My Invidia Gemini issues.
 

A couple of months ago I started hearing a faint exhaust leak on the drivers side. Did some investigating and research and it was clear the leak was coming from the drivers flex pipe on decel. No problem. Wrote Invidia and they shipped me out 2 new flex pipes for free. Which was good customer service as far as I am concerned as my ex-gf bought me it and I have no idea what vendor she went to. Finally got them and I figured all would be well.

Wrong.

Sunday night I throw the car up on jackstands and start on replacing the flex pipe portions. Drivers side was done. Fired the car up,drove a bit and heard a little leak from the passenger side. Replaced the passenger side and fired the car up again to check. Whoa, car sounds significantly louder...great. Get back under the car and start looking around. Apparently, the flex pipes sent were just SLIGHTLY shorter than the original. When i tightened the bolts on the rear section it broke the weld on the flange for the X-pipe. So basically the pipes were just kind of hanging there.

Awesome. So now I have a much bigger leak than before and no way to fix at the time (12:30AM Monday morning). The exhaust shop I normally go to opens at 7:30am so I figured I would pop over there a little early and get it rewelded back on.

Get 5 hours of sleep and head to the shop. Guy rewelds the pipes back on (with them on the car, I don't know why he didn't do some spot welds and remove, but whatever). $40 and I am on my way. Until I get home and realize I am still hearing a leak coming from the xpipe area. Turn around and go back to the shop. Guy redoes it and said there was a small leak on the top of the pipe. No problem, welds it up and I am on my way.

Drive to work today and I am still hearing a leak, and it is coming from the rear where the xpipe is located.. Won't be able to take it back until Saturday. I emailed invidia about it and they want $100+shipping for a new xpipe section. I think the price is a little steep as it is to replace a broken weld from them. However, since they were helpful with the replacement of the flex pipes, I can't be mad at them for anything. I'm in no way trying to rip them off.

My only options now are to just wait it out and go to the exhaust shop on Saturday in hopes they can hear what I am hearing and fix it or just say screw it and go with something like the CNT or topspeed exhaust. I really like the way the gemini sounds, but I am not sure if I want to deal with any other issues with welds breaking or flex pipes leaking.

I would just have the muffler shop fix it.

That's what I will most likely end up doing. Just sucks that this had to happen. Usually welds don't just break with tightening up a bolt. Hell, most exhausts I have had and worked on I had it hit the flange with a mini sledge to remotely even thin about breaking a weld. Let alone pull the pipe clear off.

When I brought it to the exhaust shop on monday, I had to go twice because there was still a little leak. When it was up in the air and they were reving it, I didn't hear it anymore. Now I am noticing the distinct ticking like sound of a leak.

It just bothers me to think that if the quality control over the exhaust was better, maybe this wouldn't be the case. But, knowing it's one of the cheapest exhausts out there, what can be expected?

I have 08 350Z with Gemini. Had it on with stock cats..no problems..and now with FI resonated HFC..no problems. I wonder if your initial problem was caused by the test pipes? Maybe the fit caused some added stress to the flex sections? Test pipes also give off more HEAT, but Invidia offers a TP...so that *shouldn't* be the problem.

Flex pipes on the gemini break quite easily if you don't re-use the factory cat-bracket that connects the cats to the transmission. Its typically removed when installing test pipes and people tend to forget to re-install it.

New Invidia flex pipes have been changed actually. They've moved the flex section further back away from the test pipe/HFC area, which prevents them from flexing at the worst location. They are now at the elbow/bend portion, about 10 inches further back. I received the new ones are replacements, they're much better.

My FI Resonated HFC doesn't use the factory bracket...no problems with Gemini (350Z HR) flex sections. HFCs weigh much less than stock cats (mine weighed 5 lbs less each), so the need for bracing should not be an issue. Just my take.

I broke 2 flex pipes within 100 miles of each other (both passenger side) after installing test pipes. After re-installing the bracket I never had an issue. I started a thread on it sometime last year, quite a few users had the exact same problem.

Bracing isn't just about weight, it's about controlling the vibrations/flexing that can occur. You have a 350 with an HR and while similar, they are different enough for an issue like this to be present in our cars but not yours.

Glad it worked out with the bracket fix. Good points...so weight wasn't an issue there. Like OP, I see you installed a TP...not an HFC. I wonder if TPs tranmit more vibrations than HFCs?