Hey guys I want to replace that grey hood liner thats on the underside of the hood. I've seen pics of some stuff that looks like dynamat (sp?) but dont know if thats what it was or not.

Any of you replace that? What did you use???

Mines looks awsome except where my vented stock bov blew a big *** hole in the damn liner!!!

Thanks guys,
STEPHEN

 

your BOV blew a hole in the liner?

damn, that must be a lot of boost!

I had a mouse chew mine up, and use it for a bed on top of my nice warm UIM. :P

that, and one corner is all oily from the BOV.

So here is a bump.

 

BTW, dynamat is really heavy. I considered doing that too, but the weight of the dynamat simply isn't worth whatever goal you might be trying to achieve (given that your car isn't a bling bling hydraulics show-mobile).

If anything I'd just consider going for a replacement from Mazduh. Dunno what that'll run you though

 

Weight is the issue. If you are trying to quiet things down this is the number one spot to go after, since sound is transmitted from here through the glass into your cabin. (believe it or not!)

Don't even think of using Dynamat - it is way to expensive, and at about 1 lb per square foot you are talking about some serious weight gain. There are other products that work as well and cost 50% less.
To be effective I think you'll need to figure about .5 lb per square foot. There are lighter materials as well.

Check out www.b-quiet.com It's about the best site I have come across so far (thanks to another forum member)

I think they have something there that is lighter and should be relatively easy to install. It's called hliner.

I am in the middle of trying to decide what to do with mine as an overall soundproofing project. My main concern is the ability of the material to handle heat over time. I hate doing things twice.

 

Ron I'm with you on wanting to do it once. I also want to to look very clean, I dont want something with writing on it that looks all homeboy.

I am picky about weight BUT if I was to just do the indented areas between the supports it wouldnt be that many sq feet. I've gone with a different bumper and battery that are all lighter so I'd still come out doing better than stock in terms of weight, even if I used 25sq feet since that would only be 25lbs.

I also like the idea of sound blocking, I like to hear my stereo and I take trips with my wife and she is starting to not like how loud my car is. If it would seriously help with the noise I would trade that for the small amount of weight. I mean even if I did the entire hood how much would that be? Its prob 30sq feet or less (5x6) so we are talking 30lbs the lest say I'm removing 5lbs (I have no idea how heavy the stock stuff is). That only leaves me gaining 25lbs, just my bumper replacement alone (which I didnt do for weight reasons) would make up for that.

Anyway, is the dynamat or the others heat resistant?

Thanks,
STEPHEN

 

What about this stuff, does anyone know anything about it???

http://www.b-quiet.com/hliner.html

STEPHEN

 

That looks like a pretty good deal. $50 bucks and it only weighs 3lbs.... I may just need to order some. I'm not sure I like or hate the aluminum "skin".

 

WHY do you want a hood liner anyways???

I took mine OFF, and cleaned the under side
of the hood, and Looks Better than with thet hood
liner.

IMO: the HOODLINER, just helps the " heatsoak"
which isn't good....

or am i missing something??

Is/are there any benefits to the hoodliner???

 

I'm sorry, but I don't see how that hi-liner material reduces the sound much. It is an open cell foam, which reduce sounds very little. The only benefits I can see is it might have some damping effect on the hood itself, which might reduce some noise.

The best looking product on there looks to be the Vcomp material. Too bad it's a half-inch thick. To be truthful SpoAutos, you're not going to achieve any significant sound reduction without going to a material that weighs 0.5 to 1.0 lbs/sq ft and is closed cell (certain foams, loaded vinyl). Unfortunately, that is going to double the weight of the stock hood and will likely trap more heat in there. Also, it seems silly but I wonder if the hinges are designed to support that much of a weight increase.

 

Having the heatsoak go into the hood isn't good for the paint, that is one thing to think about. Mcmaster has a large selection of sound insulation. One cool one I saw is melamine foam that is only 0.5" thick but has a NRC of 0.95! For only $5 for a 24"x48" square, thats pretty tough to beat, but I don't think it would work under the hood and it doesn't list the weight.

 

I think the liner is needed because the heat is going to absorb into something, either the liner or the hood itself. They heat cant be good for the paint.

I'm not really worried about the weight, its not that big a difference, I dont think 20 - 30 lbs thats spread out evenly over the entire area of the hood will make any noticeable difference to me.

STEPHEN

 

From what I've read, you don't need to cover the entire under hood surface, and Rynberg would probably know more about this - but what I think you are after is dampening. If you just did the indentations, you could put the original hood liner back on top (er, bottom....) AND save weight.

I think it is still going to look the best, and may alleviate your concerns about degrading the foam. I am going to use Brown Board or Loaded Vinyl in pieces when I do mine. (probably loaded vinyl since I can buy a roll of it and do the floor of the interior as well.) I think the stock liner will protect it from heat. I like maintaining the stock look with everything I do, because IF and WHEN I DO sell my ride (yeah, RIGHT) it will have a huge impact on the resale value.

I think the bottom line is there is some experimenting to be done. What does the acoustical god, Rynberg, think???

 

Well the main thing I was trying to accomplish was replacing the hood liner. Mine is all blown apart from my vented bov and I didnt want to replace it with the same thing as it will just get ruined like the first one did.

I'm not worried about the weight, if it will hold up to the heat, contribute to a quieter cabin, and look OK like alum or something I'll be interested in it.

The HLiner stuff I gave a link to was designed spacifically to go under the hood, it withstands head and is .5" think. It says it will help with sound but it seems pretty light to I dont know how much help it'll be.

I agree with you Ron about just doing it just in the indentions for resale value. I can always cover it later if I want to. Maybe down the road buy a decent looking used liner to cover the sounds stuff so it'll look stock.

STEPHEN

 

aw, shucks, lol

Yeah, just dampening the metal of the hood would probably reduce quite a bit of mid to high frequency noise (belt and pulley noise, etc) OUTSIDE of the car. I'm really not sure how much actual noise reduction would be experienced IN the car. It is difficult to guess how much of the sound is transmitted through the firewall and the general structure itself, vs how much is transmitted through the hood. But I can see just dampening the hood with patches of loaded vinyl reducing the sound somewhat inside the cabin.

Maybe I'll have to whip some of our accelerometers and the sound level meter out at work and do some experiments.....

 

Stephen, I used the Dynamat type with the reflective alumninum. It's heavy and it quiet my engine noise considerably. It looks great and my hood is cool to the hand. I installed for over a year now and it's holding up.

I wouldn't do it with the Dynamat again though. Too heavy.

I would use a thermotec alumninum woven fabric and use adhesive to retain the fabric instead.

 

i just ripped mine out. I didnt notice a huge difference in noise. Hood is just a little warmer, but i dont mind if it keeps my underhood temps down a few degrees.

 

You could just buy the stock one again and point your blow off valve in a different direction...

 

Check your Summit Racing Catalog. They sell the Dynamat and another Liner made by DEI that looks thinner than the Dynamat.