Exhaust Experts Unite - need help

[RPMClassic]

OK here are the basics - 2.5 liter race motor with 46 Webers that currently has open megaphones. Need to find alternative that will get me in the 90+ decibel range.

I have tried and do not like:

phase 9's
bursch
sebring
dual supertrapps
dual megaphones with restrictor plates
dansk dual pipe

There have been mentions of Coast Fabrication and Burns, however most of the case diameters available would interfere with the lower valve covers. MK seems to be popular lately.

Open to any and all suggestions that you guys have experience with!

Lets hear it...............

[mb911]

the dual in single outs are very popular and work well with ever.ything we have worked on from 2.0 3.8 liter cars. Although some think you gotta have the dual outlets for more top end I am not sure that is always true. In that sense the dual outlets work well for those folks. I have a customer that has a 2.8 that he runs in a 72 rs and uses a single outlet shiffting at 8400 so it breaths and he says out of all he has tried this worked best. although you may want to try a monty as well but no persoanl experience

[911pcars]

Have you tried these inserts in a pair of megaphones?



Sherwood

[mb911]

those are very cool looking. what brand???????

[911pcars]

Ben,
Yes, very cool. I think Kurt had them custom-made for his lightweight. If you haven't seen it yet, you're in for a treat:

http://www.early911sregistry.org/forum/showthread.php?t=6828&page=6

Sherwood

[Bill Verburg]

Originally posted by 911pcars
Have you tried these inserts in a pair of megaphones?



Sherwood

Archimedes must be turning over in his grave do they actually do anything to quiet the exhaust?

Coasts, something like this

[RPMClassic]

Bill -

Thats a great picture of the Burns Stainless unit. Don't recognize the headers with the 3 bolt flange - mine are the old RSR 2 bolt style.

Any sense of cost as shown in picture?

Thanks

[911pcars]

Originally posted by Bill Verburg
Archimedes must be turning over in his grave do they actually do anything to quiet the exhaust?

Bill,
Kurt uses these in his "street" car. You'll have to contact him and find out how loud they are. If you talk to him, remember to speak loudly and succinctly. :-)

I recall him saying low rpm is fairly tolerable, but gets progressively louder. I didn't press him on how ultimately progressive that might be. I've got a feeling it wails at WOT.

Sherwood

[Bill Verburg]

Originally posted by RPMClassic
Bill -

Thats a great picture of the Burns Stainless unit. Don't recognize the headers with the 3 bolt flange - mine are the old RSR 2 bolt style.

Any sense of cost as shown in picture?

Thanks

No, but it is a nice setup, I have never heard the Burns mufflers but the Coasts are nice

[Bill Verburg]

Originally posted by 911pcars
Bill,
I've got a feeling it wails at WOT.

Sherwood

I've got a feeling that that is an understatement

[Carrera3.5L]

Originally posted by Bill Verburg
No, but it is a nice setup, I have never heard the Burns mufflers but the Coasts are nice

Bill, Coast makes them for Burns, they are their largest muffler buyer...

Ralph

[TimT]

I made this set up for my 914/6

the mufflers are Coast.

Burns, Coast, and I think Pegasus has a similar muffler, or is reselling either the Coast or Burns. There is really nothing special about the mufflers,straight through design, You can get them with either stainless wool, or glass packing.

Ive driven my car at Lime Rock and NOT been black flagged, however I think that is an abberation. Some days the Db meter is more forgiving than others.

I need to wear earplugs in my car, with 6 carb throats gulping air just over my shoulders, the cooling fan, and the exhaust wailing..It causes smilitis

[Bill Verburg]

Coast makes them for Burns

I didn't know that

I need to wear earplugs in my car

The short cans alow a lot more noise than the long

[JohnJL]

I have a flowmaster dual-in/dual out going on now. My exhaust guy (runs and preps carrera cups for a living) said the design looked very good, similar to the custom ones he builds for customers at 10x the cost...i'll let you know how it sounds and dynos as soon as i get it back from paint...

[Bill Verburg]

Originally posted by JohnJL
I have a flowmaster dual-in/dual out going on now. My exhaust guy (runs and preps carrera cups for a living) said the design looked very good, similar to the custom ones he builds for customers at 10x the cost...i'll let you know how it sounds and dynos as soon as i get it back from paint...

Thats what i have on my 3.8, it does work well and sounds fantastic, but it's not as quet as the long can Coasts.


I finally got around to painting the mufffler can black, much less obtrusive

[JohnJL]

Hi Bill, took me a while to notice your post...that looks like the same flowmaster...I stopped by the shop today and they were just mounting up the brackets...I'm gettin anxious...do you know what db you read? What are your headers?

john

[jluetjen]

Originally posted by RPMClassic
OK here are the basics - 2.5 liter race motor with 46 Webers that currently has open megaphones. Need to find alternative that will get me in the 90+ decibel range.

I have tried and do not like:

phase 9's
bursch
sebring
dual supertrapps
dual megaphones with restrictor plates
dansk dual pipe

There have been mentions of Coast Fabrication and Burns, however most of the case diameters available would interfere with the lower valve covers. MK seems to be popular lately.

Open to any and all suggestions that you guys have experience with!

Lets hear it...............

90 dB at WOT is pretty quiet, a lot quieter then the average Harley passing on the street. You'll be hard pressed to find something that provides good engine performance and adequate noise control, and still outperforms either a factory set-up, or what you listed above. Take a look at what many of the ALMS or Speed GT cars are using. I suspect that they've got something close to a 102 dB noise limit, and most of them seem to be using a Phase-9 type of set-up.

[Bill Verburg]

Originally posted by JohnJL
Hi Bill, took me a while to notice your post...that looks like the same flowmaster...I stopped by the shop today and they were just mounting up the brackets...I'm gettin anxious...do you know what db you read? What are your headers?

john

Yes, mine is a Flowmaster w/ B&B headers, it's way louder than 90dB

[911pcars]

I wonder if the crossover pipe has anything to do with the reduced dBs.

Sherwood

[Bill Verburg]

Originally posted by 911pcars
I wonder if the crossover pipe has anything to do with the reduced dBs.

Sherwood

That is one of the strengths of a x over w/ separate mufflers.