JWT pop chargers, Berk HFCs, and Stillen Catback.....raspy...
 

my setup is jwt popcharger, berk hfcs, and stillen catback

as soon as i installed the hfcs there was a raspy sound during mild throttle.
i thought it might be a loose bolt and got the mechs at stillen to check it out during the stillen catback install. everything checked out fine and was informed that hfcs tend to have a raspy sound. Well after a couple weeks of driving around hoping the raspiness will die down... the sound keeps getting worse.. I guess the exhaust is fully broken-in and it amplifies the raspiness way more.. Anyone know how to get rid of this annoying sound? It is not very pleasant to hear that kind of noise from a new car..


Oh and anyone else notice a hisssss kind of sound when you let off the throttle? i would think its normal to hear a hiss when i
accelerate meaning that it is breathing in air from the intakes but hearing it
while decelerating... didnt make much sense to a newbie like me.

any info would be greatly appreciated :icon17:

You can pretty much guarantee that the cause of the raspy is the HFCs. This is why I will not put them on mine, raspy is a fear I have. And the intakes probably are the hiss sound you hear, they do make the intake more audible which can have a hiss sound even when letting off the gas

will it get better over time?

Can you make vid of how it sounds?

Ive listened to a Z with HFCs, CBE, and the G3 intakes, and there was no rasp. check out semtex's videos, you can see. I have test pipes, and there is a little rasp. there is also a hiss too when u drop in revs, no worries.

Semtex sounds to have a little to me. Guess it is more noticable to others and some not. Plus he did say it was after the hfc install. If it sounds raspy to you now, then no it will not sound much different later to you.

Matt, have you checked to make sure the exhaust isn't in contact with the lower crossmember? It's possible that you're mistaking rattle for rasp, as they don't sound entirely different from one another. Do you know which crossmember I'm talking about? Here's a pic, just in case. If that pipe comes into contact with the crossmember, it will resonate pretty significantly.

http://www.the370z.com/members/semte...9-p1000870.jpg

[QUOTE=semtex;65069]Matt, have you checked to make sure the exhaust isn't in contact with the lower crossmember? It's possible that you're mistaking rattle for rasp, as they don't sound entirely different from one another. Do you know which crossmember I'm talking about? Here's a pic, just in case. If that pipe comes into contact with the crossmember, it will resonate pretty significantly.

i was informed by the mechanic at stillen's shop that it cleared the crossmember just fine. It definitely is not a rattle.. im pretty sure..

[QUOTE=mattkim85;65090]Still can't hurt to pop your head under there and check.

When I installed my stillen exhaust it rest on the brace. I've tried adjusting it but no joy. Anyways it's been on for about a week and I don't hear it rattling. I don't think it the sound he is hearing.

Hmm...I don't know then. I mean, it might even be that his exhaust sounds just like mine, except I'm more used to it because I've been running exhausts with HFCs and test pipes for years now. In fact, my 370 sounds less raspy than my 350 because I had test pipes in my 350, not HFCs.

I think I'm a bit more rasp-sensitive. I'm used to a V8 sound. Some of the rasp I have now is definitely from a leak though. More than one of my gaskets may be compromised, but at least one is for sure (from playing with the flanges while dealing with the crossmember issue). Stillen and Berk are sending me a complete set of replacement gaskets for everything, so I'll get some new audio and opinion on this issue once I know that's cleared up.

Yes audio helps to see if it sounds like others:tup:

I have the hiss on the decel (after HFC install) and the rasp, but the rasp tends to go away the warmer the car gets, after 200 on the oil gauge, it's barely there, a little bit more on WOT, but not bad. It's terrible when the car is first warming up in the morning.

I also noticed this vibration right around 1800-2000 rpm, it goes away past that. when idling if I rev the engine slowly, as it's climbing and get to the 1800rpm mark I get the vibration. It's pretty noticeable when cold, and not as much when warm, but still there. I'll post a video on that later, anyone else have this vibration?? I noticed slightly before the HFC install, but way worse after. I have the Berks & the Nismo CBE.

couldnt have said it any better.. that is exactly how it is for me