Hood liner or sound insulation

[Situation]

Greetings all,

This is my first post here. However, I've reading your helpful posts for a while and learned a lot of thing.

I know this subject has come up in the past and there has been questions with regards to the function of the hood liner and whether is meant for heat or sound insulation. Well, if you don't know it already, here are the picture!

It's in fact sound insulation which to my surprise, BMW don't supply any longer on a lot of models. I took the car for a test drive after the install and for those who think it doesn't make any difference, my answer is - YES, IT DOES!

The simplest test is to honk the horn and you will see the type of sound feedback that you hear in the room. Also, the engine sounds much warmer and you won't hear the tires in higher speeds as much!

[tock172]

I'm surprised to learn it has such an effect on noise. I believe the primary purpose is for it to act as a fire retardant that can fall onto the engine and supress/retard a fire.

Either way, it looks good! I may have to consider doing this on mine!

[Situation]

The reason I included the picture of the product tag was to show the factory description which says "sound insulation". There is absolutely nothing to do with fire and if there was, there would've been a huge liability for eliminating it. I'm not sure a car maker like BMW would take such a risk to save some production cost!

[tock172]

Well, I wouldn't go that far. Any kind of hood insulation is flame retardant and designed to fall onto and smother and engine fire.

[bmw1racer]

Nice.

Debating whether or not to get it for my car... What did it cost you?

[HyeWarrior]

Looks great!

[KNS]

It is for both sound insulation and heat retention. Automakers have also been trying to quiet down the noises from engines with plastic covers (they're also to tidy up a cluttered engine bay). On our daughter's Mazda, for example, the plastic cover has insulation material underneath it. On my wife's Lincoln, the engine cover, which looks like black plastic, is actually heavy, dense foam. The hood sound pad helps here as well.

Things like lifters and injectors can be noisy and automakers use many techniques to suppress the various noises.

BMW did away with the hood insulation on some models merely as a cost saving feature (like doing away with the hidden trunk key hole on later 1s). Remember at the time the Euro/dollar exchange wasn't helping things on already pricey BMWs.

On it's latest and future models BMW wants the engine to stay warm for as long as possible so that on subsequent starts the engine is still up to temperature (cuts down on start-up emissions). Expect the hood pad to be in place on all BMW vehicles. Yes, hood pads have been around forever but they have a more important role than in the past.

[KNS]

While they may be flame retardant, I've never heard of the hood pad being used to help extinguish an engine fire. In fact, if you talk to a firefighter, engine fires are some of the most dangerous and hottest fires to try and put out. A simple hood pad would last a few seconds in a actual fire.

[Ric in RVA]

Originally Posted by KNS

While they may be flame retardant, I've never heard of the hood pad being used to help extinguish an engine fire. In fact, if you talk to a firefighter, engine fires are some of the most dangerous and hottest fires to try and put out. A simple hood pad would last a few seconds in a actual fire.

I think I will do this if I can find one not too expensively.

WRT a fire I don't think you will be putting out an engine fire if it gets going.

Especially a Magnesium Block!!!!!

[Craig in Alabam]

Nice! I want one! Looks like the going rate is about $94, which is not bad for a bmw part.

But I noticed that the underside of your hood is white, but your car is blue. The underside of my hood is LeMans Blue, just like the exterior. What's up with that? Maybe they changed it on later cars (mine's a 2010). Is your trunk lid the same?

Cheers!
Craig

[tock172]

Originally Posted by KNS

While they may be flame retardant, I've never heard of the hood pad being used to help extinguish an engine fire. In fact, if you talk to a firefighter, engine fires are some of the most dangerous and hottest fires to try and put out. A simple hood pad would last a few seconds in a actual fire.

Under hood insulation like the one being referenced in this thread is absolutely, 100% designed to act as a flame retardant in the event of a fire. While it may in fact do something in the way of NVH reduction, there is no way any automaker is going to put a piece of cloth in close proximity to the engine without it having flame retardant properties.

The process is beautiful in it's simplicity. In the event of an engine fire, the plastic expanding rivets used to secure the insulation to the hood melt, allowing the insulation to drop onto the engine, in hopes of containing the fire and acting as a retardant. The idea is that it gives the vehicle occupant enough time to exit the vehicle before the fire spreads.

Here's a photo of how it functions in a Corvette. Note how similar the material is to the photo posted in this thread.





Here's a shot of the hood after the fire raged for 10 minutes. Notice how it is essentially isolated to the engine compartment.

[MightyMouseTech]

Interesting. I thought the 128's had the hood insulation, but BMW removed it on the 135's. Must have been a reason. Maybe the turbo runs too hot?!?

[Situation]

Originally Posted by bmw1racer

Nice.

Debating whether or not to get it for my car... What did it cost you?

Paid $170 or so plus tax , Canadian dollar is not doing well now days so I would think you can get it cheaper in the US!

[Situation]

Originally Posted by HyeWarrior

Looks great!

Thanks!

[Situation]

Originally Posted by Craig in Alabam

Nice! I want one! Looks like the going rate is about $94, which is not bad for a bmw part.

But I noticed that the underside of your hood is white, but your car is blue. The underside of my hood is LeMans Blue, just like the exterior. What's up with that? Maybe they changed it on later cars (mine's a 2010). Is your trunk lid the same?

Cheers!
Craig

My car is Alpine white including the underside of the hood. Maybe the exterior looked blue on the pix!

[Situation]

Originally Posted by MightyMouseTech

Interesting. I thought the 128's had the hood insulation, but BMW removed it on the 135's. Must have been a reason. Maybe the turbo runs too hot?!?

128s don't come with it either (at least not mine which is 2012) - it's all about cost saving measures and apparently this was an item that could eliminated!

[Craig in Alabam]

Well of course it's white, now that I look at it properly. The part I thought looked blue was the dash, which I mistook for part of the bodywork (which our cars don't even have, I mean I've got one right here I could have looked at!).
I'm playing the bad eyesight card!

Cheers,
Craig

[MightyMouseTech]

Originally Posted by Situation

128s don't come with it either (at least not mine which is 2012) - it's all about cost saving measures and apparently this was an item that could eliminated!

Hmm, will look into this more. Also good for the paint on the hood.

[Dackelone]

Originally Posted by MightyMouseTech

Interesting. I thought the 128's had the hood insulation, but BMW removed it on the 135's. Must have been a reason. Maybe the turbo runs too hot?!?

I think only the diesel models get the hood insulation. And some early 125i's(128i's) got it too.

I remember being at the 'Ring a few years back with the 1er Forum.de Two guys swapped the insulation out - right there in the Brunchen parking lot! lol

Dackel

[KNS]

Agree, it is possibly a flame retardant material, as I mentioned earlier. However I'd be willing to bet that is flame resistant (there is a difference). BMW wasn't concerned about occupant safety at the start of an engine fire otherwise they wouldn't have eliminated such a (critical) piece of equipment (it's fairly inexpensive yet they still chose to do away with it).

The Corvette engine has aluminum block. The BMW N series engines found in our cars are aluminum and magnesium. On your reasoning you better get out of a 128/135 fast if the engine catches fire because BMW took away the hood pad.

[bmw1racer]

Originally Posted by MightyMouseTech

Hmm, will look into this more. Also good for the paint on the hood.

Good point... I should get one, though I do prop up the hood all the time when I get home from work, just to let the heat out.

[The Wind Breezes]

The idea that this thing will put out a fire is funny as fuck. No, it won't catch on fire itself, but it sure as hell isn't putting one out.

Yes, it's sound insulation. End of story.