quattro004

Im getting a true dual set up soon for my 96 2.8 A4 and I wanted to know what would be better for a good, really deep and low, louder then stock sound. Either one dual magnaflow dual mid main muffler or and mid muffler and a rear muffler as well. I have talked to someone with the first option and he said it sounds amazing but everyone has thier own definition of that so if anyone has done this or tried different muffler set ups, suggestions and tips would be very helpful. Thanks

BTW, heres the link with lots of pics of the guys setup.<ul><li><a href="http://www.mnaudi.com/forums/topic.asp?TOPIC_ID=13075&amp;SearchTerms=A4,True,D ual,Exhaust">http://www.mnaudi.com/forums/topic.asp?TOPIC_ID=13075&amp;SearchTerms=A4,True,D ual,Exhaust</a</li></ul>

losnova

I think the TRUE dual is a great idea on the 12V for performance reasons. You will be taking advantage of the V6s characteristic exhaust pulsing. However, the 12Vs are frequently posted as being "loud" engines. Coupled with the fact that the true dual will maintain velocity well, you are looking at an inherently loud exhaust set up with higher frequency sounds. A "balance pipe" will help with the higher frequency sounds; mellow out the tone. It would also quiet the volume because of the extra flow and quietness of the entire other exhaust branch.

The latter taylors sound but then you have the performance factor again. The weight of the extra metal tubing, the cost times two, and the performance. If these are not done carefully, you could end up with a good sounding mess. Attention needs to be paid to diameters (flow), placement of balance tube, and abrupt changes in flow. The factory places things specifically away from the engine as a balance to the restriction. The different restrictions you replace them with will need their own places.

You don't have to find the balance as long as your happy with the sound. STFA and see what Mance has posted as far as stock resonators go. You might be surprised. Others have just replaced restrictive bends with mandrel bends and replaced the rear muffler. This would seem like the safest thing theoretically. Neither affects pulses drastically and they increase flow at higher RPMs. I think someone posted their 12V sounded stock with the Magnaflow (not sure STFA)and stock resonator. Maybe a straight through will do better?

Ausfahrt

One thing to consider is that if you have a stock set up on the intake end then you have no extra CFM to push out of your "true dual" exhaust, so performance gained is little to none because the stock system is very well built.

Based on what i have read the only bottlenecks of this exhaust are the cats, muffler and some crushed bends. The resonator on the other hand reportedly flows around 600 CFM which can handle more HP than most of us are able to throw at it.

If it's sound you're after then I can tell you that replacing my cats with the ones in my sig gave me a nice deap throaty sound and I beleive the muffler will add to that as well (when it gets here from Austria :S). When it does I will post some pics and sound clips when I have the time.

NOTE: Also STFA for backpressure posts, I know JWG had lots to say about it. Too much flow and not enough HP can do more harm than good.

losnova

Back (+) pressure is key to good (-) pressure after the pulse has traveled further down. Depending on the system, sometimes you can have a (-) pulse just as strong as the initial (+) pulse. It then becomes critical WHEN it happens. You can use it to advantage. The problem lies in the higher RPMs. The total average pressure due to manifolds and flow restrictions rises with RPM. Backpressure reduction has a good effect on light throttle angles. So if you cruise, lower backpressure is good and you kill two birds with one stone.

If a dual exhaust is tuned right, you can have (-) or atmospheric pressure at the point when the next pulse comes in (improving torque at that RPM range). This will definitely help intake, just not as much as if you improve intake too. And just how much, I don't know. I bet replacing bottlenecks like Ausfahrt suggests is easier, safer, and would give a nice tone without making things FUBAR.

Exhaust pulses in our systems are so f-up that if you went to find out good placement it would all be prejudiced by the irregularity of the exhaust pulses caused by our type of exhaust manifolds anyway. So even more reason to not change things drastically and possibly have to do things over again if you are not happy. Or just as much reason to design a system from the ground up to cure as many issues as you want. That might get pricey though.

quattro004

Awsome thanks guys for all your input. I'll take it into consideration when i get around to purchasing everything. Anything else u wanna add as suggestions feel free.