I was looking at these

http://www.engineceramics.c...rdpart/ccinserts.htm

for my 2.8 exhaust build. I don't have any knowledge of the application, other than general theory.

Anybody on the forum have any experience with these, and how loud are they compared to a Flowmaster 40?

Arn

I've seen these in person at the Woodward Dream Cruise, amazing. The guys are running open headers and the sound is most acceptable until they goose it. Open headers are usually louder than crap and these sound very much like they have a full muffler system. Night and day difference, I don't know how they do it, looks so simple too. We're 5 weeks away from the Dream Cruise, London isn't to far away, see it for yourself or remind me and i'll be out there with my camera and get some video for you.

We were discussing this a couple of years back, I found my book mark on the "tube mufflers" which is the same company, same concept.

https://www.fiero.nl/forum/A...050119-2-055476.html

If I didn't hear it with my own ears, I wouldn't believe that you could put a simple insert and get an open headers down to street legal sound levels and we're talking big blocks too. It really is amazing, at least to me it is.

Thanks Jetman. Good to know. Seeing as how sound is kind of subjective, any other views?

Arn

Interesting
I found a slightly different product that claims to do the same :
dynatech


If it is as simple as it looks it shouldnt be hard to fab something yourself !

This is their explanation:
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Rules--they're everywhere. When it comes to sound requirements, they can't be ignored. Don't take chances with sound control, or you may end up on the trailer. Vortex cone inserts from Dynatech easily install near the exit of the header collector or muffler outlet to reflect and dissipate sound energy, reducing the decibel level. Because the open area of the cones is greater than the area of the collector or exhaust pipe, there's no significant backpressure, so you reduce noise with little or no power loss. The cones are made from T-304 stainless steel and weigh less than 1/2 lb. each.
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I originally used the inserts on my v8 WITH dual Flowmaster 40 series deltaflows and it was too loud in my opinion. I loved the sound at first but it was excessive for driving in the city and attracted too much attention every time I touched the gas pedal. If you're planning on using the inserts instead of mufflers be prepared for very loud exhaust under acceleration. The technology was developed for reducing sound levels to meet increasingly stringent noise regulations at the track while not significantly increasing back pressure. From http://www.carchemistry.com.../car/inserts/faq.php - "Each application will be different. Typically the 2 disk insert will reduce sound 3-5 decibels. The 3 disk insert will reduce sound 5-7 decibels." 5-7 decibels is not a tremendous amount of sound reduction, especially when you consider you're paying $100 - $140 for a pair of inserts and only getting a limited drop in noise level.

I noticed the cones give 1-3 db loss while the disks give somewhat more.

In the case of my exhaust I need to decrease the db's before the tips, and in the case of the rear bank, I have very little room. An insert is therefore a way to knock down the sound a bit before the tip muffler.

It is possible to combine inserts with a flow thru muffler and get a reasonable reduction I think, but, I haven't done it.

Arn

What exactly are you trying to do? Are you trying to remove your muffler?

The best way to quiet an exhaust is use the proper muffler. A 3 db drop will hardly be noticable. If you want to drop your ehaust noise then just get a bigger muffler. Spending money on these exhaust restrictions may not only be a waste of money but could hurt your performance.

Doug you kind of missed my situation. These are true duals. The rear bank has 33" primary tubes and very little room for any muffler. Having used a Dynomax turbo which was pretty quiet, I can tell you I lost alot of torque. The baffled Moroso muffler on the other hand, had very little or no back pressure and the Magnaflow even less.

The inserts for my application will leave lots of flow. We are talking 2.5" pipe servicing 86.5 ci. I suspect that either insert type will actually work, however, you are correct to point out that 3 db does not cut it. I need to cut the db's in two stages, at the collector and at the tip.

My tip mufflers are also problematic. There is 19" of room between the cradle and the end of the bumper. This means very few mufflers fit, especially when you measure the opening of the bumper at the inside. There is room for the Monza twin tip, the Moroso, the Spintech (ugly) and Magnaflow, (pricey).

I have used the Moroso on my stock system and it was a little too loud on its own. It needed some help. The Monza resonator tips also need help. They tend to be pretty loud at WOT.

So as to not attract unwanted attention but give my headers a chance to breath, I have to do some careful thinking.

Arn

If you can weld or know someone that can weld, you could build your own muffler. Then you could build it to fit perfectly in your space. How much it will reduce your exhaust noise is going to depend on how you build it and what materials you use. 19" is not a lot of room to do too many things.

You could build a muffler with just baffles in it that would be very low restriction but it could be hit and miss with the harmonics. Another way to go would be to have a perforated pipe go through the muffler with two 45 deg turns in it and fill the rest of the muffler with sound absorbing material. That might be the quietest low restriction muffler. You could also take a look at a muffler you like and just build a version of it that will fit in your space.

Why would I fabricate what Magnaflow makes? I don't get the logic. I can pickup a Moroso already fabricated for $51.99 at Jegs and it has 4 spiral baffle plates already welded in.

Yeah I have a welder, but making a muffler doesn't seem to make much sense to me.

Long tube headers, on the other hand, I had to make.

Arn

Remember that exhaust systems on rear engine cars are not always as long as on front engine cars. A lot of 3800 swaps have a very short exhaust systems because the headers end in front of the trunk, inches from the muffler. Thus, the exhaust doesn't always cool down as much by the time it reaches your mufflers. I had a discussion with Chris West over this. He said something about how glass packs had to be replaced every few years.

Kind of related:
During the war in nam they fitted some light FAC aircraft with mufflers based on lots of small holes to break up the sound. I read that they did good job. You could hardly hear the low flying planes untill they directly over your head.

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[IMG]




trueleo.com
RSpiderII@aol.com

I used one on my DOHC swap Went from LOAD Harley sound to nice quite street car but still had a nice grown when you hit the gas.

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Dave

www.ltlfrari.com

I wonder what the result would be if you popped one of these cones into a muffler with a 3" inlet. While the area of all of the holes in the cone is more than the diameter at the end it just may reduce sound while having a minimal effect on back pressure. .

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by ltlfrari: I used one on my DOHC swap Went from LOAD Harley sound to nice quite street car but still had a nice grown when you hit the gas.

Yes, that's the effect that I have seen out on Woodward Avenue during the Dream Cruise. I'm wondering what the efect of using both the Dynatech cone and the Car Chemisrty inserts would be? One of those sites made mention of using a cone ahead of the inserts but in Arn's case, he's running true duals, he'd need two of each. Wondering out loud what the hot rodder forums say about inserts.

I have a thread on www.hotrodders.com and no responses so far.

I appreciate all the feedback on the inserts. The CC inserts seem to be a good idea, however the Schoenfeld appear to operate the same way those Vietnam era aircraft did the muffling, with numerous small 1/4" holes in the walls of the pipes and and outer casing.

Arn

I know some bracket racers that have run with and without the Dynatech cones. Big power loss with them, despite their advertising of minimal restriction. Maybe it doesn't matter as much on the street, but if power loss is important to you, keep it in mind.

Rick

Hi, I made a set of two disc mufflers like the cc ones for my turbo formula, I put a dynomax bullit muffler where my cat used to be with 2.5" exhaust. My turbo is rear mounted with a short 3" elbow for the outlet. It was still to loud so I made some inserts to go in the ends of the exhaust alot like the cc ones, they work awsome, and I did not notice any power loss. Even if I had lost alittle power it still would have been worth it, as the car sound alot better now.

Hi Arn,

Those inserts look very similar to what 4 stroke dirt bike riders use. Typically achieving 6dB reduction in sound level. I'm sure they are effective.

daveg