Underhood insulation

Two Questions (multi part):
1. What is the real purpose of the underhood insulation? Is it for sound purposes? Would it mess anything up if i took it off?
2. What exactly do the exhaust heat shields do? Is there really any point to them?

[SHISVX]

on the second question, i know that a friend of mine, who is not on this board took his off. he's engine sounds a little deeper..like a growl instead of quiet...i don't think it holds a purpose, then again, i could be wrong. he told me that taking it off gets more cold air to the engine...but then again he could be wrong...so i don't know...can anyone contest/approve this post???

Kelli

[Aredubjay]

Underhood insulation is not only for sound, but, to keep the heat from damaging the paint on the hood.

The heat shields are there for fire protection. If you should park, say, over a pile of leaves on the curb, or, go to a party where you might park in a field, it would prevent the leaves or grass from catching fire, which is a danger if it should touch bare exhaust components.

[SVXer95]

Heat shields also protect certain components that are close in vacinity to the exhaust pipes. Such as the cv boots.

I don't think you would have a problem in taking off heat shields. I had a few that were rattling so I simply tore them off.

[SHISVX]

"exhaust heat shields"

ok, everything i said in the above statement is total BS, i thought you meant the heat shield in the front end...duh me

Kelli

[Landshark]

i can't tell you why, but isn't it beneficial to keep the exhaust hot? i thought they were there to keep the heat in, as well as protecting from radient heat, fires, etc.

anyone?

[Aredubjay]

Originally posted by Landshark
i can't tell you why, but isn't it beneficial to keep the exhaust hot? i thought they were there to keep the heat in, as well as protecting from radient heat, fires, etc.

anyone?

You're right, to a degree. Not necessarily for "keeping the exhaust hot" but, more for slow dissipation of heat. A quick cooling in cold conditions can wreak havoc on the exhaust.

I remember once hearing that the heat helps keep up the velocity of the exhaust there by improving the scavenging effect. Yes? No? Maybe?

[NikFu S.]

that was an old thread of mine.
in my own experience, taking off those shields would have damaged my pipes because ive ran over sharp pointy things.

it was also noted by someone that the scavenge effect is helped little by the shields. it doesnt have much to do with perf.

i say if you live in a flat place with no chance of parking over things that can catch fire, take them off. but, they dont weigh much so its not good for weight reduction.

just a thought.

[Aredubjay]

Originally posted by Shot king
I remember once hearing that the heat helps keep up the velocity of the exhaust there by improving the scavenging effect. Yes? No? Maybe?

I haven't heard this, but, yes, it makes sense.

but as for the underhood insulation, is it really neccesary?

[Aredubjay]

Originally posted by bthomas
but as for the underhood insulation, is it really neccesary?

Not if you want your paint to fade.

[Ron Mummert]

Originally posted by bthomas
but as for the underhood insulation, is it really neccesary?

Heck, why not just remove the hood?
Most insulation is there to reduce noise. If you're into noise, pull out all the insulation found in a "luxury" car & turn it into a Cavalier. (No offense, Mike).

I believe heat shields are there PRIMARILY to keep from igniting flammable objects (leaves, wine boxes, etc.) if parked atop them.
I asked my do-it-all mechanic to remove them when I bought the car. He said, "No, it could be dangerous - I'll tighten them down". He did, & no buzzes for 2.5 years. The buzz re-appeared a month ago. He retightened. Good for another 2.5 years.

Ron (if it ain't broke, break it, then fix it).

[svx_commuter]

The insulation on the bottom of the hood keeps tha paint on the other side looking good.

Heat shields on the exhaust are required unless you want to over heat everything next to them including your feet. In fact the first pipe after the engine manifold has insulation in it. Of course on the high mileage cars this insulation is most likely gone.

Yes insulating the exhaust does help the cars power. How much I can NOT say. I did this to my car and it does seem a little faster in the lower throttle openings.

[Chicane]

The hood insulation also helps the engine bay retain heat, which is a good thing in the winter. This allows for easier starting in the morning, if your engine is 10-20 degrees warmer.

- Rob