Has anybody converted a stock 84-89 muffler to a dual out?

[ZCAT3]

I was thinking of doing this but was not sure if it could be done (or is a smart move). Has anybody out there done this? How does it sound?

[Kurt B]

Yeah, I did it. Cut out the holes and and weld the old one shut. It's not going to be much louder, but the power is different--worse or better, I don't know. It won't be tuned by your work, put it that way. Probably no difference at all really though.
You're better off getting a bursch...you'll notice a difference, which is why I took my dual out off and put the bursch on. However, if you click below you can see how I did my dual out...

[Sarah]

Good question. We are also going to have a dual out put on this spring. Our porsche techs are doing it for us though. At the moment we are probably going with a GHL...but i'm a bit concerned if it will be too loud. Oh well, we still have 2 months to decide.

[ZCAT3]

Sarah - I presume you are doing this on your 930. If so, I strongly recommend looking into Mille Miglia or Monty - both Australian makes. I have a Mille Miglia on my 930 and it is the nicest sounding 930 muffler I have heard. No resonance, very nice sound inside the car, and very business like from the exterior. I have nothing against GHL and in fact have GHL headers on the 930 - it just seems to be that the U.S. made exhausts all have some resonance.

[Eric Mckenna]

Sarah,
I have the GHL 2 in 2 out and baby she is just right LOUD as HELL! hahahahaha! I love it tho.
Eric 78SC

[RickM]

I modified my '85 Carrera to dual outlet. I am very pleased with the finished product. Sound is lower/more agressive with a small gain in power. A small cutout has to be made on the rear valance to accomodate the new outlet. A stock tail pipe end can be fitted over the new outlet to make it look factory. This modification is popular and supposedly mimics the sport muffler.

NOTE: The modification i did was for an additional outlet on the passenger side of the muffler. Not a dual center configuration.

[BGCarrera32]

RickM-

Any additional details? Is it necessary to split the muffler open to do this or did you just cut another hole over there and weld on another pipe?

Thanks-
BG

[RickM]

BG,

Using a hole saw I carefully cut a hole on the right side of the muffler and welded a newly fabricated outlet. The toughest part was to fabricate the new outlet. I used a couple of mandrel bent scrap pipes that a muffler shop sold to me for 10 bucks. It just takes time, patience and a bit of welding ability. One wants to insure a uniform look when complete so tacking it together and a bit of playing around will yield a good result. Also I would suggest using stainless steel pipe.

I'm really surprised that no one offers a prebent pipe for the modification...perhaps something to think about.

Rick

[Sarah]

ZCAT & Eric...

Thanks for the extra info. You know...I do like the look of the Mille Miglia. I'll check the net for some pricing. Our porsche techs said they install the GHL most often and it seemed like a lot of people on the board have that kind of dual. I like the look but so many people talk about the loudness and I really don't want anything too loud...just a nice rumble... Thank you...

[Eric Mckenna]

Sarah,
You should try to hear one before you say NO to it.. it really is a GREAT set up.. Nice and Deep and great at higher RPM's!!!! like the old 911 race cars.
Eric

[Sarah]

I have heard two already. One was in the shop when we got our car once last summer. They said ours would not be that loud though. My husband just called me and said the shop said they could contact GHL and see about getting one that was quieter but there would be some custom work done to it...but I have no clue how much that would be. I don't want to go over $2000 for this. Oh well.....It will be interesting to see what we end-up with. (they also have to replace the valence and/or cut out another outlet area)...ouch.

[ZCAT3]

Rick - thanks for the feedback - that is exactly the info I was looking for.

Sarah - the GHL for the 930 definitely seems to be the U.S. muffler that gets the most positive feedback. The people at GHL are very nice to deal with as well. Remember that if you are a rennlist member they will give you a 10% discount.

On the Mille Miglia - I have never seen another 930 with one. The prior owner ordered it and raved about it almost as much as the car when we were talking with him. I have to agree - it is top quality and the sound is very nice. The best part is that from the outside it sounds pretty agressive, but inside the car you really get to hear that nice engine - not the exhaust.

[Sarah]

Zcat...Thanks. I just emailed my hubby to ask them what they know about the MM too. I apprecaite all the help!! Sarah

[johncj8989]

I LOVE SARAH!!!

[Sarah]

Uuummmmm....I'm pretty sure you meant "Sarah's 930 that will pretty soon have hot looking shinny duals" Right?

[johncj8989]

uh yeah.......... "I LUV SARAHS SHINY DUALS!!!" sorry

[Sarah]

That's OK...I thought it was funny!

[willyw]

I just converted my old stock muffler on my 76 911s to a dual outlet. I cut 2 new holes in the bottom (2 1/2 inch) and had my local muffler shop bend the pipes for me. I welded them on after some careful aligning and cut off and closed the old side outlet, sandblasted and painted with high temp black paint, added polished stainless tips. I now have dual 2 1/2 inch outlets spaced to exit just below the rubber bumper pads. Total cost not counting my labor about $20. I think it looks great and sounds better than the Bursch tuned exhaust I removed. As far as performance I doubt it will make a difference---just my 2 cents

[RickM]

Willyw, Do you have a pic of the finished product? I'd love to see it.

Regarding performance: A few years ago Excellence magazine had tested many bolt on performance products for the 3.2 and dynoed them...alone and a limited kind of mix and match. It turned out that the dual exhaust conversion (extra outlet in right side) resulted in one of the highest power increases.

Note: The test didn't include superchargers or turbos. :-)

[BGCarrera32]

I'd be interested to see a picture of the stock 84-89 muffler cut in half if anyone can post it...or pics of your modifed stock exhaust...