Custom Mufflers

[Abhishek Sheth]

I want to know what teams have had made successful custom mufflers? what did you register on the decibel meter? what was your weight?

How many people got a perforated tube style to work without making it crazy big?

[Abhishek Sheth]

I want to know what teams have had made successful custom mufflers? what did you register on the decibel meter? what was your weight?

How many people got a perforated tube style to work without making it crazy big?

[kapps]

We did. I'm not going to say it's short but it does beat 110 dB using the proper weighting scale on a Radioshack SPL meter. Aluminum shell, perforated stainless inner tube, a few baffles, and some ceramic packing. I can't remember what it weighs but it was less than the one we had to use last year to pass the noise test. The packing adds a decent amount of weight to it but we were over 125 dB without it.

[Abhishek Sheth]

kapps was it a particular type/brand of ceramic packing?

i have noticed most mufflers use fiberglass packing. what is the difference? approx how long/heavy was the guy

[Wesley]

We had a 7 pounder (made with a carbon shell and fiberglass around a steel perforated core)

It melted, but it was super quiet. 105dB.

[kapps]

Superwool 607 if I remember correctly. I'll try to get a weight if I remember. Oh yeah, stainless steel wool should also work pretty good as a packing material. Regular steel wool WILL NOT. It'll work great until you put it under load for a little while then sparks will start flying and part of the aluminum casing will start to turn red followed by lots of sparks flying out the quarter sized hole in the side. Not that I know this from personal experience...

[Abhishek Sheth]

holy ninja's kapps thats more sketch of a muffler than even I would deem unsafe...hahaha

[Macros]

We use choppy fibre glass for packing.

[Mikey Antonakakis]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by kapps:
Superwool 607 if I remember correctly. I'll try to get a weight if I remember. Oh yeah, stainless steel wool should also work pretty good as a packing material. Regular steel wool WILL NOT. It'll work great until you put it under load for a little while then sparks will start flying and part of the aluminum casing will start to turn red followed by lots of sparks flying out the quarter sized hole in the side. Not that I know this from personal experience... </div></BLOCKQUOTE>

Can anyone say thermite???

[Mikey Antonakakis]

I have a trick up my sleeve if we don't make noise this year.... last year it cut 9dB or so (we tested on the paddock with someone's pretty nice dB meter at like 118, and then I made the special device and put it in the exhaust and we were at 109 for the official test, first try). I haven't dyno-verified anything, but I will certainly test it out when our dyno is up and running.... the fit and finish were second to none. I made it with an angle grinder and a drill, sitting on the truck's lift gate in about 10 minutes lol.

[Wesley]

Header cones?

[Abhishek Sheth]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mikey Antonakakis:
I have a trick up my sleeve if we don't make noise this year.... last year it cut 9dB or so (we tested on the paddock with someone's pretty nice dB meter at like 118, and then I made the special device and put it in the exhaust and we were at 109 for the official test, first try). I haven't dyno-verified anything, but I will certainly test it out when our dyno is up and running.... the fit and finish were second to none. I made it with an angle grinder and a drill, sitting on the truck's lift gate in about 10 minutes lol. </div></BLOCKQUOTE>


Wanna let us in on the secret/hint

[kapps]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Abhishek Sheth:
holy ninja's kapps thats more sketch of a muffler than even I would deem unsafe...hahaha </div></BLOCKQUOTE>

Yeah, a brain fart on the part of four of us. It's a pretty cool site sitting at the dyno consol under full load at 10k rpm when the aluminum casing melts right in front of you.

[Mikey Antonakakis]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Wesley:
Header cones? </div></BLOCKQUOTE>

It's beautiful

http://i7.photobucket.com/albums/y294/hhspunter/DSC01159.jpg

[Abhishek Sheth]

That is so balls to the wall Mikey... Dyno that because i would be very interested in knowing. Can you feel a power drop when you drive?

[Mikey Antonakakis]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Abhishek Sheth:
That is so balls to the wall Mikey... Dyno that because i would be very interested in knowing. Can you feel a power drop when you drive? </div></BLOCKQUOTE>

Our tune wasn't good enough to really notice a difference, as we didn't spend a whole lot of time making full throttle pulls at competition... I think we got two acceleration runs in, and we didn't have much practice running through the gears (I think it was the first time there was ever a quick 1-2 shift in the car lol). In theory, there was a greater surface area with the holes and stuff than the diameter of the tube it went in to, so there wouldn't be any flow restriction, but I'm not sure what it does to any pressure waves you are taking advantage of to tune. Last year I don't think that really mattered, as our exhaust lengths were determined by how we could get aftermarket headers meant for sprint cars to fit in the car. I think we had equal length headers +/- 6 inches lol. If I get a chance, I'm definitely checking it out on the dyno to see what sort of effect on power it has.

As Welsey correctly guessed, it's basically a header cone. I didn't know about those when I made this (in fact I first saw them a day or two ago online, and said "wow that looks like what I made last year, kind of"), so I take full credit for the original design lol :P
Here are ones that you can buy:
http://www.hawkinsspeedshop.co...cts/product-688.html (http://www.hawkinsspeedshop.com/categories/exhaust-headers/products/product-688.html)
So I was a little reluctant to share, but hey, it sucks if you have a sweet car and can't compete because of something like noise, so I figured I'd share the wealth. It's not like no one has ever made them before, they are sold commercially... I only just found that out though. There goes another sweet idea of mine that happens to have already been made, it's the story of my life. No one will ever be able to make one look as cool as mine though! You guys should have seen the welder's face at the Lincoln Electric booth when I brought it to him and was like "can you weld these half-inch gaps?"

Also, as silly as it sounds, make sure you don't have any exhaust leaks.

[repeatoffender]

wollongong has made custom mufflers for years.

lightest i recall was 800g c/w fibreglass packing dB reading was 105 at comp.

made from ti.

ss equivalent version was 1.5kg

[kapps]

Just weighed it. 5.25 lbs with stainless mounting bracket attached. I'd say between 1/3 and 1/2 of that weight is packing.

[Drew Price]

FYI, we run a stock muffler from a Yamaha R1 (there are two identical ones fitted to the bike). Factory it's a titanium case and header pipe, steel packing, and passes sound (on our Suzuki 450).

It weights 4 lbs 2 oz (1.85 kg).

I can't speak for how restrictive it would be on a 600, but works great for us.


http://lh3.ggpht.com/_JNlhJgnxXHk/Se7RlEpUh4I/AAAAAAAAA5M/owS652ea_64/s640/2009%20R1%20Muffler%20001.jpg


http://lh6.ggpht.com/_JNlhJgnxXHk/Se7Rld16KJI/AAAAAAAAA5U/z46nyajqDcU/s640/2009%20R1%20Muffler%20002.jpg



Best,
Drew

[Grant Mahler]

Also, the titanium R1 muffler glows a pretty sweet orange if your crip value is off by 180'...