I see a lot of people with buzz and rasp problems after HFCs and TPs. Well, I myself have experienced both after installing the HELIX HFCs a year and a half ago. I got some rasp and some buzzing with headers, HFCs and the stock exhaust. I eventually got use to it, but then I installed a Nismo exhaust and it went away (for a little while). At that point I realized my HFCs (100 cell metal substrates) were not at fault. After 3 months of running with the Nismo exhaust, the buzz and rasp came back, along with a bad rattle, all amplified. I was like this is ODD and ANNOYING!! So I got under the car to figure out what in the hell was going on. Do my dismay, I felt and heard air coming out of my flex-sections on the Y-pipe. I was thinking, no phucking way, this exhaust is only a few months old! But sure enough, it was the guts in the flex-sections, more deterioration on the drivers side than passengers side. So I went to the auto store and bought some 3" exhaust wrap, the kind you can form with a heat gun. I wrapped and molded the tape to fit snuggling around the flex-sections, then contained the wrap with a thin aluminum sheathing. I did this for protection and to keep the wrap from coming off while it heats up and permanently solidifies. On initial start up it was amazing, so quiet in the middle of the car, with all of the exhaust note coming out the back (like it freaking should)! I've been driving for 4 days now and loving it No rasp, buzzing or rattles! I hope it lasts indefinitely...

In conclusion, you may not want to throw away those HFCs and TPs just yet. You may want to just wrap the flex-sections for added sound absorption and leaks. I believe my headers and HFCs (hot bursts of uninterrupted exhaust gases) eroded the guts in the flex-section. But that just my theory, LOL!



Zquicksilver

 

If the flex section is deteriorating, tape is not a permanent fix. Eventually it will get worse and have to be replaced.

 

My NISMO flex sections went bad also, the rest of the system is good.

 

True, it's not a permanent fix, the best fix or the most expensive fix... But it might be a fix that last a long, long time and actually work. Besides, it would be easy to replicate in the future. I wasn't willing to give up on my Nismo Y-pipe that easy. The true test will be longevity obviously... the flex-section is fine, it's the internals that seem to have failed, causing the slight exhaust leak and noise.

Zquicksilver

 

Another fix of course is to have new flex sections welded in. That is the route I will go in the end. No rush, I have another exhaust on now.

 

Do we have to have flex sections on the exhaust?

 

YES...the engine and tranny move around (vibrate) - if there's no flexibility within the exhaust system, more stress will be applied to the exhuast system as a whole (there's already problems with TP's cracking from the stress)

-Peter

 

I think that is true with the non true dual exhaust systems. True duals are seperate from one another so initially they are on the rubber hangers which can absorb movement.

The TP's you are referring to are probably cheap brands like megan racing. Some tp's have brackets which help prevent any breaking or cracking.

I only have one flex pipe on my exhaust and its a greddy evo2, mainly because I have a custom H-pipe. If I cut the center section I might as well remove the flex pipe also.

 

Yea, I thought about that... and the conclusion was it was going to cost way too much! It's going to be interesting to see how long this "temporary" fix lasts. On the package it stated, in most cases the wrap will outlast a standard exhaust, guess will see if it can outlast a SS exhuast, lol.

One of the reasons I started this thread was to show others they may not have a problem with their HFCs or TPs, it may be the flex-section just behind them. I also wanted to illustrate this quick down and dirty fix, if it works, you don't need to spend $100-350.

Zquicksilver

 

I hear you. If it lasts for a year, it's a bargin. I asked the local muffler shop hillbilly welding dude and he said if I had the y pipe off he'd weld on the new flexes for less 10 bux. Of course, now to find resonable priced flex sections.

 

i think the buzz comes from different places for differnt people. Mine is deffinitely coming from the heatshield making contact with the Ultimate racing high flow cat on the drivers side.