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YOUR RESEARCHMuffler bypass pipes
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I bought a used set locally just to try it out so this is my first hand experience.
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You should try this! I definitely feel a loss of torque at low RPM with mine, but the weight savings are worth it to me. Welding in an orifice or baffle might do the trick, but you would need someone who knew something about designing exhaust.
I agree with you completely. Someone on 6speedonline did this to their 997 with PSE and stated that with a 3 disk insert the drone was 99% reduced, in his own words. He went with the 3 disk inserts.
I'd be going for the 4 disks, but the issue is the smallest diameter they come in is 2.5" whereas the bypass pipes have a diameter of 2.25" i believe. People who've done this said with a little bit of grinding on the disks it isn't a real issue.
Could be a cool weight reduction project and nice sound result as well! I want everything but the annoying drone/anything that would attract police attention, which is quite common when you live in the People's Republic of New Jersey.
You will loose noticeable amount of power at low end and it doesn't feel like any HP improvement up top. The car will feel slower than with mufflers. The sound is good only near redline but is extremely loud. I like loud engines but this is too much for me too. OK if you only drive the car every now and then and for short trips. Anywhere below redline (normal driving rpms) it sounds like crap (like a SBC with a huge exhaust leak). I bought a used set locally just to try it out so this is my first hand experience.
I'm wondering if the bypass pipes are too short for street use. I'd have to look into it more, but maybe a loop around where the mufflers were would be a bit better, and/or maybe a slightly smaller diamater pipe.
For fun next year I may have to get some cheap flex pipe and give it a try.
Never thought about flex pipe, thats a neat idea. I've been looking for a custom exhaust job but the mufflers won't fit in place nor have easy pipes connecting to the tailpipe without heavy modification.
I am however looking into the Agency Power exhaust, but something inside me tells me that's asking for drone, which is why I wanted to try bypass pipes with resonator disks.
Cheap alternative, and even if I do lose low end torque, thats a solid amount of weight shed off.
The owner in Long Island had used 3 disk resonator inserts and had no complaints of power loss.
That's true, but off topic, do you know if aftermarket headers with stock cats and stock exhaust would make a power/sound difference at all?
My main thing is I don't want drone, because mine is a tiptronic as I do a decent amount of city driving and those run in relatively lower gears when in slower traffic. Where as I would be 1st, 2nd in stop and go in my 6MT A5.
Flex pipe would only really be to mock up and test out the length. Once that's set it would be easy to go weld something up - assuming you have access to a shop.
Guys, save yourselves the headaches and wasted efforts. These cars are 11-16 years old now and every combo has been done at some point if you poke around.
Straight pipes off the headers!
I'm going to join the bypass crowd soon, just need something to put in place of the mufflers for a bit so I can have the rattle fixed.
Mine came with B&B (Billy Boat) headers and mufflers and they sound really nice. As for power, doesn't feel like they make any more than a factory system. But is is much better than a Gundo Hacked factory muffler with factory headers. Also it is deeper than a factory header and B&B muffler too. I've tried these combinations with a buddy of mine that has a '99 996 too.
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