Sport Muffler Conversion, RSR Style?

[rennch]

I'm toying with the idea of converting my early muffler to a dual-outlet sport muffler. However, I don't want the narrow twin tips...I prefer them wider, so they match up with the rear bumperette location, as they were on the RSR.

Questions:

1. Can I simply move the exit pipes further to the outside, or were they in their locations for a reason?

This is what I am thinking of doing:



2. I also have a flowmaster 2 in 2 out that was the original plan for the muffler. Is there any advantage to sticking with the original plan and just mounting it instead of going with the sport exhaust??

[Joe Bob]

Sure, why not?

[rfn026]

It shouldn't make any difference. I put my pipes just to the inside edge of the bumperettes.

Richard Newton

Autocross Performance Handbook

Ultimate Garage Handbook

[rothaus]

Check this out, this is an other way to convert to dual exhaust pipe

http://www.dietersmotorsports.com/twinpipe911.htm



Cheers
Engelbert



http://carmagic.us

[T77911S]

let us know how it goes. i have been considering this mod too

[t6dpilot]

I considered this mod also before a really nice sport muffler (narrow pipe version) fell into my lap. I really like the look and sound of the triple outlet exhaust of Scyip Designs. It has a really great sound and I wonder what they did to the internals that is different from the factory muffler. Looking forward to your solution.

[175K911]

Originally Posted by emptyo

I'm toying with the idea of converting my early muffler to a dual-outlet sport muffler. However, I don't want the narrow twin tips...I prefer them wider, so they match up with the rear bumperette location, as they were on the RSR.

Questions:

1. Can I simply move the exit pipes further to the outside, or were they in their locations for a reason?

This is what I am thinking of doing:



2. I also have a flowmaster 2 in 2 out that was the original plan for the muffler. Is there any advantage to sticking with the original plan and just mounting it instead of going with the sport exhaust??

Something like this? This is Ben's 911R M&K muffler.
(BTW- I modified a dual in muffler like you want to do, and it's pretty loud. Basically the outlets are lined up with the inlets so there's nothing muffling the exhaust as it goes through the can.)

[rothaus]

This must be very loud !

It looks to me that the gasflow is as the arrows show below for the stock one.




The modified one is just straight through




I like the conversion with the second exhaust on the right side, like this page describeds

twinpipe911




Cheers
Engelbert

http://carmagic.us

[RWebb]

I would exercise some caution in purchasing or modifying a muffler.
Engine dyno testing has shown that most aftermarket mufflers actually REDUCED hp(!) Check out Bruce A's book and some of his columns for some of the details. Other data exist but are closely held.

As Dr. Brakeberg recently noted on another thread, reinventing the wheel is not always so smart.

One Tidbit:
On the 993, P AG spaced the rear exit tips at a precise distance apart based on wavelengths of the noise components to achieve reduced noise. That is in one of the more recent UpFookin' volumes - maybe the glossy covered one or the one before it.

Good Luck - and decide if you want performance, noise, or just Bling.

[cnielsen]

Like this one?

[rennch]

Yea...that one looks really cool. Is it loud as hell? (Or was it loud as hell?)

[Fleming]

Michael, if you start with a Dansk muffler they look somewhat different on the inside. But they can be mod'ed similar to what sculptor Mr. Jeff Gamble did (so many years ago).

[rennch]

Looks cool, but it's not what I have. I actually have a flowmaster muffler I was going to use for this, so I might just go that route. But I was thinking of doing a sport mod just to see if I could.

[911pcars]

Originally Posted by Fleming

Michael, if you start with a Dansk muffler they look somewhat different on the inside. But they can be mod'ed similar to what sculptor Mr. Jeff Gamble did (so many years ago).

I'd like to inquire the results of these modifications? The plans seem pretty defined. I wonder why that particular approach or was it just seat-of-the-pants engineering?

Is the inside of the 2in/2out Dansk different?

Sherwood

[911st]

My best guess is you might concider:

Cutting off the stock exaust tip.
Then cut it away further on the inside and up to the first bulk head.
Then, install your two tips out side of the two outer bulk heads.

You will have come close to making it a muffler equal to just adding a second tip to the right side.

A muffler with a mirrored second tube added to the right side, is a proven design that makes Hp and is not concided to loud.

This is what I would do.

[GotaT]

How can you distinguish the difference b/n a stock muffler and others?

[911st]

Note on the orange car above, the new tips are not direct accross form the in-side which would be like a a straight pipe.

They are on the out side of the outside bulk heads. You will be able to see where these bulk heads are located from the outside of the muffler.

With the mod as I noted above, if you wanted to you would be able to plug the right and have a near stock sound if needed. You might start with the right pipe only having a 1" hole in it and open it further if more sound it wanted.

[curtisaa]

I just tried this and it turns out to be cheaper to buy a new one, than doing the mods.

[rennch]

I like it.

How is it cheaper to buy a new one? I can do this in an hour or two for like, 15 bucks.

[rfn026]

I did the whole thing for less than $50. That was because I had to pay for the welding. If you can get a new 911 muffler for less than $50 please let us know.

Richard Newton

Autocross Performance Handbook

Ultimate Garage Handbook