Agreed...that's why I never did it and am following the x-pipe thread.

 

well deff let me kno if it corrects the problem. .

 

yeah that hiss is pretty noticable. Mine does hiss but not to that extreme. I think the cats probably make the difference.

 

I pulled my hair out with this exhaust. I did not have test pipes at the time, and it was just like the OP's. I'm pretty sure it's a leak because after awhile black water would run down the pipes. Borla is the devil. Seriously. I have all the information right here in this pamphlet.

 

Why were you getting black water coming from the pipes? I could be wrong but that dosen't sound like an exhaust problem.

 

How might one go about "blocking" the H-pipe on a temporary basis? Just to see if it does any good.

 

The black water is a mixture of soot and condensation. Combustion produces water which condenses in the pipes and leaks out through any available orifice.

 

you aren't alone. i got rid of my stock exhaust because it started this hissing noise (the shop foreman i worked with verified it was from the y-pipe) so i got a nismo exhaust and dammit that one started too. i think the test-pipes probably just cause it prematurely

 

he got black water cause the water mixing with the carbon build up wa seeping out past the clamps and sections .thats all. .my customer had that 2. .but thank god mine doesn't. .although it's normal!

 

mine 'hisses' too! But I dont mind the sexy noises my car makes haha ... one question for you guys though, lets say your driving at ~ 30mph and in 5th gear or so @ 2k or 2.5k rpm.... if you hit the gas pedal, do you guys hear injectors firing? I hear a light click click click like the injectors are firing so I was thinking thats what it is.

 

with my stock cats, mine didnt hiss, hfc's they hissed.

the end.

 

are you sure your cars not . .Mis firing? why would you drive in 5th doing 30?. .i think thats too low of a gear to do 30 in. .will hardly move the car your making the engine work hard then. .unless your already cruising. .but if your moving slow specially on slight inclines keep it in 3rd. . .4th or 5th to me should only be used that slow if you have momentum going, but that clicking noise. .hmm. .no CEL or SES on? try revving the car in ilde looking at the engine see if you see any sparking near wires or then listen for that click and pin point what it is .unless it only happens that low of a speed in 5th. . .

 

x-pipe fix didn't work:
https://my350z.com/forum/showthread....=1#post5036412

When are you going to try your solution?

 

99.9% sure its not a misfire. Unless just installing exhaust/testpipes can cause that. It started after those got installed. Well not just 5th gear, but any gear at a low rpm speed. It's like you can hear the injectors firing up until you get to 4k rpm. One of my neighbors was checking out my car and I asked him about it, he agreed that it sounds like injectors firing. Oh, this is with testpipes btw

 

did you have the tp's installed pro?. .reason i ask is cause the damn bolts from header's to cats if i recall 2 of them are facing up which makes it a real B_ T _ H to get to , and on the passenger side of things near the connection to the header there are fuel lines. .perhaps whoever did the job didn't go from the top with an extension to brake and remove the bolts. .and they went from the bottom trying to maneuver tools up there to get the bolt and could be possible they crimped your fuel line not allowing a minimal amount to flow causing that injector sound due to fuel starvation. . .. only a theory .

 

hmm... I forgot to mention that if im just cruising or slowly accelerating in a gear, there's no noise. Only when I WOT at like a 2k rpm in like 4th or 5th gear going 25/30mph. As the RPMs start to creap up, the noise stops. Car runs like normal. But your theory may be very possible. Ill definetely have to check on that. It was done from a pretty reputable shop, well as reputable as you can get in this area .

 

could be at higher rpm more fuels being pumped threw to compensate so the sheer force is pushing it threw. .thats if it's crimped. .but with no check engine light on im sure your injector's are running perfectly /and/or/. you'd experience a misfire in at least 1 or 2 of the cylinder's. .from lack of fuel. .try putting in a VERY GOOD fuel INJ cleaning solution like jectron made by molylube. .or even chevron techron. . then drive the car hard a few miles and see if it goes away. .could also be you let the fuel tank run too low and some crap got into the system blocking passage as well ..some of these problems i'd have to see and witness it to truly diagnose it.

 

^ see thats one thing that confuses me. If im cruising at 2.5k rpms or anything in top gear... there's no noise. It's only when I push my foot completely down that you hear like a click click injector noise , that lasts till like 3.7k or 4k rpm. Ive been driving just assuming its normal. And it can't be some bad fuel that got in because everything was A-ok pre-exhaust and testpipes install by a shop, right after I picked it up it made those firing noises I assumed normal. Another thing that may help is that the noises are only there when the car is underload.. like 5th or 4th gear going 35ish (5AT btw) and I push the pedal. If the car was in 1st or second and I go WOT from a launch, there are no noises. Same thing with the car in neutral, no noises from inside or outside the car. Maybe its trying to tell me to shift into a lower gear in morse code

 

So back to the exhaust...

 

. .A B convo. .C your way out! hahahah. . .

well im stumped man ..perhaps a Squirls in ur intake and when u jam on the gas he's suffocating. .and he's banging on the tube to let em out or let up on the gas who knows!! hah. .