Man that would of been so nice!!! You have no idea.

HAHA^^^

So Is everyone getting a crazy loud and I mean loud hissing/Whistle/Humming noise on Decel around 3.5k-2.5k?

I also Have aftermarket exhaust installed. I have had a Test Pipe Exhaust combo on my 350Z and didnt have this loud of noise.... Its bad real bad

DAN

Nice power gain, but catback exhaust is all I will ever do on this car. Headers and cats will stay on for good.

^yup...I had no clue the hiss would be this loud! What I'm more upset about is how quiet the HKS and Berk combo is. I guess I was used to the sound of the open y-pipe I ran for 3 weeks and then the open headers I ran for 2 weeks.

get used to it. i did.

Oh the wonderful hiss! One thing that could eliminate that sound is a piggy back system of some form for the ECU. the sound is around2.5-3.5k....program your throtle position sensor just slightly in that RPM range and it will disappear. As far as getting the right piece of equipment to do that, I have no clue...I'm kind of a rip the entire ECU out and replace with standalone kind of person, so I have zero knowledge with the latest piggy back systems...food for thought.

I don't see how... you can't tune exhaust pulses with the ECU :confused: (well, you sort of could if we had control over VVEL...)

Anyway, just got test pipes on, and yes, it hisses a bit.

My buddy who did the install thinks it might be due to the fact the pipes are single walled, and that's just how they vibrate.

Note the big weights on the either bank of the exhaust around the Y-pipe -- this motor just has a lot of weird resonances to work around.

How long before you know for certain you're in the clear for getting a CEL? I've not driven too much yet, but have gone through multiple "trips".

I got one after about 500 miles, then in went the steel wool, drove it 8,000+ CEL free after that.

Lol yeah I get hissing every time I release the throttle except for maybe say 7000ish.

and then that rasp while accelerating.

Hmm. Okay -- thanks. You just wedge a small piece into the bung?

Also. Mine has the long "u" bend defouler, like GTM -- was yours the shorter straight one or also a U?

Your not tuning exhaust pulses, just relieving back pressure, I don't' want to get into detail...wrong thread. I haven't heard anything about single walled pipes or weights on stock exhaust, that is kind of interesting.

As far as your CEL goes, you can get codes at any time....any time! Personally I wouldn't ever use steel wool, just seems like poor mechanics. Not that it is going to cause damage, but your just asking for problems down the road.

http://www.bigdaddiesgarage.com/mini-cat-cel-fix.html <this is one of many sites, look around you will find many more

Get some high quality fittings and do it right the first time, you shouldn't have any problems with a high quality fitting for your O2 sensor. If that doesn't work the steel wool might....but your only buying yourself time and I guarantee that it will fail at the worst opportune time.

The CEL is tripped if the ECU detects the same rate of voltage change between the two O2 sensors in either bank -- that is interpreted as an indication that the cat has failed.

All the defouler (or one with steel wool packed inside) does is allow for more distance/block gas flow so that that the rate of change is different. How different they need to be depends on the ECU logic.

Mine has an extra long, U bend defouler, so it should be fine, but if not another defouler to further extend it or the wool to slow things down should work fine.

Feel free to start another thread under tuning or shoot me a PM to explain -- I still don't see how playing with TPS will affect back pressure one way or the other (although taking out the restriction of the cat does that mechanically).

I guess you might be referring to actually commanding more or less throttle opening via VVEL or throttle blade actuator rather than simply having the ECU read from different load cells in it's fueling map. Is that what you mean? You can do that with your foot too...

Anyway, I don't see how that would work because if the resonance is RPM dependent, which is what I think, you still have to cross over that RPM, even if you physically open the throttle more.

It must be a specific resonance issue -- that would explain why some shops offer resonated test pipes to cancel out some of the vibrations. You can't tune that -- or at least I don't understand how -- with an ECU :confused:

I'm not trying to be an *** here -- expertise is relative, so if someone knows something I don't, I'd rather understand it than automatically agree or dismiss it.

I have the Stillen Gen3 installed... will I need to take this apart to get to the bolts with the extension? Please tell me I don't need to take the front fascia off again :)

I just installed my test pipes and have to say that I think everyone is exaggerating the demon bolt. Sure on the drivers side I may have snapped the stud in half, but at least it was easier than the bottom bolt that was closest to the inside of the car. Seriously. WHAT THE #$&#*?!?!?!?!

When I read through all the installs I thought I read there are 2 bolts pointing to the back of the car and 1 pointing into the engine bay. Is that correct? If so, my car was different. 2 pointing to the engine bay and 1 towards the back.

Horrible, and thats coming from someone who had a friend doing almost all the hard work.

I think the location of the Hiss is comming from the X Pipe on my ARK exhaust due to the amount of increased exhaust flow because of the Test pipes, I talked to ARK and they said that is were and how it is happening because they designed the Exhaust with stock cats in mind..... so Im going to sell it and get the HKS with the H pipe it shouldnt be as pronounced then.


DAN