MLV for exhaust noise and drone?
 

How much MLV (mass loaded vinyl) would I need? My exhaust is pretty loud and the drone at 2.5-4k RPM gets really annoying. I've been told that sound deadening might help with the drone, but wont do much for the noise.

I'll be honest with myself and say that this BRZ is more of a weekend fun car, not a race car. So a few extra pounds wouldn't bother me. But I don't want the extra weight to be an obscene amount.

I don't really care about road noise or wind noise, even when I'm on the highway. Its just the exhaust that bothers me. I would just swap with someone's stock exhaust but I love how it sounds when I go through the gears.

Would it be sufficient to cover just the bottom of the back seat and the spare tire area in the trunk? Do I need to put MLV along the sides of the rear as well? Looks like MLV is 1lb/sq ft. Guesstimating I probably need like... 25sq ft?

To get rid of drone, if you're looking for the most bang for you buck, weld a bigger resonator in your mid-pipe. People have had success with Vibrant 1141 Ultra Quiet Resonator. Read here: http://www.ft86club.com/forums/showp...8&postcount=13

My advice on sound deadening, MLV will reduce the road, tire and wind noise the most, exhaust noise, less so. If you're going to go that route anyhow and want to keep it light (under 50lbs), MLV the cockpit, not the trunk. That is not unless you planned on driving from the trunk. Seal the full cockpit floor and doors with CLD tiles, CCF + MLV. Put a double layer of MLV on the rear seat back. Make sure your MLV has full coverage (no gaps or holes). Don't bother with the roof unless rain noise bothers you most as there's not a lot of exhaust noise coming through the roof.

I was considering lining my trunk floor with MLV and CCF for the same reason. I contacted the guy at sounddeadenershowdown.com and he quoted me for:

1 18 ft² roll MLV @ 42.48 = $42.48
2 sheets 1/8" CCF @ 16.35 = 32.70
3 Velcro Strips, adh. 2 sides @ 1.63 = 4.89
1 8 oz can HH-66 Vinyl Contact Cement @ 9.50 = 9.50

If your exhaust noise is that bad, you have the wrong exhaust. Just sayin'.

I'm full catless UEL and have zero drone in any RPM range. Hell, my frontpipe is even titanium. You can pull your hair out trying to get sound damping where you want it, and believe me, I've been there, or you can do it right and get an exhaust you can live with in the first place.

Edit: If you do decide to pursue your sound damping, put closed cell foam under the mass loaded vinyl. It needs a boundary layer to separate it from the body or it isn't going to do a lot.

Hmm any idea how much that costs with installation? I'll do some research and try to find some sound clips as well. I love the exhaust note from the outside though which is why I dont wanna change the exhaust itself. But I may go this route as a compromise.

I was looking to MLV the trunk floor mainly because I wasnt even sure how to get to the seat back lol. I know the bottom of the rear seats are easily removed, haven't seen how to get under the back cushion though. Or are you saying I should just put a layer of MLV directly on the back (i.e. it'd be visible from the trunk or if i folded down the seat)?

Only one 18sq ft roll? Thats less than I expected. Do you know where that would have covered?

Maybe its just subjective? I'd be very curious to sit in your cabin and hear the sounds there. But for me its definitely very drone-y at 3-4k. Especially when I just let off the gas and the car decelerates on engine.

I'm pretty picky about drone. When I had my STi I went through four catbacks trying to find one that didn't drone. It's a matter of exhaust construction.

Just creeping on your post history a bit, I'm assuming you have the Injen SES? Beautiful exhaust, but the cans on it are basically what you find on an N1, which all drone to some extent. There's a reason I went with the "suitcase" muffler Perrin system.

Ah.. yep, you're right I have the Injen SES. I didnt realize what the differences in muffler construction meant. Looking back I probably shouldve gone with something like the Invidia Q300 exhaust :\

Well, you can always resell to recoup at least some of the cash. I just think you're going to be disappointed with the results of the material... it doesn't really solve the root problem. Anyway it's your car, I promise I'm not trying to steer you any way or another, just sharing experience on my anti-drone battles. Good luck!

an easy test is to put the stock resonator back in line.
the after market muffler will still sound good but the drone will be greatly reduced.

Haha thanks. I think you are right though, trying to cover up the sound is just gonna make me waste time and money, when I should really be going after the root of the problem.

Sadly I scrapped the stock exhaust when I got the aftermarket installed. I live in an apartment so I had no where to store it.

I tried sound deaden the trunk with no avail. Our trunk & rear area is like a bass box


Sent from my iPhone using Tapatalk

It was to cover the entire trunk floor, but as a flat sheet above the spare

maybe someone will let you buy cheep or barrow a takeout.
when I put the new system in I too had a bad drone, and like many others tried sound deadening mat in the entire back area. not much help. then I put the stock resonator back in and found a great improvement. I can live with it now, and can still hear the engine to help with shift points, very little time to look at a tach on the track. way too much going on around you. a bright shift light tells you that you are already there, I like to know when it is coming.
I am old and getting deaf, I need all the help I can get.

Feels like a waste to put a stock mid pipe back in after paying for my full stainless Injen exhaust.

So right now I'm looking at options to have an aftermarket resonator welded in. The vibrant ones are SS and have good reviews, so might go that route depending on how much the total cost of install would be.