So we have 4 different folks on this thread alone independently reporting unacceptable sidepipe rattle. One poor soul has gone as far as injecting silicon into the pipes to reduce the rattle and the other 3 have basically said "enough is enough" and willing to pay out of pocket for a solution or replacement pipes... But all we get from backdraft is "it's normal and we don't get complaints". LMFAO!!! Yeah ok thanks for that LOL!

You are misinformed. When you read a persons response you should also consider A.) What brand of car they have and B.) If it's a Backdraft what build era it is.

There are atleast 200 cars with these pipes out there from Backdraft. The other company using them has over 500 I would guess.

Have you ever owned a car with glasspacks?

Jay I've shared my experience directly as have others and we have been pretty clear that this sound is unacceptable and has worsened over time. I value your input and feedback, and I'm looking for options for an alternative set or a fix, but you sound defensive in this regard. Furthermore Backdraft has not been helpful at all. I'm certain that if you heard these pipes you would objectively agree that the excessive rattle is not normal.

My take away from this thread is the following:

1) These glass packed mufflers will have some waddle / rattle on deceleration.

2) HP of the engine is not a factor since you have 700+hp cars with these pipes and you find the rattle to not worsen

3) 200 backdraft cars plus another 500 other cars have these pipes with allegedly no complaints

So the only logical conclusion is that the folks who are experiencing this excessive rattling are:

A) uber-sensitive to this sound, since allegedly the other ~700 owners of the same pipes are happy.

or

B) is it possible, just possible that we have bad pipes that should be replaced by backdraft?

BTW Why is backdraft on backorder on these pipes? Design change?

For your consideration... there are only 2 people in this thread with the latest sidepipes from Backdraft THAT OWN A BACKDRAFT and are complaining of this sound. Now both of those people have cars from Millerspeed with Smeding engines.

Now this is vs. several hundred owners that purchased cars from other dealers with different engines that are not complaining.

That's what I am seeing here.

They are on "backorder" because they only ship enough pipes to go with each car, as that is the volume the company supplying them is contracted for.

I have a spare set in stock and I also sold a spare set about 3 months ago to a car owner in FL and he replaced the old design pipes with these and he has not complained about the sound or any change.

So again, look at the common denominator here and determine if anyone is being defensive.

Would like to add to this conversation.
i have experienced the same rattling noise on deceleration from m pipes for many years now.
I also have gone thru all the different fixes mentioned here (screws, high temp silicone, etc) to no avail.
I also went as far as purchasing 3 different sets of side pipes including firefly stainless pipes.
Nothing got rid of the rattling on deceleration.
So my conclusion is that the sound where all hearing has to do with our engines.
Not that there is anything wrong with any of our engines.
Just that there must be something internally similar that is common that is allowing this sound to make its way through the side pipes.
Eg: large overlap cam, cnc ported heads, Distributor set with large initial timing.. etc etc.

Jay if you're really going to point fingers at Alistair and his install job or Smeding, then please explain why your own customers have complained. See here:

Post by NEWBD (is this your customer with a coyote?): "BDR 1340 does the same thing. and I have taken the rubber mallet to them as well. It is not the 585 hp, because I have the 5.0 Coyote. It looks to me like back pressure, when you watch the pipe with the door open. All I know is its annoying. I talked with Jay on changing the mufflers out. If that noise is normal I don't want normal Jay and Brian will figure it out you can be sure of that."

another complaint regarding the new pipes (I don't think this your customer, but it is another data point from these new pipes)
Post by eedeutsch: "Mine also rattles when I am going slow. It probably rattles all the time, you just can not hear it going at some speed. I was told that the baffle is a straight through fiberglass pipe with holes in it. It sits in the side pipe loose. That the rattle is normal. I really do not know for sure."

Full thread here:
http://www.clubcobra.com/forums/back...questions.html

so your earlier argument was that only Jeff and I were complaining. What now?

If this is normal then let's stop the useless back and forth and I will work with Alistair and Reg on finding an alternate set of mufflers.

