Cruzer,

I knew I shoulda taken some pics while the job was in progress but I didn't, sorry. Now that it's all buttoned up it's kinda pointless because all you'd see is a big black hole around the muffler. Basically it's removing the heat shield, undercoating the daylights out of both sides and also undercoating the hell out of the chassis body panel in the area where the muffler is. Then pop the shield back on and bolt the muff back in. I also put a little foam rubber between the shield and body. I used neoprene that I got at a foam rubber place (the foam factory). The neoprene is pretty dense and doesn't break down as fast as other stuff.

Jeff M.

 

If it bothers you that much...

Drive in a Lower Gear or higher gear... 1000Rpm Difference from 3 - 4, 500 RPM Difference from 4 - 5..

Problem solved...

 

Hey everyone! grim013 knows the solution.

Thanks grim013! We couldn't have done it without your devotion and love for posting senseless comments.

 

Silver_p5

Good work, i see you push your experiment further than i did whit the heat-sheild.

What about the under driver seat heat-sheild ?
To my sense this one vibrate much more louder than the rear one.

BigBad woulf

Great work you should got it.

Sorry if i can't help much, but i'm too afraid to fail my last chance wife test.

 

I thought about the front shield but was concerned about the excessive heat there. The pipe runs really close to shield and I didn't want to risk a potential fire. The rear one works pretty well. It's still a little on the loud side during acceleration or deceleration, but at cruise speeds it seems much mellower. Waiting to see how Wulf's pipe insert works. Eventually the beast will be tamed!

Jeff M.

 

Weekend projects:

Experiment #1: Beef and bean burritos served steaming hot, sprinkled liberally with finely shredded sharp cheddar cheese, topped with a generous helping of thick and chunky salsa, and washed down with an ice cold beer served in a frosted glass.


Experiment #2: Remove the MazdaSpeed exhaust yet again; photograph the rear heat shield before and after applying undercoating/sound deadening, reinstall the exhaust and then run some more trials.

silver_p5_owner – I was encouraged by the results from the bit that I did spray, and I agree, I don’t think this shield will get hot enough to be a problem. However, I have the same reservations about doing anything with the front shield. I’m thinking that puppy gets too hot even for Nelly.


I’m still waiting on word from the metal fabricator – I’m dealing with a company called Modern Welding. They have a few locations around Kentucky and really do first class work with various metals, including stainless. Of course I’ll post photos of the piece as soon as I get it, then I’ll start the testing. I’m shooting for a design that looks and fits like it was a part of the exhaust straight from the factory with no restriction of flow, but plenty of restriction in “drone.” Also, I’ll be reviewing possible attachments – drill and screw, or if insert turns out as well as I hope, I may just have it tack-welded in place.

 

Another weekend of experiments…

I tried the undercoating/sound deadener on the rear heat shield and surrounding body panels. I can’t say I got spectacular results with this approach. However, I also have to qualify that by saying I didn’t go as far as silver_p5_owner did, either. There was a slight reduction of sound levels, but the 3 to 4K RPM drone was still there. I didn’t take any photos – it’s pretty straightforward; find your muffler and look up. The big piece of curved sheet metal is the heat shield.

Running back-to-back trials without, and with the pipe insert, I found the insert much more effective. (DISCLAIMER: Never, ever stick something in your exhaust without a mechanical attachment of some sort – screw, weld or whatever. When I’m running a trial I use a long bolt through the drip hole in the bottom end of the tip just in case the insert comes loose.) Also, I tried a 6” insert instead of the 5 ½” pipe and found that mellowed the tone somewhat throughout the RPM range.

One of these days, maybe not in my lifetime but at least in my child’s, there will come word of a stainless insert for the MazdaSpeed exhaust, tamped and welded in place to finally dampen the notorious mid-RPM range resonance and free humankind for even greater endeavors.

Cheers,
BBW

 

Wulf, I have to agree with you on the sound deadening. Just spent 6.5 hours in the car cruising at 70 -80 mph with the windows up and A/C on and the drone was nasty. I think the undercoating is OK around town at slower speeds and windows / roof open, but man, at speed for hours on end it's on the verge of unbearable. I'm gonna try some pipe inserts experiments (at least you don't have to pull the exhaust!). When you hear from you fabricator please post the details. Appreciate all your help and efforts.

Jeff M.

 

BBW,
I tried to pickup my part Friday, but they only take cash/check and all I EVER have on me is my debit CC card. I did get to look at what he did and I am impressed to say the least. I will take some pictures tonight and post them hopefully tomorrow AM.

BTW, I am in hot pursuit of the part you want (In YOUR lifetime).

 

Just got my quote from the metal fabricator - $196. WTF! Called them up to make sure they didn’t make a terrible mistake in their bid. Them: “Nope, that’s what we figure it’ll cost - labor rates are up there.” Me: “Look, I just wanted to buy a stainless insert, not the shop, welding equipment and two guys to do the work. Thanks for your time…”

silver_p5_owner – The insert worked in my trials on the interstate, a bit of tone with the windows up and AC on, but about half the sound level I had when running without. Also, I haven’t noticed any corrosion problems with the limited testing I’ve done, just a little soot and the iron looks like it’s been tempered. I may end-up revisiting this option, myself. I’m still chasing the attachment side of this solution – I’m not real keen on drilling a hole through the tip, I don’t want to weld a piece of iron in the exhaust, the long bolt through the existing drip hole is necessary for safety with a “wedge job, (you don’t want to blow a piece of pipe through someone’s windshield,) but it’s ugly, so maybe a couple of allen head set screws drilled and tapped in the insert?

