Mazda Talk Forums

IanE481 wrote:Excellent. Thanks for the suggestion Brian. I'll try to get at it sometime this week and I'll report back.

Quick question: I have this in my toolbox, will this work?

https://www.permatex.com/products/gaske ... ket-maker/

If there is something more suitable, please advise before I goop it up around the joint.

Thanks,

Ian

Grab that tube of gasket maker. As the video goes past the helmholtz bracket I can see weld does not go all the way around, there is some gap between bracket metal and pipe. That's intentional but let's fill that gap. I am skeptical it could rattle in that gap but let's see what happens if we eliminate that gap with something that will act as a damper.

Okay Brian. Will do first thing in the morning. I inspected the welds and they are all intact with zero cracking. The welds are nicely done and high quality. Seems they purposefully leave a gap between the welds. I carefully inspected that gab and there is no rubbing.

I'll put a good amount on it to see if that helps dampen. Kinda takes me back to my "Vibes" classes in Engineering school. I'll try anything right now. As I walked underneath it with my wife blipping the throttle it didn't seem to be any vibration as much as acoustical flow noise... if that makes any sense. The exhaust seems to hold rock solid.

I'll try it and let it cure then get back to you. Thanks for helping!

Actually going to go do it now so the gasket maker can cure overnight. I'll delay my movie night with my wife and get this done first. It's driving me crazy and becoming an obsession to fix.

Okay. Done. All gooped up. Ensured the gap has been filled and had a good liberal amount around the holder. Will test tomorrow.


What the heck did I do before I had a lift!

IanE481 wrote:As I walked underneath it with my wife blipping the throttle it didn't seem to be any vibration as much as acoustical flow noise...

That was my impression from the video as well.

IanE481 wrote:What the heck did I do before I had a lift!

Dunno what you did, but I work under the car relaxed on a creeper -- AKA "bed" -- rather than craning my neck under a lift. MUCH more comfortable. I admit a lift has its benefits. I even admit I crave one. But working on your back is actually more comfortable.

jboemler wrote:

IanE481 wrote:What the heck did I do before I had a lift!

Dunno what you did, but I work under the car relaxed on a creeper -- AKA "bed" -- rather than craning my neck under a lift. MUCH more comfortable. I admit a lift has its benefits. I even admit I crave one. But working on your back is actually more comfortable.

That is true. But the amount of times I've had to make adjustments... jack up the car, position the jack stands, make an adjustment, jack up the car, remove jack stands, lower car... go drive. Sound still there... repeat MANY MANY TIMES!! Driving me crazy. I can still use the lift lowered and use a creeper if I want. Now I just drive on the lift and set the height I want... with no jacking.

Brian wrote:

IanE481 wrote:Excellent. Thanks for the suggestion Brian. I'll try to get at it sometime this week and I'll report back.

Quick question: I have this in my toolbox, will this work?

https://www.permatex.com/products/gaske ... ket-maker/

If there is something more suitable, please advise before I goop it up around the joint.

Thanks,

Ian

Grab that tube of gasket maker. As the video goes past the helmholtz bracket I can see weld does not go all the way around, there is some gap between bracket metal and pipe. That's intentional but let's fill that gap. I am skeptical it could rattle in that gap but let's see what happens if we eliminate that gap with something that will act as a damper.

Okay Brian. I'm done. I give up. I took the car on errands this afternoon. The gasket maker made zero difference. I've tried everything. Somehow on this particular midpipe the HH chamber is making an awful noise. I know there are no moving pieces and I'm at a loss... but something about this particular pipe is singing a terrible song.

I've done everything you've suggested. I've tried hundreds of little tweaks. Now that I have a lift and could record it, the video clearly shows the HH chamber is not right. I've had a couple of automobile-savvy friends over to listen today. It's clearly the mid pipe. I'm done. I'm so frustrated you have no idea. I have spend more hours under that car than in it for the last several weeks.

I have driven the car on the lift and I'm not driving it again until I put on a different midpipe. I'm done with the Helmholtz concept. May work for many but this is a terrible experience. I want to go back to the traditional mid pipe. I'll put up with an occasional drone for a nice sporty sound.

I'll call your office on Monday and hopefully talk to you or Ryan. I don't want to play out the rest in public but I do ask that you, as a reputable businessman, take all this in consideration and help me salvage something out of all this time, expense and frustration.

On every application there is a certain rpm where a new Helmholtz can makes some metallic resonance when new, and 'metallic when new' is noted over and over in the forums. Also noted over and over in the forums is that the metallic nature of the setup fades as insides of entire system get a good damper coating of carbon. If you check the threads at Miata.net you will read that more than a few mention they ordered up the glass packed baffles to absorb metallic and rasp early on, and many report they used them just a few weeks to a few months before checking the system sound without the glass packed baffles and discovering the baffles were never needed again. Your video mentions super low miles for car of that year, nearly new clean motor means less carbon making in general and it would take a while for entire system to reach final sound level. Thus, suggest you try the baffles that my team already sent before you conclude you really tried 'everything'.

I did put my ear to helmholtz here and I get the same sound as your video, but we don't drive that way and your video shows the new muffler at the back is already doing a good job of filtering most of that. With time the muffler will just filter that more and more as the glass fibers gain mass with carbon addition and all bare metal gets coated start to finish in the system.

If still not happy after trying baffles we would trade you to the traditional fiberglass midpipe, but I really think you are giving up early here and going the wrong direction. Nonetheless, we are all using different ears to hear it, so if that's what you ultimately prefer we would help.

IanE481 wrote:

jboemler wrote:

IanE481 wrote:What the heck did I do before I had a lift!

Dunno what you did, but I work under the car relaxed on a creeper -- AKA "bed" -- rather than craning my neck under a lift. MUCH more comfortable. I admit a lift has its benefits. I even admit I crave one. But working on your back is actually more comfortable.

That is true. But the amount of times I've had to make adjustments... jack up the car, position the jack stands, make an adjustment, jack up the car, remove jack stands, lower car... go drive. Sound still there... repeat MANY MANY TIMES!! Driving me crazy. I can still use the lift lowered and use a creeper if I want. Now I just drive on the lift and set the height I want... with no jacking.

Absolutely agree when doing short adjustments -- I'm just jealous I don't have the option.