Spoke to Alistair, we are in agreement that you need to bring your car in or post some footage of the sound you are complaining about to properly address it and draw any conclusion. I am of the opinion the sound is normal for a sidepipe with a glasspack baffle in it and is consistent to the 200+ other cars with them. Sometimes there is a difference between an observation and a complaint.

On 1340 the deceleration sound was normal and we confirmed it when we consigned the car and resold it on his behalf (while it was here of course we drove it and did a full mechanical on it before it left for France). In a Coyote powered car the sound of the glasspack chattering is more obvious because these cars are significantly quieter at idle (when you let off the gas and coast for example).

I want to clarify that my inquiry as to who built the car and what engine is in the car was to draw conclusions on what your cars had in common so we can attempt to find some possible reasons for the sound. If the dealer was modifying the pipe or bending it to achieve a different fit then that could contribute. But my discussion with Millerspeed did not uncover anything they may have done (or not done) to cause any different sound then others are experiencing as normal.

Of course all this is being concluded with no actual recording of the sound provided...

I'll try to get a video this weekend and post it regarding my " card in the spokes" sound. I have a Roush 427R/TKO 600

I am sure that many of us older hot rodders would love to hear the sound of glass packs. I converted a '56 Chevy to dual exhausts with glass packs in my youth and the sound and increased power were memorable.

Also, it would be nice learn what Millerspeed and/or the Boynton Beach Boys have responded, if at all, about this issue and any future responses from them as well, as it is unlikely that they will post on this forum.

Here is a video of the noise mine make...

VIDEO

http://i51.photobucket.com/albums/f3...ps4oxn0bxc.jpg

I have had a rattle from the passenger side for about the last 3 years now. Today I had total failure the batting shot out of my passenger side pipe. It is hard to believe it has been 9 years since I had it built which would place the car in the older older version. What are the suggestions to fixing this $1.6k seems steep and on back order is rough. Has anyone just removed the packing and called it a day? Other than veryloud what else is the drawback? I do like the idea that the new pipes give less restriction to the motor.
THX

Screw size
 

I had similar problem with my FFR pipes (302). I used longer SS self taping screws of about 2". I could feel them grab the baffle ok and definitely quieted then down. Might last a year...

http://www.clubcobra.com/forums/pict...=15370&thumb=1

Looks like sh*t Welds. Where would one drive a screw. Tigging in their would be blind and difficult.
The Caveat is that the driver side doesn't even make a squeak.
Any one in AZ know a good Exhaust/Stainless guy?
Thanks,

What's a shame is no one make a set of aftermarket pipes we can buy and buying a new BDR pipe can put ya back in the same boat as before.....a possible crappy sound. Not sure if something is off inside my current pipes or if it's just a glass pack sound as Cashburn states.

I was trying to find a SS muffler that was the same length as my stock one (28") and have a local welder cut of my current muffler and weld in the replacement. My current BDR sidemeasurements are....

http://i51.photobucket.com/albums/f3...ps1i95i95f.jpg

We can offer this service it it makes sense to all from a cost perspective. Would not be able to offer polished pipes but could return in ceramic coating.

We've installed other mufflers before that do not have the sound your are disliking. The downside was the loss in flow.

What's the cost and the amount of flow loss you think?

picture of the new pipe
 

Can anyone post a pic of what the new less restrictive pipe interior looks like?
Much Appreciate.

We built the table to do this. I am waiting on mufflers to get here so we can experiment.

Folks:

An alternative to consider is to cut off the old sidepipes after the collector, and just after the pipe flares from 3 to 4 inches, get a spiral insert (Spiral Turbo Specialties) and a new 4 inch aft pipe section (in my case, from Stainless Specialties), cut the spiral insert to length (drill and tap holes as required to attach the spiral insert to the new aft pipe), have someone weld on the flanges for a v-band clamp, and voila! I did this not because of rattling but because I was tired of the sound of the original mufflers on my old beastie. I'll post pictures in a few minutes, once I find and reduce 'em.