P5Freak – I think this may be riding on your results, now.

 

Well I just got back from testing a pipe insert that completely bypassed the muffler's innards. It has been my most succesfull attempt yet. I got an 18" pipe from pep boys, 1.75" I.D. stretched on one end to fit another 1.75" ID (giving an OD of slightly under 1.875" on the fat end). I pushed it all the way thru until it was snugly seated inside the pipe that feeds into the muffler chamber (effectively bypassing all the muffling packing). There was a good sound (no drone in the car at all rev ranges). I had my wife nail it a few times up and down the street to listen from the out side and it was still pretty bassy with a slight bit of raspiness, nothing like a Honda "fart pipe", much nicer. If I can find a source for stainless pipe in this dimension (my goal would be 1.875 OD for the whole length, without the taper down) it will probably be my fix. Or I'll ebay, or offer thru the forum, the pipe to someone who can take the noise and I'll have a custom pipe with only a tip on the end made. It is now obvious that the muffler chamber is the main source of the resonance.

Jeff M.

 

Hello and Welcome to another exciting edition of "THAT MAZDASPEED EXHAUST IS TO DAMN LOUD!!" and I'm your host P5freak!

The part is back and the pictures are below (some have poor quality). I had the OD bumped to 2" by welding a stainless strap of steel around the exhaust. As you can tell from the side profiles, my fabricator guy read my mind...

He blended the side going into the exhaust (tapered) so that it will be able to squeeze right in. I did try it last night and it did seat fairly early so I may have to do a little bit of massaging to the OD to something less than 2". It's really close! Better to be a bit bigger than smaller.

Take a look at the pics and let me know if anyone has questions. C Ya!

REVISION!!! I REPLACED THE PHOTOS WITH LINKS BECAUSE I WAS OBSERVING BROKEN LINK ERRORS

http://www.ofoto.com/BrowsePhotos.js...id=97195459403

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Under the category of “strange science:” reducing the exhaust pipe diameter from 2” to 1 7/8” results in a 12% loss in cross sectional area. Stepping down to 1 3/4" from 2" gives you a 23% reduction.

Also interesting is the fact that the cross sectional area of a 2” exhaust pipe is equal to Pi – 3.14156”. In ancient Greek civilization a 2” exhaust pipe would have effectively represented numeric perfection. Unless you happened to be a Stoic, in which case you would have been stuck with a 1” factory system and no hope of ever upgrading.

“Dr. Wulf, what relevance does that have?”
“Not a bit, Timmy, but don’t worry about it, just turn-up the music and enjoy your MazdaSpeed.”
“But it hurts.”
“It’s okay, Timmy, soon you’ll completely lose your hearing and you won’t care anyway.”

Ah, if only poor Timmy were a Protegeclub forum reader…



P5Freak - Thanks for the photos! Looks like the shop did a great job, but damn those places are expensive.

Meanwhile, I'm researching high-power rifle silencer technology for possible insert solutions... "Click-Click-poof!"

 

Hi Guys...I know nothing about this stuff except that I've been reading this thread with a sadistic fascination. I'm just wondering at this point. By inserting things into the muffler, aren't you effectively reducing airflow, etc, etc and basically defeating the purpose of the muffler upgrade in the first place?

If this is the only solution to your noise problem, isn't it really more logical to just scrap the F'ing thing, call it a loss and go back to stock?

I'm really not trying to be a wise ***, I'm asking this seriosuly. At what point do you admit defeat? And I can hear the chorus of "When they pry my muffler from my cold dead hands." LOL

I realize you have a couple hundred bucks invested in the things, but there must be life after Mazdaspeed mufflers gentleman!

 

TexP5 –

Actually the inserts I’ve dealt with match the I.D. of the existing pipe, so there isn’t a restriction to flow. My focus has been to “retune” the resonance of the system to eliminate the drone. Also, I’ve looked to achieve this goal with a minimum (<$50) investment. Day-in-day-out I run a custom Dynomax system because the MazdaSpeed is just too loud for my taste. However, I reinstall it for whatever trial I’m running at the time.

At this point, the price of admission has been worth every dollar I paid just for the education I’ve gained in exhaust tuning and automotive acoustics. (Many thanks to everyone on this thread! And especially to P5Freak for starting it.)

A high point came when I contacted a local muffler manufacturer and asked to speak with an application engineer. Their reply: “Sorry, but we don’t have anyone like that working here.” My response: “Okay, that would explain a few things.”

And yes, I’m researching how to cut the freaking muffler and tip off and install a universal muffler that actually serves a purpose besides being a “shiny can.” But meanwhile, I was just thinking if a person took a 2” insert and cross-drilled sixteen ½” holes through it, what would that do to the exhaust pressure wave and sound? Hum…