Boig Quiet Pipe Mounting Question

[drewr]

So I have a “Chicken or Egg” question. What comes first?
I was mocking up my unfinished Boig Quiet Pipes. They came with hanger tab unattached. I’d like to have them ceramic coated white, but I don’t know where to attach the tabs. Everything I’ve read says wait till the body is mounted to figure out the pipe hangers. So I should wait till then to figure out where to attach the tab? I’d like to get the pipes and headers ceramic coated soon before my first start. Am I over thinking it? Should I just approximate the tab position? It seems suboptimal to me to coat the pipes only to grind an area to attach the tabs later.

What have others done? I can’t seem to find this specific problem in other build threads.
Thanks!

[Bob Brandle]

drewr,

I'm assuming that by Boig Quiet Pipes for the Gen 3 Coupe, you mean the thick diameter single sidepipe per side.
That's what I have for my Type 65 Gen 3 Coupe with Gen 2 Coyote. I believe that I received the 3rd or 4th production set from Boig.
They assembled onto the Coyote with ease and in fantastic alignment, as well as alongside the Coupe.
On my Boig Quiet Pipes, the hanger brackets came already welded on. They're positioned exactly 10 inches forward of the outlet tip.
One has to figure out how to mount the accompanying angle bracket to the underside of the chassis, either to a structural tube or, as I did to the floor pan. The actual fiberglass body plays no part in the positioning or attachment of the sidepipes.
Here's a few photos of mine, both before I had professionally coated the cold-roll steel sidepipes and headers with Creakote C-400 Glacier Chrome Ceramic.

One question I was faced in designing the attachment was whether to have some sort of vibration insulation or just go hard mount metal to metal. I chose to have "rubber" vibration insulation. My design might be overkill, but I wanted both strength to hold up or boost up a bit, the end of the sidepipe (if needed) and to have a break in the metal to metal path via a rubber only area.

Here's a few photos, hope that they help you.

Bob



Just the hanger bracket attached to the sidepipe bracket mount, but not yet mounted under the car.



NOTE, Elsewhere in the FFR Forum or FFCars Forum, there's been a discussion or two on whether there should be two bolts or a single bolt attaching the hanger bracket to the welded on sidepipe mount.
Even though I show two bolts here, in my actual final mounting I just have a single bolt. With 2 bolts the theory is that there is likely going to be torque movement in action here during driving and even slight sidepipe movement that could lead to a cracked weld at the weld to sidepipe wall junction.



This is how the mounted sidepipe looks and that's WITHOUT the hanger attached, just dead weight hanging. Quite an amazing horizontal alignment.



With Cabin body mounted, still WITHOUT Hanger attached.



With early body on. Look how parallel the muffler section of the sidepipe is to the body. Maybe the hanger should raise the rear tip 1/4 inch, but, as it sits there, it's all quite rigid.

Hope that helps you.

Bob

[drewr]

Thank you! That is exactly what I was looking for!

[jgray]

Great pictures! How much quieter are are the quiet pipes?

[drewr]

I haven't fired mine up yet. My understanding is while they are not quiet, they are more quiet than the stock pipes. Maybe able to pass decibel restrictions at certain tracks (95-105 Db?)? Too loud to ignore, and maybe still requiring earplugs. Supposedly more mellow with a nice growl.

[jgray]

Thanks - I live in Northern California and if I ever want to go out to Laguna Seca I know that track has a decibel limit. Once you fire yours up please report back!

[David Williamson]

I have them and you still will need ear plugs. They reduce the high frequency sound level but the low frequency is still there. At highway speeds you can't talk to your passenger, we use noise cancelling head sets.
David W

[racingandfishing]

Since this thread seems to have been derailed....hope it's okay to take the opportunity to see if anyone knows the decibel ratings for the Boig's. I know it can vary with compression, cams and other things, but wonder if there are base values.

I was told the FFR pipes are in the neighborhood of 105 decibels at idle and 120 decibels under power (not verified). I love loud, but that is a little extreme. Wish they would come up with a solution that doesn't require adding a 3500 series diesel pickup muffler to the side of your car!

With that said, I am also looking into Gas N Pipes. The decibel levels are apparently around 84 at idle and 103 under power, but not sure how that compares to the Boig quiet pipes.

P.S. apparently each 10 db = 10 times louder.

[drewr]

My understanding is that Boig pipes are similar to Gas’N. The preference seems to be regarding the finish. There was a thread on the original Boig post introducing the pipes that compared them. You can search it using “Boig Quiet Pipes”. Boig pipes are steel (not stainless) and will require paint or a coating.

[Rian_Colorado]

The folks that bought Boig will tell you that they are quieter than the gasn's. Their contention is "1 pipe vs 2", larger baffles etc. They told me that they think it's 10 fewer db.
Note: This conversation was specific to gen 3 Coyote in the coupe.....

RR

[Jeff Kleiner]

I was told the FFR pipes are in the neighborhood of 105 decibels at idle and 120 decibels under power (not verified)...

There’s a reason that isn’t verified…because it’s bogus! Do you have any idea how loud 105 dB is?

Jeff

[racingandfishing]

Info came from Gas N Pipes, so yes it could be biased!

All I have found so far is that the FFR pipes are way too loud to drive without ear plugs or noise cancelling headsets. If that is not the case, sure would save some money.

Honestly, I'm not trying to make a case for any of the three options. Just trying to get enough information to make a good choice.