This evening, I re-installed my newly Gundo-hacked mufflers. Thanks Gundo!

I've seen a few muffler threads recently, so I thought a few people might want to hear about my experience. First, I wanted people to know that I was able to remove and install the mufflers just fine without taking off the bumper. I simply backed the car onto my ramps, and had the mufflers off within 30 mins. This was after one aborted attempt where I was sure the wheels and/or bumper would have to come off. However, I read somewhere that you can simply take off the small support rod closest to the rear tires and push out on the bumper while you work the can down. For some reason, it was much easier on the left side than the right - there seems to be 1/4" more space on the left side. Either way, you can get them out without any bumper OR wheel removal.

Second, I wanted to share my thoughts about a muffler bypass... I actually thought I might get the mufflers off and decide I like the sound, in which case I'd throw on some bypass pipes instead. I like the idea of shedding all that muffler weight. At first, I though the sound was great at idle. Then I decided to take a drive while the mufflers are off. All I can say is that I didn't even get the engine up to temperature before I came back home. I drove through the neighborhood in 4th gear because I was embarrassed at how loud it was! Insane in my opinion. No sound clips because I wasn't impressed enough to bother.

But I AM very satisfied with the Gundo sound. I took just a short drive this evening because it was getting late and we hadn't had dinner yet, but I'll post more thoughts tomorrow. So far, I can confirm what most people say about it. Like the sport exhaust, but maybe a touch louder. Aggressive during hard acceleration, but almost stock when cruising. I think it's a pretty nice compromise.

For those thinking about trying it, I say go for it. And just know that taking the cans off yourself is completely doable. I just went to a local non-chain muffler shop and showed him some pictures. When I first went in, he said he wanted about $350 to do it, but that included removal of the mufflers. When I walked in with the mufflers in hand, he only charged $100, which I thought was fair.

Hope this helps!

 

Nice write up cant wait to do that setup

 

Did you photograph the completed mufflers before re-installing them? What size pipe to you have them weld in, and how close to the muffler?
Thanks for the info.

If anyone in the Irvine, CA area has a Gundo hack, I'd like to listen to them sometime. Please PM me if you are nearby.

 

I didn't photograph them because I put them back in last night and couldn't wait! But I talked with the muffler shop guy and settled on 1.75" pipe. Of course now I'm wondering what 2" would sound like, but it shouldn't be much different. When you get the mufflers off and look at them, there's really one obvious place to put the cross pipe because it's easiest to access for cutting and welding where there's more space. It ends up being fairly close to the muffler. I might be able to get under there to get a picture while it's on the car. Welds aren't going to win beauty contests, but they work!

 

you think it makes a diffrence if it was 2" rather then 1.75?

 

Just Curious, does this in anyway effect performance in terms of a change in back pressure? What about warranty? I've read several posts about how good it sounds but nobody ever mentions these issues. Is it just done for the sound?

 

Any difference in back-pressure would be so little it would make no measurable difference to the car's performance. The main creator of back pressure in the 997S system is the catalysers - by comparison everything else flows a lot better

 

in theory a larger pipe would allow more exhaust to escape through the bypass without going through the muffler, but I can't imagine the difference would be noticeable. The 1.75" pipe seems to match up pretty well with the muffler pipes.

 

Completely agree. No performance gains or losses. People have mentioned concerns about turbulence in the pipes increasing back pressure but I really don't think there's a concern there.

As for warranty, anything after the cats is fair game. They just wont warranty your mufflers