Brad4rdHay

Ok, before I get blasted for sayig I should've bought a G35 or something, the Z sounded like crap from inside the car. Im sory, but driving a G35, or my brothers 330ci was just more fun to push the car, because it sounded so ****ing good in the process. Thats part of a sports car, is to have it sound like something fun, and different while driving it. The Z just rumbled, and vibrated the whole front dash in the upper RPMS that you didn't really feel like going past 4800rpms. And it wasn't Ferrari loud, it was truck loud.

BUT, I knew it was curable. The Z's exhaust sounds like butter stock, and my Borla just improved on that further. Because it was louder than stock, it balanced out teh sound a little, but it still wasn't where i wanted it. Basicaly, the engine noises are too loud, and the exhaust is barely audible. So heres what ive been doing over tha past month, playing with various sound proofing materials/locations, WHILE keeping the weight under noticeable amounts.

B-quiet.com has everything you'll need:
2 - 10.5 sq-ft. rolls of Brown Bread
13.5 sq-feet of H-Liner
13.5 Sq-ft of V-Comp

The goal was to quiet the sund comming through the firewall, and to fix any other sound-related problems as they were found. So strip down the entire rear hatch of the car. Remove the crappy oem stuff on the wheel wells. Here, I just spot deadened problem areas. YOU DONT NEED TO COMLETELY COVER A SURFACE with Brown Bread/Dynamat for it to be usefull. The sttereo shops do this to use more product...it adds weight we don't need. NOW, cover the bare wheel well bulges with a layer of brown bread, up to the base of the strut brace. The rear/floor of the hatch is a fairly large strewtch of untreated metal, which resonated alot, so I placed a 5-12 strip of Brown Bread there to quiet things up. The rear wall of the hatch metal was too resonant, so I placed a few small peices of brown bread there, just enough to make it less resonant. The bok at the front of the hatch was also too bare, and a few small peices of BB helped. Again, we want to keep the exhaust sound, so I just used a little bit of anit-resoantn materal to keep the body fram adding its own sound.

Now, I used BB on the firewall of the Z. BB is covered with aluminum skin, and can be used uner the hood. So, I covered much of the reachable firewall with Brown Bread. Placing a hefty peice in the middle of a metal panel is usually enough. You form a U shape as it wraps around the engine, make sure you reach down far enough too. Don't cover up and hoses or such. Just use small peices to fill around holes-parts. This will prevent alot of the engine vibration and panel resonance from reaching the cabin.

Then place a few small peices in the rear oarts of the hood, between the "ribs".

I had extra BB, so i placed it arond the front speakers. This helps the stereo, and a TINNY bit with tire noise, but its hard to take apart the door, so this isn't nesecary.

Now, H-Liner is a aluminum skinned foam sound ABSORBER. Cut out a large enough peice to cover the rear 1/3 of the hood (which was pre-treated with BB. I when from just inside the hood seal, and the rear of the engine for heat/weight reasons. This stuff is light, but every pound should be monitered in a car like this. Thencover as much of the firewall as you can...using small peices, covering where you placed the BB.

Now, V-Comp. This stuff is HEAVY, to use it sparingly. Place your floor mats over the sheet, and trace their shapes. Cut them out about an inch smaller than the mats. Do some cleanup making sure you can' see the V-comp under the mats. (make sure a large area aroun the driver-side's hole is empty, so it can be punctured by the little plastic thingy that keeps that mat in place) Now hot-glue the rubber side to the bottom of the matt. The matt's rubber spike s make it dificult. Just make a few blobs of glue on the matts, and let it dry (filling in the spikes). Then glue on top of them. Finnaly, trace a line of glue around the outside of the V-Comp maing things tight. This ste takes care of alot of road, lower engine rumble.

Brad4rdHay

The car sould alot better now. Theres less vibration form the firewall, and you can hear the exhaust burble ALOT more. Overall, its not alot quieter, but the sound is better balanced.

Weight wise, you can't detect it. The heaviest part, and the material I was worried about most, V-Comp, is placed very low on the car, and within its sides, so it doesnt affect the handling at all. You want to watch the doors, as adding alot of weight there WILL affect the handling/roll. Thats why I didn't really place any there. PLUS, it doesnt help the sound at all.

silverstoneTT

iTrader: (1)

Where do you buy this stuff? Id like to see some pictures if you could of how the stuff in th wheel wells looks like.

I love the Z a lot too but there definetly is just a lot of noise at higher speeds. Some soundproofing would be good

Brad4rdHay

b-quiet.com
When its all said and done, it a little pricey. But IMO, its deffinately worth it.

By wheel wells, I don't mean the inside of the wheel wells but when you strip down the hatch, you see the bulges they create in the structure (ie. the outside of the wheel wells). This won't prevent that sand/salt pinging you hear, but it will reduce deeper, tire growling.

I'd just go to B-quiet, but the things I listed, and use this as a guide, but improvise.

Ill try to get pics today.

MY350Z.COM

iTrader: (2)

moved

dczoner

iTrader: (1)

N E 1 have the "this thread is worthless without pics" image? I'm fresh out...

I don't really mean to say this isn't a valuable writeup & product review, but I can't visualize everything you're trying to describe right now. . .

Thanks for the input tho!

PS _ Dynamat actually does work as an entire "surface treatment" - the properties of cancelling sound are extremely complicated and treating an entire surface can not only eliminate many primary waves, but also cancel secondary "reflections" as well...

Brad4rdHay

I dont have my digital camera with me. I will be able to take pics tomorow.

I understand, its a long write up and I have a TON of typos.

silverstoneTT

iTrader: (1)

thanks that would be great. I dont know about the typos but when i finished reading it all i knew was that it seemed like a good idea but had no clue what to do.