Berks HFC with nismo- rasp/rattle extremely loud -
 

So I had a custom 2.5 non resonated mandrel bent xpipe/mid pipe installed to my nismo muffler*which I got locally for super cheap** to which I thought it would help Eliminate the rasp/rattle coming from the HFC.. But of course it actually got worse!!! I was told that the rasp/rattle noise is due to the HFC is just to much for the nismo muffler. He swears he checked all seals and bolts and all were okay..

My question is the berks HFC causing the Honda civic / tin can sound or is the nismo muffler just sucks ***? I really do like the deep sound but the rasp/rattle is so loud and embarrassing!!

If it's the nismo muffler does anyone have a suggestion to which axle back paired with berks HFC that will sound good and not like a honda/tin can ?

I'm really really frustrated and lesson learned you pay for what you get but now I don't know what to do bc I already have the 2.5 xpipe/mid pipe so I don't need a full CBE.. Any advice would help thanks to everyone for helping me sleep at night ! I'm having nightmares about waking up and seeing a honda civic in my driveway!!


Video of start up - is this a rattle or rasp ?
http://youtu.be/HA-rfh90NVQ

Warm start - with revs
http://youtu.be/8Byx2KZbSJw

Well u made the problem worse by removing the resonators in the mid pipe. The HFCS do add some hiss but nothing major IMO. U should add resonators to the mid pipe and this will help out a lot.

Do you think if I removed ten nismo and went with the top speed axle back it would improve ?

Honestly if its ridiculous rasp he didn't align correctly and or use proper gaskets, as mentioned above the resonators help with the rasp, double check on the bolts and gaskets. I redid all the bolts on my Z this weekend and all of the rasp I had previously went away with proper gaskets installed
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Changing the diameter on the Y pipe -- and it seems the H pipe too -- tends to result in a "whooshing" noise.

Resonated TP's should help mitigate any rattle/rasp, but the whooshing will probably still be there on decel unless you go back to OEM diameter.

The problem lies in the non-resonated x/mid-pipe. Either find you a Nismo mid-section or get you a new cat-back exhaust. Getting a new axle back muffler section will not change anything other than possibly making it louder and even more annoying.

I was having the rattling/raspy noise to when I had the factory non nismo midpipe but not as loud.. I thought the new larger 2.5 inch xpipe would help give it more flow to help reduce it.. Just pissed paid $350 for this xpipe and it sucks lol FML I guess I will try to add resonators today to see if it helps..

Added video of start up is it a rattle or is that rasp ?

Sounds like rasp when you first start it up.

Added another video of warm start with some revs.. To me it sounds like something is rattling like something is lose inside of the nismo muffler? Or that might be rasp I dunno ?

370z nismo HFC rattle or rasp - YouTube

seems like the lack of resonators would be the culprit but after watching that last video i feel something is put together incorrectly. i see that you had the mid sections custom made? that may be your failure point.

i have full straight pipes and mine dont have that pingy/rattle sound.

i could post videos if you'd like for reference.

I had the same type of rasp with the factory midpipe berks HFC and nismo muffler.. I thought going to 2.5 inch xpipe would give it more flow and help.. But just Made it worse of course.. I'm going to add resonators today to see if it helps.

mine is 2.5" the whole way except my tips are 4.5" but that doesnt really matter.

i've never ran HFCs so that may be your issuse as well but i know some friends who run them and havent heard anything that raspy so far. may be poor fitment or just the berk HFC. most peoples ive heard are FI HFC.

Yea please post some videos and what muffler do you have and do you have HFC and no resonators ?

i have nothing lol

i'm running pure 100% straight pipes. no resonators, no cats, no mufflers.

That's bad ***!!

So I had the muffler shop remove all heat shields to see if there was a rattle and still the same sounds not even the slightest improvement... So it's deff rasp :( so I know adding resonators would help but the whole reason I wanted to remove them was bc the nismo was to quite even with the berks HFC... So back to square one..

I have someone who wants to buy nismo axleback for $150 so atleast I can get some money back..

Thinking about trying the topspeed axleback first and adding resonators to help with rasp.. I assume adding the resonators to the topspeed will still be louder then the nismo.. From what I see on YouTube I like the sound.. Short tails are to loud I think..

What I really really want is some type of axleback that has resonators already on them just can't find any..

So final ? Do you adding 2 - 12 inch resonators to the topspeed axleback will limit the rasp and still have the same loudness tone as the non resonated nismo ?

Only way to not have hiss with hfc is to be on stock y pipe piping. But quality gaskets will help.

Will see what happens I just ordered topspeed axle back hopefully be here Monday and add the 12 inch resonators to it to see if that sounds any better..

If you want to try a cheap alternative if the rasp is still there, check out garagelines X pipe. The resonators look smaller than stock and the piping is a full 2.5".

To me it sounds like a broken restrictor plate inside the muffler. If it was something more upstream like a gasket it wouldnt rattle like that it seems lighter.

Op can you post up a start up and light revs when the piping is hot?

After removing all heat shields and checking all bolts the guy at the shop said the same thing - it has to be the nismo muffler - a chamber inside is messed up and only hear it at low load- but when under the car on the lift I hear all the noise coming from the middle of the car near the xpipe- *no touching of crossmember either.. So I took his advice ordered the topspeed axleback and I'm most likely going to add 2 packed 12 inch resonators.. Fingers crossed I can get rid of this embarrassing honda civic/tin can sound.. Today I almost parked my car it's so embarrassing..

I have FI Non-Res TPs and Nismo exhaust on my base 2011. I get the same rasp on cold start and around 2-3k rpm until the engine gets to temp. I've learned to manage the throttle to reduce the sound, but it's still there.

The benefits of increased power and torque far outweigh the rasp factor. Last week, I removed the spare, and OMG it's stomp and hold on to your Nizuts!!

Monday can't get here fast enough lol question to exhaust experts
Since all the rasp is coming from the xpipe in middle of exhaust where should I add the resonators ?? Before or after the xpipe and do you think 2 packed 10inch resonators are good or should I do bigger ones - once again this is going to the Topspeed axleback with 2.5 inch mandrel bent pipes..

Also the tech did not add any flex pipes do you think adding those would help and if so where should I add ?

The topspeed axle back came in early!! I can't believe how fast that was 2 days ! Installing hopefully today and see if it sounds any better. Fingers crossed !

Okay I got the topspeed axle back installed and I can say it's a night and day difference.. still has some rasp but not as bad as before. I say a 75% percent improvement. It's very loud and aggressive as well. But I can live with this vs nismo.. I will be adding the 10 inch resonators Monday and hopefully that will eliminate 95% of the rasp and tone it done a little bit. I think lll get the perfect sound that I'm looking for Monday with the resonators.. Will see to be continued...

If anyone is intrested to hear the topspeed axleback berks HFC with custom xpipe no resonators - to aggressive for me but already got two complainants on it..

YouTube