Sport Muffler v2.0

[bugstrider]

One of our members did a mod like this on his exhaust, just FYI. Might be worth a look. It looks doable if you like doing things like this.
https://youtu.be/-aKN0ujaQcY


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[75 911s]

I also did the conversion based on the Up Fixin article.

Everything you said is right on, it's extremely loud and essentially a straight pass through system.

The other thing is that the article / instructions are lacking when it comes to details on getting the two outs centered properly on the car. Live and learn. By the way that cover you made is beautiful. Looks like a factory part.

[Trackrash]

Here is my muffler, compared to the stock 2 in 1 out. It was originally a Dansk 2 in 1 out sport. I decided after using it for a while I really wanted a dual out muffler. So I hole sawed another hole on the right side, removed the pipe on the left, and welded on two new 2 1/2" stainless outlets. The sound at first was like a blown muffler with a large hole. Not so good. To fix it, I installed a small baffle in the right side. It now sounds great. Some drone, but I kind of like some drone.

If you search around you can find some internal shots of some mufflers. Note: the Dansk sport is different internally compared to the factory stock muffler.

[rbogh901]

Originally Posted by 75 911s

I also did the conversion based on the Up Fixin article.

Everything you said is right on, it's extremely loud and essentially a straight pass through system.

The other thing is that the article / instructions are lacking when it comes to details on getting the two outs centered properly on the car. Live and learn.

Yes. What is the solution to centering and straightening?

[Movin6]

Thanks for the timely thread and responses! My 914-6 also had a similar muffler. Removed for the VA 'Dr Evil Transaxle rebuild workshop', I'm wondering about how to refinish it for the next 20 years.

Has anyone done the ceramic coating?

[blee]

"speedracer54" asked about the knarly spot welds and what size cutter I used. The gigantic spot welds the factory used are hard as hell! I tried drilling them out with an expensive 1/2" Carbide bit, but it hardly left a scratch. So, you go around them where the metal is softer...

These bad boys cut like butter! Make a starter divit with the carbide drill and use the kit's spring-loaded center alignment pin with 9/16 bit.

[blee]

[VitoV]

Brian-- and others who have peashooters-- do you find any issues with the pipes scraping when driving around town? I mean, in driveways, over speed bumps, etc. I'm considering doing this on a SWB, at stock ride height, but when I set it up in the garage the mockup seemed to reduce the departure angle noticeably. I'm curious what your experience has been.

[blee]

Have not had a single instance where it hit the ground - may be a result of them not being 12+ inches long. As such, I'd describe them more as tennis ball shooters than peashooters.

[VitoV]

Thanks, Brian.

We'll compromise and say pingpong cannons.

[chrismorse]

Was there any midrange torque/hp loss??

What does your butt dyno say?

Usually, there is a price to pay, midrange softness for top end gain, drone or intolerably loud?

Nice work, looking good.
Chris

[blee]

As mentioned earlier, I used to run a Dansk Sport single-out muffler and thought that it was a great exhaust - good craftsmanship, nice tone, and performance. Can't personally confirm, but I've also read somewhere that dyno numbers showed slight increase with the Dansk Sport.

With this setup, all my senses tell me that there is a noticeable increase in power (at all ranges), rev response, and sound, with zero droning. Can't guarantee that it's not a placebo effect, but I swear the car feels as though a "big plug" was removed somewhere and the car is breathing freely now. I've mentioned it a few times, but the rev response is really incredible - almost as if my carbs were re-tuned.

As soon as the weather improves, I'll try to post a better video of the Sport Muffler v2.0 (SMv2!) in action. Maybe a dyno comparison of the two mufflers?

[jpnovak]

I am not surprised you feel the engine runs better. You have basically created a muffler with near equal length passageways. This balances flow. The small differences between the L and R side are enough to break up the sonic interference that causes drone.

I have made many sport mufflers using the old style. However, I really like the simplicity of your changes and can see the benefits of the design.

[bkreigsr]

Very nice.
What is the spacing between the pipes?
What id's are is the new pipes?
Thanks
Bill K

[tdw28210]

Originally Posted by bkreigsr

Very nice.
What is the spacing between the pipes?
What id's are is the new pipes?
Thanks
Bill K

Bill, the tail pipe pieces are actually sourced from inside the same muffler . As for spacing, I'll let the OP chime in.

[blee]

The tail pipes are new 2.5 in. stainless - see post #11.
They are spaced 11.5 in. center to center.

[blee]

Nice work speedracer54! Thanks for filling-in the pictures of the inside mods I left out.
Almost as nice as mine. Interested to know your feedback after you try it out.

[panzerfaust]

Originally Posted by speedracer54

The patches are now welded into place...hope they last...

wow beautiful welds !

[bkreigsr]

Thanks to all the posters in this thread, I've finished my 912 E custom muffler.
Started as a 914 stainless unit from Sierra Madre Collection, (via Mittlemotor in Hamburg).
The max separation I could get between pipes is 4 inches due to the location of the internal pressure relief chamber.
Bill K

[gereed75]

I am working with this old home made muffler I picked up from a 914 world member. Sounds great, price was right, Throttle response seems improved but .....the drone is horrendous.

However I am addicted to the center twin pipe look on my 914-6 ....so looks like a welding project.


So Blee, what do you attribute the reduction in drone to in your version 2?? This muffler appears to have a common center section, my first thought is to segregate the two. What do you think?