Hmmm...
 

I'm curious to see what Tony says about that sound.

I just installed the Strup headers and FI metallic HFC's last week, then had my ECU flashed at AAM (Altered Atmosphere) here in Maryland. So far I love the results...faster, more responsive, higher red line....but there were two things I noticed that I was a bit concerend with:

1. A quite noticeable drone in the cabin. For starters, I went to a muffler shop today to check out my exhaust and we discovered that all the clamp sites for my Stillen exhaust had been leaking. So I had all five clamp points welded together (Stillen provides clamps to hold their mid-section together). We also replaced the gaskets connecting the mid-section to the rear (mufflers) section - which has also been leaking. After the welds and new gaskets, the drone subsided a bit and my exhaust is much less raspy. But I may still do Dynamat throughout the car to see if it can reduce the drone a bit more. I've heard from some other G35'ers that the Dynamat has reduced their drone about 25%...any marginal improvement is worth the money IMO.

2. The second thing is I hear a slight rattling at WOT between 3200-3700 RPM. I don't get it on deceleration like the issue I've read about in this thread. Mine only occurs when I'm flooring it, and something is definitely rattling. At first I thought it may have been the Stillen clamps but they've been cut off and replaced by welds, and the rattle remains. Anyone know how I can track this down? It doesn't rattle if I'm in neutral (otherwise I'd get under the car and listen while my buddy hit the gas...). I wonder if it's the same culprit that's causing others to rattle or hear those annoying Z-Z-Z-Z type sounds....

Anyway, let me know if you guys have any thoughts while I try to figure this out. I'll let you know if I make any progress too.

Thanks,
B

this is funny...i dont get that zzzz sound

first off, the smoke is absolutely normal for anything. Even Borla has a disclaimor on their instruction sheeet "product may smoke for 1/2 hour during initial use due to chemicals left behind from the mandrel bends"

second...the FI cats are GORGEOUS! :eek:

absolutely beautiful stainless steel. the welds look quite strong - must be better than factory quality.

the stock cats looked like these fat/ugly slugs but the F/Is look like well developed biceps in your exhaust system. It is a relief to see the glimer of stainless steel in the middle of my rusted arse chassis (as you can tell...Iam a big fan of stainless steel :p :rolleyes: )

anyways, kinetix was always known to be the cheapest. I knew that there must be a catch with kinetix products. I gave them the benefit of the doubt when someones cats just...fell off. but when I heard about the camber arm snapping--forget it. no more kinetix for me!

anyways, the exhaust sounds full bodied right now. when the motor warms up, the rasp goes away. I think most of my rasp is due to my aftermarket midpipe...which I will replace w/ stock shortly

i dont get that zzz sound. maybe b/c I dont have coupe exhaust :confused: :confused: sedans have a larger rear muffler.

the kinetix cats are kind of big too...the F/I's are quite small

It sounds like that rattling is caused by the much higher exhaust pulse...I installed the headers and FI cats at the same time. I never had the issue with just the Stillen exhuast and CAI.

I'll keep you guys posted.

Resonator gone bad?
 

I was talking about this rattling issue with a friend and he suggested that one of the resonators might have a loose baffle or something of the sort. I may contact Stillen to see if I can purchase the resonators and have them welded in to replace the existing ones.

What do you guys think?

Has Fast Intentions ever sounded off on this?

I haven't heard anything from Fast Intentions, but I did take my car to AAM and they confirmed my suspicion that a resonator in my exhuast had a loose baffle or packing. I'm not 100% sure whether that's the root cause of my issue but I'm having some 14" Magnaflows welded in next Thursday to replace the 9" Stillen resonators.

I'll let you guys know if it resolves my rattle. **Fingers crossed** If not, I guess I'll learn to live with it. (I've already begun to ignore it!) Long story short, this may not be Fast Intentions HFC issue....

-B

im pretty sure its that flex section

I read on another thread - can't remember where though...maybe MY350Z...but someone said, and he was backed up, that the firing order of the cars make certain sounds from 2400-2600 - or near that range, and when you begin to free up the exhaust, that sound comes through.

Don't know how true that is..for what it's worth.

Rick